Plant pathogenic fungi hijack phosphate signaling with conserved enzymatic effectors.

Abstract

Inorganic phosphate (Pi) is essential for life, and plant cells monitor Pi availability by sensing inositol pyrophosphate (PP-InsP) levels. In this work, we describe the hijacking of plant phosphate sensing by a conserved family of Nudix hydrolase effectors from pathogenic <i>Magnaporthe</i> and <i>Colletotrichum</i> fungi. Structural and enzymatic analyses of the Nudix effector family demonstrate that they selectively hydrolyze PP-InsP. Gene deletion experiments of Nudix effectors in <i>Magnaporthe oryzae</i>, <i>Colletotrichum higginsianum</i>, and <i>Colletotrichum graminicola</i> indicate that PP-InsP hydrolysis substantially enhances disease symptoms in diverse pathosystems. Further, we show that this conserved effector family induces phosphate starvation signaling in plants. Our study elucidates a molecular mechanism, used by multiple phytopathogenic fungi, that manipulates the highly conserved plant phosphate sensing pathway to exacerbate disease.