摘要
近年来,由弯孢属真菌侵染引发的病害在烟草上有上升的趋势,严重影响烟叶的产量和质量。为了更好地防治由弯孢属真菌引起的烟草叶斑病,本研究利用高通量测序技术对一株分离自烟草叶片的棒状弯孢菌Curvularia clavata线粒体基因组进行测序,组装得到一个环状的线粒体基因组,并对其组成特征、与典型叶斑病真菌的系统发育关系进行分析。结果表明,烟草棒状弯孢菌线粒体基因组长度为41763 bp,共编码38个基因(13个蛋白编码基因、2个rRNA基因和23个tRNA基因),其碱基组成有显著的A-T偏好性,占比高达70.35%。线粒体基因组中只有3个内含子和少量重复序列,这是造成其基因组大小收缩的主要原因。通过6个近缘病原真菌线粒体全基因的共线性分析,发现其线粒体基因组发生了基因重排事件。同时,物种同源区长度与对应物种的线粒体基因组大小呈正相关关系,同源区长度可能会影响物种的线粒体基因组大小。在选择压力分析中,发现烟草棒状弯孢菌线粒体为确保优势基因稳定遗传,自然选择和纯化选择起到了主导作用。系统发育分析表明烟草棒状弯孢菌与麦根腐平脐蠕孢Bipolaris sorokiniana和稻平脐蠕孢Bipolaris oryzae亲缘关系最为密切,与前人基于ITS序列的进化分析结果一致。本研究首次从线粒体基因组方面对弯孢属真菌进行研究,丰富了弯孢属真菌线粒体基因组序列信息,为该属真菌的系统发育、资源保护及遗传多样性研究提供基础数据。
In recent years,fungal diseases caused by Curvularia have become a serious problem in tobacco cultivation,affecting the yield and quality of tobacco.To effectively control the disease,the mitochondrial genome of Curvularia clavata isolated from tobacco was sequenced and analyzed by high-throughput sequencing,and a circular genome was assembled.The genome elements were further analyzed to explore the phylogenetic relationship between C.clavata and currently known typical leaf spot-caused fungi.The results showed that the mitochondrial genome of C.clavata had an A-T content as high as 70.35%,with a length of 41763 bp,encoding 38 genes(13 protein-coding genes,2 rRNA genes and 23 tRNA genes).Only three introns were detected,accompanied by limited number of repeat sequences,which may be the main cause for genome shrinkage.Collinearity analysis of six related pathogenic fungal species indicated that gene rearrangements occurred in the mitochondrial genome of C.clavata.The length of homology regions might affect the size of mitochondrial genome,showing a positive correlation between homological region length and mitochondrial genome size.Selection pressure analysis showed that natural selection and purifying selection may have played a dominant role,ensuring the stable inheritance of dominant genes in the mitochondrial genome.Phylogenetic analysis showed that C.clavata was most closely related to Bipolaris sorokiniana and Bipolaris oryzae,being consistent with the results of previous studies on ITS sequencing.This is the first study on the mitochondrial genome of C.clavata,and provide a valuable reference for future studies in perspectives such as phylogeny,resource conservation and genetic diversity.
作者
曹毅
陈代荣
李治模
张明娅
何世芳
陆宁
CAO Yi;CHEN Dairong;LI Zhimo;ZHANG Mingya;HE Shifang;LU Ning(Guizhou Academy of Tobacco Science,Guiyang 550081,Guizhou,China;Tongren Tobacco Company of Guizhou Province,Tongren 554300,Guizhou,China;Fenggang Branch of Zunyi Tobacco Company,Fenggang 564200,Guizhou,China;Tobacco Science College of Guizhou University,Guiyang 550025,Guizhou,China)
出处
《菌物学报》
CAS
CSCD
北大核心
2023年第12期2407-2421,共15页
Mycosystema
基金
中国烟草总公司重大科技项目(110202101027[LS-02])
贵州省烟草公司重大专项项目(2023XM05)。
关键词
线粒体基因组
烟草棒状弯孢菌
比较基因组
烟草
mitochondrial genome
Curvularia clavata
comparative genomics
Nicotiana tabacum
