稻瘟病菌无毒基因AvrPi9在2个病圃中的动态变化

Dynamic Change of Avirulence Avr Pi9 of Magnaporthe oryzae in Two Rice Blast Nurseries

为了评估水稻抗稻瘟病基因Pi9在生产上的应用前景,采用接种鉴定和PCR检测分析了2012年至2014年从云南省罗平县和腾冲县2个病圃内感病品种丽江新团黑谷的396个稻瘟病菌单胞菌株的无毒基因Avr Pi9动态变化。结果表明:Avr Pi9在此两病圃所采集菌株中出现的频率虽均高达90%以上,但有逐年下降的趋势。抗病基因Pi9仍有应用前景,特别是与抗病基因Pi zt、Pi7、Pi12联合应用,联合抗病系数都达0.81以上。然而,在PCR检测到的388个Avr Pi9菌株中,21个含有该基因片段,但仍对Pi9基因品系IRBL22有致病性,Avr Pi9基因可能正在发生结构变化。

In order to evaluate the application potential of the rice resistance gene Pi9 in practical production,the dynamic changes of avirulence gene Avr Pi9 of 396 Magnaporthe oryzae single-spore isolates collected from‘LTH＇in Luoping County and Tengchong County of Yunnan Province from 2012 to 2014 were analyzed byartificial inoculation and PCR test. The results showed that the Avr Pi9 frequency of the isolates reached morethan 90% in the three years even with a declining trend, indicating that the resistance gene Pi9 could still beuseful in the future, especially combined with the resistance genes Pizt, Pi7 and Pi12, and the resistanceassociation coefficients were all higher than 0.81. However, PCR amplification showed that 388 isolates carriedAvr Pi9 gene, among them 21 isolates contained the gene fragments but were still pathogenic to‘IRBL22＇of Pi9 gene line, it implied the structure of Avr Pi9 might be changing.