School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia.
School of Life Sciences and Engineering, Southwest University of Science and Technology, Mianyang, China.
Nat Plants. 2021 Aug;7(8):1093-1107. doi: 10.1038/s41477-021-00957-3. Epub 2021 Jun 28.
Temperature stresses affect plant phenotypic diversity. The developmental stability of the inflorescence, required for reproductive success, is tightly regulated by the interplay of genetic and environmental factors. However, the mechanisms underpinning how plant inflorescence architecture responds to temperature are largely unknown. We demonstrate that the barley SEPALLATA MADS-box protein HvMADS1 is responsible for maintaining an unbranched spike architecture at high temperatures, while the loss-of-function mutant forms a branched inflorescence-like structure. HvMADS1 exhibits increased binding to target promoters via A-tract CArG-box motifs, which change conformation with temperature. Target genes for high-temperature-dependent HvMADS1 activation are predominantly associated with inflorescence differentiation and phytohormone signalling. HvMADS1 directly regulates the cytokinin-degrading enzyme HvCKX3 to integrate temperature response and cytokinin homeostasis, which is required to repress meristem cell cycle/division. Our findings reveal a mechanism by which genetic factors direct plant thermomorphogenesis, extending the recognized role of plant MADS-box proteins in floral development.
温度胁迫会影响植物表型多样性。生殖成功所需的花序发育稳定性受到遗传和环境因素相互作用的严格调控。然而，植物花序结构如何响应温度的机制在很大程度上尚不清楚。我们证明，大麦 SEPALLATA MADS-box 蛋白 HvMADS1 负责在高温下维持不分枝的穗状结构，而功能丧失突变体则形成分枝的花序状结构。HvMADS1 通过 A 链 CArG 盒基序与靶启动子的结合增加，该基序随温度改变构象。与 HvMADS1 激活相关的高温依赖性靶基因主要与花序分化和植物激素信号转导有关。HvMADS1 直接调节细胞分裂素降解酶 HvCKX3，以整合温度响应和细胞分裂素稳态，这对于抑制分生组织细胞周期/分裂是必需的。我们的发现揭示了遗传因素指导植物热形态发生的机制，扩展了植物 MADS-box 蛋白在花发育中的作用。
