关键词: 柑橘, 植物激素, 逆境, GH3, 基因表达

Abstract: Based on genomic sequences of citrus，bioinformatics and expression analysis of two GH3 （Gretchen Hagen 3）genes，i.e. CjGH3.4 and CjGH3.7 were done in Citrus junos Sieb. ex Tanaka. The Open Reading Frame（ORF）of CjGH3.4 and CjGH3.7 contained 1 830 bp and 1 800 bp，encoding a protein of 609 and 599 amino acid residues，respectively. Comparing cDNA with their corresponding DNA sequences showed that 2 and 3 introns were contained by CjGH3.4 and CjGH3.7，respectively. CjGH3.4 and CjGH3.7 shared 66%–81% amino acids identities with other plant GH3s from Arabidopsis，Oryza sativa，Glycine max and Populous trichocarpa. CjGH3.7 predominantly expressed in leaves，CjGH3.4 highly expressed in both leaves and roots with slightly higher expression level in leaves. In roots andleaves，CjGH3.4 and CjGH3.7 were both up-regulated by cold，salt and PEG，indicating their pleiotropic roles in stresses. Additionally，these two genes were also induced by ABA，ACC，MeJA and SA in leaves，and inhibited in roots，showing opposite expression pattern.

Key words: citrus, phytohormone, stress, GH3, gene expression