Tomaso-Peterson M, Trevathan L E
Mississippi State University, Mississippi State 39762.
United States Department of Agriculture APHIS-PPQ, St. Ann, MO 63074.
Plant Dis. 2007 Mar;91(3):260-265. doi: 10.1094/PDIS-91-3-0260.
Twenty-three isolates of Rhizoctonia spp. from agronomic crops and turfgrasses were characterized by cytological and pathological methods in order to establish the identity, pathogenicity, and virulence of Rhizoctonia spp. and anastomosis groups that occur on these hosts in Mississippi. Twelve isolates were identified as R. solani, including the five anastomosis groups (AGs) AG-1-IB, AG-2-2, AG-4, AG-5, and AG-13. Rhizoctonia zeae, R. oryzae, and eight binucleate Rhizoctonia sp., including R. cerealis, also were identified. R. solani AG-4 isolates were consistently the most virulent isolates on all hosts in pathogenicity evaluations. Pathogenicity of AG-2-2 and AG-5 isolates, binucleate Rhizoctonia spp., and R. oryzae varied between hosts. Two AG-2-2 isolates from bermudagrass or wheat were determined to be clonal isolates, with numerous self-anastomosis reactions. R. solani (AG-1-IB) was pathogenic on all graminaceous hosts. R. cerealis produced sharp eyespot symptoms on wheat and corn and minimal symptoms on cotton and soybean. This is a first report of R. cerealis as a pathogen of corn. R. zeae isolates were pathogenic on all hosts, including cotton and soybean. These results indicate that a diverse group of Rhizoctonia spp. occurs as pathogens on a wide variety of agronomic crops and turfgrasses in Mississippi.
为确定密西西比州这些寄主上丝核菌属物种及其融合群的身份、致病性和毒力，采用细胞学和病理学方法对从农作物和草坪草中分离出的23株丝核菌属菌株进行了鉴定。12株菌株被鉴定为立枯丝核菌，包括5个融合群（AGs）AG-1-IB、AG-2-2、AG-4、AG-5和AG-13。还鉴定出了玉米丝核菌、稻丝核菌以及8株双核丝核菌，包括禾谷丝核菌。在致病性评估中，立枯丝核菌AG-4菌株始终是所有寄主上毒力最强的菌株。AG-2-2和AG-5菌株、双核丝核菌属以及稻丝核菌的致病性因寄主而异。从狗牙根或小麦中分离出的两株AG-2-2菌株被确定为克隆菌株，有大量的自身融合反应。立枯丝核菌（AG-1-IB）对所有禾本科寄主都有致病性。禾谷丝核菌在小麦和玉米上产生眼斑症状，在棉花和大豆上产生的症状较轻。这是关于禾谷丝核菌作为玉米病原菌的首次报道。玉米丝核菌菌株对所有寄主都有致病性，包括棉花和大豆。这些结果表明，在密西西比州，多种丝核菌属物种作为病原菌存在于各种农作物和草坪草上。
