P-263 - Tomato histone lysine methyltransferase, as a component of the COMPASS-like complex, promotes tolerance against ToLCNDV infection in tomato

Tomato leaf curl New Delhi virus (ToLCNDV) outbreak imposes a great threat to the worldwide crop production belonging to the family Solanaceae, Cucurbitaceae, Malvaceae, Fabaceae, etc. due to its rapid emergence rate of mutant strains and devastating infection efficiency with a wide host range. As a bipartite begomovirus of the family Geminiviridae, ToLCNDV infection significantly hampered tomato plant immunity with severe leaf curling, stunted growth, vein thickening, and leaf chlorosis, leading to more than 90% yield loss. In search of novel resistance sources against ToLCNDV infection, differential upregulation of candidate histone lysine methyltransferase (HKMT) in tolerant tomato variety promotes further investigation. As a component of COMPASS-like complex, candidate HKMT incorporates active histone mark on the promoter to regulate the transcriptional upregulation of defense-responsive genes at the onset of ToLCNDV infection. Virus-induced gene silencing of candidate HKMT in tolerant variety interrupts the transcriptional activation of downstream defense signaling pathways, making the plants susceptible to viral infection. This study will contribute to understanding how the reprogramming of histone signature regulates ToLCNDV-induced immune responses in tomato plants and can be incorporated into susceptible varieties to achieve robust tolerance against ToLCNDV.