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锌铁调控转运蛋白(ZRT,IRT-like protein,ZIP)在植物生长发育过程中起重要的调控作用。研究采用实时定量PCR(QPCR)和RACE技术,首次从珍稀濒危兰科药用铁皮石斛Dendrobium officinale中克隆得到1个ZIP基因c DNA全长,命名为Do ZIP1,提交Gen Bank获得注册号KJ946203。生物信息学分析显示,该基因开放阅读框1 056 bp,编码1条由351个氨基酸组成的肽链,相对分子质量37.57 k Da,等电点6.09。推定的Do ZIP1蛋白具有保守的锌铁调控转运相关蛋白结构域,二级结构包含α螺旋50.71%、延伸链11.11%、β转角1.99%与随机卷曲36.18%,具有信号肽和8个跨膜域,预测定位在质膜。该蛋白质氨基酸序列与拟南芥、苜蓿、水稻等物种ZIP蛋白相似性较高,系统进化分析表明其与At ZIP10,Os ZIP3蛋白的亲缘关系较近,聚在一个分支。QPCR分析表明,Do ZIP1基因转录本在根中相对表达量较高,为茎中的4.19倍;叶次之,为茎的1.12倍。Do ZIP1基因的分子特征为下一步研究其在铁皮石斛生长发育过程的生物学功能奠定基础。
Zinc (ZRT) plays an important regulatory role in plant growth and development. The full-length cDNA of ZIP gene was cloned from Dendrobium officinale, a rare and endangered Orchidaceae Dendrobium officinale by real-time quantitative PCR (QPCR) and RACE techniques. The full length cDNA of ZIP gene was named Do ZIP1 and submitted to Gen Bank for registration number KJ946203. Bioinformatics analysis showed that the open reading frame of this gene was 1 056 bp, encoding a peptide chain consisting of 351 amino acids with a relative molecular mass of 37.57 kDa and an isoelectric point of 6.09. The putative Do ZIP1 protein has a conserved zinc-iron regulatory transport-related protein domain. The secondary structure contains 50.71% of α-helix, 11.11% of extension chain, 1.99% of β-turn and 36.18% of random curl. The secondary structure has signal peptide and 8 transmembrane domains , Predicted to be located at the plasma membrane. The amino acid sequence of this protein is highly similar to the ZIP protein of Arabidopsis, alfalfa, rice and other species. Phylogenetic analysis showed that it has a close relationship with At ZIP10 and Os ZIP3 proteins and clustered in one branch. QPCR analysis showed that the relative expression level of Do ZIP1 gene in roots was 4.19 times of that in stems and 1.12 times of that in leaves. The molecular characterization of Do ZIP1 gene laid the foundation for further study on its biological function in the process of Dendrobium candidum growth and development.