南方淮山炭疽病菌的致病力分化

Pathogenicity differentiation of Dioscorea opposita Thunb.anthracnose pathogen in southern China

【目的】明确我国南方淮山炭疽病病原菌种类及其致病力分化状况,为淮山炭疽病的综合防治和抗病育种提供理论依据。【方法】采用形态学观察,结合r DNA-ITS序列比对和系统发育进化分析,对从我国南方6省(区)四川、贵州、云南、广西、福建和海南淮山种植区典型炭疽病病叶分离获得的45株炭疽病病原菌进行鉴定,并通过接种在4种不同淮山种质(Do6-3、Do6、Do108和Do21)叶片上进行致病力检测,分析不同来源菌株的致病力差异。【结果】45株炭疽菌均鉴定为胶孢炭疽菌(Colletotrichum gloeosporioides)。45株炭疽菌对4种淮山种质材料均能致病,根据综合致病力可将45株炭疽菌分为强、中、弱3种致病类型。其中,6株强致病性菌株均来自广西,7株弱致病性菌株主要来自云南,32株中等致病力菌株主要来自贵州、福建和海南。【结论】来源于我国南方6省(区)的45株淮山炭疽病病原菌均为胶孢炭疽菌(C.gloeosporioides),其致病力分化明显,且与地理来源具有相关性。

【Objective】The pathogenic bacteria species of Dioscorea opposita Thunb.anthracnose in southern China and pathogenicity differentiation were studied to provide reference for comprehensive control of D.opposita anthracnose and disease resistant varieties breeding.【Method】Forty-five strains of pathogenic bacteria were isolated from D.opposita leaves with typical anthracnose lesions collected from six provinces(Sichuan,Guizhou,Yunnan,Guangxi,Fujian,and Hainan)in southern of China.These strains were identified by morphological observation,rDNA-ITS sequence and phylogenetic tree analysis.Pathogenicity of them were tested by inoculating four D.opposita gerplasms(Do6-3,Do6,Do108 and Do21)on the leaves,then the pathogenicity strength of strains with various sources were analyzed.【Result】All 45 strains were identified as Colletotrichum gloeosporioides.They were all pathogenic to the four D.opposita gerplasms.These strains were classified into three groups based on their comprehensive pathogenicity.Six highly pathogenic strains came from Guangxi,seven weakly pathogenic strains mainly came from Yunnan,thirty-two moderately pathogenic strains mainly from Guizhou,Fujian and Hainan.【Conclusion】The 45 D.opposita anthracnose pathogenic bacteria from six provinces(autonomous region)in southern China are identified as C.gloeosporioides.The pathogenicity differentiation of them are obvious and related to geographical origin.