Cloning And Functional Studies Of SiERD15 Gene Of Foxtail Millet(Setaria Italica)

ERD（Early Response to Dehydration protein）is a rapidly expressed protein in plants under stress.The ERD15 protein contains highly conserved PAM2 and PAE1（Pectin Acetylesterase 1）structures,an acidic domain and a unique C-terminal amino acid Iq QPR.It is involved in plant stress tolerance and can be rapidly induced by various stresses and stress related Plant hormone,such as drought,salt,low temperature,external damage,abscisic acid（ABA）,salicylic acid（SA）,and plant pathogens.ERD15,as a negative regulator factor in response to ABA,can weaken the regulation of ABA in plants.As a dryland plant,millet has developed into a model plant for C4 plants due to its small genome and simple chromosomes.In this study,SiERD15（ERD15 of Setaria italica）gene and its promoter subsequence of millet are cloned from millet,and the sequence of the coding region and promoter subsequence of the SiERD15 gene are analyzed by bioinformatics.The SiERD15 overexpression vector is constructed and transferred into Arabidopsis thaliana（Columbia-0）.The function of SiERD15 gene under abiotic and biological stresses is determined by studying the expression rules of the SiERD15 gene and stress resistance related genes in transgenic plants and millet under stress.The main results are as follows:1.Sequence analysis shows that the SiERD15 protein contains one PAM2structure,one PAE1 structure,and one acidic domain each.It is found that SiERD15protein is located in the nucleus and belongs to nucleoprotein by transient transfection of onion lower epidermis.2.Overexpression of SiERD15 with ABA and SA shows that SiERD15 is involved in the rapid response of ABA.3.The expression of drought related genes RD29A（Responsive to Desiccation 29A）and RAB18（Responsive to ABA 18）is significantly reduced in Arabidopsis thaliana overexpressed by SiERD15 after mannitol treatment.In fact,Col and overexpressed plants could be completely restored after 3 days of rehydration after drought treatment,while the mutant does not,indicating that SiERD15 could enhance the drought resistance of plants.4.Through ABA,jasmonate（JA）,PEG6000,Na Cl and light stress treatment of millet and analysis of the expression of SiERD15,it is found that SiERD15 responded significantly to ABA,JA,PEG6000 and strong light（7000 Lux）,but do not respond significantly to Na Cl.5.Using pathogenic bacteria Pst DC3000 to treat SiERD15 overexpressing plants,it is found that the area of H₂O₂ and dead cells in the leaves of SiERD15overexpressing plants is significantly smaller than that of Col and mutants,and the leaf color is also lighter,with a lower CFU value,indicating that the SiERD15 gene can improve the plant’s resistance to pathogenic bacteria.