Preliminary Study On Two RxLR Effectors (RxLR107 And RxLR129) Of Phytophthora Capsici

Phytophthora capsici is an important pathogen of soil-borne plant pathogens.It can infect more than 70 species of Cucurbitaceae and Solanaceae,often causing devastating diseases of various crops and causing serious losses to agricultural production.P.capsici is easy to infect a variety of vegetables,leading to large-scale epidemics,moreover,the occurrence and prevalence of pepper blight often cause huge losses to pepper production.P.capsici in the process of infecting the host can secrete a variety of effector proteins,including RxLR,CRN and NLP,which have multiple functions,including destroying host cells or activating defense.The P.capsici genome contains more than 400 RxLR effectors,and only a few of them have been studied for the immunological properties of RxLR effectors.Yet the functional characteristics of most RxLR effectors are not clear.In this paper,two RxLR effectors,RxLR107 and RxLR129,were cloned from P.capsici,and the pathogenic functions of RxLR107 and RxLR129 were studied by gene knockout and silencing techniques.The specific experimental procedures and the valuable results are as follows:1.The laboratory-preserved P.capsici phytopathogenic strain LT1534 was used as experimental material to isolate and clone two effector molecules RxLR107 and RxLR129.It was previously proved that RxLR107 does not cause host necrosis,but inhibits the function of Bax,while RxLR129 can cause leaf necrosis.In order to further explore the functional characteristics of RxLR107 and RxLR129 in the host process of P.capsici infection,this paper used genetic manipulation techniques to genetically edit these two genes.2.The knockout experiment of RxLR107 gene was carried out by using CRISPR/Cas9 gene editing technology,and several transformants were obtained.We verified a homozygous knockout transformant by extracting the DNA,PCR amplifing and sequencing.However,it was found that the effector RxLR107 had no effect on the pathogenicity to the host by editing the gene.3.Using the principle of RNA interference,the RxLR129 gene was edited to obtain silencing transformants.The RxLR129 effector was successfully silenced which was verified by qRT-PCR.The gene editing technique and pathogenicity assay method proved that the effector RxLR129 silenced transformant had significant changes in pathogenicity and the pathogenic was recovered after gene replenishment,thus demonstrating that RxLR129 is a key effector.4.RxLR107 effector is indirectly involved in the pathogenesis,and its pathogenesis will continue to be further studied in the future research.RxLR129 plays an important role in the infection of P.capsici.The laboratory screened the RxLR129 interaction protein,acetaldehyde dehydrogenase.By verifying the relationship between the effector molecule and its interaction protein,it is expected to discover the pathogenic molecular mechanism of RxLR129 effector.The research provides theoretical basis and technical reference for follow-up research.