组氨醇脱氢酶将组氨醇氧化成组氨酸,是组氨酸合成途径中的最后一步,调控植物的生长和发育过程.为了更好地理解大叶落地生根中胎生苗调控的分子机制,利用RACE-PCR技术从大叶落地生根中克隆了1个新的组氨醇脱氢酶基因KdHDH.该基因编码的蛋白质具有483个氨基酸残基,分子量为52 130,等电点为5.78,其开放阅读框长度为1 452 bp.KdHDH蛋白与葡萄、拟南芥、蓖麻等植物的蛋白相似性都很高,聚类分析结果表明该蛋白与甜菜和菠菜的遗传距离最近.实时荧光定量PCR分析结果表明,该蛋白基因在大叶落地生根的根中表达量最高,且受渗透胁迫(甘露醇)的诱导下调表达.%Catalyzing histidinol to histidine by histidinol dehydrogenase(HDH) is the final step of his biosynthetic pathway, playing an important role in plant growth and development.To better understand the molecular mechanisms of plantlet formation involved in Kalanchoe daigremontiana, a KdHDH gene was identified using rapid amplification of cDNA end (RACE) PCR.KdHDH gene consists of an ORF of 1 452 bp that was predicted to encode a 483 amino acid residue-long protein of 52 130 with an isoelectric point of 5.78.KdHDH was related most closely to VvHDH, AtHDH and RcHDH, and phylogenetic analysis showed the closest genetic distance with BvHDH and SoHDH.Real-time PCR analysis revealed that KdHDH transcript was expressed highly in root and down-regulated under osmotic stress.
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