Ta COLD 1 defines a new regulator of plant height in bread wheat

Summary 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 Ta COLD 1 , whose encoding protein is homologous to cold sensor COLD 1 in rice. We show that Ta COLD 1 protein is localized to the endoplasmic reticulum ( ER ) and plasma membrane. Phenotypic analyses show that overexpression of a mutated form of Ta COLD 1 (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 Ta COLD 1 (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 Ta COLD 1 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 Ta COLD 1. Intriguingly, the C‐terminal region of TaGα‐7A is also physically associated with the Ta DEP 1 protein (an atypical Gγ subunit). Significantly, we discover that Ta COLD 1 and mTaCOLD 1 (M187K) can interfere with the physical association between TaGα‐7A and Ta DEP 1. Together, this study reveals that Ta COLD 1 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.