Research Progress in the Regulation of Plant Immune Mechanisms by Type Ⅲ Effector Proteins in Ralstonia solanacearum

Abstract

Ralstonia solanacearum usually infects the vascular bundle system through the roots of host plants, causing bacterial wilt and leading to irreversible wilting and death of plants. Bacterial wilt is a devastating soil-borne bacterial disease. At present, it has been one of the main diseases restricting the production of Solanaceae crops in China. Type Ⅲ secretion system (T3SS) plays an important role in the pathogenesis of R. solanacearum, using T3SS to inject large amounts of Type Ⅲ effectors (T3Es) into host cells to interfere with the immune response of the host. Scholars at home and abroad are committed to exploring how R. solanacearum interferes with host cells and regulates host immune function by identifying target proteins in the host. Therefore, the identification of host proteins that can be targeted by T3Es is helpful to understand the biological function of R. solanacearum T3Es, the pathogenic process of R. solanacearum, and to explore the R. solanacearum resistance-related proteins and their mechanism of action in hosts. Although most of the functions of T3Es are still unknown, so far, it has been reported that R. solanacearum T3Es can regulate host resistance to bacterial wilt by interfering with plant innate immunity, inducing plant hypersensitivity response and affecting plant metabolism and hormone signal transduction through a variety of molecular mechanisms. In this review, we summarize the current research progress on the characteristics and functional identification methods of T3Es of R. solanacearum, and its research progress in participating in the regulation of pathogenicity and plant immunity mechanism of R. solanacearum, which can provide an in-depth understanding of the pathogenic mechanism of R. solanacearum and the response mechanism of the host immune system. The mechanism of interaction between R. solanacearum T3Es and the host are prospected, which will provide an effective reference for the analysis of the host resistance mechanism induced by R. solanacearum and the prevention and control of bacterial wilt.

Keywords

• ralstonia solanacearum
• bacterial wilt
• type ⅲ secretion system
• effector
• target protein
• pathogenicity
• immune response