Cloning And Expression Analyses Of GH3-Like Gene GbGH3 In Sea-Island Cotton(Gossypium Barbadense)

Plant GH3 gene family is a typical auxin-responsive gene family, which plays an important role in maintaining the auxin homeostasis, as well as enhancing plant stress resistance. A GH3-LIKE gene GbGH3 was cloned from sea-island cotton. The study on the expression of GbGH3 was to give reference to the further research of its function. The results are as following.1. The cDNA sequence of GbGH3 was 2274bp with a 137bp 5'UTR and a 376bp 3'UTR. The GbGH3 had an open reading frame of 1761 bp, encoding a putative protein of 587 amino acids with a calculated molecular weight of 65.9kDa and pI of 5.35. GbGH3 had the highest homology and latest evolutionary relationship with the GH3 proteins in group III GH3 family in Arabidopsis.2. RT-PCR analysis showed that GbGH3 expressed highly in flowers, followed by in stems and leaves, and very low level was detected in roots and ovules, suggesting that GbGH3 expressed differently in different organs. Besides, the expression level of GbGH3 in the ovules post anthesis was higher than that in the ovules before the anthesis, which suggested that GbGH3 was related to the development of cotton fiber.3. When the sea-island cotton was treated for 30 minutes, the expression level of GbGH3 in roots, stems, and leafs became obviously higher than the untreated ones. The expression level of GbGH3 got its peak at about 6 hours after the treatment was applied.4. Plant expression vector (pCAMBIA1304-GbGH3) containing the GbGH3 gene driven by CaMV35S promoter was constructed and introduced into Arabidopsis. RT-PCR showed that GbGH3 had expressed in transgenic lines, and there was obvious diversity between different lines.