Selectively targeting UDP-glucose 4-epimerase MoUGE1 for controlling rice blast disease

MoUGE1, a UDP-glucose 4-epimerase, is central to maintaining fungal cell wall integrity and plays a crucial role in the growth, development, and pathogenicity of M. oryzae . MoUGE1 mediates the interconversion between UDP-galactose and UDP-glucose, which is vital for the synthesis of galactosaminogalactan (GAG) and other cell wall components. GAG is essential for appressorium adhesion and masking chitin from host recognition. MoUGE1 also influences the levels of various metabolites and N-glycosylation modifications, which in turn affect cell membrane fluidity and appressorium function. The deletion of MoUGE1 leads to UDP-galactose accumulation, altered N-glycosylation modification levels, reduced cell membrane fluidity due to changes in phospholipid components, and compromised cell wall integrity, ultimately resulting in impaired appressorium penetration and invasive growth. UGE1i, a specific inhibitor of MoUGE1, blocks the function of MoUGE1, thereby inhibiting the infection of M. oryzae . • MoUGE1 encodes a UDP-glucose 4-epimerase required for cell wall biosynthesis. • MoUGE1 is required for appressorium penetration and invasive growth in Magnaporthe oryzae. • Metabolomic analysis and western blot reveals roles of MoUGE1 in UDP-galactose metabolism and N-glycosylation. • Virtual screening identifies UGE1i(lig122132) as a potential MoUGE1 inhibitor for controlling rice blast. The fungal cell wall, a dynamic structure critical for pathogenesis, is composed of polysaccharides and proteins. UDP-glucose 4-epimerases (UGEs) play a pivotal role in cell wall synthesis by converting UDP-galactose between UDP-glucose. This study investigates the role of MoUGE1 in Magnaporthe oryzae pathogenesis and explores its potential as an antifungal target for fungal disease control. A lead inhibitor targeting MoUGE1 was identified through virtual screening. The aims of this study were to elucidate the role of MoUGE1 in M. oryzae during rice blast pathogenesis, assess its potential as an antifungal target, and identify potential MoUGE1 inhibitors through virtual screening to control rice blast. To analyses the role of MoUGE1 in M. oryzae , we generated Δ uge1 mutants via split-PCR-mediated gene knockout. The impact of MoUGE1 on fungal growth, cell wall composition, and plant infection was assessed. Metabolomic analysis revealed the impact of MoUGE1 deletion on metabolic processes of rice blast. Structure-based virtual screening, molecular dynamics (MD) simulation and surface plasmon resonance (SPR) used to find hit compounds inhibiting MoUGE1. The Δ uge1 exhibited reduced mycelial growth, altered cell wall and cell membrane composition, and impaired plant infection. Metabolomic analysis and western blot revealed accumulation in UDP-galactose and alteration of N-glycosylation, leading to cell wall instability and increased sensitivity to cell wall stressors. Virtual screening identified lig122132 as a potential MoUGE1 inhibitor, which was further confirmed through MD simulation and SPR, showing stable binding to the MoUGE1. Our findings emphasize the significance of MoUGE1 in fungal cell wall integrity, appressorium function, and virulence in M. oryzae . Identifying MoUGE1 as a target for antifungal intervention provides new insights into the molecular mechanisms of rice blast pathogenesis and paves the way for developing innovative strategies against this major agricultural disease. The potential MoUGE1 inhibitor, lig122132, is a promising starting point for the development of novel fungicides to control rice blast.