田间不同繁殖代数烟草赤星病菌毒力变异的遗传本质

为弄清烟草赤星病菌毒力与DNA多态性的关系及田间不同繁殖代数烟草赤星病菌毒力变异的遗传本质,分别采用毒力测定和RAPD技术对采集于同一烟田不同生长期的6个烟草赤星病菌株进行测定。结果表明,田间赤星病菌繁殖代数越高毒力越强,毒力差异是病菌基因组DNA致病相关基因差异所致。根据供试菌株在3个烟草品种上的毒力反应,可将其分为2个组,利用RAPD标记可将其分为3个组。12个随机引物扩增供试菌株共产生105个RAPD标记,其中多态性标记占95.24%,表明烟草赤星病菌群体中具有丰富的遗传多样性,毒力多态性与DNA多态性之间存在一致性,但也存在一定的差异。

Virulence Variation Genetic Basis among Different Field Reproductive Generations of Alternaria alternata

For better understand the relationship between the virulence of Alternaria alternata and DNA polymorphism, as well as the virulence variation genetic basis of Alternaria alternata among different reproductive generations in a tobacco field, 6 Alternaria alternata isolates collected from the same tobacco field at different growth stage were tested with virulence determination and random amplified polymorphic DNA (RAPD) marker. The results showed that pathogen virulence increased with the increase of reproductive generations, the virulence variation was caused by the variation of pathogenetic DNA gene of pathogen. The tested isolates could be divided into 2 groups based upon the virulence tests on 3 tobacco cultivars or 3 groups according to the RAPD marker. Of the 105 RAPD marker generated by the tested isolates amplified with 12 random primers, 95.24% showed polymorphism. The (results) indicated that there existed genetic diversity among these isolates, and a coherence relationship between virulence polymorphism and DNA polymorphism, however, there existed some variations as well.