Characterization of Rhizoctonia spp. Isolates Associated with Damping-Off Disease in Cotton and Tobacco Seedlings in Greece
Characterization of Rhizoctonia spp. Isolates Associated with Damping-Off Disease in Cotton and Tobacco Seedlings in Greece
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DOI：
10.1094/pdis-12-09-0847
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发表时间：
2010-11-01
期刊：
影响因子：
4.5
通讯作者：
Karaoglanidis, G. S.
中科院分区：
文献类型：
--
作者：
Bacharis, C.;Gouziotis, A.;Karaoglanidis, G. S.
丝核菌属 (Rhizoctonia spp.) 的分离株是在 2007 年春季从表现出猝倒病症状的患病棉花和烟草幼苗中获得的。采样田地位于希腊中部和北部的主要棉花和烟草种植区。从棉花植物中获得的 79 个分离株中，17 个是双核的，62 个是多核的，而从烟草植物中获得的 89 个分离株中，87 个是多核的，只有 2 个是双核的。使用已知 AG 组的测试分离株通过菌丝吻合反应来表征吻合组 (AG)。棉花多核分离株吻合反应显示，其中54株属于立枯丝核菌AG-4，6株属于AG-7，1株属于AG-2，1株属于AG-3。在87个烟草多核分离株中，吻合反应显示其中70个属于立枯丝核菌AG-2，16个属于AG-4，1个属于AG-5。此外，在随机选择的分离株中，使用特定核糖体 DNA 内部转录间隔区进行了分子表征。在棉花中，最常见的 AG 是 AG-4，HG-I 亚组有 18 个分离株，HG-II 亚组有 1 个分离株，HG-III 亚组有 7 个分离株，其次是 AG-7（7 个分离株）、AG-2-1（1 个分离株）和 AG-3（1 个分离株）。在烟草中，最常见的组是 AG-2-1（70 个分离株），其次是 AG-4（HG-I 亚组有 6 个分离株，HG-III 亚组有 5 个分离株）和一个属于 AG-5 的分离株。系统发育分析表明，分离株根据其 AG 类型明显分离。确定了分离株对几种宿主的致病性和攻击性。来自棉花或烟草的 AG-4 分离株对测试的宿主最具攻击性，而 AG-2-1 分离株具有中等攻击性，对大麦不具有致病性。
Isolates of Rhizoctonia spp. were obtained during the spring of 2007 from diseased cotton and tobacco seedlings showing damping-off symptoms. The sampled fields were located in the main cotton- and tobacco-cultivating regions of central and northern Greece. Among the 79 isolates obtained from cotton plants, 17 were binucleate and 62 were multinucleate whereas, among the 89 isolates obtained from tobacco plants, 87 were multinucleate and only 2 were binucleate. Characterization of anastomosis groups (AGs) was performed with hyphal anastomosis reactions using tester isolates of known AG groups. Anastomosis reactions in cotton mutlinucleate isolates showed that 54 of them belonged in Rhizoctonia solani AG-4, 6 in AG-7, 1 in AG-2, and 1 in AG-3. In the 87 tobacco multinucleate isolates, anastomosis reactions showed that 70 of them belonged in R. solani AG-2, 16 in AG-4, and 1 in AG-5. In addition, molecular characterization was carried out using the specific ribosomal DNA internal transcribed spacer region, in a randomly selected number of isolates. In cotton, the most prevalent AG was AG-4, with 18 isolates to the subgroup HG-I, 1 isolate to the subgroup HG-II, and 7 isolates to the subgroup HG-III, followed by AG-7 (7 isolates), AG-2-1 (1 isolate), and AG-3 (1 isolate). In tobacco, the most prevalent group was AG-2-1 (70 isolates), followed by AG-4 (6 isolates to the subgroup HG-I and 5 isolates to the subgroup HG-III) and a single isolate belonging to AG-5. Phylogenetic analysis showed that the isolates were distinctly separated based on their AG types. Pathogenicity and aggressiveness of the isolates to several hosts was determined. AG-4 isolates from either cotton or tobacco were the most aggressive on the hosts tested, while AG-2-1 isolates were of moderate aggressiveness and were not pathogenic on barley.