Rice seedling blight,caused by various fungi,including Fusarium oxysporum,poses a severe threat to rice production.As awareness grows regarding the environmental and safety hazards associated with the application of f...Rice seedling blight,caused by various fungi,including Fusarium oxysporum,poses a severe threat to rice production.As awareness grows regarding the environmental and safety hazards associated with the application of fungicides for managing rice seedling blight,there has been a shift in focus towards biological control agents.In this study,we isolated biocontrol bacteria from paddy fields that significantly inhibited the growth of F.oxysporum in vitro and identified the strains as Bacillus amyloliquefaciens T40 and Bacillus pumilus T208.Additionally,our findings indicated that the combined application of these Bacillus strains in soil was more effective in reducing the incidence of rice seedling blight than their individual use.Analysis of 16S and internal transcribed spacer rRNA gene sequencing data revealed that the mixture of the T40 and T208 strains exhibited the lowest average clustering coefficients,which were negatively correlated with the biomass of F.oxysporum-inoculated rice seedlings.Furthermore,this mixture led to higher stochastic assembly(average|βNTI|<2)and reduced selection pressures on rice rhizosphere bacteria compared with individual strain applications.The mixture of the T40 and T208 strains also significantly increased the expression of defense-related genes.In conclusion,the mixture of the T40 and T208 strains effectively modulates microbial community structures,enhances microbial network stability,and boosts the resistance against rice seedling blight.Our study supports the development and utilization of biological resources for crop protection.展开更多
Rice grain size is a primary characteristic essential for artificial domestication and breeding,governed by grain length,width,and thickness.In this study,we cloned Grain Size 10(GS10),a novel gene via mapbased clonin...Rice grain size is a primary characteristic essential for artificial domestication and breeding,governed by grain length,width,and thickness.In this study,we cloned Grain Size 10(GS10),a novel gene via mapbased cloning.Biochemical,molecular,and genetic studies were performed to elucidate the GS10 involved grain size mechanism in rice.Mutant of GS10 lead to reduced grain size due to alterations in cell expansion.Additionally,GS10 is responsible for the formation of notched-belly grains,especially in smaller grain varieties possessing loss-function mutations.Overexpression of GS10 in Nipponbare results in increasing grain length,grain weight and improve the appearance quality of rice.GS10 encodes conserved protein with uncharacterized function.Furthermore,GS10 regulates the grain size by interacting OsBRICK1,a subunit of the WAVE complex that governs actin nucleation and affects the assembly of microfilaments in rice.Together,our study demonstrates that,GS10 positively regulates the grain length and grain weight,which is beneficial for further improvements in yield characteristics.展开更多
Efficient and high-quality estimation of key phenological dates in rice is of great significance in breeding work. Plant height(PH) dynamics are valuable for estimating phenological dates. However, research on estimat...Efficient and high-quality estimation of key phenological dates in rice is of great significance in breeding work. Plant height(PH) dynamics are valuable for estimating phenological dates. However, research on estimating the key phenological dates of multiple rice accessions based on PH dynamics has been limited. In 2022, field traits were collected using unmanned aerial vehicle(UAV)-based images across 435 plots, including 364 rice varieties. PH, dates of initial heading(IH) and full heading(FH), and panicle initiation(PI), and growth period after transplanting(GPAT) were collected during the rice growth stage. PHs were extracted using a digital surface model(DSM) and fitted using Fourier and logistic models. Machine learning algorithms, including multiple linear regression, random forest(RF), support vector regression, least absolute shrinkage and selection operator, and elastic net regression, were employed to estimate phenological dates. Results indicated that the optimal percentile of the DSM for extracting rice PH was the 95th(R^(2) = 0.934, RMSE = 0.056 m). The Fourier model provided a better fit for PH dynamics compared with the logistic models. Additionally, curve features(CF) and GPAT were significantly associated with PI, IH, and FH. The combination of CF and GPAT outperformed the use of CF alone, with RF demonstrating the best performance among the algorithms. Specifically, the combination of CF extracted from the logistic models, GPAT, and RF yielded the best performance for estimating PI(R^(2) = 0.834, RMSE = 4.344 d), IH(R^(2) = 0.877, RMSE = 2.721 d), and FH(R^(2) = 0.883, RMSE = 2.694 d). Overall, UAV-based rice PH dynamics combined with machine learning effectively estimated the key phenological dates of multiple rice accessions, providing a novel approach for investigating key phenological dates in breeding work.展开更多
How to balance rice resistance and yield is an important issue in rice breeding.Plants with mutated necrotic lesion genes often have persistent broad-spectrum resistance,but this broad-spectrum resistance usually come...How to balance rice resistance and yield is an important issue in rice breeding.Plants with mutated necrotic lesion genes often have persistent broad-spectrum resistance,but this broad-spectrum resistance usually comes at the expense of yield.Currently,many necrotic lesion mutants in rice have been identified,and these genes are involved in disease resistance pathways.This review provides a detailed introduction to the characteristics,classification,and molecular mechanisms of necrotic lesion formation.Additionally,we review the molecular regulatory pathways of genes involved in rice disease resistance.Concurrently,we summarize the relationship between resistance and yield in rice using newly developed gene editing methods.We discuss a rational and precise breeding strategy to better utilize molecular design technology for breeding disease-resistant and high-yield rice varieties.展开更多
Temperature is an important environmental factor affecting heading date of rice.Despite its importance,genes responsible for temperature-sensitive heading in rice have remained elusive.Our previous study identified a ...Temperature is an important environmental factor affecting heading date of rice.Despite its importance,genes responsible for temperature-sensitive heading in rice have remained elusive.Our previous study identified a quantitative trait locus qHd1 which advances heading date under high temperatures.A 9.5-kb insertion was found in the first intron of OsMADS51 in indica variety Zhenshan 97(ZS97).However,the function of this natural variant in controlling temperature sensitivity has not been verified.In this study,we used CRISPR/Cas9 to knock out the 9.5-kb insertion in ZS97.Experiments conducted under cotrolled conditions in phytotrons confirmed that deletion increased temperature sensitivity and advanced heading by downregulating the expression level of OsMADS51.One-hybrid assays in yeast,ChIP-quantitative polymerase chain reaction,electrophoretic mobility shift,and luciferase-based transient transactivation assays collectively confirmed that OsMADS51 affects heading date by regulation of heading date gene Ehd1.We further determined that the long non-coding RNA HEATINR is generated from the first intron of OsMADS51,offering an explanation for how the 9.5-kb insertion affects temperature sensitivity.We also found that OsMADS51 was strongly selected in early/late-season rice varieties in South China,possibly accounting for their strong temperature sensitivity.These insights not only advance our understanding of the molecular mechanisms underlying the temperature-responsive regulation of heading date in rice but also provide a valuable genetic target for molecular breeding.展开更多
