Construction Of A Root Specific Expression Vector And Cloning And Functional Analysis Of ZmBRI In Maize

Pkc10 is a root-specific promoter from Arabidopsis thaliana.In this study,Pyk10 was amplified by polymerase chain reaction(PCR)from A.thaliana genomic DNA.Blastn results showed that the isolated pyk10 promoter shared 98%identity with Arabidopsis pyk10 promoter(Genbank no.AJ292756.1).The isolated pyk10 fragment was inserted into pCambia3301 expression vector through replacing the 35S promoter located in10776 bp-11313 bp.The pyk10 root-specific expression vector was constructed successfully named pyk 10-3301,and transferred into Arabidopsis(Col-o)using the floraldip method.The results of GUS histochemical detection showed that the pyk10 promoter could drived gus gene specifically expression in the transgenic Arabidopsis roots.Brassinosteroids(BRs)are detected at the cell surface by the leucine-rich repeat receptor-like kinase BRASSINOSTEROID INSENSITIVE1(BRI1),which,through genetic and molecular analyses,has been determined to play a critical role in BR signal transduction.In the present study,a brassinosteroid insensitive gene ZmBRI was isolated from maize.The sequence analysis showed that ZmBR1 encoded a polypeptide of 604 amino acids,with a predicted molecular weight of 66.81 kDa and a pi of 6.16,and bioinformatic analysis revealed that ZmBRI has a conserved kinase domain,is a member of the PKC superfamily,and has leucine-rich repeats(LRRs).Then I studied the analysis of function of ZmBRI.Expression analysis revesled that ZmBRI was strongly induced by salinity and BR treatment,but,it was downregulated by dehydration,drought stress,abscisic acid(ABA)and NO treatment.In addition,the leaf areas of the ZmBRI-overexpressing Arabidopsis thaliana is bigger than the wild-type,and it also flowered earlier than wild-type A.thaliana.It also showed that ZmBRI could induced stomatal closure in the ZmBRI-overexpressing Arabidopsis thaliana.ZmBRI transgenic maize were successfully obtained.This study indentified the bio-function of the ZmBRI gene preliminary and supported a theoretical basis for molecular breeding of maize.