江苏省稻瘟病菌致病力分化及无毒基因组成分析

Pathogenicity differentiation and composition analysis of avirulence genes of Magnaporthe oryzae in Jiangsu province

针对2013-2017年从江苏省采集标样并分离得到的共计621个稻瘟病菌[Magnaporthe oryzae (Hebert)Barr]单孢菌株,利用10对稻瘟病菌无毒基因(ACE1、PWL1、Avr-Pita、Avr1-CO39、Avr-Pizt、Avr-Pib、Avr-Pia、Avr-Pii、Avr-Pik、Avr-Pi9)特异性引物进行扩增,分析江苏省稻瘟病菌无毒基因的分布及频率。结果表明:上述10个无毒基因在江苏省均有分布,但出现频率不同,其中平均扩增频率最高的为Avr-Pib,达到74. 56%,最低的是Avr-Pia,只有9. 34%。Avr-Pib、Avr-Pik、Avr-Pizt连续5年扩增频率较高且稳定遗传。此外,采用日本清泽鉴别品种对稻瘟病菌供试菌株进行致病力测定,结果表明供试菌株对Pi-zt、Pi-z、Pi-ta、Pi-ta2、Pi-i表现为弱毒力。综上所述,江苏省稻瘟病菌群体组成较为复杂,且存在较大易变性;无毒基因的分布存在较大差异,且与地理区域密切相关。

In this study,10 pairs of specific primers of avirulence genes( ACE1,PWL1,AvrP i-ta,Avr1-CO39,AvrPizt,Avr-Pib,Avr-Pia,Avr-Pii,Avr-Pik and Avr-Pi9) in a total of 621 single spore strains of Magnaporthe oryzae [Magnaporthe oryzae( Hebert) Barr] isolated from Jiangsu province during 2013-2017 were used to analyze the distribution and frequency of avirulence genes. The PCR results showed that the above 10 avirulence genes were distributed in M. oryzae strains of Jiangsu province,but the frequency of occurrence was different. Among them,Avr-Pib and Avr-Pia showed the highest and lowest frequency( 74.56% and 9.34%,respectively),Avr-Pib,Avr-Pik and Avr-Pizt had high frequency of amplification and stable heritability for five consecutive years. In addition,the pathogenicity of the M. oryzae was evaluated by using Kiyosawa’ s differential varieties( KDV). The results revealed that the tested stains showed weak virulence against Pizt,Pi-z,Pi-ta,Pi-ta2,Pi-i. In summary,the population composition of M. oryzae in Jiangsu province is relatively complex,and it comes instable. The distribution of avr-genes is quite different and closely related to the geographical area.