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Domain-based interactions between a kinase of Gossypium hirsutum and a protein encoded by a betasatellite associated with Cotton leaf curl virus

Hanumantha Pappu: Department of Plant Pathology, Washington State University

<div>Geminiviruses infect several economically important crops that include cassava, corn, cotton, and tomato. Cotton leaf curl disease (CLCuD) is one of the major limiting factors for cotton production in Pakistan, caused by begomoviruses belonging to family <em>Geminiviridae</em>. CLCuD is predominantly caused by a complex that includes <em>Cotton leaf curl</em> <em>Kokhran virus-</em>Burewala (CLCuKoV-Bu) and a beta satellite molecule βC1 known as pathogenicity determinant. Yeast two hybrid assay (Y2H) was used to find cotton plant (<em>Gossypium hirsutum)</em> proteins interacting with βC1 protein. In Y2H, <em>G. hirsutum</em> SNF1-related kinase (GhSNF1), a key enzyme in energy metabolism and protection of plants against abiotic stresses, was found to interact with βC1. <em>In-silico</em> study predicted four domains in GhSNF1, namely Conserved <u>k</u>inase <u>d</u>omain (KD), <u>Ub</u>iquitin <u>a</u>ssociated domain (UBA), <u>A</u>uto<u>i</u>nhibitory <u>s</u>equence domain and <u>C</u>-<u>t</u>erminal <u>d</u>omain. Among these, the UBA domain preferentially interacted with the βC1 protein. Y2H confirmed the computational predictions that the UBA domain among all of the domains helps GhSNF to interact with βC1 and further supports CLCuD to spread and cause infection. Furthermore, to study the in vivo protein-protein interaction of βC1 and GhSNF1, full length genes and domain based mutants were cloned for studying bimolecular fluorescence complementation system and pull-down assay. These studies contributed to better understand the virus-host interactions at the molecular level.</div>