我国小麦条锈菌体细胞遗传重组的分子证据

 小麦条锈病是影响我国小麦生产的重要病害之一,条锈菌毒性变异是引致小麦品种抗病性丧失的主要原因。本文应用SSR分子标记技术,研究了陇南越夏区小麦条锈菌群体遗传结构,以期寻找条锈菌群体遗传重组的分子证据。研究结果表明,陇南地区小麦条锈菌群体遗传多样性比较丰富而遗传分化较小,遗传变异主要存在于群体内部,而在群体之间,遗传多样性有显著的差异。在11对SSR引物中,有4对能够检测到陇南地区小麦条锈菌群体存在遗传重组,而且重组体出现的频率不同,CPS15揭示的条锈菌重组体出现的频率为20.0%,CPS34揭示的条锈菌重组体出现的频率为18.5%,RJ20揭示的条锈菌重组体出现的频率为12.8%,RJ18揭示的条锈菌重组体出现的频率为15.0%,陇南地区小麦条锈菌群体重组体出现频率平均为16.6%。本文揭示的遗传重组现象表明陇南地区条锈菌体细胞结合十分普遍,由此推测我国小麦条锈菌在自然条件下通过遗传重组而导致毒性变异的可能性。

Molecular evidence of somatic genetic recombination of Puccinia striiformis f. sp. Tritici in China

Stripe rust (or yellow rust), caused by Puccinia striiformis Westend. f. sp. tritici Eriks. , is one of the most important diseases of wheat worldwide. However, cultivars with race-specific resistance often become susceptible within a few years after their release due to the rapid evolution of new virulent races of the pathogen. For detecting the molecular evidence of somatic genetic recombination of Puccinia striiformis f. sp. tritici, population genetic diversity and variation of P. striiformis f. sp. tritici from Longnan were investigated using the SSR marker. The populations of P. striifornis f. sp. tritici possessed relatively high levels of genetic diversity but a lower genetic differentiation in Longnan of Gansu. The somatic genetic recombination of P. striiformis f. sp. tritici in Longnan was detected by 4 of 11 SSR markers. Recombinant frequency of P. striiformis f. sp. tritici was 20.0%, 18.5% , 12.8% and 15.0% detected by CPS15, CPS34, RJ20 and RJ18 respectively. The average recombinant frequency of P. striiformis f. sp. tritici was 16.6% in Longnan. This study revealed genetic recombination by molecular markers. Thus the somatic genetic recombination is another way of producing a new race of P. striiformis f. sp. tritici and lead to virulence variation.