Identification And Functional Analysis Of The Target Of Effector CRN63from Phytophthora Sojae

Soybean root rot caused by Phytophthora sojae is a devastating disease of soybean, and the disease can cause billions of dollars losses around the world. Its large genomic size and difficulty in genetic manipulation make it hard to understand the mechanism underlying the Phytophthora pathogenesis and develop effective control against the pathogens are lacking. To successfully infect plants, plant pathogens secrete arsenal of effectors to interfere with plant immunity. These effector proteins can interfere with the normal metabolism and function of the host plant cells, resulting in successful infection and colonization in plant tissues. Genome sequencing identified abundant of effector genes in Phytophthora, and CRN belong to the cytoplasmic effectors that function inside the plant cells, however little is known about their functions and mechanism. In this study, we tested the biological activities of the9members from the same group named CRN-A5. We also demonstrated that CRN63could target host catalases, and primarily elucidated the mechanisms underlying the CRN63virulence activities and these results will better our understanding of CRN effectors.Functional analysis of P. sojae effectors and identification of the target of CRN63in plants:we found that only CRN172-2could cause cell death in this group, while the other members suppress the plant cell death induced by PsojNIP、Avh241、Bax、CRN63or Avr3a/R3a. We uesd CRN63as the bait to identify the interacting proteins by Co-IP (co-immunoprecipitation), and we found CRN63interacted with plant catalase. Then we confirmed that CRN63could specifically interact with CAT useing BiFC (bimolecular fluorescence) approach. CAT is classified as oxidoreductases, and it can break down H2O2to H2O and O2.Functional analysis of N. benthamiana catalase genes:using the virus-induced gene silencing and overexpression approaches, we demonstrated that silenceing of catalase reduced plant resistance to P. capsici while overexpression of CAT1a improved plant resistance to P. capsici and suppressed the CRN63-triggered cell death. Interaction mechanism of CRN63and plant CAT:according to our results, CRN63induced accumulation of H2O2in plants tissue and alter the CAT la subcellular localization, making it localize in the nucleus. We also found CRN63could reduce the stability of the CAT1a protein. In summary, CRN63could directly interact with the host CAT by altering the CAT localization and protein stability, furthermore affect the removal of H2O2, resulting in plant cell death.