The Dynamin-Like GTPase FgSey1 Plays a Critical Role in Fungal Development and Virulence in Fusarium graminearum

Abstract

Fusarium graminearum, the main pathogenic fungus causing Fusarium head blight (FHB), produces deoxynivalenol (DON), a key virulence factor, which is synthesized in the endoplasmic reticulum (ER). Sey1/atlastin, a dynamin-like GTPase protein, is known to be required for homotypic fusion of ER membranes, but the functions of this protein are unknown in pathogenic fungi. Here, we characterized Sey1/atlastin homologue FgSey1 in F. graminearum. Like Sey1/atlastin, FgSey1 is located in the ER. The FgSEY1 deletion mutant exhibited significantly reduced vegetative growth, asexual development, DON biosynthesis, and virulence. Moreover, the ΔFgsey1 mutant was impaired in the formation of normal lipid droplets (LDs) and toxisomes, both of which participate in DON biosynthesis. The GTPase, helix bundle (HB), transmembrane segment (TM), and cytosolic tail (CT) domains of FgSey1 are essential for its function, but only the TM domain is responsible for its localization. Furthermore, the mutants FgSey1K63A and FgSey1T87A lacked GTPase activity and failed to rescue the defects of the ΔFgsey1 mutant. Collectively, our data suggest that the dynamin-like GTPase protein FgSey1 affects the generation of LDs and toxisomes and is required for DON biosynthesis and pathogenesis in F. graminearum. IMPORTANCE Fusarium graminearum is a major plant pathogen that causes Fusarium head blight (FHB) of wheats worldwide. In addition to reducing the plant yield, F. graminearum infection of wheats also results in the production of deoxynivalenol (DON) mycotoxins, which are harmful to humans and animals and therefore cause great economic losses through pollution of food products and animal feed. At present, effective strategies for controlling FHB are not available. Therefore, understanding the regulation mechanisms of fungal development, pathogenesis, and DON biosynthesis is important for the development of effective control strategies of this disease. In this study, we demonstrated that a dynamin-like GTPase protein Sey1/atlastin homologue, FgSey1, is required for vegetative growth, DON production, and pathogenicity in F. graminearum. Our results provide novel information on critical roles of FgSey1 in fungal pathogenicity; therefore, FgSey1 could be a potential target for effective control of the disease caused by F. graminearum.

WeCoNET: a host–pathogen interactome database for deciphering crucial molecular networks of wheat-common bunt cross-talk mechanisms

“…While the pathogen protein “OAJ08159” showed its role in GTPase activity (GO:0003924). A recent study showed the role of dynamin-like GTPase protein homologue (FgSey1) in the development and pathogenicity of a pathogenic fungus, Fusarium graminearum [ 43 ]. The functional analysis of the above-mentioned host–pathogen PPI pair shows it to be a candidate pair for experimental validation, thus confirming the viability of the database.…”

Spindle Dynamics during Meiotic Development of the Fungus Podospora anserina Requires the Endoplasmic Reticulum-Shaping Protein RTN1

“…Interestingly, in contrast to the vegetative phase, where RTN1 seems to be partially redundant with YOP1 and YOP2, the latter proteins do not appear to be involved in meiotic development. Notably, no ascospore formation defects were observed in the plant-pathogenic fungus Fusarium graminearum upon disruption of the atlastin Sey1—a dynamin-like GTPase that mediates the fusion between the ER tubules, which generates the ER reticular network ( 75 ). These observations could indicate a specific role for RTN1 in meiotic development.…”

The Endoplasmic Reticulum Cargo Receptor FgErv14 Regulates DON Production, Growth and Virulence in Fusarium graminearum

“…Trichothecene biosynthesis induction (TBI) medium was used to analyze trichothecene production. To examine mycelial growth under different stress conditions, CM supplemented with 1 M NaCl, 1 M sorbitol, 0.05% sodium dodecyl sulfate (SDS), and 5 mM H 2 O 2 were used separately [ 50 ]. Genomic DNA and RNA were extracted from mycelia harvested from all strains that were cultured in CM for 2 days.…”

“…DON biosynthesis was tested by culturing 3 fresh mycelial plugs of each strain on 5 g of wheat grains [ 54 ]. The production of DON and ergosterol production were analyzed using the plugs incubated at 25 °C for 20 days [ 50 ].…”