The t-SNARE protein FgPep12, associated with FgVam7, is essential for ascospore discharge and plant infection by trafficking Ca2+ ATPase FgNeo1 between Golgi and endosome/vacuole in Fusarium graminearum

Abstract

Soluble N-ethylmaleimide-sensitive factor attachment receptors (SNAREs) play a crucial role in the development and virulence through mediation of membrane fusion and vesicle trafficking in pathogens. Our previous studies reported that the SNARE protein FgVam7 and its binding proteins FgVps39/41 are involved in vesicle trafficking and are important for vegetative growth, asexual/sexual development, deoxynivalenol production and virulence in the Fusarium head blight fungus Fusarium graminearum . Here, we identified and characterized another FgVam7 binding protein in F . graminearum , FgPep12, an ortholog of yeast t-SNARE Pep12 with both the SNARE and TM domains being essential for its localization and function. Deletion of FgPep12 caused defects in vegetative growth, conidiogenesis, deoxynivalenol production and virulence. Cytological observation revealed that FgPep12 localizes to the Golgi apparatus, late endosomes and vacuoles, and is necessary for transport from the vacuole to prevacuolar compartment. Further investigation revealed that both FgPep12 and FgVam7 are essential for ascospore discharge through interaction with and trafficking of the Ca 2+ ATPase FgNeo1 between the Golgi and endosomal/vacuolar system. FgNeo1 has similar biological roles to FgPep12 and is required for ascospore discharge in F . graminearum . Together, these results provide solid evidence to help unravel the mechanisms underlying the manipulation of ascospore discharge and plant infection by SNARE proteins in F . graminearum .

Flippases play specific but distinct roles in the development, pathogenicity, and secondary metabolism of Fusarium graminearum

“…We also found functional redundancy Study of the flippases in A. nidulans revealed their functions in the regulation of vegetative growth and asexual sporulation (Schultzhaus et al, 2015(Schultzhaus et al, , 2019. Here, we also confirmed the involvement of flippases in growth and conidia production in F. graminearum (Figure 1 and Table 1) is required for ascospore discharge in an ion-dependent manner (Li et al, 2019). However, in this study we found that the deletion mutant of FgDNFD produces smaller perithecia than the wild-type strain and does not produce ascospores (Figure 1), indicating that FgDnfD is essential for maturation of perithecia in F. graminearum.…”

“…In fungal pathogens, flippases are known to be required for effective pathogenesis. Documented reports in the rice blast fungus M. oryzae, the opportunistic fungal pathogen C. neoformans, and F. graminearum suggest that flippases have conserved roles in the regulation of pathogenicity, but different homologs display functional diversity in different fungal pathogens (Balhadere and Talbot, 2001;Gilbert et al, 2006;Hu and Kronstad, 2010;Rizzo et al, 2014;Li et al, 2019). (Balhadere and Talbot, 2001;Hu and Kronstad, 2010;Rizzo et al, 2014).…”

“…Li et al . constructed a conditional suppress mutant for FgDNFD and found that FgDNFD is required for ascospore discharge in an ion‐dependent manner (Li et al ., 2019). However, in this study we found that the deletion mutant of FgDNFD produces smaller perithecia than the wild‐type strain and does not produce ascospores (Figure 1), indicating that FgDnfD is essential for maturation of perithecia in F. graminearum .…”

“…In the rice blast fungus Magnaporthe oryzae , the biological functions of two flippases, MoPde1 and MoApt2, have been characterized, and both proteins are involved in fungal virulence (Balhadere and Talbot, 2001; Gilbert et al ., 2006). In F. graminearum recent studies identified FgDnfB and FgNeo1 (FgDnfD homologs) as flippases, and FgDnfB plays a minor role in fungal vegetative growth, polarity maintenance, and conidiation (Zhang et al ., 2019), while FgNeo1 is important for asexual/sexual developments and virulence in F. graminearum (Li et al ., 2019), but the remaining family proteins remain unknown. In addition, the roles of flippases in the biosynthesis of secondary metabolites have not been established in filamentous fungi.…”

Calcineurin-Responsive Transcription Factor CgCrzA Is Required for Cell Wall Integrity and Infection-Related Morphogenesis in Colletotrichum gloeosporioides

“…CaCl 2 (0.2 M), SDS (0.005%), CFW (200 μg/ml), Congo red (200 μg/ml), and lysing enzyme (15 μg/ml) were added to the CM agar to determine the various stress resistance of tested strains. Fungal protoplast preparation and transformation were conducted according to the method described by Li et al (2019) . TB3 agar medium supplemented with 250 μg/ml hygromycin B (Solarbion, Beijing, China) and 400 μg/ml geneticin (MP Biochemical, Santa Ana, CA, USA) was used for the selection of candidate transformants.…”