王存等《The Plant Journal》2023年

论文题目：Brassinosteroid transcription factor BES1 modulates nitrate deficiency by promoting NRT2.1 and NRT2.2 transcription inArabidopsis

论文作者：Tian Wang，Mengjiao Li，Jize Yang，Min Li，Zhenqian Zhang，Huiling Gao，Cun Wang*，Hui Tian*

论文摘要：

Nitrogen (N) is one of the most essential mineral elements for plants. Brassinosteroids (BRs) play key roles in plant growth and development. Emerging evidence indicates that BRs participate in the responses to nitrate deficiency. However, the precise molecular mechanism underlying the BR signaling pathway in regulating nitrate deficiency remains largely unknown. The transcription factor BES1 regulates the expression of many genes in response to BRs. Root length, nitrate uptake, and N concentration ofbes1-Dmutants were higher than those of wild type under nitrate deficiency. In addition, BES1 levels strongly increased under low nitrate conditions, especially in the non-phosphorylated (active) form. Furthermore, BES1 directly bound to the promoters ofNRT2.1andNRT2.2to promote their expression under nitrate deficiency. Taken together, this study elucidates the mechanism by whichBR signaling is directly involved in regulating nitrate transporters and plant nitrate uptake,providing direct evidence for crosstalk between BR signaling and nitrate absorption.

氮（N）是植物所必需的矿质元素之一。油菜素内酯(BRs)在植物生长发育中起着重要作用。前期研究结果暗示BRs参与硝酸盐的响应过程。然而，BR信号通路参与低氮胁迫响应的具体分子机制还鲜有报道。BR信号核心转录因子BES1广泛参与基因的转录调控过程。表型分析发现功能获得性突变体bes1-D在低氮条件下表现出明显的根系较长、氮吸收速率提高的表型。进一步研究表明，低浓度硝酸盐处理显著提高了BES1蛋白的积累，尤其是非磷酸化状态的活性形式，进而促进其对下游靶基因的转录调控。通过EMSA和ChIP-qPCR进一步证明BES1直接结合并调控高亲和氮转运体NRT2.1和NRT2.2的表达。综上所述，该研究阐明了BR信号直接参与调节硝酸盐转运蛋白和植物硝酸盐吸收的机制，为BR信号传导与硝酸盐吸收之间的串扰提供了直接证据。

论文链接：https://doi.org/10.1111/tpj.16203