福建、湖南自育型致病疫霉生物学特性研究

Biological characteristics of self-fertile Phytophthora infestans from Fujian and Hunan provinces

[目的]对分离自马铃薯晚疫病组织的自育型致病疫霉的生物学特性开展研究,为自育导致的有性生殖对马铃薯晚疫病菌群体结构的可能影响提供参考。[方法]测定致病疫霉菌株的交配型,观测并比较自育型菌株在黑麦培养基上和马铃薯叶片组织内产生卵孢子的状况,并通过MTT染色法测定卵孢子的活性。[结果]2014至2016年,自育型(A1A2)致病疫霉在福建省霞浦县、福安市和湖南省永顺县的比例呈显著的上升趋势,至2016年达到100%,且自育性状在单游动孢子无性系后代中稳定遗传;2015—2016年的自育型菌株在黑麦培养基上产生卵孢子的败育率高达74%~100%,自育型致病疫霉单孢株在马铃薯叶片组织内产生的具活性的健康卵孢子比例则达到54%~68%,显著高于黑麦培养基上产生的健康卵孢子的比例。[结论]致病疫霉自育型群体已成为福建霞浦、福安和湖南永顺地区的优势群体,自育型致病疫霉在马铃薯叶片组织内能产生大量具活性的健康卵孢子。提示:大量A1A2型菌株出现可能对以上地区致病疫霉的群体遗传结构产生影响。

[ Objectives] The biological characteristics of self-fertile Phytophthora in]~stans isolates from potato diseased tissues were studied to provide the reference for possible influences of sexual reproduction caused by self-fertile on the P. infestans population structure. [ Methods] The mating types of P. infestans isolates were determined. Then, the abortive rate of the oospores produced by self-fertile isolates was measured. Finally, MTY staining method was used to determine the oospore viability. [ Results ] The proportion of self-fertile isolates in Xiapu County and Fu＇ an City in Fujian Province and Yongshun County in Hunan Province had been changing with a highly significant rising trend from 2014 to 2016, of which in 2016 the self-fertile isolates occupied 100% of the P. infestans isolates, and the character of self-fertility was stable in clonal progeny of single zoospore. The oospores abortive rate of self-fertile isolates cultured on rye medium from Fujian and Hunan provinces during 2015-2016 was up to 74%-100%. However, the proportion of healthy oosopres produced by self-fertile isolates in potato leaf tissues was up to 54% to 68%, which was significantly higher than that on rye medium. [ Conclusions ] Self-fertile P. infestans had become the dominant populations in Xiapu County and Fu＇ an City of Fujian Province and Yongshun County of Hunan Province, and the self-fertile isolates could produce a large number of healthy oospores in potato leaves. Therefore, it was inferred that the high proportion of self-fertile P. infestans isolates might have an influence on population genetic structures of P. infestans in the above districts.