CaWRKY58/14-3-3 Interaction And Its Role In Regulation Of Defense Associated Gene Expression And Pepper’s Response To Phosphorous Starvation

WRKY transcription factor is one of the largest transcription factor family that play important role in the regulation of growth and adopt to environment in plant.But the mechanisms of function specific in different members are still unclear.14-3-3 protein is a regulatory protein encoded by multi-gene,they combine with phosphorylated target protein by homo-or heterodimers,lead to the change of target protein’s activation,localization or stability etc,but there are few reports about the molecular association between 14-3-3 protein and member of WRKY family.Our previous study found that CaWRKY58 is a negative regulator in pepper response to Ralstonia solanacearum.This time we further research the interaction of CaWRKY58 and 14-3-3 protein(Ca14-3-3),and involve in the function of pepper response to phosphorous starvation stress,the result are as follows:(1)Using CaWRKY58 as a bait,we separate a 14-3-3 protein from pepper cDNA library by yeast two-hybrid technique,and found Ca14-3-3 distribute in whole cell,we validate the interaction of CaWRKY58 and Ca14-3-3 by CO-immunoprecipitation(CoIP);(2)Through the analysis by real-time PCR we found that over-expression CaWRKY58 could significantly inhibit the expression of Cal4-3-3 in pepper leaves,and silencing of CaWRK58 gene significantly up-regulated the expression of Ca14-3-3;(3)Through the analysis of the expression of S A,JA,ET and ABA related gene by over-expression and real-time PCR,we discover that CaWRKY58 is involved in ABA and ET signaling pathway,Ca14-3-3 is involved in SA signaling pathway;analysis found by co-expression show that Ca14-3-3 inhibit the expression of CaABR1,CaACO1 up-regulated by CaWRKY58,and CaWRKY58 restore the expression of CaPR1 down-regulate by Ca14-3-3.(4)The research found that phosphorous starvation stress significantly positive regulate the expression of CaPT1,the homologous gene of transporter AtPHT1 in Arobidopsis thaliana and Ca14-3-3,but negative regulate CaWRKY58.The expression levels of CaPT1 decline both in over-expression CaWRKY58,Ca14-3-3 respectively and co-expression CaWRKY58 and Ca14-3-3The above result show that CaWRKY58 play a negative regulatory role in phosphorous starvation stress and disease resistance,and this function is adjusted by Ca14-3-3 interaction with CaWRKY58.