MYB转录因子是植物体内最大的转录因子家族之一,参与植物生长发育的调控、对逆境的响应等生理过程。本研究通过RACE技术从中间锦鸡儿(Caragana intermedia)中克隆了一个MYB转录因子CiMYBJ2(GenBank登录号:KJ937783),并对其在植物中的表达及其启动子进行了初步研究。本研究克隆得到该基因cDNA全长1368 bp,3’UTR长196 bp,5’UTR长203 bp。其中开放阅读框长969 bp,编码一个含322个氨基酸的亲水蛋白。gDNA序列长1285 bp,有2个内含子和3个外显子。采用实时荧光定量PCR技术分析了CiMYBJ2的表达模式,结果发现,在高温、脱水、NaCl、干旱等处理条件下,CiMYBJ2基因对不同胁迫均有响应。在高温处理后,CiMYBJ2基因的表达量在1和3 h明显降低,之后维持一个较低值,在不同时间点基因表达量与0 h相比差异均达到极显著水平(P<0.01);在脱水处理1 h后CiMYBJ2基因的表达量上升,且与0 h相比差异极显著(P<0.01),然后逐渐降低,在3 h CiMYBJ2基因的表达量与0 h相比差异不显著(P>0.05),在8和12 h该基因的表达量与0 h相比差异均达到极显著(P<0.01),在24 h的表达量是0 h的一半,且差异显著(P<0.05);在NaCl处理1 h后CiMYBJ2基因的转录水平开始增加,3 h达到最高,之后总体呈下降趋势,在8h表达量最低,在1、3、8和24h该基因的表达量与0h相比差异极显著(P<0.01),在12 h CiMYBJ2基因的表达量与0 h相比差异不显著(P>0.05);干旱处理6 d后,CiMYBJ2基因的表达量上升,之后一直下降,且与0 d相比差异达到极显著水平(P<0.01),15 d表达量最低。研究结果暗示CiMYBJ2基因可能在植物对胁迫的响应过程中起作用。利用染色体步移技术克隆了中间锦鸡儿CiMYBJ2基因启动子序列,长度为873 bp,分析显示,该启动子具有响应多种非生物胁迫的顺式作用元件。研究结果为进一步?
MYB transcription factor is one of the largest family of transcription factors in plants which play impotant roles in regulation of plant growth and development, and response to many environmental stimuli. In this study, a gene named CiMYBJ2 (GenBank accession No.KJ937783) was cloned by RACE technique fromCaragana intermedia and its expression level along with the promoter was analysed. The full-length cDNA of CiMYBJ2 was 1 368 bp with the 3’UTR of 196 bp and the 5’UTR of 203 bp. The ORF of CiMYBJ2 was 969 bp, encoding a protein of 322 amino acids which was hydrophilia. The full-length gDNA was 1 285 bp, including two introns and three exons. The expression pattern of CiMYBJ2 analysed by qRT-PCR showed that it was altered by heat, dehydration, NaCl and drought treatments. After heat treatment, the expression of CiMYBJ2 decreased at 1 and 3 h, and then maintained a lower level expression. the change of gene expression at different time points was extremely significant compared with the 0 h (P〈0.01). After dehydration treatment for 1 h, the expression of CiMYBJ2 increased shortly, and then gradually decreased at 3 h, and the expression difference was not significant compared with the 0 h (P〉0.05). After 8 h , the expression of the gene showed extremely significant comapred with that of the 0 h (P〈0.01), and the expression level of the gene at 24 h reached only half of that at 0 h (P〈0.05). Under NaCl treatment, the transcript level of CiMYBJ2 began to increase after 1 h, and reached the maximum at 3 h. After that the overall trend kept downward, the expression dropped to the lowest level at 8 h, and expression of the gene was extremely significant at different time points except for 12 h (P〈0.01). After drought treatment of 6 d, the expression of CiMYBJ2 increased slightly, and dropped significanly after compared with 0 d (P〈0.01), reached the minimum expression at 15 d. The promoter sequence of CiMYBJ2 with 873 bp in length was obtained by genome walking technique and ma