Laby R J, Kincaid M S, Kim D, Gibson S I
Department of Biochemistry & Cell Biology - MS140, Rice University, Houston, TX 77005, USA.
Plant J. 2000 Sep;23(5):587-96. doi: 10.1046/j.1365-313x.2000.00833.x.
Although soluble sugar levels affect many aspects of plant development and physiology, little is known about the mechanisms by which plants respond to sugar. Here we report the isolation of 13 sugar-insensitive (sis) mutants of Arabidopsis that, unlike wild-type plants, are able to form expanded cotyledons and true leaves when germinated on media containing high concentrations of glucose or sucrose. The sis4 and sis5 mutants are allelic to the ABA-biosynthesis mutant aba2 and the ABA-insensitive mutant abi4, respectively. In addition to being insensitive to glucose and sucrose, the sis4/aba2 and sis5/abi4 mutants also display decreased sensitivity to the inhibitory effects of mannose on early seedling development. Mutations in the ABI5 gene, but not mutations in the ABI1, ABI2 or ABI3 genes, also lead to weak glucose- and mannose-insensitive phenotypes. Wild-type and mutant plants show similar responses to the effects of exogenous sugar on chlorophyll and anthocyanin accumulation, indicating that the mutants are not defective in all sugar responses. These results indicate that defects in ABA metabolism and some, but not all, defects in ABA response can also alter response to exogenous sugar.
尽管可溶性糖水平影响植物发育和生理的许多方面，但对于植物响应糖的机制却知之甚少。在此，我们报告了拟南芥13个糖不敏感（sis）突变体的分离情况，这些突变体与野生型植物不同，在含有高浓度葡萄糖或蔗糖的培养基上萌发时能够形成扩展的子叶和真叶。sis4和sis5突变体分别与ABA生物合成突变体aba2和ABA不敏感突变体abi4等位。除了对葡萄糖和蔗糖不敏感外，sis4/aba2和sis5/abi4突变体对甘露糖对早期幼苗发育的抑制作用也表现出降低的敏感性。ABI5基因突变而非ABI1、ABI2或ABI3基因突变也会导致弱的葡萄糖和甘露糖不敏感表型。野生型和突变体植物对外源糖对叶绿素和花青素积累的影响表现出相似的反应，表明这些突变体并非在所有糖反应中都存在缺陷。这些结果表明，ABA代谢缺陷以及ABA反应中的一些（但不是全部）缺陷也会改变对外源糖的反应。
