大豆疫霉菌对大豆幼苗致病性的遗传变异研究

On inheritance of pathogenicity of Phytophthora sojae to soybean seedlings

【目的】研究黑龙江省大豆疫霉菌的致病性特性及其遗传变异特点,为进一步探讨大豆疫霉菌致病力的遗传变异机制奠定基础。【方法】用国际标准鉴别寄主和黑龙江省部分主栽大豆品种测定黑龙江省大豆疫霉菌株的致病性,以大豆疫霉野生型菌株的单游动孢子分离物为亲本,建立连续2代单游动孢子无性后代和1代单卵孢后代,测定大豆疫霉菌致病力的遗传变异特性。【结果】黑龙江省大豆疫霉菌株对黑龙江省大豆主栽品种表现出不同的致病性,但对国际标准鉴别寄主不致病。控制大豆疫霉菌致病力的某些致病基因在连续2代单游动孢子后代和1代单卵孢后代中发生变异,而其他致病基因遗传稳定。【结论】黑龙江省大豆疫霉菌株和大豆品种具有美国大豆疫霉菌株和大豆品种所不具有的更为复杂的遗传多样性,用国际标准鉴别寄主鉴别黑龙江省大豆疫霉菌株的致病性存在明显的局限性。控制大豆疫霉菌的致病基因分布在不同位点,有的遗传稳定,由纯合的核基因控制;有的遗传不稳定,由杂合核基因或细胞质基因控制,其有性和无性后代均发生变异。

[Objective] The pathogenicity and inherited characteristic of pathogenicity of phytophthorasojae in Heilongjiang were studied, which will be helpful to reveal the genetic variation mechanism of the pathogenicity of P. sojae. [Method] The pathogenicity of P. sojae was identified by international standard differential cultivars and main soybean cultivars in Heilongjiang. The single-zoospore from a wild-type of P. sojae was selected as the parent isolate,from which two successive single-zoospore progenies and one single-oopore generation were established to evaluate the inheritance of the pathogenicity of P. sojae. [Result] The P.sojae in Heilongjiang had pathogenicity to some main soybean cultivars in Heilongjiang, but no pathogenicity to international standard differential cultivars. The successive variation of some pathogenicity genes was observed in both two single-zoospore and one single-oospore progenies,and the inheritance of other pathogenicity genes was stable. [Conclusion] The P. sojae and some main soybean cultivars in Heilongjiang have more complex genetic diversity than that of in America. There are obvious limitations to identity the pathogenicity of P. sojae in Heilongjiang by international standard differential cultivars. The pathogenicity genes which controlled the pathogenicity of P. sojae were located difference inheritance site. Some pathogenicity was steadily inherited, which suggested that the virulence genes controlling the pathogenicity appeared to be homozygous nuclear gene. Some pathogenicity was not steadily inherited, which suggested that the pathogenicity genes controlling the pathogenicity appeared to be heterozygous nuclear gene or cytoplasmic gene,and the variation of pathogenicity of P. sojae maybe occur in single-zoospore and single-oospore progenies.