The brown planthopper, Nilaparvata lugens St?l, has become a major threat in tropical Asian and China since the rice green revolution of the 1960 s. Currently, insecticide application remains the primary choice for co...The brown planthopper, Nilaparvata lugens St?l, has become a major threat in tropical Asian and China since the rice green revolution of the 1960 s. Currently, insecticide application remains the primary choice for controlling this rice insect pest, but heavy use of insecticides poses dangerous risks to beneficial natural enemies and pollinators, and stimulates N. lugens reproductivity, and has caused a resurgence of the pest in the major rice-planting regions throughout Asia. Achieving the long-lasting goal of sustainable management of N. lugens requires understanding of the molecular basis of outbreaks of the pest and the development of environment-friendly pest-control strategies. Here, we review the recent molecular advances in N. lugens research on the aspects of its endosymbionts, virus transmission, insecticide resistance, and interaction between N. lugens and rice plants. We also put forward further research directions that may shed some lights on management of the rice pest.展开更多
Rice blast,caused by the fungus Magnaporthe oryzae,reduces rice yields by 10%to 35%.Incorporating blast resistance genes into breeding programs is an effective strategy to combat this disease.Understanding the genetic...Rice blast,caused by the fungus Magnaporthe oryzae,reduces rice yields by 10%to 35%.Incorporating blast resistance genes into breeding programs is an effective strategy to combat this disease.Understanding the genetic variants that confer resistance is crucial to this strategy.The gene Bsr-d1 encodes a C2H2-like transcription factor,and its recessive allele confers broad-spectrum resistance against infections by various strains of M.oryzae.In this study,we investigated the molecular evolution of the rice blast resistance gene bsr-d1 in a representative population consisting of 827 cultivated and wild rice accessions.Our results revealed that wild rice exhibited significantly higher nucleotide diversity,with polymorphic regions primarily concentrated in the promoter region,in contrast to indica and japonica rice varieties.The Bsr-d1 gene displayed significant differentiation between indica and japonica rice varieties,with the bsr-d1 resistance allele being unique to indica rice.Haplotype network and phylogenetic analyses suggested that the bsr-d1 resistance allele most likely originated from Oryza nivara in the region adjacent to the Indian Peninsula and the Indochina Peninsula.Moreover,we explored the utilization of bsr-d1 resistance alleles in China and designed a pair of DNA primers based on the polymorphic sites for the detection of the bsr-d1 resistance gene.In summary,our study uncovering the origin and evolution of bsr-d1 will enhance our understanding of resistance gene variation and expedite the resistance breeding process.展开更多
Two-line hybrid rice with excellent quality is preferred in the Chinese market.However,there is a trade-off between reducing costs for hybrid seed production and lowering the outcrossing rate of the sterile line,which...Two-line hybrid rice with excellent quality is preferred in the Chinese market.However,there is a trade-off between reducing costs for hybrid seed production and lowering the outcrossing rate of the sterile line,which is largely determined by the stigma exsertion rate(SER).In this study,we constructed mutants of male sterility lines with improved grain length(GL)and SER in three elite early-season indica rice varieties through targeted manipulation of the TMS5 and GS3 genes using CRISPR/Cas9-mediated multiplex systems.We obtained a series of marker-free gs3 single mutants and gs3tms5 double mutants with significantly higher SER,longer grains,and increased 1000-grain weight compared with the wild type(WT).Importantly,the typically thermo-sensitive genic male sterile(TGMS)trait with a higher SER was observed in gs3tms5 mutants,and their F1 hybrids exhibited remarkable improvements in grain shape and yield-related traits.Our findings provided an efficient method to generate new valuable TGMS germplasm with improved SER through the mutagenesis of GS3 and TMS5 synergistically,and demonstrated that GS3 had pleiotropic effects on grain size,SER,and grain quality in early-season indica rice.展开更多
Plant architecture is a collection of major agronomic traits that determines rice grain production,and it is mainly influenced by tillering,tiller angle,plant height and panicle morphology(Wang and Li 2006).Tiller ang...Plant architecture is a collection of major agronomic traits that determines rice grain production,and it is mainly influenced by tillering,tiller angle,plant height and panicle morphology(Wang and Li 2006).Tiller angle is one of the critical components that determines rice plant architecture,which in turn influences grain yield mainly due to its large impact on plant density(Wang et al.2022).展开更多
Numerous Bt rice lines expressing Cry protein derived from Bacillus thuringiensis Berliner （Bt） have been developed since 1989. However, the potential risks posed by Bt rice on non-target organisms still remain deba...Numerous Bt rice lines expressing Cry protein derived from Bacillus thuringiensis Berliner （Bt） have been developed since 1989. However, the potential risks posed by Bt rice on non-target organisms still remain debate. The white-backed planthopper （WBPH）, Sogatella furcifera （Horváth）, is one of the most economically important insect pests of rice in Asian countries and also one of the main non-target herbivores of transgenic rice. In the current study, impacts of transgenic cry1Ab/vip3H＋epsps rice （G6H1） with both insect and herbicide resistance on WBPH were evaluated to ascertain whether this transgenic rice line had potential risks for this sap-sucking pest under laboratory and ifeld conditions. The laboratory results showed that no signiifcant difference in egg developmental duration, nymphal survival rate and female fecundity was found for WBPH between G6H1 and its non-transgenic isoline （XS110）. However, the development duration of nymphs was signiifcantly shorter and female longevity signiifcantly longer when WBPH fed on G6H1 by comparison with those on its control. To verify the results found in laboratory, a 3-yr ifeld trial was conducted to monitor WBPH population using both the vacuum-suction machine and beat plate methods. Although the seasonal density of WBPH nymphs and total density of nymphs and adults were not signiifcantly affected by transgenic rice regardless of the sampling methods, the seasonal density of WBPH adults in transgenic rice plots was slightly lower than that in the control when using the vacuum-suction machine. Based on these results both from laboratory and ifeld, it is clear that our tested transgenic rice line will not lead higher population of WBPH. However, long-term ifeld experiments to monitor the population dynamics of WPBH at large scale need to be conducted to conifrm the present conclusions in future.展开更多
