甘肃省大麦条纹病病原菌致病力分化、rDNA-ITS及遗传多样性分析

Pathogenic analysis,rDNA-ITS and genetic diversity of Pyrenophora garminea in Gansu Province

为明确甘肃省大麦条纹病病原菌麦类核腔菌Pyrenophora garminea的致病力分化、r DNA-ITS序列特征及变异,采用"三明治"法测定甘肃省大麦条纹菌的致病力,通过r DNA-ITS序列分析菌株间变异类型,并对菌株进行ISSR遗传多样性分析。结果表明,共筛选到43株大麦条纹病菌,生长7 d后的菌落直径为2.60~7.93 cm,其中菌株TB生长速度最快,菌株JT生长速度最慢,强、中等和弱致病力菌株分别为2、21和20株;43株菌的核糖体DNA-ITS序列与麦类核腔菌菌株SMCD2015同源性在99%以上;在9个菌株中检测到15个变异位点,共17种变异类型;8个ISSR标记从43个菌株中扩增出41条带,平均每个标记5.13条带,90.24%片段具有多态性,遗传相似系数为0.44~1.00,平均值为0.71,当遗传相似系数为0.68时,可将供试菌株划分为4个类群。表明甘肃省大麦条纹病病原菌存在致病力分化,菌株核糖体DNA-ITS序列变异丰富,且菌株间遗传结构复杂。

In order to clarify the pathogenicity differentiation,rDNA-ITS characteristic and genetic variation of Pyrenophora graminea in Gansu Province,the pathogenicity of the P. graminea isolates collected from different regions were tested by using the ＂sandwich ＂ method, the rDNA-ITS characterization was determined and the genetic diversity was detected with ISSR markers. The results showed that colony diameters of all 43 isolates ranged from 2. 60 to 7. 93 cm after being cultured for seven days. Among all isolates,the isolate TB had the fastest growth rate,and that of isolate JT was theslowest. There were two high virulent isolates,21 moderate virulent isolates and 20 weak virulent isolates. The homology of rDNA-ITS between 43 isolates and P. graminea SMCD2015 was more than99%. Compared with the rDNA-ITS sequence of SMCD2015,15 mutation sites and 17 mutation types were detected in nine isolates. The genetic diversity was analyzed with eight ISSR markers,a total of 41 fragments were obtained. Among them,90. 24% of the fragments were polymorphic,with an average of5. 13 fragments per marker; the genetic similarity coefficient ranged from 0. 44 to 1. 00,with the average of 0. 71. Forty-three isolates were classified into four groups at a genetic similarity level of 0. 68. The results indicated that there was pathogenicity differentiation,rich variation of rDNA-ITS and complex genetic structure of P. graminea in Gansu Province.