Role of Specific Phosphorylation Sites of Arabidopsis Brassinosteroid-Insensitive 1 Receptor Kinase in Plant Growth and Development
Role of Specific Phosphorylation Sites of Arabidopsis Brassinosteroid-Insensitive 1 Receptor Kinase in Plant Growth and Development
复制标题
拟南芥油菜素类固醇不敏感1受体激酶特异性磷酸化位点在植物生长发育中的作用
DOI：
10.1007/s00344-016-9580-7
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发表时间：
2016-09-01
影响因子：
4.8
通讯作者：
Wang, Xiaofeng
中科院分区：
文献类型：
--
作者：
Wang, Qiannan;Wang, Shufen;Wang, Xiaofeng
油菜素甾醇不敏感蛋白1（BRI 1）是油菜素甾醇（brassinosteroids，BR）的受体，是一种具有丝氨酸/苏氨酸/酪氨酸双重功能的蛋白激酶，通过其蛋白激酶活性启动BR信号传导并调节植物生长。已有研究在体内和体外鉴定了拟南芥BRI 1的磷酸化位点，但其对BR信号转导和植物发育的意义尚未得到全面讨论。为了研究这一点，我们系统地描述了拟南芥BRI 1定点突变体在弱bri 1 -5背景。对于营养器官发育调节，我们证明了Thr-1039，Ser-1042和Ser-1044对营养发育是至关重要的，因为在这些残基上消除磷酸化的突变体表现出异常的叶片生长，而Ser-1172和Ser-1187轻微抑制叶片生长。对于生殖器官发育调节，首先，Thr-1039，Ser-1042和Ser-1044对正常植物高度至关重要的观点得到了以下证据的支持：阻止Thr-1039，Ser-1042和Ser-1044磷酸化的突变降低了植物高度。其次，种子产量相关性状的比较表明，未磷酸化的Ser-1168-Ala、Ser-1172-Ala和Ser-1179-Ala+Thr-1180-Ala突变体显着降低了种子产量，而消除Ser-1042的磷酸化则导致种子产量增加。此外，我们发现Ser-1042和Ser-1044是BR信号传导所必需的。未磷酸化的Ser-1042-Ala和Ser-1044-Ala突变体表现出低敏感表型，伴随着去磷酸化的BRI 1-EMS抑制子1（BES 1）蛋白的积累减少和组成型光形态建成矮秆表达水平的增加，以及对下胚轴和根伸长的有限抑制。综上所述，我们的数据表明，在特定位点的BRI 1磷酸化差异影响生长和发育，这可能提供新的方法来精确地调节经济产量通过修改特定的BRI 1磷酸化位点在作物物种。
Brassinosteroid-insensitive 1 (BRI1), the receptor of brassinosteroids (BRs), is a dual-function serine/threonine/tyrosine protein kinase which initiates BR signaling and regulates plant growth via its protein kinase activity. Previous research has identified phosphorylation sites of Arabidopsis BRI1 in vivo and in vitro, but the significance of which to BR signaling and plant development has not been discussed comprehensively. To investigate this, we systematically characterized Arabidopsis BRI1 site-directed mutants in the weak bri1-5 background. For vegetative organ development regulation, we demonstrated that Thr-1039, Ser-1042, and Ser-1044 were critical for vegetative development because mutants with eliminated phosphorylation at these residues exhibited aberrant leaf growth, whereas Ser-1172 and Ser-1187 slightly inhibited leaf growth. For reproductive organ development regulation, first, the notion that Thr-1039, Ser-1042, and Ser-1044 were essential for normal plant height is supported by the evidence that mutations preventing phosphorylation at Thr1039, Ser-1042, and Ser-1044 decreased plant height. Second, comparison of seed yield-related traits showed that unphosphorylated Ser-1168-Ala, Ser-1172-Ala, and Ser-1179-Ala+Thr-1180-Ala mutants reduced seed yield dramatically, whereas eliminating phosphorylation at Ser-1042 caused increased seed production. In addition, we found that Ser-1042 and Ser-1044 were essential for BR signaling. The unphosphorylated Ser-1042-Ala and Ser-1044-Ala mutants displayed hyposensitive phenotypes accompanied with decreased accumulation of dephosphorylated BRI1-EMS suppressor 1 (BES1) protein and increased Constitutive Photomorphogenesis Dwarf expression levels as well as limited inhibition of hypocotyl and root elongation under exogenous brassinolide. Taken together, our data suggest that BRI1 phosphorylation at specific sites differentially affects growth and development which may provide novel approaches to precisely regulate economic yield through modifying specific BRI1 phosphorylation sites in crop species.