In rice fields,rice plants usually grow alongside wild weeds and are attacked by various invertebrate species.Viruses are abundant in plants and invertebrates,playing crucial ecological roles in controlling microbial ...In rice fields,rice plants usually grow alongside wild weeds and are attacked by various invertebrate species.Viruses are abundant in plants and invertebrates,playing crucial ecological roles in controlling microbial abundance and maintaining community structures.To date,only 16 rice viruses have been documented in rice-growing regions.These viruses pose serious threats to rice production and have traditionally been identified only from rice plants and insect vectors by isolation techniques.Advances in next-generation sequencing(NGS)have made it feasible to discover viruses on a global scale.Recently,numerous viruses have been identified in plants and invertebrates using NGS technologies.In this review,we discuss viral studies in rice plants,invertebrate species,and weeds in rice fields.Many novel viruses have been discovered in rice ecosystems through NGS technologies,with some also detected using metatranscriptomic and small RNA sequencing.These analyses greatly expand our understanding of viruses in rice fields and provide valuable insights for developing efficient strategies to manage insect pests and virus-mediated rice diseases.展开更多
As an important agronomic trait, inclination of leaves is crucial Ior crop architecture and grain yields. 10 understand the molecular mechanism controlling rice leaf angles, one rice leaf inclination2 （1c2, three all...As an important agronomic trait, inclination of leaves is crucial Ior crop architecture and grain yields. 10 understand the molecular mechanism controlling rice leaf angles, one rice leaf inclination2 （1c2, three alleles） mutant was identified and functionally characterized. Compared to wild-type plants, lc2 mutants have enlarged leaf angles due to increased cell division in the adaxial epidermis of lamina joint. The LC2 gene was isolated through positional cloning, and encodes a vernalization insensitive 3-like protein. Complementary expression of LC2 reversed the enlarged leaf angles of lc2 plants, confirming its role in controlling leaf inclination. LC2 is mainly expressed in the lamina joint during leaf development, and particularly, is induced by the phytohormones abscisic acid, gibberellic acid, auxin, and brassinosteroids. LC2 is localized in the nucleus and defects of LC2 result in altered expression of cell division and hormone-responsive genes, indicating an important role of LC2 in regulating leaf inclination and mediating hormone effects.展开更多
Wild-type （Zhonghua 11） and mutant rice （Oryza sativa L.） plants were used to investigate the effect of cadmium （Cd） application on biomass production, to characterize the influx of Cd from roots to shoots, and ...Wild-type （Zhonghua 11） and mutant rice （Oryza sativa L.） plants were used to investigate the effect of cadmium （Cd） application on biomass production, to characterize the influx of Cd from roots to shoots, and to determine the form, content, and subcellular distribution of Cd in the roots, leaf sheaths, and leaves of the rice plants. Seedlings were cultivated in a nutrient solution and were treated with 0.5 mmol L^-1 of Cd^2＋ for 14 d. The sensitivity of rice plants to Cd toxicity was tested by studying the changes in biomass production and by observing the onset of toxicity symptoms in the plants. Both the wild-type and mutant rice plants developed symptoms of Cd stress. In addition, Cd application significantly （P ≤ 0.01） decreased dry matter production of roots, leaf sheaths, and leaves of both types, especially the mutant. The Cd content in roots of the mutant was significantly （P ≤0.05） higher than that of the wild-type rice. However, there was no significant difference in the Cd content of roots, leaf sheaths, and leaves between the wild-type and mutant rice. Most of the Cd was bound to the cell wall of the roots, leaf sheaths, and leaves, and the mutant had greater Cd content in cell organelles than the wild type. The uneven subcellular distribution could be responsible for the Cd sensitivity of the mutant rice. Furthermore, different chemical forms of Cd were found to occur in the roots, leaf sheaths, and leaves of both types of rice plants. Ethanol-, water-, and NaCl-extractable Cd had greater toxicity than the other forms of Cd and induced stunted growth and chlorosis in the plants. The high Cd content of the toxic forms of Cd in the cell organelles could seriously damage the cells and the metabolic processes in mutant rice plants.展开更多
Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice f...Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice flowering stage is the most sensitive period to high temperatures, and therefore, the key for heat stress happening is the flowering stage coinciding with high temperature, which causes spikelet fertility decreasing in heat-sensitive varieties, and is the major factor for heat injury differences among various rice planting regions. With the development of rice breeding, temperature indexes for heat stress has been converted from daily maximum temperature of 35 oC to 38 oC with the stress duration of more than 3 d. During the flowering stage, anther dehiscence inhibition and low pollen shedding onto the stigma are two main reasons for spikelet fertility reduction under high temperatures. At panicle initiation stage, high temperatures aggravate spikelet degeneration, and destroy floral organ development. Various types of rice varieties coexist in production, and indica-japonica hybrid rice demonstrates the highest heat resistance in general, followed by indica and japonica rice varieties. In production, avoiding high temperature is the main strategy of preventing heat stress, and planting suitable cultivars and adjustment of sowing date are the most effective measures. Irrigation is an effective real-time cultivation measure to decline the canopy temperature during the rice flowering stage. We suggested that further study should be focused on exploring heat injury differences among different rice variety types, and innovating rice-planting methods according to planting system changes in rice planting regions with extreme heat stress. Meanwhile, high temperature monitor and warning systems should be improved to achieve optimal heat stress management efficiencies.展开更多
Rice （Oryza safiva L.） is highly susceptible to the rhizosphere salinity than other cereals. High sensitivity has been ob- served, mainly at vegetative and reproductive stages in rice. It is the duty of plant physio...Rice （Oryza safiva L.） is highly susceptible to the rhizosphere salinity than other cereals. High sensitivity has been ob- served, mainly at vegetative and reproductive stages in rice. It is the duty of plant physiologists to comprehend the growth, development, and physiological processes of rice plants under stress. This paper includes the overview of rice growth and developmental processes influenced by salt stress and the regulation pathways involved in these processes. It also includes the promising salt tolerance strategies, i.e., genetic modification techniques, agronomic practices to improve rice growth, yield; and role of phytohormones and their management, especially inhibition of ethylene biosynthesis by using inhibitors 1-methylcyclopropene （1-MCP）. Rice cultivation may be a first choice for improvement of salt tolerance through plant growth regulators and improved cultivation techniques. This study will significantly improve the understanding toward low rice grain yield and poor rice resistance under salt stress and will also stream scientific knowledge for effective utilization of salt affected soils by using different regulating ways.展开更多
