Quantitative Proteomics Analysis Reveals the Function of the Putative Ester Cyclase UvEC1 in the Pathogenicity of the Rice False Smut Fungus Ustilaginoidea virens.

Xiaoyang Chen,Zhangxin Pei,Yuhang Duan,Pingping Li,Lu Zheng,Xiabing Li,Xiaolin Chen,Hao Liu,Chaoxi Luo,Junbin Huang

doi:10.3390/ijms22084069

Abstract

Rice false smut is a fungal disease distributed worldwide and caused by Ustilaginoidea virens. In this study, we identified a putative ester cyclase (named as UvEC1) as being significantly upregulated during U. virens infection. UvEC1 contained a SnoaL-like polyketide cyclase domain, but the functions of ketone cyclases such as SnoaL in plant fungal pathogens remain unclear. Deletion of UvEC1 caused defects in vegetative growth and conidiation. UvEC1 was also required for response to hyperosmotic and oxidative stresses and for maintenance of cell wall integrity. Importantly, ΔUvEC1 mutants exhibited reduced virulence. We performed a tandem mass tag (TMT)-based quantitative proteomic analysis to identify differentially accumulating proteins (DAPs) between the ΔUvEC1-1 mutant and the wild-type isolate HWD-2. Proteomics data revealed that UvEC1 has a variety of effects on metabolism, protein localization, catalytic activity, binding, toxin biosynthesis and the spliceosome. Taken together, our findings suggest that UvEC1 is critical for the development and virulence of U. virens.

Highlights

Rice false smut (RFS), caused by the pathogenic ascomycete fungus Ustilaginoidea virens (U. virens), is one of the most devastating grain diseases in the majority of rice-growing areas of the world [1]
Uv8b_4649 gene was significantly up-regulated during the infection process (Figure S1), we speculated that it may be involved in the pathogenic process of U. virens
Characterizing additional genes participating in the pathogenic mechanism of U. virens will deepen our understanding and provide clues for the development of more effective strategies to control the disease

Summary

Introduction

Rice false smut (RFS), caused by the pathogenic ascomycete fungus Ustilaginoidea virens (U. virens), is one of the most devastating grain diseases in the majority of rice-growing areas of the world [1]. Conidia germinate on the surface of rice (Oryza sativa) spikelets, and the emerging hyphae extend randomly and enter the inner space of spikelets through small gaps between lemma and palea to colonize floral organs [2,3] Once inside these organs, the pathogen first attacks the filaments, preventing pollen from maturing and blocking normal fertilization, and invades the stigma and style to simulate fertilization, resulting in the hijacking of nutrients normally earmarked for developing seeds to form rice false smut balls [4,5]. Understanding of the pathogenic mechanism of U. virens to provide more effective strategies to control RFS

Methods

Results

Conclusion