Flores-Estévez N, Silva-Rosales L, Acosta-Gallegos J A
Department of Genetic Engineering, CINVESTAV-IPN, Apdo. Postal 629 Irapuato, Gto.36500 Mexico.
Bean Program, INIFAP Apdo. Postal 10, Chapingo, Mexico 56230.
Plant Dis. 2000 Aug;84(8):923. doi: 10.1094/PDIS.2000.84.8.923C.
Bean common mosaic necrosis virus (BCMNV) is a pathogen of Phaseolus vulgaris L. BCMNV was previously classified in serogroup A (for necrotic strains) of the Bean common mosaic virus (BCMV) subgroup; serogroup B included non-necrotic strains of BCMV. Both serogroups are currently classified as two different species in the BCMV subgroup of the Poytvirus genus; strains of either species will produce mosaic symptoms and, in the presence of hypersensitive I gene, necrosis in bean plants (1). Prior to this classification, BCMV was reported in Mexico by the presence of mosaic and necrotic symptoms (2). To investigate the presence of BCMNV in Mexico, samples were collected in two of the main bean producing states. The total extracted RNA was used for reverse transcription polymerase chain reaction using primers complementary to the middle portion of the NIa gene (5') and the 3' UTR of the NL3 Michigan isolate (accession number U19287). Two cDNA segments of 2 and 3 kb were obtained from infected plants from the state of Aguascalientes, in the highlands of central Mexico, and from the state of Veracruz, in the lowlands of the Gulf of Mexico, respectively. The cDNAs were cloned and sequenced. Alignment analysis of these sequences with the NL3 strain of BCMNV showed a similarity of 96.4 and 96.7%, respectively. The similarity between the Aguascalientes (accession number AJ01265) and Veracruz isolates was 99.6%, indicating that both are variants of the same species. On the other hand, alignment analysis of these isolates with some published BCMV strain sequences (i.e., accession numbers L15332 and U55315) displayed low similarities of 52.9 and 64.4%, respectively. These comparisons indicate that the Aguascalientes and Veracruz viral isolates belong to the BCMNV species and is the causal agent of mosaic and necrosis observed on the bean plants in those states. References: (1) C. W. Collmer et al. Mol. Plant-Microbe Interact. 9:758, 1996. (2) E. Jimenez-García. SARH. Mexico. D. F. pp: 3-4, 1994.
菜豆普通花叶坏死病毒（BCMNV）是菜豆（Phaseolus vulgaris L.）的一种病原体。BCMNV先前被归类于菜豆普通花叶病毒（BCMV）亚组的A血清群（针对坏死株系）；B血清群包括BCMV的非坏死株系。目前，这两个血清群在马铃薯Y病毒属BCMV亚组中被归类为两个不同的种；任何一个种的株系都会在菜豆植株上产生花叶症状，并且在存在过敏I基因的情况下产生坏死症状（1）。在这一分类之前，墨西哥曾有报道称出现了花叶和坏死症状（2）。为了调查墨西哥是否存在BCMNV，在两个主要的菜豆生产州采集了样本。提取的总RNA用于反转录聚合酶链反应，使用与NIa基因中部（5'）和NL3密歇根分离株（登录号U19287）的3'非翻译区互补的引物。分别从墨西哥中部高地的阿瓜斯卡连特斯州和墨西哥湾低地的韦拉克鲁斯州的受感染植株中获得了2 kb和3 kb的两个cDNA片段。对这些cDNA进行了克隆和测序。将这些序列与BCMNV的NL3株系进行比对分析，相似度分别为96.4%和96.7%。阿瓜斯卡连特斯州分离株（登录号AJ01265）和韦拉克鲁斯州分离株之间的相似度为99.6%，表明两者是同一物种的变体。另一方面，将这些分离株与一些已发表的BCMV株系序列（即登录号L15332和U55315）进行比对分析时，相似度分别较低，为52.9%和64.4%。这些比较表明，阿瓜斯卡连特斯州和韦拉克鲁斯州的病毒分离株属于BCMNV种，是在那些州的菜豆植株上观察到的花叶和坏死症状的致病因子。参考文献：（1）C. W. Collmer等人，《分子植物 - 微生物相互作用》9:758，1996年。（2）E. Jimenez - García，《墨西哥农业研究与推广局》，墨西哥城，第3 - 4页，1994年。
