摘要
【目的】明确广东省番木瓜果实疑似炭疽病病害的致病菌,并筛选防控该病害的适宜化学药剂,为番木瓜炭疽病的诊断和有效防治提供科学依据。【方法】在广东省广州市番木瓜果园采集番木瓜果实水渍状炭疽病疑似病果,对番木瓜病果进行组织分离及致病性测定,利用传统形态学和分子生物学方法鉴定病原菌;采用菌丝生长速率法测定8种杀菌剂对该病原菌的室内毒力。【结果】从病果样品中分离出5个形态特征相似的菌株(C1~C5),随机选取C1作为代表性菌株进行致病性测定和鉴定。致病性分析发现,番木瓜果实接种C1病原菌2 d即可表现出明显的水渍状病斑,从表现症状的部位可以重新分离到该病原菌。形态学观察发现,C1初生菌丝为白色辐射状,随后变灰白色,菌丝体上覆盖着一些橘红色分生孢子盘;孢子梗透明,有分隔;分生孢子透明,单细胞,细胞壁光滑,两端圆,形状规则呈圆柱形,壁薄,内含物呈颗粒状;分生孢子大小为13.2μm×5.1μm。这些形态学特征与短孢炭疽菌(Colletotrichum brevisporum)一致。分子生物学鉴定结果显示,供试菌株C1核糖体内转录间隔区(internal transcribed spacer,ITS)、甘油醛-3-磷酸脱氢酶(glyceraldehyde-3-phosphate dehydrogenase,GAPDH)、β微管蛋白(β-tubulin,TUB2)和肌动蛋白(actin,ACT)基因序列与短孢炭疽菌(C.brevisporum)模式菌株BCC 38876对应基因的序列一致性分别为100%,93%,98%和100%。系统发育树分析结果表明,供试菌株C1与短孢炭疽菌单独聚为一支。结合形态学、分子生物学、致病性及发病特征明确了导致广东省番木瓜炭疽病的病原菌为短孢炭疽菌。室内毒力测定结果显示,在8种杀菌剂中,45%咪鲜胺水乳剂对C1菌株的抑制效果最明显,抑制中浓度(EC_(50))为0.082 0 mg/L,其次为250 g/L丙环唑乳油和40%苯醚甲环唑悬浮剂,EC_(50)分别为0.263 5和9.714 3 mg/L。【结论】在中国内地首次鉴定了番木瓜果实炭疽病的致病菌短孢炭疽菌。45%咪鲜胺水乳剂、250 g/L丙环唑乳油和40%苯醚甲环唑悬浮剂对番木瓜短孢炭疽菌具有明显的抑制作用。
【Objective】This study clarified pathogen species causing anthracnose of papaya in Guangdong and screened suitable chemical agents for prevention and control of anthracnose to provide basis for the diagnosis and effective control of papaya anthracnose.【Method】Diseased fruit samples of papaya showing anthracnose symptoms were collected from Guangzhou.Strains were isolated and purified using the traditional tissue separation method,and the pathogenicity of strains was determined.The pathogen was identified based on morphological characteristics,polygene sequence analysis and phylogenetic analysis.The indoor toxicity of 8 fungicides to the pathogen was determined by the mycelia growth rate method.【Result】Five strains(C1-C5)with similar morphological characteristics were obtained from diseased samples,and C1 was randomly selected as the representative strain for pathogenicity tests.The isolated strain could infect papaya fruit and cause typical anthracnose symptoms in 2 days.The pathogen was obtained from the location with symptoms.Morphological observation found that the primary hyphae of C1 were white and radiant,and then turned grayish white.The mycelium was covered with some orange-red conidia discs,the spore peduncles were transparent.Conidia were transparent,unicellular,with smooth cell walls,rounded ends,regular cylindrical shape,thin walls,and granular inclusions.The size of conidia was 13.2μm×5.1μm.These morphological characteristics were consistent with Colletotrichum brevisporum.Molecular biology identification revealed that the test strain gene sequences of internal transcribed spacer(ITS),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),β-tubulin(TUB2)and actin(ACT)displayed 100%,93%,98%and 100%nucleotide identity to the respective gene sequences of C.brevisporum BCC 38876.C1 and C.brevisporum clustered together in the phylogenetic tree.Combined with morphology,molecular biology,pathogenicity and pathogenesis characteristics,it was determined that the pathogen causing papaya anthracnose in Guangdong was C.brevisporum.The virulence test of 8 fungicides to C.brevisporum differed greatly with the best inhibitory effect from 45%prochloraz water emulsion and the EC 50 was 0.0820 mg/L.The fungicides with good virulence included 250 g/L propiconazole emulsifiable and 40%difenoconazole suspension with EC 50 of 0.2635 mg/L and 9.7143 mg/L.【Conclusion】This study firstly identified that C.brevisporum caused papaya fruit anthracnose in Chinese mainland and found that 45%prochloraz water emulsion,250 g/L propiconazole emulsifiable and 40%difenoconazole suspension could inhibit the growth of its mycelium.
作者
杨敏
李庆萌
周陈平
邝瑞彬
杨护
黄炳雄
魏岳荣
YANG Min;LI Qingmeng;ZHOU Chenping;KUANG Ruibin;YANG Hu;HUANG Bingxiong;WEI Yuerong(Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization,Ministry of Agriculture and Rural Affairs,Guangdong Provincial Key Laboratory of Tropical and Subtropical Fruit Tree Research,Institute of Fruit Tree Research,Guangdong Academy of Agricultural Sciences,Guangzhou,Guangdong 510640,China)
出处
《西北农林科技大学学报（自然科学版）》
CSCD
北大核心
2023年第11期106-115,共10页
Journal of Northwest A&F University(Natural Science Edition)
基金
广东省基础与应用基础研究基金项目(2022A1515010697,2021A1515010739)
广东省农业科学院果树研究所培育项目(22100)
广东省科技专项资金项目(2021A05192)
广东省现代农业产业技术体系创新团队建设项目(2021KJ116)。
关键词
番木瓜炭疽病
短孢炭疽菌
病原菌鉴定
室内毒力测定
防治药剂筛选
papaya anthracnose
Colletotrichum brevisporum
pathogen identification
virulence test
fungicide screening
