Molecular characterization of chilli leaf curl Ahmedabad virus: homology modelling and evaluation of viral proteins interacting with host protein SnRK1 and docking against flavonoids-an in silico approach.

Chilli leaf curl Ahmedabad virus (ChiLCAV), a begomovirus belonging to the family Geminiviridae, has been reported for its occurrence in India, infecting chilli and tomato plants. The viral proteins associated with ChiLCAV involves in the primary pathogenesis and transmission of the virus by whitefly. Viral protein interactions with host proteins show the dynamics of structural binding and interaction in their infection cycle. At the same time, plants have multiple defence mechanisms against bacterial and viral infections. Secondary metabolites play a significant role in the inborne defence mechanism of plants. Host proteins are also the prime producers of secondary metabolites. In the present study, we evaluated the host protein SnRK1 interaction with all six viral proteins (V1, V2, C1, C2, C3 and C4). Apart from C4, all the other viral proteins showed appreciable binding and interaction with SnRK1. SnRK1 has the regulation mechanism for the accumulation of diterpenoids, secondary metabolites. Flavonoids are secondary metabolites produced by the plant under stress conditions. Further, we studied the binding and interaction of six selected flavonoids produced by Solanaceae family members with all the ChiLCAV proteins. All six selected flavonoids showed considerable binding energy with all viral proteins. Each flavonoid showed high binding energy with different viral proteins. Molecular docking is carried out for both flavonoids and the host protein SnRK1. These in silico interactions and docking studies could be useful for understanding the plants defence mechanism against viral infections at the molecular level.