Shih S L, Tsai W S, Green S K, Hanson P M, Valand G B, Kalloo G, Shrestha S K, Joshi S
The Asian Vegetable Research and Development Center (AVRDC), Shanhua, Tainan 741, Taiwan, Republic of China.
Gujarat Agricultural University, Anand, India.
Plant Dis. 2003 May;87(5):598. doi: 10.1094/PDIS.2003.87.5.598A.
The Asian Vegetable Research and Development Center's (AVRDC) tomato breeding lines derived from Lycopersicon hirsutum f. glabratum B 6013 × L. esculentum H-24 and carrying the Ty-2 resistance gene located on chromosome 11 are tolerant to tomato leaf curl disease in Karnataka State, southern India (3), where several isolates of Tomato leaf curl Virus-Bangalore (GenBank Accession Nos. L11746, Z48182, and AF165098) and Tomato leaf curl virus-Karnataka (GenBank Accession No. U38239) are reported to infect tomatoes. The only area in south and southeast Asia where these AVRDC tomato breeding lines were found susceptible to begomovirus infection is Thailand, where several bipartite Tomato yellow leaf curl virus isolates (GenBank Accession Nos. X63015, X63016; AF141922, AF141897; and AF511529, AF511528) are reported to be prevalent. However, in field trials conducted in the fall of 1999 in Bodeli, Gujarat State, western India, the AVRDC breeding lines showed typical symptoms of begomovirus infection, such as leaf curling and vein clearing. The presence of a different tomato begomovirus was suspected. Viral DNA from a symptomatic plant from Bodeli was amplified by polymerase chain reaction (PCR) using the begomovirus-specific degenerate primer pair PAL1v1978/PAR1c715 (4) and the expected 1.4-kb PCR product was obtained. Based on the sequence of the 1.4-kb DNA product, specific primers were designed to complete the DNA-A sequence. The DNA-A of the virus associated with tomato leaf curl from Bodeli consists of 2,759 nucleotides (GenBank Accession No. AF413671) and contains six open reading frames (ORFs V1, V2, C1, C2, C3, and C4). The DNA-A sequence of the Bodeli isolate had highest sequence identities of 98 and 98.3%, respectively, with viruses causing tomato leaf curl from Varanasi, Uttar Pradesh State, northern India (GenBank Accession No. AF449999) collected in the fall of 1999 and Panchkhal, Nepal (GenBank Accession No. AY234383) collected in early 2000. There was no evidence for the presence of DNA-B in the Bodeli, Panchkhal, or Varanasi virus isolates using DNA-B specific primer pairs DNABLC1/DNABLV2 and DNABLC2/DNABLV2 (2). However, a 1.3-kb DNA-beta was detected in the Panchkhal and Varanasi isolates using the primer pair Beta01/Beta02 (1). Sequence comparisons with begomovirus sequences available in the GenBank database showed that these three virus isolates and GenBank Accession No. AY190290 collected in 2001 from Varanasi shared more than 97% sequence identity with each other and should be considered closely related strains of the same virus. These four virus isolates belong to a new distinct tomato geminivirus species because their sequences share less than 88% sequence identities with the next most closely related virus, Tomato leaf curl virus-Karnataka (GenBank Accession No. U38239). This new tomato leaf curl virus is prevalent in western India, northern India, and Nepal. References: (1) R. W. Briddon et al. Mol. Biotechnol. 20:315, 2002. (2) S. K. Green et al. Plant Dis. 85:1286, 2001. (3) V. Muniyappa et al. HortScience 37:603, 2002. (4) M. R. Rojas et al. Plant Dis. 77:340, 1993.
亚洲蔬菜研究与发展中心（AVRDC）的番茄育种系源自多毛番茄光滑变种B 6013×普通番茄H-24，携带位于11号染色体上的Ty-2抗性基因，在印度南部卡纳塔克邦对番茄卷叶病具有耐受性（3），据报道，该地区有几种番茄卷叶病毒-班加罗尔分离株（GenBank登录号L11746、Z48182和AF165098）以及番茄卷叶病毒-卡纳塔克邦分离株（GenBank登录号U38239）感染番茄。在南亚和东南亚，这些AVRDC番茄育种系唯一被发现易受双生病毒感染的地区是泰国，据报道，该国几种双分体番茄黄叶卷叶病毒分离株（GenBank登录号X63015、X63016；AF141922、AF141897；以及AF511529、AF511528）普遍存在。然而，1999年秋季在印度西部古吉拉特邦博代利进行的田间试验中，AVRDC育种系表现出双生病毒感染的典型症状，如叶片卷曲和叶脉清晰。怀疑存在一种不同的番茄双生病毒。使用双生病毒特异性简并引物对PAL1v1978/PAR1c715（4）通过聚合酶链反应（PCR）扩增了来自博代利一株有症状植株的病毒DNA，并获得了预期的1.4 kb PCR产物。基于1.4 kb DNA产物的序列，设计了特异性引物以完成DNA-A序列。与来自博代利的番茄卷叶相关病毒的DNA-A由2759个核苷酸组成（GenBank登录号AF413671），包含六个开放阅读框（ORFs V1、V2、C1、C2、C3和C4）。博代利分离株的DNA-A序列与1999年秋季在印度北部北方邦瓦拉纳西采集的导致番茄卷叶的病毒（GenBank登录号AF449999）以及2000年初在尼泊尔潘奇哈尔采集的病毒（GenBank登录号AY234383）的序列同一性分别最高，为98%和98.3%。使用DNA-B特异性引物对DNABLC1/DNABLV2和DNABLC2/DNABLV2（2），在博代利、潘奇哈尔或瓦拉纳西病毒分离株中未发现DNA-B存在的证据。然而，使用引物对Beta01/Beta02（1）在潘奇哈尔和瓦拉纳西分离株中检测到了1.3 kb的DNA-β。与GenBank数据库中可用的双生病毒序列进行的序列比较表明，这三个病毒分离株以及2001年从瓦拉纳西采集的GenBank登录号AY190290彼此之间的序列同一性超过97%，应被视为同一病毒的密切相关菌株。这四个病毒分离株属于一个新的独特番茄双生病毒物种，因为它们的序列与下一个最密切相关的病毒番茄卷叶病毒-卡纳塔克邦（GenBank登录号U38239）的序列同一性低于88%。这种新的番茄卷叶病毒在印度西部、印度北部和尼泊尔普遍存在。参考文献：（1）R. W. Briddon等人，《分子生物技术》20：315，2002年。（2）S. K. Green等人，《植物病害》85：1286，2001年。（3）V. Muniyappa等人，《园艺科学》37：603，2002年。（4）M. R. Rojas等人，《植物病害》77：340，1993年。
