A putative N-BAR-domain protein is crucially required for the development of hyphae tip appressorium-like structure and its plant infection in Magnaporthe oryzae

Abstract

Membrane remodeling modulates many biological processes. The binding of peripheral proteins to lipid membranes results in membrane invaginations and protrusions, which regulate essential intra-cellular membrane and extra-cellular trafficking events. Proteins that bind and re-shape bio-membranes have been identified and extensively investigated. The Bin/Amphiphysin/Rvs (BAR) domain proteins are crescent-shape and play a conserved role in tubulation and sculpturing of cell membranes. We deployed targeted gene replacement technique to functionally characterize two hypothetical proteins (MoBar-A and MoBar-B) containing unitary N-BAR domain in Magnaporthe oryzae . The results obtained from phenotypic examinations showed that MoBAR-A deletion exerted a significant reduction in the growth of the defective ∆ Mobar-A strain. Also, MoBAR-A disruption exclusively compromised hyphae-mediated infection. Additionally, the targeted replacement of MoBAR - A suppressed the expression of genes associated with the formation of hyphae tip appressorium-like structure in M. oryzae . Furthermore, single as well as combined deletion of MoBAR-A and MoBAR-B down-regulated the expression of nine different membrane-associated genes. From these results, we inferred that MoBAR-A plays a key and unique role in the pathogenesis of M. oryzae through direct or indirect regulation of the development of appressorium-like structures developed by hyphae tip. Taken together, these results provide unique insights into the direct contribution of the N-BAR domain proteins to morphological, reproduction, and infectious development of M. oryzae .