Isolation of blt4.9 Gene Encoding LTP Protein in Hulless Barley and Its Re-sponse to Abiotic Stresses

Abstract

Higher plant lipid transfer protein (LTP) is a class of small molecular weight alkaline single protein that can transfer phospholipids between biomembrane and form the biomembrane in cells. The objective of this study was to understand the func- tion of LTP gene in hulless barley (Hordeum vulgare L. var. nudum Hook. f.). The cDNA sequence of the LTP gene, blt4.9 (Gen- Bank accession number KU170187), was cloned from hulless barley variety Kunlun 12. The full length of blt4.9 cDNA is 720 bp including 348 bp of open reading frame and encodes 115 amino acids. The encoding product is a stable protein with a molecular weight of 11.2 kD, theoretical pI of 9.04, and instability coefficient of 28.41. This protein is rich in Gly, Ala, Leu, and Val amino acids excluding Trp, Glu, and Phe and similar to proteins encoded by other LTP genes. Sequence alignment indicated high simila- rity (98.3%) of protein encoded by blt4.9 from hulless barley and barley (Hordeum vulgare L.). The Real-time PCR assay showed that blt4.9 was up-regulated by 20-30% PEG-6000, 4oC and 50 mol L 1 ABA and the expression level was higher in the most tolerant variety Handizi than in the most susceptible variety Dama, indicating a possible relationship between stress tolerance and blt4.9 in hulless barley. These results provide basic information in the utilization of LTP genes to improve hulless barley tolerance