白羊草NAC转录因子基因的克隆及表达分析

Cloning and Expression Analyses of NAC Transcription Factor Gene in Bothriochloa ischaemum

NAC转录因子是植物特有的转录因子并在植物的生长发育过程中发挥重要的作用,根据其他植物NAC转录因子基因的氨基酸保守序列设计简并引物,通过RT-PCR和RACE技术从白羊草(Bothriochloa ischaemum)中获得了全长cDNA,命名为BiNAC。序列分析表明,该cDNA片段全长为1549bp,开放阅读框1125bp,编码374个氨基酸,具有典型的NAC类蛋白的结构特征。进化树分析表明,该蛋白属于ATAF亚族,与高粱(Sorghum bi-color)亲缘关系最近,同源性达到94%。Real-time PCR检测结果表明,BiNAC基因在茎中的表达量最高,根中表达量最少,并且受NaCl胁迫表达上调。同时成功构建了植物表达载体pBI121-BiNAC-GUS,为进一步开展NAC基因的功能研究创造了条件。

NAC transcription factors are specific to plants and play an important role in a diverse set of developmental processes.Using RT-PCR and RACE technology with a pair of degenerate primer designed base on the sequence of the homologous gene from other plants,a cDNA of NAC gene was cloned from Bothriochloa ischaemum,named BiNAC.Sequence analysis showed that the full-length of cDNA sequence was 1549 bp including an 1125 bp open reading frame which encoded a 374-amino-acid polypeptide and had the typical characteristics of NAC family.Phylogenetic tree analysis indicated that NAC gene belonged to the ATAF subfamily,and the BiNAC gene of B.ischaemum was closely related to that of Sorghum bicolor with 94% homology.Real-time PCR results revealed that the expression of BiNAC was the most abundant in stem and the least in root.The expression level of BiNAC gene was increased in leaves with NaCl stress.Meanwhile,the plant expression plasmid pBI121-BiNAC-GUS was constructed successfully,which will lay a foundation for the functional analysis of BiNAC gene in the future.