REGULATION OF TUBEROUS ROOT FORMATION BY CDK-ACTIVATING KINASE IN SWEET POTATO

克隆了CDK活化激酶和细胞周期蛋白H的两个cDNA，并分别命名为Ipoba; CDKD; 1和Ipoba; CycH; 1。推导的Ipoba; CDKD; 1的氨基酸序列包含一个ATP结合位点、一个激酶活性位点和T环内保守的苏氨酸残基。推导的Ipoba; CycH; 1的氨基酸序列含有N端结构域。Ipoba; CDKD; 1基因在所有器官中均有表达，但在块根中表达量最低。在不同器官中的转录本的相对丰度之间几乎没有变化。在块根形成过程中，蔗糖、阿坝和细胞分裂素含量增加。因此，这些信号分子对Ipoba; CDKD; 1和Ipoba; CycH; 1表达的影响。Ipoba的表达; CDKD; Ipoba; CycH; 1的表达受蔗糖溶液的影响不显著。阿坝诱导Ipoba; CDKD; 1的表达，而Ipoba; CycH; 1的表达不受阿坝的影响。Ipoba; CDKD; 1 mRNA的相对量被苄基腺嘌呤降低，而苄基腺嘌呤增加Ipoba; CycH; 1 mRNA的相对量。蔗糖拮抗苄基腺嘌呤对Ipoba; CDKD; 1基因表达的抑制作用。当补充蔗糖时，苄基腺嘌呤增强Ipoba; CycH; 1的表达。这些结果表明，细胞增殖是通过调节CDK激活激酶和细胞周期蛋白H基因表达的蔗糖，阿坝和细胞分裂素的浓度的变化来控制。

Two cDNAs for a CDK-activating kinase and a cyclin H were cloned and designated Ipoba; CDKD; 1 and Ipoba; CycH; 1, respectively. The deduced amino acid sequences for Ipoba; CDKD; 1 contained an ATP-binding site, an kinase active-site and the conserved threonine residue within the T-loop. The deduced amino acid sequences for Ipoba; CycH; 1 contained N-terminal domain. Ipoba; CDKD; 1 transcript was detected in tuberous roots with the lowest level, although the gene was expressed in allorgans. There was little variety found among the relative abundance of transcripts in different organs. The levels of sucrose, ABA and cytokinins increase in the process of tuberous root formation. Therefore, the effect of these signal molecules on the expression of both Ipoba; CDKD; 1 and Ipoba; CycH; 1. The expression of Ipoba; CDKD; 1 increased by application of sucrose solution, while the expression of Ipoba; CycH; 1 was not significantly affected by sucrose. ABA induced the expression of Ipoba; CDKD; 1, whereas the expression of Ipoba; CycH; 1 was not influenced by ABA. The relative amount of Ipoba; CDKD; 1 mRNA was reduced by benzyladenine, while benzyladenine increased the relative amount of Ipoba; CycH; 1 mRNA. Sucrose antagonized the inhibitory effect of benzyladenine for Ipoba; CDKD; 1 gene expression. Benzyladenine enhanced the expression of Ipoba; CycH; 1 when sucrose was supplemented. These results suggested that cell proliferation was controlled via regulation of CDK-activating kinase and cyclin H gene expression by alterations in the concentration of sucrose, ABA and cytokinin.