DWARF AND LOW-TILLERING Acts as a Direct Downstream Target of a GSK3/SHAGGY-Like Kinase to Mediate Brassinosteroid Responses in Rice
DWARF AND LOW-TILLERING Acts as a Direct Downstream Target of a GSK3/SHAGGY-Like Kinase to Mediate Brassinosteroid Responses in Rice
复制标题
矮化和低分蘖作为 GSK3/SHAGGY 样激酶的直接下游靶点介导水稻中油菜素类固醇反应
DOI：
10.1105/tpc.112.097394
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发表时间：
2012-06-01
期刊：
影响因子：
11.6
通讯作者：
Chu, Chengcai
中科院分区：
文献类型：
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作者：
Tong, Hongning;Liu, Linchuan;Chu, Chengcai
在拟南芥中，GSK3/SHAGGY-like kinase brassinosteroid - insensitive2 （BIN2）通过负向调控brassinosteroids （BR）下游响应基因表达的bri1- em - suppressor1 /BRASSINAZOLE-RESISTANT1家族转录因子的活性，在brassinosteroids （BR）信号通路中发挥关键作用。在这项研究中，我们分析了水稻（Oryza sativa） GSK3/SHAGGY-like激酶（GSK2）的功能，它是BIN2的同源物之一。过表达GSK2 （Go）导致植物具有典型的BR功能丧失表型，抑制GSK2导致BR信号表型增强。矮低分蘖（DLT）是水稻多种BR响应的正向调节因子。抑制DLT可增强BR受体突变体d61-1的表型，过表达DLT可明显抑制d61-1和Go的BR功能缺失表型，提示DLT在GSK2下游起调节BR应答的作用。事实上，GSK2可以与DLT相互作用并使DLT磷酸化。此外，油菜素内酯处理可以诱导DLT的去磷酸化，导致去磷酸化的DLT蛋白积累。在GSK2转基因植物中，DLT磷酸化水平由GSK2水平决定。这些结果表明，DLT是GSK2的底物，进一步强化了BIN2/GSK2激酶有多种底物进行不同的BR反应。
In Arabidopsis thaliana, the GSK3/SHAGGY-like kinase BRASSINOSTEROID-INSENSITIVE2 (BIN2) plays a critical role in the brassinosteroid (BR) signaling pathway by negatively regulating the activities of bri1-EMS-SUPPRESSOR1/BRASSINAZOLE-RESISTANT1 family transcription factors that regulate the expression of downstream BR-responsive genes. In this study, we analyzed the function of a rice (Oryza sativa) GSK3/SHAGGY-like kinase (GSK2), which is one of the orthologs of BIN2. Overexpression of GSK2 (Go) led to plants with typical BR loss-of-function phenotypes, and suppression of GSK2 resulted in enhanced BR signaling phenotypes. DWARF AND LOW-TILLERING (DLT) is a positive regulator that mediates several BR responses in rice. Suppression of DLT can enhance the phenotypes of BR receptor mutant d61-1, and overexpression of DLT obviously suppressed the BR loss-of-function phenotypes of both d61-1 and Go, suggesting that DLT functions downstream of GSK2 to modulate BR responses. Indeed, GSK2 can interact with DLT and phosphorylate DLT. Moreover, brassinolide treatment can induce the dephosphorylation of DLT, leading to the accumulation of dephosphorylated DLT protein. In GSK2 transgenic plants, the DLT phosphorylation level is dictated by the GSK2 level. These results demonstrate that DLT is a GSK2 substrate, further reinforcing that the BIN2/GSK2 kinase has multiple substrates that carry out various BR responses.