Gámez-Jiménez C, Romero-Romero J L, Santos-Cervantes M E, Leyva-López N E, Méndez-Lozano J
CIIDIR-IPN, Unidad Sinaloa, Juan de Dios Bátiz Paredes 250, Guasave, Sinaloa, México CP 81101.
Plant Dis. 2009 May;93(5):545. doi: 10.1094/PDIS-93-5-0545A.
Tomatillo, also known as husk or green tomato, is cultivated in 29 of 32 states in Mexico, with the main production areas located in the states of Sinaloa, Michoacán, Puebla, Sonora, Guanajuato, Jalisco, and Hidalgo. The national production of tomatillo in 2006 was 805,721 tons with a value of $259 million. Tomato yellow leaf curl virus (TYLCV) is one of the most damaging begomoviruses affecting tomato worldwide. TYLCV was first identified in Mexico in 1999 in Yucatán (1) and most recently identified as infecting tomato in Sinaloa (3). During December of 2006, symptoms including chlorotic margins, yellowing, and interveinal yellowing were observed in tomatillo fields. Symptomatic plants were associated with the presence of whiteflies in many fields, suggesting a begomovirus etiology. Total DNA was extracted from leaves of 77 symptomatic tomatillo plants from Guasave and Ahome counties and amplified by PCR using a degenerate primer pair (2). These primers can differentiate between monopartite and bipartite begomoviruses on the basis of the size of the amplification products, approximately 750 and 650 bp, respectively. A PCR product of 742 bp was obtained from 48 of 97 samples. The PCR product of two representative samples from each county were cloned into pGEM-T Easy Vector (Promega, Madison, WI) and sequenced. The sequences of the four amplicons were identical (GenBank Accession No. EU224314) and were compared with sequences of others begomoviruses in the NCBI/GenBank database using the Clustal V alignment method (MegAlign, DNASTAR software, London). The highest sequence identity of 100% was with a TYLCV isolate from Sinaloa (GenBank Accession No. DQ377367), 99.8% with a TYLCV isolate from Tosa (GenBank Accession No. AB192965), 98.4% with a TYLCV isolate from China (GenBank Accession No. AM282874), 95.8% with a TYLCV isolate from Yucatán (GenBank Accession No. AF168709), and 94.6% with TYLCV-Is (GenBank Accession No. X15656). The genome of tomatillo TYLCV isolate was amplified using PCR and overlapping primer pair (TYLCV NcoI Forward GGCCCATGGCCGCGCAGCGG and Reverse CGGCCATGGAGACCCATAAG). Sequence of a 2,781-bp fragment was obtained (GenBank Accession No. FJ609655) and sequence analysis corroborated that the tomatillo TYLCV has 99.3% identity with two TYLCV isolates from Sinaloa (GenBank Accession Nos. EF5234478 and FJ012358). To our knowledge, this is the first report of tomatillo as a natural host of TYLCV in Mexico. These results suggest that TYLCV has begun to establish itself in others crops since it was first reported to be infecting tomato in Sinaloa, Mexico. References: (1) J. T. Ascencio-Ibañez et al. Plant Dis. 83:1178, 1999. (2) J. T. Ascencio-Ibañez et al. Plant Dis. 86:692, 2002. (3) C. Gámez-Jímenez et al. (Abstr.) Phytopathology 96(suppl.):S38. 2006.
墨西哥酸浆，也被称为带壳酸浆或绿番茄，在墨西哥32个州中的29个州均有种植，主要产区位于锡那罗亚州、米却肯州、普埃布拉州、索诺拉州、瓜纳华托州、哈利斯科州和伊达尔戈州。2006年墨西哥酸浆的全国产量为805,721吨，价值2.59亿美元。番茄黄化曲叶病毒（TYLCV）是全球影响番茄的最具破坏性的双生病毒之一。TYLCV于1999年在墨西哥尤卡坦首次被发现（1），最近在锡那罗亚州被确定感染番茄（3）。2006年12月，在墨西哥酸浆田中观察到包括叶缘褪绿、黄化和脉间黄化等症状。在许多田地中，有症状的植株与粉虱的存在有关，这表明病因是双生病毒。从瓜萨韦和阿霍梅县的77株有症状的墨西哥酸浆植株的叶片中提取总DNA，并使用一对简并引物通过PCR进行扩增（2）。这些引物可以根据扩增产物的大小区分单分体和双分体双生病毒，扩增产物大小分别约为750 bp和650 bp。从97个样本中的48个获得了742 bp的PCR产物。来自每个县的两个代表性样本的PCR产物被克隆到pGEM-T Easy载体（普洛麦格公司，威斯康星州麦迪逊）中并进行测序。四个扩增子的序列相同（GenBank登录号EU224314），并使用Clustal V比对方法（MegAlign，DNASTAR软件，伦敦）与NCBI/GenBank数据库中其他双生病毒的序列进行比较。与来自锡那罗亚州的TYLCV分离株（GenBank登录号DQ377367）的最高序列同一性为100%，与来自土佐的TYLCV分离株（GenBank登录号AB192965）为99.8%，与来自中国的TYLCV分离株（GenBank登录号AM282874）为98.4%，与来自尤卡坦的TYLCV分离株（GenBank登录号AF168709）为95.8%，与TYLCV-Is（GenBank登录号Xl5656）为94.6%。使用PCR和重叠引物对（TYLCV NcoI正向引物GGCCCATGGCCGCGCAGCGG和反向引物CGGCCATGGAGACCCATAAG）扩增墨西哥酸浆TYLCV分离株的基因组。获得了一个2,781 bp片段的序列（GenBank登录号FJ609655），序列分析证实墨西哥酸浆TYLCV与来自锡那罗亚州的两个TYLCV分离株（GenBank登录号EF5234478和FJ012358）具有99.3%的同一性。据我们所知，这是墨西哥酸浆作为TYLCV在墨西哥的天然寄主的首次报道。这些结果表明，自首次报道TYLCV在墨西哥锡那罗亚州感染番茄以来，它已开始在其他作物中定殖。参考文献：（1）J. T. Ascencio-Ibañez等人，《植物病害》83:1178，1999年。（2）J. T. Ascencio-Ibañez等人，《植物病害》86:692，2002年。（3）C. Gámez-Jímenez等人（摘要），《植物病理学》96（增刊）：S38，2006年。
