玉蜀黍赤霉有性重组体的诱导及其生物学特性

Induction and biological properties of sexual recombinants of Gibberella zeae

本研究以硝酸盐营养缺陷型突变体(nit)和多菌灵抗性为遗传标记,在5个所选菌株中设计了3个玉蜀黍赤霉病菌Gibberella zeae的杂交组合,使各菌株之间进行杂交,从而诱导有性重组体。从各杂交组合的后代中任意挑选出3个有性重组体,比较了这些有性重组体与其亲本在无性和有性阶段的主要生物学性状。结果表明,玉蜀黍赤霉中的nit基因及对杀菌剂多菌灵的抗药性基因可以通过有性杂交的方式重组,即发生了有性重组。有性重组体与其亲本在菌落生长、培养性状和致病性方面没有显著差异;但某些有性重组体中,产孢量和产子囊壳能力方面存在一定差异。总体看来,有性重组体仍然保持了较高的适合度。因此,可以认为有性重组在玉蜀黍赤霉群体对多菌灵抗药性发生发展以及群体遗传进化中可能起着重要的作用。

In order to induce sexual recombinants of Gibberella zeae, five selected isolates were adopted as parents and crossed in three designed pairs by using nitrate non-utilizing （nit） mutants and carbendazim-resis- tance as genetic markers. Three sexual recombinants from each of the three combinations were randomly selec- ted to compare the major biological properties with their parental isolates. The results showed that the nit gene and carbendazim-resistance gene could be recombined by sexual crosses. There were no significant differences in mycelial growth, traits of culture and pathogenicity between the sexual recombinants and their parental isolates. Sporulation and perithecigerous capacities, however, changed more or less in some sexual recombinants. The fitness of the sexual recombinants was comparable to the parents in general. Therefore, it is concluded that sexual recombination may play an important role in carbendazim resistance development and genetic evolution of G. zeae populations.