A Ring Finger Protein Of Powdery Mildew Functions In Pathogenesis And RPW8.2 Mediated Resistance

Powdery mildew is a fungal disease that affects a wide range of plants.The powdery mildew broad-spectrum resistance protein RPW8.2 has good research value.In the previous study,the interaction protein of RPW8.2 was selected from the yeast two-hybrid c DNA library prepared from the Arabidopsis leaves material infected by powdery mildew,and its gene was named R8IP1.We successfully found another key protein PAPP2 C targeted by R8IP1,and we continued research on the function of R8IP1.The specific research results are as follows:1.We labeled the slices of Arabidopsis leaf infected with powdery mildew by immunofluorescence technology and found that R8IP1 can enter into the host cells.2.We initially found that R8IP1 could inhibit chitin-induced callose deposition and also reduce the rate of spontaneous cell death induced by RPW8.2-CC by the plant transient expression system.3.Through analysis of Col-0 and Wa-1 plants which ectopically expression R8IP1,we found that the expression of R8IP1 can inhibit the production of reactive oxygen species in the leaves,which is more conducive to the infection of powdery mildew,but the powdery mildew spores production did not increase significantly on Wa-1 transgenic plants.4.We generated transgenic R8IP1 host-induced gene silencing Arabidopsis lines which named with R8IP1-IR.We performed powdery mildew inoculation,and we observed that the number of powdery mildew spores of R8IP1-IR lines was significantly reduced compared to the GFP-IR lines.5.We identifying an R8IP1 interaction protein PAPP2 C in plants,and found that overexpression of PAPP2 C in plants suppresses plant immune responses.6.We found PAPP2 C regulates RBOHD by suppressing the phosphorylation sites Ser39,Ser343,and Ser347,which are essential for PTI and ETI.7.R8IP1 enhances the phosphorylation level of PAPP2 C in vivo,and a highly phosphorylated PAPP2 C shows higher phosphatase activity.8.Co-expression of R8IP1 and RPW8.2-GFP can change the distribution of RPW8.2-GFP in the nucleus-cytoplasm.9.R8IP1 increased the accumulation level of RPW8.2-e YFP in cells is RPW8.2dependent.Thus,powdery mildew protein R8IP1 indirectly regulates the phosphorylation of RBOHD by enhancing the enzyme activity of the host’s susceptibility(S)factor PAPP2 C.R8IP1 suppressed plant immune response in the fungi infection process.The powdery mildew resistance protein RPW8.2 interacts with R8IP1,and accumulated in the host cell nucleus,and initiate resistance to powdery mildew.