玉米弯孢霉叶斑病菌的寄生适合度与RAPD分析

对采自河北省14个玉米产区的28个玉米弯孢霉叶斑病标样进行了分离鉴定,发现新月弯孢(Curvularialunata)占57.1%,棒状弯孢(C.clavata)占17.9%,画眉草弯孢(C.eragrostidis)占14.3%,中隔弯孢(C.inter-media)占10.7%。将4种玉米弯孢霉叶斑病菌接种在9个玉米自交系和杂交种上进行寄生适合度测定,发现新月弯孢和中隔弯孢的致病性最强,其次为棒状弯孢,画眉草弯孢的致病性最弱。用23条随机引物对28个菌株进行RAPD扩增,共获得了185个RAPD标记,其中多态性标记142个,多态性几率P=76.8%。利用菌株间的遗传相似性进行聚类分析,发现4种弯孢在种间存在的遗传差异可能是导致致病性差异的一个原因。在新月弯孢种内也存在较大的遗传差异,部分新月弯孢菌株与其它3种弯孢霉亲缘关系较近。

Parasitic fitness and RAPD analysis of Curvularia species on corn

Twenty-eight isolates collected from 14 cornplanting areas in Hebei Province were identified to be four Curvularia species,i.e.C.lunata(57.1%),C.clavata(17.9%) and C.eragrostidis(14.3%),C.intermedia(10.7%).The pathogenicity of C.lunata and C. intermedia was much stronger than C.clavata and C.eragrostidis after tested on 9 corn cultivars and inbred lines.Twenty-three primers were employed for RAPD analyses of the 28 isolates.Out of the 185 RAPD markers,142 polymorphic markers(P=76.8%) were obtained.Based on the genetic similarity,the 28 isolates were clustered by NTSYS software and the results revealed the genetic difference among four Curvularia species,which possibly resulted in pathogenic difference.The cluster analyses also indicated greater genetic difference within C.lunata,which was shown by some isolates of C.lunata genetically similar to the other three Curvularia species.