The Preliminary Research On The Molecular Mechanism Of A Salicylic Acid-responsive New Gene OsAAA1 In Rice Broad-spectrum Disease Response

AAA-ATPase gene family which widely exist in eukaryotes and prokaryotes,contain the conserved Walk A and Walk B motifs as well as the specific SRH domain.They are involved in very diverse cellular processes,including protein degradation,protein folding,membrane transport and the cytoskeletal expression and regulation.The AAA-ATPase gene family involved in plant disease resistance is rarely reported.In previous research,using the gene microarray we got a new member of the AAA-ATPase family—OsAAA1,which is involved in the response of the rice blast resistance.And then the plant hormone as well as the rice blast fungus inoculation were used to analysis the expression of OsAAA1,we found that the expression of OsAAA1 could be induced by both SA and the rice blast fungus.Overexpression plants of the OsAAA1 conferred to the enhanced resistance to the rice blast and the bacterial blight,which may make it a new genetic resource with broad-spectrum resistance.Studies about the resistance mechanism of OsAAA1 will be contributed to clarify the mechanism of broad-spectrum resistance.Thus,we conducted the preliminary study about the resistance mechanism of the OsAAA1 gene.The main contents are as follows:（1）The expression profiles of OsAAA1 gene in different tissues,different stages of rice and under abiotic stress treatment were analysised.The results showed that OsAAA1 gene expressed lowly in each tissues of seedling and tillering stages,highly in each tissues of heading stage and highest in leaf and panicles.Abiotic stress treatment showed that the expression level of OsAAA1 was down-regulated under salt,temperature,pH and heavy metal CdCl₂ stress,while significantly up-regulated under H₂O₂ stress,which suggests that OsAAA1gene may be involved in H₂O₂ mediated signal pathway.（2）The bioinformatics analysis of gene microarray from OsAAA1 overexpression transgenic rice indicated that 927 genes may be directly interrelated to blast resistance after OsAAA1 gene was tansfered.Futher significant trend and time series of co-expression network analysis indicated that six key genes were involved in resistance responses,these expression of six genes were verified by qRT-PCR.GO analysis demonstrated that there six gene may be involved in abiotic stress,cellular metabolism,signal transduction and so on.The relationship between OsAAA1 and the six genes needs to further research.（3）The interaction between OsAAA1 and OsSSI2,WRKY13,WRKY68,Pib and Pit was successfully identified with yeast two-hybrid system.The OSAAA1 was cloned into prokaryotic expression vector pGEX-6P1 and the condition of protein expression was optimized,the target protein in soluble supernatant was obtained.This will lay the foundations for testing the protein interactions.