A quantitative survey of rice planthoppers in paddy fields is important to assess the population density and make forecasting decisions. Manual rice planthopper survey methods in paddy fields are time-consuming, fatig...A quantitative survey of rice planthoppers in paddy fields is important to assess the population density and make forecasting decisions. Manual rice planthopper survey methods in paddy fields are time-consuming, fatiguing and tedious. This paper describes a handheld device for easily capturing planthopper images on rice stems and an automatic method for counting rice planthoppers based on image processing. The handheld device consists of a digital camera with WiFi, a smartphone and an extrendable pole. The surveyor can use the smartphone to control the camera, which is fixed on the front of the pole by WiFi, and to photograph planthoppers on rice stems. For the counting of planthoppers on rice stems, we adopt three layers of detection that involve the following：（a） the first layer of detection is an AdaBoost classifier based on Haar features;（b） the second layer of detection is a support vector machine（SVM） classifier based on histogram of oriented gradient（HOG） features;（c） the third layer of detection is the threshold judgment of the three features. We use this method to detect and count whiteback planthoppers（Sogatella furcifera） on rice plant images and achieve an 85.2% detection rate and a 9.6% false detection rate. The method is easy, rapid and accurate for the assessment of the population density of rice planthoppers in paddy fields.展开更多
A rhizobox experiment with two phosphorus (P) treatments, zero-P (0 mg P kg-1) and plus-P (100 mg P kg-1) as Ca(H2PO4)2·H2O, was conducted to study the chemical and biochemical properties in the rhizosphere of tw...A rhizobox experiment with two phosphorus (P) treatments, zero-P (0 mg P kg-1) and plus-P (100 mg P kg-1) as Ca(H2PO4)2·H2O, was conducted to study the chemical and biochemical properties in the rhizosphere of two rice genotypes (cv. Zhongbu 51 and Pembe) different in P uptake ability and their relationship with the depletion of soil P fractions. Plant P uptake, pH, phosphatase activity, and soil P fractions in the rhizosphere were measured. Both total dry weight and total P uptake of Pembe were significantly (P < 0.05) higher than those of Zhongbu 51 in the zero-P and plus-P treatments. Significant depletions of resin-Pi, NaHCO3-Pi, NaHCO3-Po, and NaOH-Pi, where Pi stands for inorganic P and Po for organic P, were observed in the rhizosphere of both Zhongbu 51 and Pembe under both P treatments. Pembe showed a greater ability than Zhongbu 51 in depleting resin-Pi, NaHCO3-Pi, NaHCO3-Po, NaOH-Pi, and NaOH- Po in the rhizosphere. HCl-Pi and residual-P were not depleted in the rhizosphere of both genotypes, regardless of P treatments despite significant acidification in the rhizosphere of Pembe under zero-P treatment. Higher acid phosphatase (AcPME) activity and alkaline phosphatase (AlPME) activity were observed in the rhizosphere of both Zhongbu 51 and Pembe compared to the corresponding controls without plant. AcPME activity was negatively (P < 0.01) correlated to NaHCO3-Po concentration in the rhizosphere of both Zhongbu 51 and Pembe, suggesting that AcPME was associated with the mineralization of soil organic P.展开更多
Two rice maintaining lines with different drought tolerances, viz., Jin 23B （tolerant） and Zhenshan 97B （sensitive）, were used to study the oxidative stress and soluble sugar in rice anthers and pollen viability u...Two rice maintaining lines with different drought tolerances, viz., Jin 23B （tolerant） and Zhenshan 97B （sensitive）, were used to study the oxidative stress and soluble sugar in rice anthers and pollen viability under drought stress during flowering stage. Higher antioxidant enzyme activities and lower malonaldehyde （MDA） content in rice anthers were observed in Jin 23B than in Zhenshan 97B under drought stress. Further, a great increase in the content of soluble sugar in rice anthers of Jin 23B was observed across the whole drought exposure, while Zhenshan 97B showed significant decrease in soluble sugar during 9-12 d after drought stress （DADS）. Accordingly, a marked decline of pollen fertility and activity, pollen numbers in an anther and pollen numbers on a stigma was observed in Zhenshan 97B, whereas little difference was found in Jin 23B. Thus, we suggest that pollen abortion caused by drought stress may be related with the reciprocity between oxidative stress and soluble sugar content in rice anthers.展开更多
Isoamylase 1(ISA1) is an isoamylase-type debranching enzyme which plays a predominant role in amylopectin synthesis. In this study, the clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associat...Isoamylase 1(ISA1) is an isoamylase-type debranching enzyme which plays a predominant role in amylopectin synthesis. In this study, the clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated endonuclease 9(CRISPR/Cas9) system was used to edit ISA1 gene in rice via Agrobacterium-mediated transformation. We identified 36 genetic edited lines from 55 T_0 transgenic events, and classified the mutation forms into 7 types. Of those, two homozygous mutants, cr-isa1-1(type 1, with an adenine insertion) and cr-isa1-2(type 3, with a cytosine deletion) were selected for further analysis. Seed sizes of both cr-isa1-1 and cr-isa1-2 were affected, and the two mutants also displayed a shrunken endosperm with significantly lower grain weight. Electron microscopy analysis showed that abnormal starch granules and amyloplasts were found in cr-isa1-1 and cr-isa1-2 endosperm cells. The contents of total starch, amylose and amylopectin in the endosperm of the cr-isa1 mutants were significantly reduced, whereas sugar content and starch gel consistency were observably increased compared to the wild-type. The gelatinization temperature and starch chain length distributions of the cr-isa1 mutants were also altered. Moreover, transcript levels of most starch synthesis-related genes were significantly lower in cr-isa1 mutants. In conclusion, the results indicated that gene edition of ISA1 affected starch synthesis and endosperm development, and brought potential implications for rice quality breeding.展开更多
A thermo-insensitive pale green leaf mutant （pgl2） was isolated from T-DNA inserted transgenic lines of rice （Oryza sativa L. subsp, japonica cv. Nipponbare）. Genetic analysis indicated that the phenotype was caus...A thermo-insensitive pale green leaf mutant （pgl2） was isolated from T-DNA inserted transgenic lines of rice （Oryza sativa L. subsp, japonica cv. Nipponbare）. Genetic analysis indicated that the phenotype was caused by a recessive mutation in a single nuclear-encoded gene. To map the PGL2gene, an F2 population was constructed by crossing the mutant with Longtefu （Oryza sativa L. subsp, indica）. The PGL2 locus was roughly linked to SSR marker RM331 on chromosome 8. To finely map the gene, 14 new InDel markers were developed around the marker, and PGL2 was further mapped to a 2.37 Mb centromeric region. Analysis on chlorophyll contents of leaves showed that there was no obvious difference between the mutant and the wild type in total chlorophyll （Chl） content, while the ratio of Chl a / Chl b in the mutant was only about 1, which was distinctly lower than that in the wild type, suggesting that the PGL2 gene was related to the conversion between Chl a and Chl b. Moreover, the method of primer design around the centromeric region was discussed, which would provide insight into fine mapping of the functional genes in plant centromeres.展开更多
基金supported by the Zhejiang Provincial Natural Science Foundation,China(Grant No.LQ24C010007)Zhejiang Science and Technology Major Program on Rice New Variety Breeding,China(Grant No.2021C02063)+4 种基金the Agricultural Sciences and Technologies Innovation Program,China(Grant No.CAAS-CSCB-202301)the Key Projects of Zhejiang Provincial Natural Science Foundation,China(Grant No.LZ23C130002)the Youth Innovation Program of Chinese Academy of Agricultural Sciences(Grant No.Y2023QC22)the Joint Open Competitive Project of the Yazhou Bay Seed Laboratory and China National Seed Company Limited(Grant Nos.B23YQ1514 and B23CQ15EP)the External Cooperation Projects of Biotechnology Research Institute,Fujian Academy of Agricultural Sciences,China(Grant No.DWHZ2024-07).
