Regulation of Expression of D3-type Cyclins and ADP-Glucose Pyrophosphorylase Genes by Sugar, Cytokinin and ABA in Sweet Potato (Ipomoea batatas Lam.)
Regulation of Expression of D3-type Cyclins and ADP-Glucose Pyrophosphorylase Genes by Sugar, Cytokinin and ABA in Sweet Potato (Ipomoea batatas Lam.)
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DOI：
10.1626/pps.12.434
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发表时间：
2009-01
影响因子：
2.5
通讯作者：
T. Nagata;Kazuyuki Saitou
中科院分区：
文献类型：
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作者：
T. Nagata;Kazuyuki Saitou
摘要甘薯的产量既受细胞分裂速率的控制，又受块根的库活性控制。本研究旨在揭示块根形成过程中细胞分裂活性和库活性的调控机制。作为细胞分裂活性的指标，我们使用了两个D3型细胞周期蛋白的转录水平，它们通过形成细胞周期蛋白依赖的激酶复合体的调节亚单位来调节细胞周期的进展。利用淀粉合成的关键酶之一ADP-葡萄糖焦磷酸化酶(AGPase)的基因表达作为光合作用产物库活性的指标。在块根形成过程中，D3细胞周期蛋白基因的表达达到最高水平，然后下降。相反，AGPase基因的表达持续增加。蔗糖促进D3细胞周期蛋白和AGPase基因的表达，但高浓度蔗糖抑制D3细胞周期蛋白基因的表达。在蔗糖存在的情况下，细胞分裂素增加D3细胞周期蛋白的表达，而脱落酸(ABA)不能。然而，细胞分裂素和ABA抑制蔗糖诱导的AGPase基因表达。这些结果表明，糖、细胞分裂素和脱落酸对甘薯的细胞分裂活性和库活性具有调节作用。
Abstract The productivity of sweet potato is governed by both the rate of cell division and sink activity of its tuberous root. The aim of this study was to reveal the mechanisms that regulate cell division activity and sink activity during tuberous root formation. As an indicator of the cell division activity, we used the transcript level of two D3-type cyclins, which regulate cell cycle progression through the formation of the regulatory subunit of the cyclin-dependent kinase complex. As an indicator of photosynthetic product sink activity, we used the gene expression of ADP-glucose pyrophosphorylase (AGPase), one of the key enzymes of starch synthesis. During tuberous root formation, the expression of D3 cyclin genes increased to the maximal levels and then decreased. In contrast, the expression of the AGPase gene increased continuously. Sucrose enhanced the expression of D3 cyclin and AGPase genes, but a high concentration of sucrose repressed the expression of a D3 cyclin gene. In the presence of sucrose, cytokinin increased the expression of D3 cyclins, but abscisic acid (ABA) did not. However, cytokinin and ABA repressed the induction of AGPase gene expression by sucrose. These results suggested that sugars, cytokinin and ABA regulate the cell division activity and the sink activity in sweet potato.