小麦叶枯病病原菌的形态学与多基因系统学鉴定

Morphological and Polygenetic Identification of Pathogen of Wheat Leaf Blight

为明确造成新疆塔城小麦主产区小麦叶枯、斑点现象的原因,确定致病菌,从塔城地区额敏县多地随机采集干枯叶片或带有不规则病斑的感病植株,通过常规组织分离法对病叶进行病原菌分离、纯化;通过针刺接种法进行致病性测定;结合形态学观察与多基因序列分析的方法鉴定病原菌种类。结果表明,经分离纯化得到76个链格孢属(Alternaria)菌株,经致病性测定均为致病菌株。通过形态学鉴定,76个菌株分别属于交链链格孢(A.alternata)、玫瑰链格孢(A.rosae)和侵染链格孢(A.infectoria),其中,交链链格孢为主要致病菌,分离频率为50%。基于EF-1和Alt基因及ITS构建的系统进化树显示,选取的代表菌株YC3、LK19和LK3分别与交链链格孢、玫瑰链格孢、侵染链格孢菌聚为一支,同源性分别为100%、100%和99%,多基因鉴定结果与形态鉴定结果一致。由此表明,新疆塔城地区冬小麦田间出现的小麦叶枯现象为链格孢侵染发生,其病原菌为交链链格孢、玫瑰链格孢、侵染链格孢,以交链链格孢为主。

In order to clarify the causes and pathogens of wheat leaf blight and spot phenomenon in Tacheng wheat producing area of Xinjiang,more random sampling dry leaf or with irregular disease spot disease of plants were collected from Tacheng prefecture Emin county,and pathogenic bacteria were isolated and purified from diseased leaves by routine tissue separation.The pathogenicity was determined by acupuncture inoculation.And the species of pathogens were identified by morphological observation and multi-gene sequence analysis.The results showed that 76 strains of Alternaria spp were isolated and identified,which confirmed as pathogens by pathogenicity determination.Through the morphological identification,76 strains belonged to A.alternata,A.rosae and A.infectoria,among which,A.alternata as the main pathogen with 50%frequency of separation.Based on sequences of EF-1 and Alt genes and ITS,the evolutionary tree was constructed,and the three kinds of representative strains YC3,LK19,LK3 showed 100%,100%and 99%homology with A.alternata,A.rosea and A.infectoria,respectively,which was consistent with morphological identification results.The above results showed that,in Tacheng prefecture,Xinjiang winter wheat field of area,the phenomenon of wheat leaf blight for chain and spore wheat leaf blight was caused by Alternaria infection,and A.alternata,A.rosae and A.infectoria were the main pathogens.