Component Interaction of ESCRT Complexes Is Essential for Endocytosis-Dependent Growth, Reproduction, DON Production and Full Virulence in Fusarium graminearum.

Qiurong Xie,Mingyue Yuan,Zonghua Wang,Guangpu Li,Wenhui Zheng,Yunzhi Zhang,Jie Zhou,Wei Xie,Chengkang Zhang,Ahai Chen

doi:10.3389/fmicb.2019.00180

Abstract

Multivesicular bodies (MVBs) are critical intermediates in the trafficking of ubiquitinated endocytosed surface proteins to the lysosome/vacuole for destruction. Recognizing and packaging ubiquitin modified cargoes to the MVB pathway require ESCRT (Endosomal sorting complexes required for transport) machinery, which consists of four core subcomplexes, ESCRT-0, ESCRT-I, ESCRT-II, and ESCRT-III. Fusarium graminearum is an important plant pathogen that causes head blight of major cereal crops. Our previous results showed that ESCRT-0 is essential for fungal development and pathogenicity in Fusarium graminearum. We then, in this study, systemically studied the protein-protein interactions within F. graminearum ESCRT-I, -II or -III complex, as well as between ESCRT-0 and ESCRT-I, ESCRT-I and ESCRT-II, and ESCRT-II and ESCRT-III complexes and found that loss of any ESCRT component resulted in abnormal function in endocytosis. In addition, ESCRT deletion mutants displayed severe defects in growth, deoxynivalenol (DON) production, virulence, sexual, and asexual reproduction. Importantly genetic complementation with corresponding ESCRT genes fully rescued all these defective phenotypes, indicating the essential role of ESCRT machinery in fungal development and plant infection in F. graminearum. Taken together, the protein-protein interactome and biological functions of the ESCRT machinery is first profoundly characterized in F. graminearum, providing a foundation for further exploration of ESCRT machinery in filamentous fungi.

Highlights

The filamentous fungus Fusarium graminearum is the major causal agent of Fusarium head blight (FHB) disease of cereal crops including wheat, barley, and other small grains (Goswami and Kistler, 2004; Starkey et al, 2007)
To identify orthologs of components of ESCRT-I, -II, and -III complexes in F. graminearum, the sequences of corresponding ESCRT genes from the budding yeast S. cerevisiae were used for BLASTP searches in the F. graminearum genome database
With proper positive and negative controls (Figure 1A), we found strong interactions between individual components with high β-galactosidase signal within ESCRTI and ESCRT-II complexes, while ESCRT-III complex displayed several interactions, including FgVps20-FgVps32, FgVps32-FgVps24, and FgVps24-FgVps2 in addition to FgVps32 self-interaction (Figure 1B)

Summary

Introduction

The filamentous fungus Fusarium graminearum is the major causal agent of Fusarium head blight (FHB) disease of cereal crops including wheat, barley, and other small grains (Goswami and Kistler, 2004; Starkey et al, 2007). Epidemics of this destructive disease can destroy high-yielding crop within a few weeks and result in significant yield losses (Mcmullen et al, 1997). Another component of Vps complex, binds to Vps and enhances ATPase activity and ESCRT-III binding (Yeo et al, 2003; Shiflett et al, 2004; Lottridge et al, 2006; Shestakova et al, 2010)

Methods

Results

Conclusion