文摘Rice seedling blight,caused by various fungi,including Fusarium oxysporum,poses a severe threat to rice production.As awareness grows regarding the environmental and safety hazards associated with the application of fungicides for managing rice seedling blight,there has been a shift in focus towards biological control agents.In this study,we isolated biocontrol bacteria from paddy fields that significantly inhibited the growth of F.oxysporum in vitro and identified the strains as Bacillus amyloliquefaciens T40 and Bacillus pumilus T208.Additionally,our findings indicated that the combined application of these Bacillus strains in soil was more effective in reducing the incidence of rice seedling blight than their individual use.Analysis of 16S and internal transcribed spacer rRNA gene sequencing data revealed that the mixture of the T40 and T208 strains exhibited the lowest average clustering coefficients,which were negatively correlated with the biomass of F.oxysporum-inoculated rice seedlings.Furthermore,this mixture led to higher stochastic assembly(average|βNTI|<2)and reduced selection pressures on rice rhizosphere bacteria compared with individual strain applications.The mixture of the T40 and T208 strains also significantly increased the expression of defense-related genes.In conclusion,the mixture of the T40 and T208 strains effectively modulates microbial community structures,enhances microbial network stability,and boosts the resistance against rice seedling blight.Our study supports the development and utilization of biological resources for crop protection.
基金supported by Projects of International Cooperation NSFC(31961143016,31101203)Guizhou Provincial Science and Technology Projects(QKHJC-ZK[2022]YB537)+4 种基金the Fundamental Research Funds of Central Public Welfare Research Institutions(CPSIBRF-CNRRI-202102,Y2020YJ17)Independent Project of State Key Laboratory of Rice Biology(2020Z2KT10201)High-quality and Resistant Hybrid Rice Germplasm Creation and New Varieties Development with International Competitiveness(2022KJCX45,YBXM2437)Zhejiang Provincial Science and Technology Projects(2022R51009)Inner Mongolia Breeding Joint Research Project(YZ2023004).
文摘Rice grain size is a primary characteristic essential for artificial domestication and breeding,governed by grain length,width,and thickness.In this study,we cloned Grain Size 10(GS10),a novel gene via mapbased cloning.Biochemical,molecular,and genetic studies were performed to elucidate the GS10 involved grain size mechanism in rice.Mutant of GS10 lead to reduced grain size due to alterations in cell expansion.Additionally,GS10 is responsible for the formation of notched-belly grains,especially in smaller grain varieties possessing loss-function mutations.Overexpression of GS10 in Nipponbare results in increasing grain length,grain weight and improve the appearance quality of rice.GS10 encodes conserved protein with uncharacterized function.Furthermore,GS10 regulates the grain size by interacting OsBRICK1,a subunit of the WAVE complex that governs actin nucleation and affects the assembly of microfilaments in rice.Together,our study demonstrates that,GS10 positively regulates the grain length and grain weight,which is beneficial for further improvements in yield characteristics.
基金supported by the National Key Research and Development Program of China (Grant No.2022YFD2300700)the Open Project Program of the State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute (Grant No.2023ZZKT20402)+1 种基金the Agricultural Science and Technology Innovation Program, the Central Public-Interest Scientific Institution Basal Research Fund, China (Grant No.CPSIBRF-CNRRI-202119)the Zhejiang ‘Ten Thousand Talents’ Plan Science and Technology Innovation Leading Talent Project, China (Grant No.2020R52035)。
文摘Efficient and high-quality estimation of key phenological dates in rice is of great significance in breeding work. Plant height(PH) dynamics are valuable for estimating phenological dates. However, research on estimating the key phenological dates of multiple rice accessions based on PH dynamics has been limited. In 2022, field traits were collected using unmanned aerial vehicle(UAV)-based images across 435 plots, including 364 rice varieties. PH, dates of initial heading(IH) and full heading(FH), and panicle initiation(PI), and growth period after transplanting(GPAT) were collected during the rice growth stage. PHs were extracted using a digital surface model(DSM) and fitted using Fourier and logistic models. Machine learning algorithms, including multiple linear regression, random forest(RF), support vector regression, least absolute shrinkage and selection operator, and elastic net regression, were employed to estimate phenological dates. Results indicated that the optimal percentile of the DSM for extracting rice PH was the 95th(R^(2) = 0.934, RMSE = 0.056 m). The Fourier model provided a better fit for PH dynamics compared with the logistic models. Additionally, curve features(CF) and GPAT were significantly associated with PI, IH, and FH. The combination of CF and GPAT outperformed the use of CF alone, with RF demonstrating the best performance among the algorithms. Specifically, the combination of CF extracted from the logistic models, GPAT, and RF yielded the best performance for estimating PI(R^(2) = 0.834, RMSE = 4.344 d), IH(R^(2) = 0.877, RMSE = 2.721 d), and FH(R^(2) = 0.883, RMSE = 2.694 d). Overall, UAV-based rice PH dynamics combined with machine learning effectively estimated the key phenological dates of multiple rice accessions, providing a novel approach for investigating key phenological dates in breeding work.
基金supported by the National Natural Science Foundation of China(Grant Nos.31971872,32372118,32071993)the QIAN Qian Academician Workstation,the Specific Research fund of the Innovation Platform for Academicians of Hainan Province,China(Grant No.YSPTZX202303)the Key Research and Development Program of Zhejiang Province,China(Grant No.2021C02056)。
文摘How to balance rice resistance and yield is an important issue in rice breeding.Plants with mutated necrotic lesion genes often have persistent broad-spectrum resistance,but this broad-spectrum resistance usually comes at the expense of yield.Currently,many necrotic lesion mutants in rice have been identified,and these genes are involved in disease resistance pathways.This review provides a detailed introduction to the characteristics,classification,and molecular mechanisms of necrotic lesion formation.Additionally,we review the molecular regulatory pathways of genes involved in rice disease resistance.Concurrently,we summarize the relationship between resistance and yield in rice using newly developed gene editing methods.We discuss a rational and precise breeding strategy to better utilize molecular design technology for breeding disease-resistant and high-yield rice varieties.
基金supported by the Laboratory of Lingnan Modern Agriculture Project(NT2021001)Guangdong Province Basic and Applied Basic Research Fund-Provincial and Municipal Joint Fund Project(2023A1515110882)+3 种基金Guangzhou Science and Technology Plan Project(2023A04J0811)Guangdong Province Rural Revitalization Strategy Special Fund Seed Industry Revitalization Project(2022-NPY-00-013)Natural Science Foundation of Zhejiang Pro-vince(LY22C130006)Key Laboratory of New Rice Breeding Technologies in Guangdong Province(2023B1212060042).
文摘Temperature is an important environmental factor affecting heading date of rice.Despite its importance,genes responsible for temperature-sensitive heading in rice have remained elusive.Our previous study identified a quantitative trait locus qHd1 which advances heading date under high temperatures.A 9.5-kb insertion was found in the first intron of OsMADS51 in indica variety Zhenshan 97(ZS97).However,the function of this natural variant in controlling temperature sensitivity has not been verified.In this study,we used CRISPR/Cas9 to knock out the 9.5-kb insertion in ZS97.Experiments conducted under cotrolled conditions in phytotrons confirmed that deletion increased temperature sensitivity and advanced heading by downregulating the expression level of OsMADS51.One-hybrid assays in yeast,ChIP-quantitative polymerase chain reaction,electrophoretic mobility shift,and luciferase-based transient transactivation assays collectively confirmed that OsMADS51 affects heading date by regulation of heading date gene Ehd1.We further determined that the long non-coding RNA HEATINR is generated from the first intron of OsMADS51,offering an explanation for how the 9.5-kb insertion affects temperature sensitivity.We also found that OsMADS51 was strongly selected in early/late-season rice varieties in South China,possibly accounting for their strong temperature sensitivity.These insights not only advance our understanding of the molecular mechanisms underlying the temperature-responsive regulation of heading date in rice but also provide a valuable genetic target for molecular breeding.
