Cloning and Sequence Analysis of the Aquaporins Gene SlAQP in Tomato

【Objective】 To provide basal data for mechanism of tomato's drought resistance and cultivar development,the sequence characteristics of the aquaporin gene SlAQP in tomato were analyzed,the coded protein was intracellar located and the expression profiling of the Mirco Tom tomato was studied after treatment under drought stress.【Method】 The rapid-amplification of cDNA ends(RACE) was used to amplify the full-length SlAQP gene,and the bioinformatics software was used to analyze the structures and function of the coded protein.In order to follow the intracellular localisation of the protein,the GFP sequence was fused downstream to the SlAQP coding region and the fusion gene SlAQP::GFP transferred into onion epidermal cells by biolistic method.The Mirco Tom tomato was used as material,the real time-PCR was adopted to study the expression profile of gene SlAQP.【Result】 The full-length cDNA of SlAQP gene(GenBank Accessin No.HQ433337) consists of 1 107 bp and contains a 852 bp open reading frame(ORF) encoding 283 amino acid proteins.Bioinformatics analysis demonstrated that SlAQP gene exhibited a typical structure with six membrane-spanning domains and an internal symmetry showing two highly conserved Asn-Pro-Ala(NPA) motifs,and possessing the MIP family signal consensus sequence.The SlAQP amino acids showed high identity with other 10 plant species PIP subfamily by NCBI homology comparison analysis.Phylogenetic analysis among 11 species indicated that SlAQP was clustered with the StAQP from Solanum tuberosum.The result of transient expression showed that SlAQP gene was located in the membrane.Southern blot analysis indicated that SlAQP was a single-copy gene.Real time-PCR analysis showed that the expression of SlAQP gene was down-regulated by drought stress.【Conclusion】The expression profiling of this gene indicates that the SlAQP gene may regulared by drought stress.This paper provides important information for the future study on the gene-expression regulation during drought stress.