西南地区玉米纹枯病病菌融合群鉴定和UP-PCR分析
Population structure of Rhizoctonia spp. isolated from maize in southwestern China and UP-PCR analysis

为明确西南地区玉米纹枯病病菌组成结构,从西南地区(四川、贵州、云南和重庆)玉米纹枯病样上分离获得285个疑似丝核菌菌株,根据培养性状、菌丝形态和细胞核染色对其进行鉴定,通过载玻片配对培养法对鉴定出的菌株进行菌丝融合群鉴定,并采用UP-PCR方法从各融合群中选取代表性菌株进行遗传变异分析。结果显示,供试疑似菌株中共鉴定出253个丝核菌,分别为224株立枯丝核菌Rhizoctonia solani 和29株玉蜀黍丝核菌R. zeae。立枯丝核菌包括5个融合群,其中AG1-ⅠA共201株,出现频率为79.4%;AG1-ⅠB共2株,出现频率为0.8%;AG2-2ⅢB共3株,出现频率为1.2%; AG4-HGⅠ共10株,出现频率为3.9%;AG-5共8株,出现频率为3.2%。29株玉蜀黍丝核菌融合群均为WAG-Z,出现频率为11.5%。遗传变异分析中,当相似系数为0.78时,按照出现频率从立枯丝核菌和玉蜀黍丝核菌选取的不同融合群的20株菌株被划分为6个类群,与菌丝融合分析结果完全吻合,其中AG2-2ⅢB融合群首次从西南地区玉米上分离到。
In order to identify the composition structure of Rhizoctonia spp. from maize in southwestern China, 285 suspected isolates of diseased samples were collected from Sichuan, Guizhou, Yunnan and Chongqing. Based on cultural traits, colonial morphology and the number of nucleuses, the isolates were identified. Furthermore, anastomosis groups were investigated through the slide cell culture method; in addition, the genetic variation was analyzed by using the representative strains from different anastomosis groups with universally primed PCR (UP-PCR). In total, 253 isolates were identified as Rhizoctonia spp., among which 224 isolates were Rhizoctonia solani and 29 isolates belonged to Rhizoctonia zeae. The isolates of R. solani included five anastomosis groups (AG):AG1-ⅠA (201 isolates, accounting for 79.4%), AG1-ⅠB (2, 0.8%), AG2-2ⅢB (3, 1.2%), AG4-HGⅠ (10, 3.9%) and AG-5 (8, 3.2%). The all 29 isolates of R. zeae belonged to WAG-Z (11.5%). In the genetic variation study, the 20 representative isolates from R. solani and R. zeae were divided into six groups and the similarity coefficient was 0.78, which was completely consistent with the result of anastomosis group analysis. Moreover, AG2-2ⅢB was firstly found in maize in southwestern China.