基金supported by the National Natural Science Foundation of China(31672025,31471765 and 31630057)
文摘The brown planthopper, Nilaparvata lugens St?l, has become a major threat in tropical Asian and China since the rice green revolution of the 1960 s. Currently, insecticide application remains the primary choice for controlling this rice insect pest, but heavy use of insecticides poses dangerous risks to beneficial natural enemies and pollinators, and stimulates N. lugens reproductivity, and has caused a resurgence of the pest in the major rice-planting regions throughout Asia. Achieving the long-lasting goal of sustainable management of N. lugens requires understanding of the molecular basis of outbreaks of the pest and the development of environment-friendly pest-control strategies. Here, we review the recent molecular advances in N. lugens research on the aspects of its endosymbionts, virus transmission, insecticide resistance, and interaction between N. lugens and rice plants. We also put forward further research directions that may shed some lights on management of the rice pest.
基金supported by the National Key Research and Development Program of China (Grant No.2023YFD1202600)the Zhejiang Lab independently establishes research projects (Research and Development of Intelligent Technologies and Platforms for Rice Breeding,Grant No.2021PE0AC05)the Natural Science Foundation of Zhejiang Province,China (Grant No.LQ22C130006)。
文摘Rice blast,caused by the fungus Magnaporthe oryzae,reduces rice yields by 10%to 35%.Incorporating blast resistance genes into breeding programs is an effective strategy to combat this disease.Understanding the genetic variants that confer resistance is crucial to this strategy.The gene Bsr-d1 encodes a C2H2-like transcription factor,and its recessive allele confers broad-spectrum resistance against infections by various strains of M.oryzae.In this study,we investigated the molecular evolution of the rice blast resistance gene bsr-d1 in a representative population consisting of 827 cultivated and wild rice accessions.Our results revealed that wild rice exhibited significantly higher nucleotide diversity,with polymorphic regions primarily concentrated in the promoter region,in contrast to indica and japonica rice varieties.The Bsr-d1 gene displayed significant differentiation between indica and japonica rice varieties,with the bsr-d1 resistance allele being unique to indica rice.Haplotype network and phylogenetic analyses suggested that the bsr-d1 resistance allele most likely originated from Oryza nivara in the region adjacent to the Indian Peninsula and the Indochina Peninsula.Moreover,we explored the utilization of bsr-d1 resistance alleles in China and designed a pair of DNA primers based on the polymorphic sites for the detection of the bsr-d1 resistance gene.In summary,our study uncovering the origin and evolution of bsr-d1 will enhance our understanding of resistance gene variation and expedite the resistance breeding process.
基金the Natural Science Foundation of Zhejiang Province,China(Grant Nos.LY24C130004,LY22C135104,and LY23C130002)the National Natural Science Foundation of China(Grant No.31501288)+1 种基金the Open Project Program of State Key Laboratory of Rice Biology and Breeding,China(Grant No.20210207)Central Publicinterest Scientific Institution Basal Research Fund,China(Grant No.CPSIBRF-CNRRI-202203).
文摘Two-line hybrid rice with excellent quality is preferred in the Chinese market.However,there is a trade-off between reducing costs for hybrid seed production and lowering the outcrossing rate of the sterile line,which is largely determined by the stigma exsertion rate(SER).In this study,we constructed mutants of male sterility lines with improved grain length(GL)and SER in three elite early-season indica rice varieties through targeted manipulation of the TMS5 and GS3 genes using CRISPR/Cas9-mediated multiplex systems.We obtained a series of marker-free gs3 single mutants and gs3tms5 double mutants with significantly higher SER,longer grains,and increased 1000-grain weight compared with the wild type(WT).Importantly,the typically thermo-sensitive genic male sterile(TGMS)trait with a higher SER was observed in gs3tms5 mutants,and their F1 hybrids exhibited remarkable improvements in grain shape and yield-related traits.Our findings provided an efficient method to generate new valuable TGMS germplasm with improved SER through the mutagenesis of GS3 and TMS5 synergistically,and demonstrated that GS3 had pleiotropic effects on grain size,SER,and grain quality in early-season indica rice.
基金grants from the Natural Science Foundation of Zhejiang Province,China(LTGN23C130001)the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City,China(2021JJLH0045)+1 种基金the State Key Laboratory of Rice Biology and Breeding-Independent Project,China(2023ZZKT20304)the China Agriculture Research System(CARS-01-14)。
文摘Plant architecture is a collection of major agronomic traits that determines rice grain production,and it is mainly influenced by tillering,tiller angle,plant height and panicle morphology(Wang and Li 2006).Tiller angle is one of the critical components that determines rice plant architecture,which in turn influences grain yield mainly due to its large impact on plant density(Wang et al.2022).
基金provided by the Special Research Projects for Developing Transgenic Plants, China (2013ZX08011-001)China National Science Fund for Innovative Research Group of Biological Control (31021003)the National Basic Research Progarm of China (973 Program, 2007CB109202)
文摘Numerous Bt rice lines expressing Cry protein derived from Bacillus thuringiensis Berliner （Bt） have been developed since 1989. However, the potential risks posed by Bt rice on non-target organisms still remain debate. The white-backed planthopper （WBPH）, Sogatella furcifera （Horváth）, is one of the most economically important insect pests of rice in Asian countries and also one of the main non-target herbivores of transgenic rice. In the current study, impacts of transgenic cry1Ab/vip3H＋epsps rice （G6H1） with both insect and herbicide resistance on WBPH were evaluated to ascertain whether this transgenic rice line had potential risks for this sap-sucking pest under laboratory and ifeld conditions. The laboratory results showed that no signiifcant difference in egg developmental duration, nymphal survival rate and female fecundity was found for WBPH between G6H1 and its non-transgenic isoline （XS110）. However, the development duration of nymphs was signiifcantly shorter and female longevity signiifcantly longer when WBPH fed on G6H1 by comparison with those on its control. To verify the results found in laboratory, a 3-yr ifeld trial was conducted to monitor WBPH population using both the vacuum-suction machine and beat plate methods. Although the seasonal density of WBPH nymphs and total density of nymphs and adults were not signiifcantly affected by transgenic rice regardless of the sampling methods, the seasonal density of WBPH adults in transgenic rice plots was slightly lower than that in the control when using the vacuum-suction machine. Based on these results both from laboratory and ifeld, it is clear that our tested transgenic rice line will not lead higher population of WBPH. However, long-term ifeld experiments to monitor the population dynamics of WPBH at large scale need to be conducted to conifrm the present conclusions in future.
