Cloning and Sequence Analysis of Expansin Genes in Citrus Fruits

摘要

Degenerate oligonucleotide primers were designed on the basis of conserved domain of known expansions to amplify cDNA fragment of 531 bp in Citrus peel by RT-PCR. According to the cDNA fragment sequence, the 5' end and 3 ' end fragment sequences were obtained by RACE technology. The full length cDNA of expansion gene, named Ct-Exp 1, was cloned. Ct-Exp 1 was composed of 1 196 bp, encoding 246 amino acids. Eight cysteine residues and 4 tryptophan residues, which are supposed to be the characteristics of expansins, are conserved in Ct-Exp 1, and it contains histidine function region. Its BLAST search against GenBank database showed that it showes 88% , 88% , 87% and 86% , 85% homology with the sequences of EXP proteins in Malus X domestica, Dimocarpus longan, Prunus cerasus, Vitis labruscax Vitis vinifera, Prunus persica.