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Resarch of metabolic responses to environmental stress in halophyte and regulation by protein kinase

盐生植物对环境胁迫的代谢响应及蛋白激酶调控研究

基本信息

批准号：
15380015
负责人：
YASUDA Takeshi
金额：
$ 9.79万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15380015/
关键词：
Atriplex betain environmental stress halophyite protein kinase salt tolerance Atriplex nummularia

项目摘要

Glycinebetaine (betaine) highly accumulates as a compatible solute in certain plants and has been considered to play a role in the protection from salt stress. The betaine biosynthesis pathway of betaine-accumulating plants involves choline monooxygenase (CMO) as the key enzyme and phosphoethanolamine N-methyltransferase (PEAMT), which require S-adenosyl-L-methionine (SAM) as a methyl donor. SAM is synthesized by SAM synthetase (SAMS), and is needed not only for betaine synthesis but also for the synthesis of other compounds, especially lignin. We cloned CMO, PEAMT and SAMS isogenes from a halophyte Atriplex nummularia L. (Chenopodiaceous). The transcript and protein levels of CMO were much higher in leaves and stems than in roots, suggesting that betaine is synthesized mainly in the shoot. The regulation patterns of transcripts for SAMS and PEAMT highly resembled that of CMO in the leaves during and after relief from salt stress, and on a diurnal rhythm. In the leaves, the betaine con … More tent was increased but the lignin content was not changed by salt stress. These results suggest that the transcript levels of SAMS are coregulated with those of PEAMT and CMO to supply SAM for betaine synthesis in the leaves.We have constructed a series of deletion mutants of Arabidopsis MAPK kinase kinase (AtMEKK1) and obtained a constitutively active mutant, AtMEKK1 Δ166, which lacks in self-inhibitory sequence of N-terminal 166 amino acids but still has substrate specificity. AtMEKK1 Δ166 predominantly phosphorylates AtMEK1, an Arabidopsis MAPKK, but not its double mutant (AtMEK1T218A/S224E), suggesting that Thr-218 and Ser-224 are the phosphorylation sites.In wounded seedlings, AtMEKK1 was activated and phosphorylated its downstream AtMEK1. Furthermore, analysis using anti-AtMEKK1 and anti-AtMEK1 antibodies revealed that the interaction between the two proteins was signal dependent. These results suggest the presence of AtMEKK1-AtMEK1 pathway induced by wounding. Taking account of our previous data supporting the AtMEK1-ATMPK4 pathway, we provide here new data to complete the AtMEKK1-AtMEK1-AtMPK4 cascade that works under wounding of Arabidopsis seedling. Less

甘氨酸甜菜碱（甜菜碱）在某些植物中作为相容性溶质高度积累，并被认为在盐胁迫下起保护作用。甜菜碱积累植物的甜菜碱生物合成途径涉及胆碱单加氧酶（CMO）作为关键酶和磷酸乙醇胺N-甲基转移酶（PEAMT），后者需要S-腺苷-L-甲硫氨酸（SAM）作为甲基供体。SAM是由SAM合成酶（SAMS）合成的，它不仅是甜菜碱合成所必需的，而且也是其它化合物，特别是木质素合成所必需的。我们从盐生植物滨藜中克隆了CMO、PEAMT和SAMS等基因。（藜科）。CMO在叶和茎中的转录水平和蛋白质水平均高于根，表明甜菜碱主要在地上部合成。SAMS和PEAMT的转录调控模式与CMO在盐胁迫缓解期间和缓解后的调控模式高度相似，且具有昼夜节律。在叶子里，甜菜碱 ...更多信息盐胁迫增加了木质素含量，但对木质素含量没有影响。我们构建了一系列拟南芥MAPK激酶激酶（AtMEKK 1）的缺失突变体，获得了一个组成型活性突变体AtMEKK 1 Δ166，该突变体N端166个氨基酸的自抑制序列缺失，但仍具有底物特异性。AtMEKK 1 Δ166主要磷酸化AtMEK 1（拟南芥MAPKK），但不磷酸化其双突变体（AtMEK 1 T218 A/S224 E），表明其Thr-218和Ser-224是磷酸化位点。此外，使用抗AtMEKK 1和抗AtMEK 1抗体的分析显示，两种蛋白质之间的相互作用是信号依赖性的。这些结果表明存在由创伤诱导的AtMEKK 1-AtMEK 1通路。考虑到我们以前的数据支持AtMEK 1-ATMPK 4途径，我们在这里提供新的数据来完成AtMEKK 1-AtMEK 1-AtMPK 4级联反应，拟南芥幼苗受伤。少