To Study The Function Of Rice WRKY42Transcription Factor In Xa21-mediated Defense Responses

Background: Rice (Oryza sativa L.) is one of the most important food crops in theworld, and is also the basic research pattern of life. The bacterial leaf blight is one of themost serious bacterial diseases to rice, Xa21is among the first cloning of rice bacterial leafblight resistance genes, the gene encoding type of receptor protein kinase, which is widelyapplied in rice disease resistance breeding. WRKY transcription factors in the process ofplant for biological and non-biological adversity stress, growth, metabolism and oxidationaging regulation all play a role. Of WRKY transcription factors in Xa21mediated ricebacterial leaf blight resistance mechanism under the function of the research is of greatsignificance.Research purposes: The preparation of rice WRKY42protein specific antibodies,understand its in rice growth and after leaf blight pathogen inoculation in different periodsof expression patterns; WRKY42protein in vitro expression, investigation it interactionwith the cis element W-box that in the pathogenesis-related gene PR1a and PR1b promoterregion; To summary WRKY transcription factors model of action in the process of rice andrice bacterial leaf blight pathogen interactions.Materials and methods: To predict antigenic determinant of rice WRKY42gene forpeptide synthesis and immune rabbit that preparation of WRKY42protein specificpolyclonal antibody, using Western blotting (WB) technology to detect WRKY42proteinin rice growth and the Xa21mediated expression in the process of resistance to bacterialleaf blight of rice. Using microscale thermophoresis technology to survey the WRKY42interaction with the cis element W-box that in the pathogenesis-related gene PR1a andPR1b promoter region. Introduction of WRKY42gene RNA-Seq FPKM data and MPSSdata for transcription analysis.Results: The transcription analysis found that in the process of normal growth of rice,WRKY42in leaves, flowers and seeds after pollination has transcription, among them indifferent days after pollination seeds presents downtrend transcription WRKY42induced bydrought and salt stress, but deal with cold stress has no effect on WRKY42transcription.WRKY42after in rice stripe virus and rice blast fungus infection that the transcriptionincreases; WB results show the expression of the WRKY42protein in rice seedlingquantity is relatively low, the expression quantity increased gradually with the growth ofrice, signal with slightly larger molecular weight after the tillering stage, may be WRKY42protein modification happened at this time;3days after inoculated leaf blight pathogenWRKY42protein began to significantly enhance signal, the signal enhancement have the dependence of inoculation time, and appear a molecular weight slightly larger than50kDastripe; Compare the expression in resistance, susceptible and Mock reactions are foundWRKY42protein expression in disease resistance, susceptible are similar, both in the lateinoculation appear high molecular weight bands, but not detected the stripe in the Mock;MST results show WRKY42in combination with the cis element W-box that in thepathogenesis-related gene PR1a and PR1b promoter region and the dissociation constant is73.3μM and58.3μM respectively.Conclusion: WRKY42play a regulation role in both of the normal leaf developmentand rice bacterial leaf blight resistance. The study of WRKY42transcription factors willprovide clues to understand WRKY transcription factor family function and in Xa21mediated rice bacterial leaf blight resistance mechanism.