链格孢属小孢子种的RAPD分析

RAPD ANALYSIS ON SMALL-SPORED ALTERNARIA SPECIES

用筛选出的12个随机引物,对链格孢属Alternaria13个小孢子种和作为对照的3个大孢子种共55个分离系(isolates)进行RAPD分析。大孢子种Alternariasolani、A.porri和形态独特的A.leucanthemi在树状聚类图上遗传距离0.44处与所有供试小孢子种区分开,它们彼此之间在遗传距离0.25处相区分,表明所采用的RAPD分析方法适于链格孢种间亲缘关系的研究。所有供试的链格孢小孢子种在遗传距离0.31水平上被聚在一起,表明它们之间的亲缘关系较近。A.infectoria与其它链格孢小孢子种之间遗传距离较远;A.longipes的3个分离系和A.brassicicola的7个分离系在较低的遗传距离上被聚在一起,表明它们是独立的种。其它供试链格孢小孢子种的不同分离系在树状聚类图上未显示明确区分。

RAPD profiles of 55 isolates of Alternaria belonging to 13 small-spored species and 3 large-spored species (as contrast) were performed using 12 arbitrarily primers. Among them, the large-spored species Alternaria solani、A. porri and A. leucanthemi were differentiated from all small-spored species at genetic distance 0.44, and being distinguished each other according to genetic distance 0.25. These indicated that the RAPD analysis method used was adapted to analyzing the phylogenetic relationships of Alternaria species. On the other hand, 13 small-spored species as a cluster group at genetic distance 0.31 conformed that genetic relationship of them were relatively close. Among them, A. infectoria had relatively long genetic distance from others, and 3 isolates of A. longipes and 7 isolates of A. brassicicola were clustered in same group on the cluster tree, respectively. These indicated that they were independent species. Others could not be seperated on the cluster tree.