Bacharis C, Gouziotis A, Kalogeropoulou P, Koutita O, Tzavella-Klonari K, Karaoglanidis G S
Aristotelian University of Thessaloniki, Faculty of Agriculture, Plant Pathology Laboratory, Thessaloniki, Greece.
Plant Breeding Department of Hellenic Sugar Industry S.A., Thessaloniki, Greece.
Plant Dis. 2010 Nov;94(11):1314-1322. doi: 10.1094/PDIS-12-09-0847.
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.
2007年春季，从表现出猝倒症状的患病棉花和烟草幼苗中分离出丝核菌属菌株。采样田地位于希腊中部和北部的主要棉花和烟草种植区。从棉花植株中获得的79个分离株中，17个是双核的，62个是多核的；而从烟草植株中获得的89个分离株中，87个是多核的，只有2个是双核的。使用已知融合群（AG）组的测试菌株，通过菌丝融合反应对融合群进行鉴定。棉花多核分离株的融合反应表明，其中54个属于立枯丝核菌AG-4，6个属于AG-7，1个属于AG-2，1个属于AG-3。在87个烟草多核分离株中，融合反应表明，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，对随机选择的一些分离株使用特定的核糖体DNA内部转录间隔区进行分子鉴定。在棉花中，最常见的AG是AG-4，其中18个分离株属于HG-I亚组，1个分离株属于HG-II亚组，7个分离株属于HG-III亚组，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（6个分离株属于HG-I亚组，5个分离株属于HG-III亚组）和1个属于AG-5的分离株。系统发育分析表明这些分离株根据其AG类型明显分开。测定了这些分离株对几种寄主的致病性和侵袭性。来自棉花或烟草的AG-4分离株对所测试的寄主侵袭性最强，而AG-2-1分离株侵袭性中等，对大麦无致病性。
