Potato Virus Y Coat Protein Interacts With Cytosolic Phosphoglucomutase and Reprogrammes Host Primary Metabolism During Disease Development.

Abstract

Potato virus Y (PVY) is one of the top five economically important plant viruses in the world that affects several plant species including potato, pepper and tomato. We have combined untargeted metabolomics with protein-protein interaction studies to understand the mechanistic details of PVY-induced metabolic changes that lead to disease development. For this purpose, PVY necrotic strain, PVYNTN, and Nicotiana benthamiana were used as a model system. Gas chromatography-mass spectrometry (GC-MS)-based metabolomic profiling revealed that PVY infection significantly alters carbohydrate and amino acid metabolism, with elevated levels of glucose-6-phosphate, fructose-6-phosphate and key amino acids associated with nucleotide biosynthesis. Using yeast two-hybrid, bimolecular fluorescence complementation and GST pull-down assays, we identified a direct interaction between the PVY coat protein (CP) and cytosolic phosphoglucomutase (cPGM), a central enzyme regulating cytosolic sugar-phosphate partitioning among different pathways. Subcellular localization analyses showed that PVY CP localizes to the cytosol, forms aggregates and alters cPGM distribution, recruiting it into CP-associated cytosolic aggregates. Silencing of cPGM restricted PVY accumulation and disease development, indicating that cPGM is required for efficient PVY infection and contributes to disease development in N. benthamiana. Based on these findings, we propose a working model in which PVY CP hijacks cPGM to redirect carbohydrate flux towards respiratory and pentose phosphate pathways, thereby increasing the availability of energy, reducing equivalents, and biosynthetic precursors required for viral replication. Together, this study provides mechanistic insight into PVY-induced metabolic reprogramming and identifies cPGM as a key host factor linking viral infection to primary metabolism.

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