Functions of type III effectors from multigenic family of Ralstonia solanacearum in plant disease development and immunity defense system

Abstract:

Ralstonia solanacearum causes lethal wilting disease in many economic plants, threatening food security in tropical and subtropical agriculture. It injects type III effectors (T3Es) into the host cells via the type III secretion system. T3Es act as molecular double agents that are involved in either pathogenicity in the susceptible host plants or induction of hypersensitive response in the resistant host plants. A notable feature in this T3E repertoire is the existence of several multigenic families and their various internal repeats. T3Es from multigenic family of R. solanacearum contribute differently to pathogenicity towards the host plants and localize on the plant cell plasma membrane or nucleus. Previous researches demonstrate that the multigenic effectors jointly contribute to the plant disease development but are barely activated individually. However, the pathogenicity mechanism on the most multigenic effectors remains unclear. This review summarizes the recent achievements on elucidating the function of T3Es from multigenic family (GALA, HLK, SKWP, AWR and PopP) in R. solanacearum.

Key words:Ralstonia solanacearum;type III effectors;multigenic family;plant immunity and disease development