Recycling of Trans-Golgi SNAREs Promotes Apoplastic Effector Secretion for Effective Host Invasion in Magnaporthe oryzae.

Abstract

Vesicle transport is crucial for pathogenic fungi, but the mechanisms that control the secretion of effector proteins are not yet fully understood. Here, we have uncovered a novel pathway in which retromer and trans-Golgi (TGN) SNARE proteins co-regulate the proper secretion of apoplastic effectors in Magnaporthe oryzae. It was found that a TGN-associated SNARE complex, consisting of MoSnc1, MoTlg1, MoTlg2 and MoVti1, is critical for growth, development and pathogenicity in the fungus. In addition, the TGN-associated SNARE complex is indispensable for the proper secretion of apoplastic effectors. Furthermore, we found that the dynamin-like protein MoVps1, an upstream regulator of the retromer complex, regulates the fission of MoVps35-coated vesicles and the proper localisation of the TGN-associated SNARE complex. Additionally, treatment with perphenazine, a potent dynamin inhibitor, perturbs the fungal developmental similar to MoVPS1 disruption, highlighting the central regulatory role of dynamin in M. oryzae and suggesting the potential efficacy the control and management of the rice blast. Taken together, the study uncovered a specific mechanism by which MoVps1 and the retromer complex co-regulate the positioning of TGN-associated SNARE proteins to effectively promote effector secretion. This study widens our horizon on the mechanism of effector secretion in phytopathogenic fungi and underscores the importance of vesicle transport in fungal pathogenesis.