Interaction Mechanism Of Phytophthora Sojae RXLR Effector Avh5 And Host Target E3 Ubiquitin Ligase RNF181

Soybean Phytophthora Root Rot（SPRR）caused by Phytophthora sojae is a destructive disease,which seriously endangers the global soybean production and food security.Therefore,it is an urgent task to deeply understand the pathogenic mechanism and infection mechanism of Phytophthora sojae,to develop and transform the host target,and to explore new resources of disease resistance molecular breeding.Phytophthora,as a semi-living pathogen,does not destroy the integrity of host cells in the early stage of infection and obtains nutrients and water in a parasitic way.Therefore,the inhibition of host programmed cell death（PCD）is considered to be an important infection strategy of Phytophthora.In recent years,it has been found that Phytophthora inhibits plant PCD by secreting a large number of RXLR effectors.Most of the RXLR effectors of Phytophthora have conserved L/W/Y-motif at the C-terminal,which makes an important contribution to their virulence.It is known that 60%of the RXLR effectors that can inhibit plant PCD have WY-motif,so it is speculated that WY-motif is the key region for the inhibition of plant PCD.The C-terminal of Phytophthora sojae RXLR effector Avh5 of has a WY-motif,which can strongly inhibit plant PCD.In this study,it was found that overexpression of PsAvh5 in tobacco and soybean could enhance the infection ability of Phytophthora to plants,indicating that PsAvh5 is the key virulent effector of Phytophthora sojae.Overexpression of Avh5 C-terminal WY-motif(PsAvh5^WY)in plants can also significantly promote the infection of Phytophthora,which proves that WY-motif is the key to the toxic function of PsAvh5.The interaction between PsAvh5^WY and soybean E3 ubiquitin ligase Gm RNF181 was found in yeast two-hybrid.It has been reported that RNF181 is closely related to apoptosis in mammals,and it is speculated that Gm RNF181 may be involved in the occurrence of PCD in plants.It was found that overexpression of Gm RNF181 in tobacco could promote the infection of Phytophthora to plants,so it was inferred that RNF181 was a negative regulator of plant immunity.The interaction between PsAvh5 and RNF181 was further confirmed by Pull-down,BiFC,Co-IP and other methods,and the key region of the interaction was found by truncating mutations.In this study,the 3D structural interaction model between PsAvh5 and target RNF181 protein complex was analyzed by computer homology modeling.,and it was confirmed that the key regions were WY-motif and 174th～182th amino acid.In this study,transcriptome was used to analyze the downstream genes and metabolic pathways affected by the interaction between PsAvh5 and RNF181.It was found that there were similar gene transcriptional changes after overexpression of PsAvh5 and RNF181.It is speculated that PsAvh5 may promote Phytophthora sojae infection by stabilizing or manipulating the negative regulation of plant immunity by RNF181.In this study,the interaction mechanism between Phytophthora sojae RXLR effector PsAvh5 and host target E3 ubiquitin ligase Gm RNF181 was preliminarily discovered and verified.he key regions of the interaction were identified and the interaction model was constructed,which provided an theoretical basis for further analysis of Phytophthora resistance mechanism,exploration of resistance breeding targets and formulation of Phytophthora control strategies.