Abstract:

In order to explore the role of citrus MYB96 gene in the process of citrus stress resistance,four MYB transcription factor genes were cloned from sweet orange,lemon,kumquat and ponkan,and named CsMYB96,ClMYB96,FmMYB96 and CrMYB96,respectively.Their bioinformatics and expression patterns under different abiotic stress treatments were analyzed.The results showed that the open reading frame of CsMYB96,ClMYB96,FmMYB96 and CrMYB96 were 1 032,1 035,1 035 and 1 032 bp,respectively.The citrus MYB96 proteins were composed of 343,344,344 and 343 amino acids,respectively,with a molecular weight of about 38.16, 38.27, 38.22 and 38.13 ku and an isoelectric points of 6.31,6.35,6.35 and 6.31,these proteins were all unstable hydrophilic proteins and the prediction results of subcellular localization were all located in the nucleus.The secondary structures of four MYB96 proteins were similar,mainly composed of α-helix and random curls.And all of four MYB96 proteins had a highly conserved R2 and R3 domains.In terms of evolutionary relationship,the proteins encoded by these four genes are most closely related to Citrus clementine CcMYB96 protein.The promoter of CsMYB96 gene contained abscisic acid response element(ABRE),low temperature response element(LTR),anaerobic response element(ARE),MYB binding site(MBS)involved in drought induction and other abiotic stress response related cis acting elements.Real-time quantitative PCR analysis showed that CsMYB96 could be induced by low temperature and drought stress,while ClMYB96 and FmMYB96 were induced under high salt stress.The expression of CrMYB96 was down-regulated in different degrees under low temperature,drought and high salt stress.

Key words: Citrus, MYB96, Bioinformatics analysis, Abiotic stress, Expression analysis