Shih S L, Tsai W S, Green S K, Khalid S, Ahmad I, Rezaian M A, Smith J
The Asian Vegetable Research and Development Center (AVRDC), Shanhua, Tainan 741, Taiwan, R.O.C.
Crop Disease Research Institute, National Agricultural Research Centre, Islamabad, Pakistan.
Plant Dis. 2003 Feb;87(2):200. doi: 10.1094/PDIS.2003.87.2.200A.
Leaf curl or yellowing symptoms, typical of those caused by begomovirus infection, are commonly observed in chili (Capsicum annuum) and tomato (Lycopersicon esculentum) plantings in Pakistan. One chili sample with leaf curl symptoms was collected in 1998 in Multan (Punjab Province), and two tomato samples with leaf curl and yellowing symptoms were collected from Islamabad and Dargai (North West Frontier Province) in 2000 and 2001, respectively. Virus DNA was first amplified by polymerase chain reaction using the degenerate primer pair PAL1v1978/PAR1c715 (3). The expected 1.4-kb PCR products were obtained from the three samples. Based on the sequences of the 1.4-kb DNA products, specific primers were designed to complete each of the DNA-A sequences. Two primer pairs, DNABLC1/DNABLV2 and DNABLC2/DNABLV2, were used for the detection of DNA-B (2). The genome of the tomato leaf curl isolate from Islamabad contained a DNA-A of 2,739 nucleotides (GenBank Accession No. AF448059), a DNA-B of 2,728 nucleotides (GenBank Accession No. AY150304), and had 94% nucleotide identity in the common region. The genome of the tomato leaf curl isolate from Dargai contained a DNA-A of 2,740 nucleotides (GenBank Accession No. AF448058), a DNA-B of 2,686 nucleotides (GenBank Accession No. AY150305), and had 96% nucleotide identity in the common region. Each of the tomato isolates contained eight predicted open-reading frames (ORFs) (AV1, AV2, AV3, AC1, AC2, AC3, AC4, and AC5) in the DNA-A and two predicted ORFs (BV1 and BC1) in the DNA-B. The DNA-A nucleotide sequence identity of the Islamabad isolate and Dargai tomato isolate is 96% and that of DNA-B is 88%. Sequence comparisons with begomovirus sequences available in the GenBank sequence database showed that these two tomato virus isolates had the highest sequence identity with Tomato leaf curl New Delhi virus-Severe (GenBank Accession No. U15015) from northern India (more than 95% for DNA-A and less than 90% for DNA-B). The DNA-A of the virus associated with chili leaf curl from Pakistan (GenBank Accession No. AF336806) consists of 2,754 nucleotides, containing six predicted ORFs (AV1, AV2, AC1, AC2, AC3, and AC4). The chili virus was unrelated to the two tomato begomovirus isolates from Pakistan, with which it shares less than 75% nucleotide identity. Sequence comparisons show highest sequence identity (87%) with Tomato leaf curl Bangladesh virus (GenBank Accession No. AF188481). DNA-beta of 1.3 kb was detected in the chili begomovirus isolate using Beta01/Beta02 primers (1). There was no evidence for the presence of a DNA-B in the chili begomovirus isolate when tested by the two DNA-B specific primer pairs. Based on DNA sequence comparisons, the chili leaf curl virus from Pakistan, to our knowledge, constitutes a distinct, new monopartite begomovirus. References: (1) R. W. Briddon et al. Mol. Biotechnol. 20:315, 2002. (2) S. K. Green et al. Plant Dis. 85:1286, 2001. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993.
在巴基斯坦的辣椒（辣椒属）和番茄（番茄属）种植中，常见叶片卷曲或黄化症状，这是由双生病毒感染引起的典型症状。1998年在木尔坦（旁遮普省）采集了一个有叶片卷曲症状的辣椒样本，2000年和2001年分别从伊斯兰堡和达盖伊（西北边境省）采集了两个有叶片卷曲和黄化症状的番茄样本。首先使用简并引物对PAL1v1978/PAR1c715通过聚合酶链反应扩增病毒DNA（3）。从这三个样本中获得了预期的1.4kb PCR产物。根据1.4kb DNA产物的序列，设计了特异性引物以完成每个DNA - A序列。使用两对引物DNABLC1/DNABLV2和DNABLC2/DNABLV2检测DNA - B（2）。来自伊斯兰堡的番茄卷叶分离株的基因组包含一个2739个核苷酸的DNA - A（GenBank登录号AF448059），一个2728个核苷酸的DNA - B（GenBank登录号AY150304），并且在共同区域具有94%的核苷酸同一性。来自达盖伊的番茄卷叶分离株的基因组包含一个2740个核苷酸的DNA - A（GenBank登录号AF448058），一个2686个核苷酸的DNA - B（GenBank登录号AY150305），并且在共同区域具有96%的核苷酸同一性。每个番茄分离株在DNA - A中包含八个预测的开放阅读框（ORF）（AV1、AV2、AV3、AC1、AC2、AC3、AC4和AC5），在DNA - B中包含两个预测的ORF（BV1和BC1）。伊斯兰堡分离株和达盖伊番茄分离株的DNA - A核苷酸序列同一性为96%，DNA - B的为88%。与GenBank序列数据库中可用的双生病毒序列进行序列比较表明，这两个番茄病毒分离株与来自印度北部 的番茄卷叶新德里病毒 - 严重株（GenBank登录号U15015）具有最高的序列同一性（DNA - A超过95%，DNA - B小于90%）。与巴基斯坦辣椒卷叶相关的病毒的DNA - A（GenBank登录号AF336806）由2754个核苷酸组成，包含六个预测的ORF（AV1、AV2、AC1、AC2、AC3和AC4）。该辣椒病毒与来自巴基斯坦的两个番茄双生病毒分离株无关，与它们的核苷酸同一性小于75%。序列比较显示与番茄卷叶孟加拉病毒（GenBank登录号AF188481）具有最高的序列同一性（87%）。使用Beta01/Beta02引物在辣椒双生病毒分离株中检测到1.3kb的DNA - beta（1）。当用两对DNA - B特异性引物进行检测时，在辣椒双生病毒分离株中没有证据表明存在DNA - B。据我们所知，基于DNA序列比较，来自巴基斯坦的辣椒卷叶病毒构成了一种独特的新的单分体双生病毒。参考文献：（1）R.W.布里登等人，《分子生物技术》20：315，2002年。（2）S.K.格林等人，《植物病害》85：1286，2001年。（3）M.R.罗哈斯等人，《植物病害》77：340，1993年。
