我国冬小麦主产省小麦茎基腐镰孢菌的组成及其致病力

为了解我国小麦茎基腐病的致病菌镰孢菌(Fusariumspp.)的组成,2009-2012年从江苏、安徽、河南、河北、山东等5个冬小麦主产省采集茎基腐病样本,从中分离了135个镰孢菌菌株,用PCR-RFLP和ITS序列分析的方法进行了种群鉴定,并分别在温室和田间条件下对不同种群及化学型菌株进行致病力测定。结果表明,在分离的135株病菌中,103株为F.asiaticum,17株为F.graminearum,其余为F.acuminatum、F.pseudoraminearum和F.avenaceum,说明引起我国小麦茎基腐的镰孢菌主要由F.asiaticum和F.graminearum组成,且以F.asiaticum种群分布为主。在120个镰孢菌综合物种菌株(F.asiaticum和F.graminearum)中,79株为3-AcDON化学型,17株为15-AcDON化学型,24株为NIV化学型。在F.graminearum菌株中只发现15-AcDON化学型;在F.asiaticum菌株中存在2种化学型,以3-AcDON化学型菌株为主,少部分为NIV化学型菌株。F.asiaticum种群致病力略高于F.graminearum种群,DON化学型菌株致病力略高于NIV化学型菌株,但均无显著性差异。

Composition and Pathogenicity of Fusarium Crown Rot Pathogens of Wheat in Major Winter Wheat Production Areas of China

Wheat crown rot caused by Fusarium spp. has become more prevalent in China in recent years. To understand the structure of the Fusarium spp.in main areas of wheat production of China, wheat basal stems showing crown rot symptoms were collected from Jiangsu, Anhui, Henan, Hebei and Shandong provinces from 2009 to 2012. Totally 135 isolates were selected to analyze the distribution and chemotype composition in different geographic areas. The analysis showed that 103 isolates were F. asiaticum among 135 isolates, which were of 3 acetyldeoxynivalenol (3 AcDON), and nivalenol (NIV) type. Seventeen isolates belonged to F. graminearum species, which were all of 15 AcDON type. F. asiaticum species with 3 AcDON type was the predominant pathogen causing crown rot in these 5 provinces. The pathogenicity of 120 F. asiaticum and F. graminearum isolates to wheat heads and crown was tested. The results suggested that isolates of F. asiaticum were more aggressive toward wheat crown and heads than F. graminearum. The isolates of DON chemotype were more aggressive toward wheat than isolates of NIV chemotype, but there was no significant difference between them.