Septin-dependent assembly of the exocyst is essential for plant infection by Magnaporthe oryzae

Yogesh K. Gupta, Yasin F. Dagdas, Ana Lilia Martinez-Rocha, Michael J. Kershaw, George R. Littlejohn, Lauren S. Ryder, Jan Sklenar, Frank Menke, Nicholas J. Talbot

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)

Abstract

Magnaporthe oryzae is the causal agent of rice blast disease, the most devastating disease of cultivated rice (Oryza sativa) and a continuing threat to global food security. To cause disease, the fungus elaborates a specialized infection cell called an appressorium, which breaches the cuticle of the rice leaf, allowing the fungus entry to plant tissue. Here, we show that the exocyst complex localizes to the tips of growing hyphae during vegetative growth, ahead of the Spitzenkörper, and is required for polarized exocytosis. However, during infection-related development, the exocyst specifically assembles in the appressorium at the point of plant infection. The exocyst components Sec3, Sec5, Sec6, Sec8, and Sec15, and exocyst complex proteins Exo70 and Exo84 localize specifically in a ring formation at the appressorium pore. Targeted gene deletion, or conditional mutation, of genes encoding exocyst components leads to impaired plant infection. We demonstrate that organization of the exocyst complex at the appressorium pore is a septin-dependent process, which also requires regulated synthesis of reactive oxygen species by the NoxR-dependent Nox2 NADPH oxidase complex. We conclude that septinmediated assembly of the exocyst is necessary for appressorium repolarization and host cell invasion.

Original languageEnglish
Pages (from-to)3277-3289
Number of pages13
JournalPlant Cell
Volume27
Issue number11
DOIs
Publication statusPublished - 13 Nov 2015

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