Molecular And Functional Analyses Of MaASR3 In Banana

ASR(ABA Stress Ripening)encodes a small hydrophilic protein,which typically exists in higher plant,such as tomato,corn,rice,potato,lily,grapes,banana and pine.MaASR3,as a member of the MaASR gene families in banana,its mechanism still unclear.In this study,methods such as bioinformatics analysis,gene expression analysis,yeast mutant complementary analysis and biochemical analysis were adopted to study the molecular mechanism of MaASR3 in responding to different stresses.The results were as follows:(1)The bioinformatics analysis showed that,like other members of MaASR gene family,MaASR3 was composed of 1 intron and 2 exons.In its promoter region,there were cis-acting elements related to hormone response,environmental stress,or regulation of the growth and development.The MaASR3 protein contained a conserved ABA/WDS domain.(2)The gene expression analysis showed that the expression pattern of MaASR3 in banana(Brazil)was tissue-specific.The expressing level decreased in turn in mature leaf,mature roots,stems,young leaves,leaf sheath and young root.Generally,the expression level of MaASR3 in mature tissues was higher than that in tender tissues.In addition,the expression of MaASR3 was induced by oxidative stress(methyl violet),ABA,osmotic stress(mannitol)and low temperature.(3)The pYES2-MaASR3 recombinant vector was constructed and introduced into ?yap1 and ?skn7,which were two strains of oxidation defect yeast mutants,and the result showed that MaASR3 could complement the oxidation defect of these two yeast mutants.(4)The MaASR3-GST recombinant protein was induced in E.coli and purified with GST affinity column chromatography,and the antioxidant capacity of MaASR3-GST recombinant protein was detected.(5)The over-expression vector of MaASR3 was constructed and transferred into Arabidopsis thaliana by agrobacterium.Four independent transgenic lines wereobtained for the following physiological and biochemical analysis.