Phylogenetic Analysis Of LTP Genes In Triticeae

Lipid transfer proteins (LTPs) play a significant role in plant growth, development and defense. Phylogenetic analysis of LTP genes were conducted on the basis of LTP gene sequences from Au, Am, D, Eb, Ee, F, H, I, M, N, Ns, P,O, Q, R, St, Ss, Sl, Ssh, Ta, C, G and ABD genomes of 31 different materials in Triticeae. The main results were listed as follows:1. Eighty-six LTP genes from different genomes were cloned and sequenced. All the open reading frames were 348 bp except for the sequences obtained from barley (354 bp). The homology percentage of nucleotide sequences of each material ranged from 89.94 to 100%. The identity of the LTP genes with known genes from NCBI ranged from 88 to 100%. There is no difference between the LTP genes from the materials containing D, Au, Am, F, I, H or ABD genomes respectively. The similarity of all sequences was 92.56% and the sequences were in most of the very conservation region. The conversion between T and C happened 38 times each other, and concentrated in the 30-130 bp region. One ATTTAC insertion occurred in the 3'partial of cDNA of barley LTP genes.2. All the deduced amino acids sequences contained 115 residues except for that of barley LTP (117 residues), and the deduced molecular weight was from 11807 Da to 12281 Da. The N terminal signal peptide contained 26 amino acid residues. The similarity of the primary structure was 86.70%. According to the difference in the number and placement of the cysteine residue and the formation of disulfide bond in LTP, the AA sequences were divided into three categories:The LTPs from Au, Am, G and F genomes were classified as the first category. Their disulfide bonds were formed between C29 and C74, C39 and C53, C54 and C98, C76 and C113 respectively; The second category contains the LTPs from CD, D, Eb, F, H, I, M, N, Ns, P, Q, R, St, Ss,Sl,Ssh, O, Ta and ABD genomes. Their disulfide bonds were formed between C29 and C76, C39 and C53, C54 and C98, C74 and C113 respectively; The 75th residue of LTP18-P and LTP19-P was a basic amino acid, K, from Henrardia persica (O genome). The eight conserved cysteines of all the LTP were located at the 29,39,53,54,74,76,98 and 113th position respectively. LTP17-P from O genome contains 10 cysteines locating at the 29,39,53, 54,58,76,86,94,99 and 113th position respectively, which was recognized as the third class.3. Homology analysis of the deduced amino acids indicated that:D, N, Ssh, ABD, Au, P, Am, AG, Sl, M, CD, Ss, St, F and Ta; Eb, Ss, St, Ee, O, F and R; I and H; M, P, Ssh, Ns, Q, H and Ta genomes were clustered together respectively. LTP17-P (O genome) was clustered the unique class. Phylogenetic analysis indicated that:Eb, Ee and Ns; ABD, D, N, Ssh, Sl,AG, Am, Au, F, M, CD, Ss,Ta and R; H, I, P, Q and Sl genomes were clustered together respectively, indicating that these genomes had close relationship in the same class.O genome was clustered the unique class. The LTPs from different materials had the high homology but with the different evolutionary relationship.