Functional Analysis Of The Role Of PtBP1 In PeaT1 Induced Resistance And Of A Novel Rice Paired NLR Proteins

The plant innate immunity is theoretically divided into two branches.To detect and ward off pathogens,Plants recognize the Microbial-or Pathogen-Associated Molecular Patterns(MAMPs or PAMPs)through Pattern Recognition Receptors(PRRs)localized on the cell surface,followed by the PAMP triggered immunity(PTI).Apart from the above immunity branch,plants could also employ polymorphic NLRs encoded by Resistance genes(R gene)to perceive the stimulus from pathogen effectors,initiating effector triggered immunity(ETI).In this article,we will focus on two projects: the role of plasma membrane protein PtBP1 playing in PeaT1 induced systematic acquired resistance in Nicotina Benthamina,and gene cloning and functional analysis of NLR paired protein RPR1 and RPR2.Study on these two projects will help us gain a better understanding of the plant immunity mechanism through PTI and ETI levels.The main findings are as below:1.Plasma membrane protein Pt BP1 is involved in PeaT1 induced systematic acquired resistance in N.Benthamina plant.PtBP1 silencing lines are obtained via VIGS method with the silencing efficiency more that 70%.According to the data of TMV-GFP inoculation assay,the TMV lesion number of Pt BP1 silencing line(with the lesion number 130.25±19.99)is about three times as big as the control plants(43.25±8.73).The amount of TMV-Coating protein accumulation of PtBP1 silencing line is significantly higher than the control plants,as well.In addition,the absence of Pt BP1 can block the PeaT1 induced upregulation of resistance related genes.In view of the above experimental results,we speculate that Pt BP1 could perceive the stimulus from PeaT1 and mediate the downstream signaling.2.The rice paired receptors-NLR protein RPR1 and RPR2 of Oryza sativa Japonica-are screened through bioinformatics analysis and identified as our research subject.This protein pair is a homologues pair of RPS4/RRS1 from Arabidopsis,consisting RX-CC domain at the N-terminal of both proteins,and two WRKY domains at the C-terminal within RPR2.By using Golden Gate cloning strategy,constructs for RPR1 and RPR2 of Level-1,Level 0,Level 1 are obtained.3.The subcellular location pattern of RPR1 and RPR2 is analyzed by doing transient expression and confocal imaging,indicating that this protein pair is localized within cell nucleus.RPR1 and RPR2 can also recognize effector PopP2,which triggers HR-like response with chlorosis symptoms shown within co-infiltrated region.Those two projects introduced as above has increased our knowledge of plant innate immunity through ETI and PTI levels,and the understanding of the co-evolution and interaction between plants and their pathogens.Our research of plasma membrane protein PtBP1 will lay a foundation for the research of PeaT1 induced plant immunity;the study of RPR1 and RPR2 will help us deduce the demonstrated paired NLR-decoy model from Arabidopsis(Brassicaceae)to rice(Gramineae),providing profound effects on cross-taxon resistance research.