基金supported by the National Natural Science Foundation of China(Grant Nos.31972983 and 32072487)the Key Technology R&D Program of Zhejiang Province,China(Grant No.2021C02006)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY23C140001).
文摘In rice fields,rice plants usually grow alongside wild weeds and are attacked by various invertebrate species.Viruses are abundant in plants and invertebrates,playing crucial ecological roles in controlling microbial abundance and maintaining community structures.To date,only 16 rice viruses have been documented in rice-growing regions.These viruses pose serious threats to rice production and have traditionally been identified only from rice plants and insect vectors by isolation techniques.Advances in next-generation sequencing(NGS)have made it feasible to discover viruses on a global scale.Recently,numerous viruses have been identified in plants and invertebrates using NGS technologies.In this review,we discuss viral studies in rice plants,invertebrate species,and weeds in rice fields.Many novel viruses have been discovered in rice ecosystems through NGS technologies,with some also detected using metatranscriptomic and small RNA sequencing.These analyses greatly expand our understanding of viruses in rice fields and provide valuable insights for developing efficient strategies to manage insect pests and virus-mediated rice diseases.
文摘As an important agronomic trait, inclination of leaves is crucial Ior crop architecture and grain yields. 10 understand the molecular mechanism controlling rice leaf angles, one rice leaf inclination2 （1c2, three alleles） mutant was identified and functionally characterized. Compared to wild-type plants, lc2 mutants have enlarged leaf angles due to increased cell division in the adaxial epidermis of lamina joint. The LC2 gene was isolated through positional cloning, and encodes a vernalization insensitive 3-like protein. Complementary expression of LC2 reversed the enlarged leaf angles of lc2 plants, confirming its role in controlling leaf inclination. LC2 is mainly expressed in the lamina joint during leaf development, and particularly, is induced by the phytohormones abscisic acid, gibberellic acid, auxin, and brassinosteroids. LC2 is localized in the nucleus and defects of LC2 result in altered expression of cell division and hormone-responsive genes, indicating an important role of LC2 in regulating leaf inclination and mediating hormone effects.
基金the National Natural Science Foundation of China (No30671255)the National Key Technologies R&D Program of China during the 11th Five-Year Plan Period (No2006BAK02A18)the National Basic Research Program (973) of China (No2002CB410804)
文摘Wild-type （Zhonghua 11） and mutant rice （Oryza sativa L.） plants were used to investigate the effect of cadmium （Cd） application on biomass production, to characterize the influx of Cd from roots to shoots, and to determine the form, content, and subcellular distribution of Cd in the roots, leaf sheaths, and leaves of the rice plants. Seedlings were cultivated in a nutrient solution and were treated with 0.5 mmol L^-1 of Cd^2＋ for 14 d. The sensitivity of rice plants to Cd toxicity was tested by studying the changes in biomass production and by observing the onset of toxicity symptoms in the plants. Both the wild-type and mutant rice plants developed symptoms of Cd stress. In addition, Cd application significantly （P ≤ 0.01） decreased dry matter production of roots, leaf sheaths, and leaves of both types, especially the mutant. The Cd content in roots of the mutant was significantly （P ≤0.05） higher than that of the wild-type rice. However, there was no significant difference in the Cd content of roots, leaf sheaths, and leaves between the wild-type and mutant rice. Most of the Cd was bound to the cell wall of the roots, leaf sheaths, and leaves, and the mutant had greater Cd content in cell organelles than the wild type. The uneven subcellular distribution could be responsible for the Cd sensitivity of the mutant rice. Furthermore, different chemical forms of Cd were found to occur in the roots, leaf sheaths, and leaves of both types of rice plants. Ethanol-, water-, and NaCl-extractable Cd had greater toxicity than the other forms of Cd and induced stunted growth and chlorosis in the plants. The high Cd content of the toxic forms of Cd in the cell organelles could seriously damage the cells and the metabolic processes in mutant rice plants.
基金financially supported by the National Key Research and Development Program of China(Grant No.2017YFD0300409)the National Natural Science Foundation of China(Grant No.31701374)+1 种基金the Special Fund for China Agricultural Research System(Grant Nos.CARS-01-22 and CARS-01-65)the Basic Research Foundation of National Commonweal Research Institute of China(Grant No.2017RG004-4)
文摘Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice flowering stage is the most sensitive period to high temperatures, and therefore, the key for heat stress happening is the flowering stage coinciding with high temperature, which causes spikelet fertility decreasing in heat-sensitive varieties, and is the major factor for heat injury differences among various rice planting regions. With the development of rice breeding, temperature indexes for heat stress has been converted from daily maximum temperature of 35 oC to 38 oC with the stress duration of more than 3 d. During the flowering stage, anther dehiscence inhibition and low pollen shedding onto the stigma are two main reasons for spikelet fertility reduction under high temperatures. At panicle initiation stage, high temperatures aggravate spikelet degeneration, and destroy floral organ development. Various types of rice varieties coexist in production, and indica-japonica hybrid rice demonstrates the highest heat resistance in general, followed by indica and japonica rice varieties. In production, avoiding high temperature is the main strategy of preventing heat stress, and planting suitable cultivars and adjustment of sowing date are the most effective measures. Irrigation is an effective real-time cultivation measure to decline the canopy temperature during the rice flowering stage. We suggested that further study should be focused on exploring heat injury differences among different rice variety types, and innovating rice-planting methods according to planting system changes in rice planting regions with extreme heat stress. Meanwhile, high temperature monitor and warning systems should be improved to achieve optimal heat stress management efficiencies.
基金supported by the Natural Science Foundation of Zhejiang Province,China(LY13C130007)the National Key Research and Development Program of China(2016YFD0200801)the Basic Research Foundation of National Commonweal Research Institute,China(2014RG004-5)
文摘Rice （Oryza safiva L.） is highly susceptible to the rhizosphere salinity than other cereals. High sensitivity has been ob- served, mainly at vegetative and reproductive stages in rice. It is the duty of plant physiologists to comprehend the growth, development, and physiological processes of rice plants under stress. This paper includes the overview of rice growth and developmental processes influenced by salt stress and the regulation pathways involved in these processes. It also includes the promising salt tolerance strategies, i.e., genetic modification techniques, agronomic practices to improve rice growth, yield; and role of phytohormones and their management, especially inhibition of ethylene biosynthesis by using inhibitors 1-methylcyclopropene （1-MCP）. Rice cultivation may be a first choice for improvement of salt tolerance through plant growth regulators and improved cultivation techniques. This study will significantly improve the understanding toward low rice grain yield and poor rice resistance under salt stress and will also stream scientific knowledge for effective utilization of salt affected soils by using different regulating ways.
