Mita S, Suzuki-Fujii K, Nakamura K
Laboratory of Biochemistry, School of Agricultural Sciences, Nagoya University, Japan.
Plant Physiol. 1995 Mar;107(3):895-904. doi: 10.1104/pp.107.3.895.
The levels of beta-amylase activity and of the mRNA for beta-amylase in rosette leaves of Arabidopsis thaliana (L.) Heynh. increased significantly, with the concomitant accumulation of starch, when whole plants or excised mature leaves were supplied with sucrose. A supply of glucose or fructose, but not of mannitol or sorbitol, to plants also induced the expression of the gene for beta-amylase, and the induction occurred not only in rosette leaves but also in roots, stems, and bracts. These results suggest that the gene for beta-amylase of Arabidopsis is subject to regulation by a carbohydrate metabolic signal, and expression of the gene in various tissues may be regulated by the carbon partitioning and sink-source interactions in the whole plant. The sugar-inducible expression of the gene in Arabidopsis was severely repressed in the absence of light. The sugar-inducible expression in the light was not inhibited by 3(3,4-dichlorophenyl)-1,1-dimethylurea or by chloramphenicol, but it was inhibited by cycloheximide. These results suggest that a light-induced signal and de novo synthesis of proteins in the cytoplasm are involved in the regulation. A fusion gene composed of the 5' upstream region of the gene for beta-amylase from Arabidopsis and the coding sequence of beta-glucuronidase showed the sugar-inducible expression in a light-dependent manner in rosette leaves of transgenic Arabidopsis.
给拟南芥（L.）海因里希莲座叶供应蔗糖时，β-淀粉酶活性水平及β-淀粉酶的mRNA水平显著增加，同时淀粉积累。给植株供应葡萄糖或果糖而非甘露醇或山梨醇，也会诱导β-淀粉酶基因的表达，且这种诱导不仅发生在莲座叶中，还发生在根、茎和苞片里。这些结果表明，拟南芥β-淀粉酶基因受碳水化合物代谢信号调控，该基因在不同组织中的表达可能受整株植物的碳分配及库源相互作用调控。在无光照条件下，拟南芥中该基因的糖诱导表达受到严重抑制。在光照条件下，糖诱导表达不受3-(3,4-二氯苯基)-1,1-二甲基脲或氯霉素抑制，但受环己酰亚胺抑制。这些结果表明，光诱导信号及细胞质中蛋白质的从头合成参与了调控过程。由拟南芥β-淀粉酶基因的5'上游区域与β-葡萄糖醛酸酶编码序列组成的融合基因，在转基因拟南芥的莲座叶中呈现出依赖光照的糖诱导表达。
