Gillaspie A G, Ghabrial S A
USDA, ARS, Griffin, GA 30223.
University of Kentucky, Lexington 40546.
Plant Dis. 1998 Dec;82(12):1402. doi: 10.1094/PDIS.1998.82.12.1402A.
Plant species in the genus Desmodium (Fabaceae) are used as forage and cover crops and include a number of common weeds such as beggarweed (D. tortuosum) and beggarlice (D. intortum). Accessions of the genus are part of the plant genetic resources collection maintained at Griffin, GA. Peanut stunt cucumovirus (PSV) was detected in naturally infected plants of Desmodium sp. PI 322505 (from Brazil) in a germ plasm regeneration plot by a direct antigen coating-enzyme-linked immunosorbent assay (DAC-ELISA) with an antiserum against PSV strain ER (subgroup I) originally isolated from cowpea in Georgia. The infected plants showed mild mosaic symptoms. Indicator host studies in the greenhouse revealed symptoms characteristic of PSV on Nicotiana tabacum cv. Burley 21 (ringspots and oak leaf pattern), Chenopodium album subsp. amaranticolor (chlorotic local lesions), and Vigna unguiculata (chlorotic spots followed by systemic mild mosaic). These symptomatic indicator plants tested positive for PSV by DAC-ELISA. Greenhousegrown plants of D. incanum (kaimi-clover) and D. uncinatum (Spanish tick-clover) were inoculated with the field isolate and the plants were tested for PSV by DAC-ELISA (10 infected of 10 tested and 3 infected of 9 tested, respectively). The PSV isolate infecting Desmodium spp. was found to contain satellite RNA and it generated the predicted products in reverse transcription-polymerase chain reactions (RT-PCRs) with primers based on specific PSV-ER sequences. The RT-PCR products were confirmed by restriction-enzyme digestion (1). This is the first report of PSV naturally infecting a member of the genus Desmodium. Because some members of this genus may grow as perennial weeds near peanut, cowpea, or other host crops, this genus may serve as an alternate/overwintering host for the virus. Reference: (1) R. A. Naidu et al. Phytopathology 85:502, 1995.
山蚂蝗属（豆科）的植物物种被用作饲料和覆盖作物，其中包括一些常见杂草，如乞丐草（D. tortuosum）和虱草（D. intortum）。该属的种质资源保存在佐治亚州格里芬的植物遗传资源库中。通过直接抗原包被-酶联免疫吸附测定（DAC-ELISA），使用针对最初从佐治亚州豇豆中分离出的PSV株系ER（亚组I）的抗血清，在种质再生田中检测到花生矮化黄瓜花叶病毒（PSV）自然感染山蚂蝗属植物PI 322505（来自巴西）。受感染的植物表现出轻度花叶症状。温室中的指示寄主研究表明，烟草品种白肋21（环斑和橡树叶图案）、苋色藜（褪绿局部病斑）和豇豆（褪绿斑点，随后是系统轻度花叶）上出现了PSV特有的症状。这些有症状的指示植物通过DAC-ELISA检测PSV呈阳性。用田间分离株接种温室种植的灰叶山蚂蝗（开米三叶草）和钩状山蚂蝗（西班牙三叶草）植株，并通过DAC-ELISA检测植株是否感染PSV（分别为10株检测中有10株感染和9株检测中有3株感染）。发现感染山蚂蝗属植物的PSV分离株含有卫星RNA，并且在基于特定PSV-ER序列的引物进行的逆转录-聚合酶链反应（RT-PCR）中产生了预期产物。RT-PCR产物通过限制性酶切得到证实（1）。这是PSV自然感染山蚂蝗属植物的首次报道。由于该属的一些成员可能在花生、豇豆或其他寄主作物附近多年生杂草中生长，因此该属可能成为该病毒的替代/越冬寄主。参考文献：（1）R. A. Naidu等人，《植物病理学》85:502，1995年。
