ABR1, an APETALA2-domain transcription factor that functions as a repressor of ABA response in Arabidopsis
ABR1, an APETALA2-domain transcription factor that functions as a repressor of ABA response in Arabidopsis
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DOI：
10.1104/pp.105.066324
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发表时间：
2005-11-01
期刊：
影响因子：
7.4
通讯作者：
Luan, S
中科院分区：
文献类型：
--
作者：
Pandey, GK;Grant, JJ;Luan, S
植物激素脱落酸（阿坝）在植物生长发育和逆境响应中起着重要作用。阿坝作用的一个重要步骤是基因表达的激活或失活。虽然一些转录因子被确定为ABA诱导的基因表达的正调控因子，但对ABA调控的基因表达的负调控因子知之甚少。在这里，我们已经确定了APETALA 2（AP 2）结构域转录因子，作为种子萌发和阿坝和应力诱导的基因表达在拟南芥（拟南芥）阿坝反应的阻遏物。AP 2-like阿坝repressor 1（ABR 1）基因本身的表达对阿坝和包括冷、高盐和干旱在内的胁迫条件有响应。ABR 1的破坏导致种子萌发和根生长测定中对阿坝的过敏反应。突变体植株对高盐和高浓度甘露醇等渗透胁迫条件也高度敏感。进一步的分析表明，增加的胁迫敏感性可能是由于阿坝生物合成抑制剂拯救了胁迫超敏表型的ABA超敏反应。与野生型植物相比，abr 1突变体植物积累了显著更高水平的阿坝和胁迫诱导基因转录物，支持了这种AP 2结构域蛋白作为阿坝调节基因表达的阻遏物的假设。
The plant hormone abscisic acid (ABA) plays an important role in plant development and stress responses. An important step of ABA action is activation or inactivation of gene expression. Although several transcription factors are identified to function as positive regulators of ABA-induced gene expression, little is known about the negative regulators of ABA-regulated gene expression. Here, we have identified an APETALA2 (AP2) domain transcription factor that serves as a repressor of ABA response during seed germination and ABA- and stress-induced gene expression in Arabidopsis (Arabidopsis thaliana). The expression of the AP2-like ABA repressor 1 (ABR1) gene itself was responsive to ABA and stress conditions including cold, high salt, and drought. Disruption of ABR1 led to hypersensitive response to ABA in seed germination and root growth assays. The mutant plants were also hypersensitive to osmotic stress conditions, such as high salt and high concentrations of mannitol. Further analyses indicated that increased stress sensitivity may result from hypersensitivity to ABA as ABA biosynthesis inhibitor rescued the stress hypersensitivity phenotype. The abr1 mutant plants accumulated significantly higher levels of ABA- and stress-inducible gene transcripts as compared to the wild-type plants, supporting the hypothesis that this AP2 domain protein serves as a repressor of ABA- regulated gene expression.