Mishra Megha, Verma Rakesh Kumar, Marwal Avinash, Sharma Pradeep, Gaur R K
Department of Biosciences, School of Liberal Arts and Sciences, Mody University of Science and Technology, Sikar, India.
Department of Biotechnology, Mohanlal Sukhadia University, Udaipur, India.
Front Microbiol. 2020 Oct 7;11:512957. doi: 10.3389/fmicb.2020.512957. eCollection 2020.
Chili ( L.) is an important vegetable and spice crop of tropical and sub-tropical regions. Chili plants showing upward leaf curling, leaf crinkling, and leaf yellowing symptoms, collected from Sikar district of Rajasthan, India, were found to be associated with begomovirus and satellite molecules. The presence of virus was confirmed by PCR using virus-specific primer. The full-length genomic DNA-A of three begomovirus (MM-1, CS-1 and RV-1) and two satellites (MM-2 and MM-3) were cloned which was identified from single symptomatic chili plant. The genome organization of isolated three viruses is similar to those of other Old World monopartite begomoviruses. The comparison of the sequences and closest phylogenetic relationships for the begomoviruses, betasatellite and alphasatellite DNAs revealed that MM-1 was designated as DNA-A of (ChiLCV), CS-1 is considered to be a new distinct species of (ToLCGV) whereas RV-1 as a new strain of (CLCuMuV). The DNA-A component of ChiLCV showed 8.6%, ToLCGV of 16.6% and CLCuMuV of 7.7% average evolutionary divergence, concomitantly, the betasatellite and alphasatellite molecule had 9.9% and 5.9% overall sequence divergence, respectively. Interestingly, most of the begomoviruses were found to be intra-species recombinants. The dN/dS ratio and Tajima value of all viral DNA-A component and their associated betasatellite showed their selective control on evolutionary relationships. The nucleotide substitution rates were determined for the DNA-A genomes of ChiLCV (7.22 × 10 substitutions site year), CLCuMuV (1.49 × 10 substitutions site year), ToLCGV (7.47 × 10 substitutions site year), the genome of associated ChiLCB (4.20 × 10 substitutions site year) and CLCuMuA (1.49 × 10 substitutions site year). Agro-inoculation studies indicate that the presence of DNA betasatellite induce severe symptoms in and chili, suggesting prerequisite association for typical disease development.
辣椒（L.）是热带和亚热带地区一种重要的蔬菜和香料作物。从印度拉贾斯坦邦锡卡尔地区采集的表现出叶片向上卷曲、皱缩和发黄症状的辣椒植株，被发现与双生病毒和卫星分子有关。使用病毒特异性引物通过聚合酶链反应（PCR）证实了病毒的存在。从一株有症状的辣椒植株中克隆出了三种双生病毒（MM - 1、CS - 1和RV - 1）以及两种卫星分子（MM - 2和MM - 3）的全长基因组DNA - A。分离出的三种病毒的基因组结构与其他旧世界单分体双生病毒相似。对双生病毒、β卫星和α卫星DNA的序列比较及最近的系统发育关系显示，MM - 1被指定为辣椒轻斑驳病毒（ChiLCV）的DNA - A，CS - 1被认为是番茄黄化曲叶病毒（ToLCGV）的一个新的不同种，而RV - 1是棉花曲叶多芽病毒（CLCuMuV）的一个新毒株。辣椒轻斑驳病毒的DNA - A组分显示平均进化分歧为8.6%，番茄黄化曲叶病毒为16.6%，棉花曲叶多芽病毒为7.7%，同时，β卫星和α卫星分子的总体序列分歧分别为9.9%和5.9%。有趣的是，大多数双生病毒被发现是种内重组体。所有病毒DNA - A组分及其相关β卫星的dN/dS比值和 Tajima 值显示了它们对进化关系的选择性控制。测定了辣椒轻斑驳病毒（7.22×10代换位点⁻¹年⁻¹）、棉花曲叶多芽病毒（1.49×10代换位点⁻¹年⁻¹）、番茄黄化曲叶病毒（7.47×10代换位点⁻¹年⁻¹）的DNA - A基因组，以及相关的辣椒轻斑驳β卫星（ChiLCB，4.20×10代换位点⁻¹年⁻¹）和棉花曲叶多芽α卫星（CLCuMuA，1.49×10代换位点⁻¹年⁻¹）的核苷酸替换率。农杆菌接种研究表明，DNAβ卫星的存在会在烟草和辣椒中引发严重症状，表明其对于典型病害发展存在必要关联。
