Isolation and molecular characterization of a novel homogalacturonan galacturonosyl- transferase gene (GbGAUT1) from Gossypium barbadense

Abstract

A novel gene, designated as GbGAUT1 (Gossypium barbadense homogalacturonan galacturonosyltransferase gene 1), was successfully cloned from G. barbadense (GenBank accession No. EF552432) by bioinformatics methods, RT-PCR and RACE. The open reading frame (ORF) was 1797 bp long and putatively encoded a polypeptide of 598 amino acids, with a predicted molecular mass of 69 kDa. GbGAUT1 could be considered as a homogalacturonan (HG) galacturonosyltransferase protein since the conserved GAUT1-related supperfamily motif had been found and it was clustered into GAUT-A group in the phylogenetic tree. Semi quantitative RT-PCR showed that GbGAUT1 preferentially expressed in the fiber secondary cell wall thickening, especially in the fibers of 35 day post anthesis (DPA). These results suggested that the novel cotton GbGAUT1 might play an important role in fiber development.