Research Projects

Tomato Leaf Curl New Delhi Virus (ToLCNDV), a whitefly-transmitted ssDNA begomovirus, causes severe yield losses (up to 100%) in tomato and cucurbit crops. It suppresses host immunity via multiple viral effectors but lacks any known genetic resistance in key crops. One underexplored plant defense mechanism is autophagy, a conserved degradation pathway that recycles damaged organelles and can eliminate viral components. However, whether autophagy restricts ToLCNDV (as antiviral) or is manipulated by the virus to aid infection (as proviral) remains unknown. Importantly, plant autophagy is tightly regulated by circadian rhythms and metabolic signals. The plant circadian clock, which governs gene expression over a 24-hour cycle, is known to control immunity under pathogenic infestations. Viral infections impose high metabolic burden and require hijacking of host systems for replication. The timing of defense responses, including autophagy, may therefore determine whether infection is restricted or facilitated. This project hypothesizes that host circadian regulation of autophagy will inhibit the ToLCNDV by repressing viral (any or more) protein. Yet, no studies have addressed the role of biological timing or energy gating in plant virus pathogenesis. This proposal tests the hypothesis that circadian rhythms coordinate autophagy to influence ToLCNDV infection outcomes. The study is structured around three core objectives: • To explore the functional role of autophagy in plant defense against Tomato Leaf Curl Virus (ToLCNDV) • To characterize how ToLCNDV-encoded viral proteins interact with and influence the host autophagy machinery • To unravel the regulatory interplay between circadian clock components and sugar signaling pathways in modulating autophagy during ToLCNDV infection Experiments for obj 1: Proteome analysis, GFP-ATG8e reporter lines, atg-mutants, confocal microscopy, qPCR, ATG gene expression, ATG8 lipidation. Experiments for obj 2: Transient expression of viral ORFs (AC1–AC4, AV1–AV2, BC1, BV1), GFP-ATG8e imaging, autophagy flux assays, Co-immunoprecipitation. Experiments for obj 3: Clock and sugar mutants (toc1, cca1, gi, snrk1, hxk1), diel expression profiling, sugar feeding, confocal microscopy during infection. By dissecting how ToLCNDV interacts with the host autophagy machinery and how this process is influenced by circadian and sugar signaling, this project aims to identify key viral effectors, temporal checkpoints, and metabolic regulators of defense. These findings will pave the way for time-optimized, energy-efficient antiviral strategies. The outcomes will support the development of non-transgenic, climate-resilient crop protection tools, empowering farmers with sustainable solutions against ToLCNDV and similar emerging viral threats, thus contributing to global goals of Zero Hunger (SDG 2) and Climate Action (SDG 13).