Analysis of ABA hypersensitive germination2 revealed the pivotal functions of PARN in stress response in Arabidopsis.
Analysis of ABA hypersensitive germination2 revealed the pivotal functions of PARN in stress response in Arabidopsis.
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DOI：
10.1111/j.1365-313x.2005.02589.x
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发表时间：
2005-11
期刊：
影响因子：
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通讯作者：
N. Nishimura;Nobutaka Kitahata;M. Seki;Y. Narusaka;M. Narusaka;T. Kuromori;T. Asami;K. Shinozaki;T. Hirayama
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文献类型：
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作者：
N. Nishimura;Nobutaka Kitahata;M. Seki;Y. Narusaka;M. Narusaka;T. Kuromori;T. Asami;K. Shinozaki;T. Hirayama
越来越多的证据表明，信使核糖核酸降解系统在真核生物的各种生物过程中起着至关重要的作用。在这里，我们提供的证据表明，mRNA降解系统与某些植物激素和植物的逆境反应有关。我们分析了一个新的拟南芥脱落酸(ABA)超敏突变体ahg2-1，该突变体不仅在萌发阶段表现出ABA超敏，而且在发育后期也表现出多效性。我们发现，AHG2-1在种子和甘露醇处理的植株中积累了比野生型更多的内源ABA。基因芯片实验表明，在正常生长的Ag2-1植株中，ABA-、水杨酸和胁迫诱导基因的表达增加，这表明Ag2-1突变在一定程度上影响了各种胁迫反应和ABA反应。基于图谱的AHG2克隆表明，该基因编码一种多聚(A)特异性核糖核酸酶(AtPARN)，该酶被认为在mRNA降解中起作用。对ahg2-1突变的详细分析表明，该突变会减少AtPARN的产生。有趣的是，AtPARN的表达被ABA、高盐和渗透胁迫诱导。这些结果表明，AtPARN的mRNA不稳定活性上调和下调基因表达对于适当的ABA、水杨酸和胁迫反应都是至关重要的。
Accumulating evidence suggests that mRNA degradation systems are crucial for various biological processes in eukaryotes. Here we provide evidence that an mRNA degradation system is associated with some plant hormones and stress responses in plants. We analysed a novel Arabidopsis abscisic acid (ABA)-hypersensitive mutant, ahg2-1, that showed ABA hypersensitivity not only in germination, but also at later developmental stages, and that displayed pleiotropic phenotypes. We found that ahg2-1 accumulated more endogenous ABA in seeds and mannitol-treated plants than did the wild type. Microarray experiments showed that the expressions of ABA-, salicylic acid- and stress-inducible genes were increased in normally grown ahg2-1 plants, suggesting that the ahg2-1 mutation somehow affects various stress responses as well as ABA responses. Map-based cloning of AHG2 revealed that this gene encodes a poly(A)-specific ribonuclease (AtPARN) that is presumed to function in mRNA degradation. Detailed analysis of the ahg2-1 mutation suggests that the mutation reduces AtPARN production. Interestingly, expression of AtPARN was induced by treatment with ABA, high salinity and osmotic stress. These results suggest that both upregulation and downregulation of gene expression by the mRNA-destabilizing activity of AtPARN are crucial for proper ABA, salicylic acid and stress responses.