油茶炭疽病病原鉴定及生物学特性

Identification and biological characteristics of anthracnose in Camellia oleifera

【目的】炭疽病影响油茶正常生长发育并降低其产量。通过对抗性优良的普通油茶“攸杂2”和易感炭疽病的“华硕”油茶F1子代进行病原鉴定,为油茶炭疽病抗性育种及其防治提供依据。【方法】选用普通油茶“攸杂2”ד华硕”油茶F1子代中主要发病叶片,通过分离提纯和分子鉴定等方法鉴定感染菌株种类;同时根据生物学特性改变生长环境,了解菌株的生长习性。【结果】在调查的474株“攸杂2”ד华硕”F1子代中,出现了明显的抗性分离现象,群体整体的抗病指数DI为31.1,抗病等级处于抗病(R)。通过分子鉴定比对和柯赫氏验证后得出该群体侵染菌株为果生炭疽菌(Colletotrichumfructicola)和胶孢炭疽菌(Colletotrichumgloeosporioides);使用不同培养基培养菌株后,在PSA(马铃薯蔗糖琼脂)培养基上两种菌生长情况最佳。CMA(玉米粉琼脂)培养基上生长情况最差;使用Czapek培养基通过改变碳源、氮源、pH、光照条件后发现,果生炭疽菌对于环境酸碱度pH的适应范围更加广,胶孢炭疽菌则适应酸碱度为中性的环境;以牛肉膏作为氮源更适合两个菌株生长;以葡萄糖作为碳源可以使两个菌株生长状态最佳;两个菌株全光照培养的生长情况最佳。【结论】油茶“攸杂2”ד华硕”F1子代感染的炭疽病真菌为果生炭疽菌和胶孢炭疽菌,根据这两个菌株的生物学特性可以有针对性地改进油茶病害的防治措施;同时F1子代个体间的感病性状分离,为油茶炭疽病遗传规律的挖掘和选育高抗品种奠定基础。

[Objective]Anthracnose affects the normal growth and development of Camellia oleifera and so reduces its yield.The pathogen of the diseases was identified by comparing the F1 progeny of‘YZ2’with that of‘HS’,and the results provided basis for the resistance breeding and control of Anthracnose in Camellia oleifera.[Method]Diseased leaves of F1 progeny of Camellia oleifera‘YZ2’בHS’were selected to identify the infected strains by isolation,purification and molecular identification.At the same time,according to the biological characteristics,the growth environment was changed so to understand the growth habit of the strains.[Result]The disease resistance index(DI)of the population was 31.1,and the disease resistance level was at the level of resistance(R)among 474 progenies of‘YZ2’בHS’.The isolates were identified as Colletotrichum fructicola and C.gloeosporioides by molecular identification and Koch’s test.The growth of the two strains was the best on PSA(potato sucrose agar)medium.While,that on CMA(corn meal agar)medium was the worst.It was found that C.fructicola was more adaptable to pH,while C.gloeosporioides was more adaptable to neutral acidity.Beef extract as nitrogen source,glucose as carbon source and under full-illumination condition were more suitable for the growth of these two strains.[Conclusion]The pathogen infected from F1 progeny of Camellia oleifera‘YZ2’בHS’were C.fructicola and C.gloeosporioides.According to the biological characteristics of these two strains,the control measures of Camellia oleifera diseases could be improved.At the same time,the segregation of susceptible characters among F1 progenies laid a foundation for mining the genetic law of Anthracnose of Camellia oleifera and breeding high resistant varieties.