四川省阿坝州小麦条锈菌遗传多样性分析

对阿坝及其周边地区条锈病菌生理小种和AFLP多态性进行了研究.49个参试菌株条锈病菌生理小种分为2种类型:水源11致病类群类型和Hybrid46致病类群,分别占44.9 %和55.1 %,其中水-14和CY32为优势小种.CY31仅在黑水县检测到,云南盐津菌株CY32比例显著高于其他采样点.利用E2M3、E4M3、E7M3、E2M4、E6M4、E4M6、E6M7等7个引物组合,对各菌株基因组DNA进行扩增出,共扩增出168条可统计的条带,其中多态性条带为32条,多态率为19.05 %.49个样品AFLP的Dice相似系数范围为:0.4063~1.0,其中阿坝州菌株聚类分析后被分作A、B两组,后者在相似系数0.7814水平上又分为两个亚组.松潘县的菌株中,4个菌株属于A组,9个菌株属于B组第一亚组,6个菌株属于第二亚组.来自黑水县和九寨沟县的菌株均属B组的第二亚组.第二亚组遍及阿坝州各采样点.来自凉山州普格县的菌株与阿坝州的菌株的遗传相似性很低,在相似系数0.73水平时归入C组.但在阿坝和凉山分别个测出1个菌株,与区内其它菌株均不相似,但彼此间相似系数为0.7813;可见四川条锈病菌阿坝群体独立于梁山州群体,但又有一定的联系.来自云南盐津的条锈病菌根据AFLP多态性被划成B组的第三亚组,与普格县菌株相差较大而与阿坝州菌株更相似,其来源尚有待进一步研究.在同一块田中,条锈病菌的组成可以相差很大,遗传相似系数为1.0的菌株一块田内发现两株.松潘青云乡至川主寺沿公路晒场、院坝子上自生麦苗上菌株在不同采样点间病菌也有差别.未发现生理小种和AFLP性之间的关联性.以CY32为例,其AFLP多态性十分明显,菌株分属A、B1、B2、B3等不同类型.表明病菌毒性突变可以在不同遗传背景的菌株中发生,新小种的发生可能不是由1个突变克隆不断繁殖扩大而来.

Population Structure of Puccinia striiformis f. sp. tritici in Aba of Sichuan

Totally 49 isolatyes were collected form the Aba and neighbouring areas in Sichuan and Yunnan province. Physiologic races and virulent types fell into two groups which were respectively virulent to Suweon 11 (22.9 %) and Hybrid 46 (55.1 %), with the most frequent ones to be Su-14 and CY32. The results indicated, to a certain degree, the heterogenecity of the fungal population in the different areas. For example, Race CY31 was only detected in Heishui County of Aba whereas the frequency of Race CY32 at Miaoba in Yanjing County of Yunnan Province was significantly higher than that at other sampling sites. AFLP analysis was applied to study the genetic structure of the yellow rust fungus. 7 out of 64 primer combinations, namely E2M3, E4M3, E7M3, E2M4, E6M4, E4M6, and E6M7 yielded length polymorphes of the amplified fragments. Totally 168 distinguisable bands were amplified by such 7 primer combinations, of which 32 bands were polymorhic. The rates of the polymorphic bands were 19.05 %. The Dice similarity coefficent of AFLP of 49 tested isolated ranged from 0.4063 to 1.0. At the similarity level of 0.73, all the tested isolated fell into 4 groups: Group A, B, C and D. The members in the Groups B could further differentiated into 3 subgoups at the similarily level of 0.7814: B1, B2 and B3. Isolates from Songpan County in Aba area were more polymorphic: 4 isolates from Songpan fell into Group A, 9 in B1 and 6 in B2. 13 out of 14 isolates from Heishui Countyand and all of the 3 isolates from Jiuzhai Gou County belonged to Subgroup B2. The majority isolates from Puge County in Liangshan area were different from those from Aba. 6 out of 7 Puge isolated belonged to Group C. There were two isolates in Group D: Isolates 28 and 49, wichh were respectively from Heishui and Puge, with a similarity coefficient at 0.7813. So the population of the yellow rust in Aba was indenpendent of that in Liangshan but genetic exchanges were possible between two populations. All the isolates from Yanjin County of Ynnan fell into a distinguished subgroup B3, which were more closer to isolates from Aba areas than the neibouring Liangshan area.