National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
Plant Biotechnol J. 2019 Mar;17(3):687-699. doi: 10.1111/pbi.13008. Epub 2018 Sep 24.
Plant height is among the most important agronomic traits that influence crop yield. However, in addition to the Rht-1 alleles, the molecular basis of plant height in bread wheat remains largely unclear. Based on wheat gene expression profiling analysis, we identify a light-regulated gene from bread wheat, designated as TaCOLD1, whose encoding protein is homologous to cold sensor COLD1 in rice. We show that TaCOLD1 protein is localized to the endoplasmic reticulum (ER) and plasma membrane. Phenotypic analyses show that overexpression of a mutated form of TaCOLD1 (M187K) in bread wheat cultivar Kenong199 (Rht-B1b) background resulted in an obvious reduction in plant height. Further, we demonstrate that the hydrophilic loop of TaCOLD1 (residues 178-296) can interact with TaGα-7A (the α subunit of heterotrimeric G protein) protein but not TaGα-1B, and the mutation (M187K) in TaCOLD1 remarkably enhances its interaction with TaGα-7A. Physical interaction analyses show that the C-terminal region of TaGα-7A, which is lacking in the TaGα-1B protein, is necessary for its interaction with TaCOLD1. Intriguingly, the C-terminal region of TaGα-7A is also physically associated with the TaDEP1 protein (an atypical Gγ subunit). Significantly, we discover that TaCOLD1 and mTaCOLD1 (M187K) can interfere with the physical association between TaGα-7A and TaDEP1. Together, this study reveals that TaCOLD1 acts as a novel regulator of plant height through interfering with the formation of heterotrimeric G protein complex in bread wheat and is a valuable target for the engineering of wheat plant architecture.
株高是影响作物产量的最重要的农艺性状之一。然而，除了 Rht-1 等位基因外，小麦株高的分子基础仍不清楚。基于小麦基因表达谱分析，我们从普通小麦中鉴定出一个光调控基因，命名为 TaCOLD1，其编码蛋白与水稻冷传感器 COLD1 同源。我们表明 TaCOLD1 蛋白定位于内质网 (ER) 和质膜。表型分析表明，在普通小麦品种 Kenong199（Rht-B1b）背景下过表达 TaCOLD1 的一种突变形式（M187K）导致株高明显降低。此外，我们证明 TaCOLD1 的亲水环（残基 178-296）可以与 TaGα-7A（异三聚体 G 蛋白的α亚基）蛋白相互作用，但不能与 TaGα-1B 相互作用，并且 TaCOLD1 中的突变（M187K）显著增强了其与 TaGα-7A 的相互作用。物理相互作用分析表明，TaGα-7A 的 C 端区域，在 TaGα-1B 蛋白中缺失，是其与 TaCOLD1 相互作用所必需的。有趣的是，TaGα-7A 的 C 端区域也与 TaDEP1 蛋白（一种非典型的 Gγ 亚基）发生物理关联。重要的是，我们发现 TaCOLD1 和 mTaCOLD1（M187K）可以干扰 TaGα-7A 和 TaDEP1 之间的物理关联。总之，这项研究揭示了 TaCOLD1 通过干扰普通小麦异三聚体 G 蛋白复合物的形成来充当一种新的株高调控因子，是小麦植株结构工程的一个有价值的目标。
