Cloning And Analysis Of CDNA Of Plasma Membrane Aquaporin Subfamily Genes PIP In Stipa Grandis

A typical grassland plants, Stipa grandis P.Smirn, growing in the Inner Mongolia steppe region of central as an important role in ecological and economic significance in Asia was collected and cultured. Three full-length cDNAs encoding plasma membrane aquaporin genes cDNA sequence were cloned from Stipa grandis by RT-PCR and RACE technology. The full cDNA characteristics were analyzed by bioinformatics software in order to further elucidate their involvement in eremic plant water transport. The mainly results as follows:Degenerate primers were designed based on the conserved amino acid sequence of the published AQPs from allied species, the method of RACE was adopted and three full-length cDNAs encoding aquaporin genes were cloned from Stipa grandis P., named SgPIP2-1、SgPIP1-4and SgPIP1-5. The SgPIP2-1gene consists of1066bp, encoding288amino acids. SgPIP1-4gene consists of1054bp, encoding288amino acids. SgPIP1-5gene consists of1053bp, encoding289amino acids.The SgPIP2-1nucleotide sequence showed the highest identity (96%) with HvPIP2-1by Blast homology comparison analysis; The SgPIP1-4nucleotide sequence showed the highest identity (83%) with ZmPIP1-4; The SgPIP1-5nucleotide sequence showed the highest identity(85%)with HvPIP1-5. The amino acids phylogenetic analysis of SgPIP2-1、SgPIPl-4and SgPIP1-5indicated that SgPIP2-1is a member of the PIP2gene subfamily, SgPIP1-4and SgPIP1-5were members of the PIP1gene subfamily.Bioinformaties analysis of SgPIP2-1、SgPIP1-4and SgPIP1-5showed that they not only had the MIP family of signal sequence SGXHXNPAVT, but also the characteristics of plasma membrane water channel protein signal sequence GGGANXXXXGY and TGI/TNPAR SL/FGAAI/VI/VF/YN. Analysis of predicted lyophobic/hydropathy plot、 membrane spaning domain for SgPIP2-1、SgPIP1-4and SgPIP1-5indicated that they comprised functional architecture of model membranin characteristics.Prediction of three-dimensional structure of SgPIP2-1、SgPIPl-4and SgPIP1-5showed that they included six transmembrane helices、five hydropathy loops、short a-helix and Asn-Pro-Ala (NPA) amine acid which located in the top of short a-helix.