Endoplasmic reticulum‐associated degradation mediated by MoHrd1 and MoDer1 is pivotal for appressorium development and pathogenicity of Magnaporthe oryzae

Abstract

Most secretory proteins are folded and modified in the endoplasmic reticulum (ER); however, protein folding is error-prone, resulting in toxic protein aggregation and cause ER stress. Irreversibly misfolded proteins are subjected to ER-associated degradation (ERAD), modified by ubiquitination, and degraded by the 26S proteasome. The yeast ERAD ubiquitin ligase Hrd1p and multispanning membrane protein Der1p are involved in ubiquitination and transportation of the folding-defective proteins. Here, we performed functional characterization of MoHrd1 and MoDer1 and revealed that both of them are localized to the ER and are pivotal for ERAD substrate degradation and the ER stress response. MoHrd1 and MoDer1 are involved in hyphal growth, asexual reproduction, infection-related morphogenesis, protein secretion and pathogenicity of M. oryzae. Importantly, MoHrd1 and MoDer1 mediated conidial autophagic cell death and subsequent septin ring assembly at the appressorium pore, leading to abnormal appressorium development and loss of pathogenicity. In addition, deletion of MoHrd1 and MoDer1 activated the basal unfolded protein response (UPR) and autophagy, suggesting that crosstalk between ERAD and two other closely related mechanisms in ER quality control system (UPR and autophagy) governs the ER stress response. Our study indicates the importance of ERAD function in fungal development and pathogenesis of M. oryzae.

Ero1‐Pdi1 module‐catalysed dimerization of a nucleotide sugar transporter, FonNst2, regulates virulence of Fusarium oxysporum on watermelon

“…Unfolded or misfolded proteins accumulated in ER are degraded by ER‐associated protein degradation (ERAD) through 26S proteasomes (Tang et al ., 2020). FonNst2 C171W ‐GFP, FonNst2 C263G ‐GFP, FonNst2 C326S ‐GFP, FonNst2 C171W/C263G ‐GFP, FonNst2 C171W/C326S ‐GFP, FonNst2 C263G/C326S ‐GFP and FonNst2 C171W/C263G/C326S ‐GFP in ΔFonNst2 were hardly detectable in immunoblotting assays.…”

The Histone Acetyltransferase CfGcn5 Regulates Growth, Development, and Pathogenicity in the Anthracnose Fungus Colletotrichum fructicola on the Tea-Oil Tree

“…As the concentration of H 2 O 2 increased, the inhibition rates of all the strains were also increased, but that of Δ Cfgcn5 was still significantly higher than that of WT and Δ Cfgcn5 / CfGCN5 ( Figures 7A,B ). The recent studies showed that pathogens also face host-derived ER stress during infection ( Tang et al, 2020 ; Yin et al, 2020 ). We thus used DTT to mimic ER stress derived from plants.…”

Early Secretory Pathway-Associated Proteins SsEmp24 and SsErv25 Are Involved in Morphogenesis and Pathogenicity in a Filamentous Phytopathogenic Fungus

“…Disruption of certain proteins involved in the conventional ER-to-Golgi secretory pathway could affect effector secretion, morphogenesis, and pathogenicity in phytopathogenic fungi ( 41 – 43 ). Apoplastic effector secretion relies on the conventional fungal ER-to-Golgi secretory pathway in M. oryzae .…”