DIFFERENTIAL ACCUMULATION OF S-ADENOSYLMETHIONINE SYNTHETASE TRANSCRIPTS IN RESPONSE TO SALT STRESS
DIFFERENTIAL ACCUMULATION OF S-ADENOSYLMETHIONINE SYNTHETASE TRANSCRIPTS IN RESPONSE TO SALT STRESS
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DOI：
10.1007/bf00023239
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发表时间：
1994-05-01
影响因子：
5.1
通讯作者：
PARDO, JM
中科院分区：
文献类型：
--
作者：
ESPARTERO, J;PINTORTORO, JA;PARDO, JM
NaCl胁迫导致番茄幼苗中几种mRNA的积累。发现上调的cDNA克隆SAM 1编码S-腺苷-L-甲硫氨酸合成酶（S-腺苷-L-甲硫氨酸合成酶）。在缺乏功能性SAM基因的酵母突变体中表达cDNA SAM 1导致高的γ-Met合成酶活性和γ-Met积累。我们表明，番茄植物含有至少四个SAM isogenes。对应于同源基因SAM 2和SAM 3的克隆也已被分离和测序。它们编码的预测多肽分别与SAM 1编码的C3 Met合成酶有95%和92%的同一性。RNA杂交分析表明SAM基因对盐和其他胁迫处理的差异反应。SAM 1和SAM 3 mRNA在根中积累响应NaCl，甘露醇或阿坝处理。SAM 1 mRNA在叶组织中也有积累。这些增加的mRNA水平是明显的，只要8小时后开始的盐处理，并保持至少3天。一个可能的作用，在适应盐胁迫的AMMET合成酶进行了讨论。
NaCl stress causes the accumulation of several mRNAs in tomato seedlings. An upregulated cDNA clone, SAM1, was found to encode a S-adenosyl-L-methionine synthetase enzyme (AdoMet synthetase). Expression of the cDNA SAM1 in a yeast mutant lacking functional SAM genes resulted in high AdoMet synthetase activity and AdoMet accumulation. We show that tomato plants contain at least four SAM isogenes. Clones corresponding to isogenes SAM2 and SAM3 have also been isolated and sequenced. they encode predicted polypeptides 95% and 92% identical, respectively, to the SAM1-encoded AdoMet Synthetase. RNA hybridization analysis showed a differential response of SAM genes to salt and other stress treatments. SAM1 and SAM3 mRNAs accumulated in the root in response to NaCl, mannitol or ABA treatments. SAM1 mRNA accumulated also in leaf tissue. These increases of mRNA level were apparent as soon as 8 h after the initiation of the salt treatment and were maintained for at least 3 days. A possible role for AdoMet synthetases in the adaptation to salt stress is discussed.