Tomato leaf curl disease (ToLCD) is manifested by yellowing of leaf lamina with upward leaf curl, leaf distortion, shrinking of the leaf surface, and stunted plant growth caused by tomato leaf curl virus (ToLCV). In the present study, using computational methods we explored the evolutionary and molecular prospects of viral coat protein derived from an isolate of Vadodara district, Gujarat (ToLCGV-[Vad]), India. We found that the amino acids in coat protein required for systemic infection, viral particle formation, and insect transmission to host cells were conserved amongst Indian strains. Phylogenetic studies on Indian ToLCV coat proteins showed evolutionary compatibility with other viral taxa. Modeling of coat protein revealed a topology similar to characteristic Geminate viral particle consisting of antiparallel β-barrel motif with N-terminus α-helix. The molecular interaction of coat protein with the viral DNA required for encapsidation and nuclear shuttling was investigated through sequence- and structure-based approaches. We further emphasized the role of loops in coat protein structure as molecular recognition interface. 1. Introduction Tomato leaf curl virus (ToLCV) is one of the most devastating causal agents of tomato (Solanum lycopersicum) crop which had emerged causing damage and encroaching new areas in tropical and subtropical continents every year. Plant-infecting geminiviruses belong to the family Geminiviridae in which Begomovirus is one among the genera possessing both mono- and bipartite genomes that infect especially dicotyledonous plant species [1]. The disease is marked by symptoms such as yellowing of leaf lamina with upward leaf curl as well as distortion, reduction in internodes, new leaves size reduction, wrinkle facade, stunted growth, and dissemination of flower from plant before onset of fruiting. ToLCV is primarily transmitted by sweet potato whitefly (Bemisia tabaci) and silver leaf whitefly (also called Biotype B; Bemisia argentifolii). Whiteflies harboring virus can nonspecifically infect a wide spectrum of plant crops and weeds including eggplant, potato, tobacco, pepper, and common bean. Infected plants seem healthy but develop symptoms leading to enormous economic loss [2]. In Indian subcontinent, ToLCV is a major problem for tomato-growing regions as several reports on new strains have been documented including New Delhi, Lucknow, Bangalore, Varanasi, Mirzapur, Vadodara, and so forth and posed a threat to crop productivity [6]. Indian ToLCV isolates are mostly monopartite (DNA-A) in nature with few isolates
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