The interaction of the Arabidopsis response regulator ARR18 with bZIP63 mediates the regulation of PROLINE DEHYDROGENASE expression.
The interaction of the Arabidopsis response regulator ARR18 with bZIP63 mediates the regulation of PROLINE DEHYDROGENASE expression.
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DOI：
10.1093/mp/ssu074
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发表时间：
2014-10
期刊：
影响因子：
27.5
通讯作者：
Manikandan Veerabagu;Tobias Kirchler;K. Elgass;Bettina Stadelhofer;M. Stahl;K. Harter;Virtudes Mira-Rodado-Virtudes-M
中科院分区：
文献类型：
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作者：
Manikandan Veerabagu;Tobias Kirchler;K. Elgass;Bettina Stadelhofer;M. Stahl;K. Harter;Virtudes Mira-Rodado-Virtudes-M
脯氨酸脱氢酶（proline DEHYDROGENASE1, PDH1）作为脯氨酸降解的第一酶和限速酶，在植物逆境响应中受到严格调控，包括低渗诱导和缺水抑制。植物受体组氨酸激酶AHKs是拟南芥双组分系统（two-component system， TCS）的元件，被认为通过调节不同的胁迫应答基因在水分胁迫应答中起作用。然而，关于AHK磷中继介导的下游信号的信息很少。本研究表明，拟南芥b型响应调节因子18 （ARR18）在拟南芥种子中作为正渗透胁迫响应调节因子发挥作用，并影响PDH1启动子的活性，已知PDH1启动子受c组bZIP转录因子控制。此外，我们还发现了ARR18与bZIP63之间的直接物理相互作用，并证明其依赖于ARR18受体域中保守的天冬氨酸残基的磷酸化。我们进一步证明bZIP63本身在渗透胁迫下作为种子萌发的负调节因子。通过原生质体的报告基因分析，我们证明了ARR18的相互作用会对PDH1启动子上bZIP63的转录活性产生负向干扰。我们的研究结果为ARR18和bZIP63作为拟南芥基因表达的拮抗调节因子的功能提供了新的见解。
As the first and rate-limiting enzyme of proline degradation, PROLINE DEHYDROGENASE1 (PDH1) is tightly regulated during plant stress responses, including induction under hypoosmolarity and repression under water deficit. The plant receptor histidine kinases AHKs, elements of the two-component system (TCS) in Arabidopsis thaliana, are proposed to function in water stress responses by regulating different stress-responsive genes. However, little information is available concerning AHK phosphorelay-mediated downstream signaling. Here we show that the Arabidopsis type-B response regulator 18 (ARR18) functions as a positive osmotic stress response regulator in Arabidopsis seeds and affects the activity of the PDH1 promoter, known to be controlled by C-group bZIP transcription factors. Moreover, direct physical interaction of ARR18 with bZIP63 was identified and shown to be dependent on phosphorylation of the conserved aspartate residue in the ARR18 receiver domain. We further show that bZIP63 itself functions as a negative regulator of seed germination upon osmotic stress. Using reporter gene assays in protoplasts, we demonstrated that ARR18 interaction negatively interferes with the transcriptional activity of bZIP63 on the PDH1 promoter. Our findings provide new insight into the function of ARR18 and bZIP63 as antagonistic regulators of gene expression in Arabidopsis.