基金the National Natural Science Foundation of China (31071678)the National High Technology Research and Development Program of China (863 Program, 2013AA102402)Zhejiang Provincial Natural Science Foundation of China (LY13C140009)
文摘A quantitative survey of rice planthoppers in paddy fields is important to assess the population density and make forecasting decisions. Manual rice planthopper survey methods in paddy fields are time-consuming, fatiguing and tedious. This paper describes a handheld device for easily capturing planthopper images on rice stems and an automatic method for counting rice planthoppers based on image processing. The handheld device consists of a digital camera with WiFi, a smartphone and an extrendable pole. The surveyor can use the smartphone to control the camera, which is fixed on the front of the pole by WiFi, and to photograph planthoppers on rice stems. For the counting of planthoppers on rice stems, we adopt three layers of detection that involve the following：（a） the first layer of detection is an AdaBoost classifier based on Haar features;（b） the second layer of detection is a support vector machine（SVM） classifier based on histogram of oriented gradient（HOG） features;（c） the third layer of detection is the threshold judgment of the three features. We use this method to detect and count whiteback planthoppers（Sogatella furcifera） on rice plant images and achieve an 85.2% detection rate and a 9.6% false detection rate. The method is easy, rapid and accurate for the assessment of the population density of rice planthoppers in paddy fields.
基金the National High Technology Research and Development Program (863 Program) of China(No.2001AA241025-1).
文摘A rhizobox experiment with two phosphorus (P) treatments, zero-P (0 mg P kg-1) and plus-P (100 mg P kg-1) as Ca(H2PO4)2·H2O, was conducted to study the chemical and biochemical properties in the rhizosphere of two rice genotypes (cv. Zhongbu 51 and Pembe) different in P uptake ability and their relationship with the depletion of soil P fractions. Plant P uptake, pH, phosphatase activity, and soil P fractions in the rhizosphere were measured. Both total dry weight and total P uptake of Pembe were significantly (P < 0.05) higher than those of Zhongbu 51 in the zero-P and plus-P treatments. Significant depletions of resin-Pi, NaHCO3-Pi, NaHCO3-Po, and NaOH-Pi, where Pi stands for inorganic P and Po for organic P, were observed in the rhizosphere of both Zhongbu 51 and Pembe under both P treatments. Pembe showed a greater ability than Zhongbu 51 in depleting resin-Pi, NaHCO3-Pi, NaHCO3-Po, NaOH-Pi, and NaOH- Po in the rhizosphere. HCl-Pi and residual-P were not depleted in the rhizosphere of both genotypes, regardless of P treatments despite significant acidification in the rhizosphere of Pembe under zero-P treatment. Higher acid phosphatase (AcPME) activity and alkaline phosphatase (AlPME) activity were observed in the rhizosphere of both Zhongbu 51 and Pembe compared to the corresponding controls without plant. AcPME activity was negatively (P < 0.01) correlated to NaHCO3-Po concentration in the rhizosphere of both Zhongbu 51 and Pembe, suggesting that AcPME was associated with the mineralization of soil organic P.
基金supported by the National Natural Science Foundation of China (30871473)the project from the China National Rice Research Institute (2009RG0035)+1 种基金the projects from Local Government of Zhejiang Province, China (2008C22073, 2009C32048, and SN200806)the Zhejiang Provincial Natural Science Foundation, China (Y3100060 and Y3100090)
文摘Two rice maintaining lines with different drought tolerances, viz., Jin 23B （tolerant） and Zhenshan 97B （sensitive）, were used to study the oxidative stress and soluble sugar in rice anthers and pollen viability under drought stress during flowering stage. Higher antioxidant enzyme activities and lower malonaldehyde （MDA） content in rice anthers were observed in Jin 23B than in Zhenshan 97B under drought stress. Further, a great increase in the content of soluble sugar in rice anthers of Jin 23B was observed across the whole drought exposure, while Zhenshan 97B showed significant decrease in soluble sugar during 9-12 d after drought stress （DADS）. Accordingly, a marked decline of pollen fertility and activity, pollen numbers in an anther and pollen numbers on a stigma was observed in Zhenshan 97B, whereas little difference was found in Jin 23B. Thus, we suggest that pollen abortion caused by drought stress may be related with the reciprocity between oxidative stress and soluble sugar content in rice anthers.
基金supported by the National Nature Science Foundation of China (Grant Nos. 31471472 and 31521064)the National S&T Major Project of China (Grant No. 2016ZX08001006)the Central Level, Non-Profit, Scientific Research Institutes Basic R and D Operations Special Fund (Grant Nos.Y2017PT46 and 2017RG002-1)
文摘Isoamylase 1(ISA1) is an isoamylase-type debranching enzyme which plays a predominant role in amylopectin synthesis. In this study, the clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated endonuclease 9(CRISPR/Cas9) system was used to edit ISA1 gene in rice via Agrobacterium-mediated transformation. We identified 36 genetic edited lines from 55 T_0 transgenic events, and classified the mutation forms into 7 types. Of those, two homozygous mutants, cr-isa1-1(type 1, with an adenine insertion) and cr-isa1-2(type 3, with a cytosine deletion) were selected for further analysis. Seed sizes of both cr-isa1-1 and cr-isa1-2 were affected, and the two mutants also displayed a shrunken endosperm with significantly lower grain weight. Electron microscopy analysis showed that abnormal starch granules and amyloplasts were found in cr-isa1-1 and cr-isa1-2 endosperm cells. The contents of total starch, amylose and amylopectin in the endosperm of the cr-isa1 mutants were significantly reduced, whereas sugar content and starch gel consistency were observably increased compared to the wild-type. The gelatinization temperature and starch chain length distributions of the cr-isa1 mutants were also altered. Moreover, transcript levels of most starch synthesis-related genes were significantly lower in cr-isa1 mutants. In conclusion, the results indicated that gene edition of ISA1 affected starch synthesis and endosperm development, and brought potential implications for rice quality breeding.
文摘A thermo-insensitive pale green leaf mutant （pgl2） was isolated from T-DNA inserted transgenic lines of rice （Oryza sativa L. subsp, japonica cv. Nipponbare）. Genetic analysis indicated that the phenotype was caused by a recessive mutation in a single nuclear-encoded gene. To map the PGL2gene, an F2 population was constructed by crossing the mutant with Longtefu （Oryza sativa L. subsp, indica）. The PGL2 locus was roughly linked to SSR marker RM331 on chromosome 8. To finely map the gene, 14 new InDel markers were developed around the marker, and PGL2 was further mapped to a 2.37 Mb centromeric region. Analysis on chlorophyll contents of leaves showed that there was no obvious difference between the mutant and the wild type in total chlorophyll （Chl） content, while the ratio of Chl a / Chl b in the mutant was only about 1, which was distinctly lower than that in the wild type, suggesting that the PGL2 gene was related to the conversion between Chl a and Chl b. Moreover, the method of primer design around the centromeric region was discussed, which would provide insight into fine mapping of the functional genes in plant centromeres.
