毛白杨转录因子PtCBF5的表达模式分析(英文)

Expression Pattern of PtCBF5,a CBF Homologue Gene Encoding Transcription Activator in Populus tomentosa

利用RT-PCR手段克隆得到1个毛白杨CBF基因cDNA,命名为PtCBF5(GenBank注册:DQ354395)。PtCBF5全长837bp,该序列包括起始密码子ATG和42bp的5′末端非编码区,终止密码子TGA和98bp的3′末端非编码区,开放阅读框编码231个氨基酸。RT-PCR半定量研究表明:PtCBF5在叶片组织中的表达量高,茎、根中的表达量低。组培苗在低温、干旱、NaCl、ABA条件下处理诱导24h,在低温和干旱的条件下PtCBF5表达量在诱导30min后开始增加,分别在2h和6h达到峰值,24h后又恢复到初始水平;而高盐和ABA存在的条件下未有显著变化。PtCBF5在植物体适应寒冷和干旱的过程中可能有着重要作用,尤其在逆境初期。

Cold repeat binding factor （ CBF） proteins,specifically binding to the cold repeat （ CRT） /dehydration-responsive element （DRE）,have been identified as a group of important transcription activators of plants which regulate the expression of genes in response to the cold,drought and high-salt stresses. PtCBF5 from Populus tomentosa was cloned by RT-PCR methods,GenBank accession No. DQ354395. It contained an ORF of 696 bp encoding 231 amino acids domain that showed the typical characteristics of CBF gene family. The transcripts of PtCBF5 were the most abundant mRNA products in leaves,however relatively scarce in stem and roots using semi-quantitative RT-PCR. The shoots were treated with low-temperature,dehydration,NaCl,and ABA （ abscisic acid）. PtCBF5 gene could be greatly induced by low-temperature and dehydration stresses. Expression of PtCBF5 gene was increased in 30 min after freezing or drought treatments,and reached to a peak after 2 h in freezing or 6 h in dehydration. PtCBF5 may play very important roles in early signal transduction related to the cold and dehydration stresses.