A plasma membrane H + ‐ ATPase –lipid–cytoskeleton axis regulates appressorium‐mediated infection in Colletotrichum gloeosporioides

Summary Plasma membrane H + ‐ATPases (PMAs) are essential to cellular physiology, yet their spatial dynamics and functional integration during fungal infection remain poorly defined. Here, we demonstrate for the first time that the PMA isoform CgPMA2 in Colletotrichum gloeosporioides assembles into a distinct ring encircling the appressorium pore. CgPMA2 binds phosphatidylinositol phosphates (PIPs) via a conserved N‐terminal polybasic domain, and this interaction is essential for its pore‐localized ring formation. Strikingly, the septin CgSep4 also binds PIPs and forms a concentric ring smaller than the CgPMA2 ring, together defining a multilayered pore‐associated structure. Because very‐long‐chain fatty acids (VLCFAs) constitute the acyl chains of PIPs and stabilize curved membranes, we further identified the elongase CgELO2 as indispensable for VLCFA biosynthesis. Loss of either CgPMA2 or CgELO2 disrupted F‐actin and septin‐ring assembly in appressoria, severely impairing appressorium function and pathogenicity. Moreover, disruption of CgELO2, CgSep4, or the actin‐bundling protein CgFimbrin1 markedly reduced CgPMA2 ring formation. In summary, our findings uncover a previously unrecognized PMA–lipid–cytoskeleton regulatory axis that governs appressorium development and host penetration in C. gloeosporioides , thus providing new insights into the mechanism underlying invasive structure formation and pathogenicity in phytopathogenic fungi.