Barroso C, Romero L C, Cejudo F J, Vega J M, Gotor C
Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, CSIC and Universidad de Sevilla, Spain.
Plant Mol Biol. 1999 Jul;40(4):729-36. doi: 10.1023/a:1006285016296.
The expression of Atcys-3A gene coding for cytosolic O-acetylserine(thiol)lyase, a key enzyme in cysteine biosynthesis, from Arabidopsis thaliana is significantly induced by exposure to salt and heavy-metal stresses. Addition of NaCl to mature plants induced a rapid accumulation of the mRNA throughout the leaf lamina and roots, and later on in stems, being mainly restricted to vascular tissues. The salt-specific regulation of Atcys-3A was also mediated by abscisic acid (ABA) since: (1) exogenous addition of ABA to the culture medium mimicked the salt-induced plant response by raising the level of Atcys-3A transcript, and (2) Arabidopsis mutants aba-1 and abi2-1 were not able to respond to NaCl. Our results suggest that a high rate of cysteine biosynthesis is required in Arabidopsis under salt stress necessary for a plant protection or adaptation mechanism. This hypothesis was supported by the observation that intracellular levels of cysteine and glutathione increased up to 3-fold after salt treatment.
拟南芥中编码胞质O-乙酰丝氨酸（硫醇）裂解酶（半胱氨酸生物合成中的关键酶）的Atcys-3A基因的表达，在暴露于盐和重金属胁迫时会显著被诱导。向成熟植株添加氯化钠会诱导该mRNA在整个叶片和根部迅速积累，随后在茎中积累，且主要局限于维管组织。Atcys-3A的盐特异性调控也由脱落酸（ABA）介导，原因如下：（1）向培养基中外源添加ABA通过提高Atcys-3A转录本水平模拟了盐诱导的植物反应；（2）拟南芥突变体aba-1和abi2-1无法对氯化钠作出反应。我们的结果表明，盐胁迫下拟南芥需要高比率的半胱氨酸生物合成，这对于植物保护或适应机制而言是必要的。这一假设得到了以下观察结果的支持：盐处理后，细胞内半胱氨酸和谷胱甘肽水平增加了高达3倍。
