REGULATION OF TUBEROUS ROOT FORMATION BY D-TYPE CYCLIN IN SWEET POTATO

克隆了两种用于d3型细胞周期蛋白的cdna，命名为Ipoba；CycD3；CycD3;2；Ipoba;CycD3；1和Ipoba；CycD3；2包含一个视网膜母细胞瘤结合基序和一个周期蛋白盒，而它们只有49%的同一性。在块根形成过程中，Ipoba;CycD3；1在粗根和块根中表达量最高。Ipoba; CycD3;2个基因的表达量在粗根中达到最高水平。adp -葡萄糖焦磷酸化酶大亚基iAGPLI-1转录物水平持续升高。为了更准确地阐明蔗糖和植物激素对基因表达的影响，采用叶柄扦插的方法。Ipoba;CycD3；1在施用50 mM和100 mM蔗糖溶液后逐渐增加，其中以100 mM和150 mM蔗糖的表达量最高。1 . Ipoba、CycD3在100 mM的表达量最大。在150 mM蔗糖浓度下，iAGPLI-1基因的表达随蔗糖浓度的增加呈上升趋势。1和增强蔗糖诱导Ipoba；CycD3；1表达。Ipoba;CycD3；在添加蔗糖的情况下，2 mRNA的转录本增加，而在添加苄ladenine的情况下，2 mRNA的转录本略有减少。蔗糖对iAGPLI-1的诱导作用被苄腺嘌呤抑制。ABA降低了Ipoba、CycD3的相对量；1 mRNA。蔗糖可拮抗ABA对Ipoba、CycD3的抑制作用；1基因表达。Ipoba;CycD3；2不受ABA的影响。ABA对iAGPLI-1基因表达无显著影响，而蔗糖对iAGPLI-1的诱导作用被ABA抑制。这些结果表明，蔗糖、细胞分裂素和ABA浓度的改变可能通过调控D3细胞周期蛋白和adp -葡萄糖焦磷酸化酶基因的表达来调控块根形成过程中的细胞增殖和储存实质分化。少

Two cDNAs for D3-type cyclins were cloned and designated Ipoba;CycD3;1 and Ipoba;CycD3;2. The deduced amino acid sequences for Ipoba;CycD3;1 and Ipoba;CycD3;2 contained a retinoblastoma-binding motif and a cyclin box, whereas they shared only 49% identity. In the process of tuberous root formation, Ipoba;CycD3;1 was expressed in thick roots and tuberous roots at the highest level. The Ipoba;CycD3;2 gene expression reached a maximum level in thick roots. The transcript level of ADP-glucose pyrophosphorylase large subunit iAGPLI-1 increased continuously. In order to clarify the effect of sucrose and plant hormones on gene expression more precisely, leaf-petiole cuttings were used. The expression of Ipoba;CycD3;1 increased stepwise by application of 50 mM and 100 mM sucrose solution, and the highest expression level was obtained with 100 mM and 150 mM sucrose. A hundred mM was optimal for maximum expression of Ipoba;CycD3;2. The expression of iAGPLI-1 gene kept an increasing tendency with … More an increase in sucrose concentration up to 150 mM. Benzyladenine induced the expression of Ipoba;CycD3;1 and enhanced sucrose induction of Ipoba;CycD3;1 expression. The relative amount of Ipoba;CycD3;2 mRNA was slightly reduced by benzyladenine, while the transcripts increased in response to benzyladenine when sucrose was supplemented. The induction of iAGPLI-1 by sucrose was repressed by benzyladenine. ABA reduced the relative amount of Ipoba;CycD3;1 mRNA. Sucrose antagonized the inhibitory effect of ABA for Ipoba;CycD3;1 gene expression. The expression of Ipoba;CycD3;2 was not influenced by ABA. iAGPLI-1 gene expression was not significantly affected by ABA, whereas the induction of iAGPLI-1 by sucrose was inhibited by ABA. These results suggested that cell proliferation and storage parenchyma differetiation in the process of tuberous root formation were controlled via regulation of D3 cyclins and ADP-glucose pyrophosphorylase gene expression by alterations in the concentration of sucrose, cytokinin and ABA. Less