*Corresponding author: Yonghong Wang yhwang@genetics.ac.cn

Wheat (Triticum aestivum L.) is a major staple food for more than one-third of the world’s population. Tiller number is an important agronomic trait determining panicle number and grain yield in wheat, and the development of tillers in winter wheat requires overwintering. Currently, understanding of the underlying mechanisms is very limited.

Here, we identified a cold response gene TaCRG1 (Cold Response Gene 1) that plays an important role in tiller development of winter wheat. We generated TaCRG1 knockout transgenic lines (Tacrg1) and TaCRG1 overexpressed transgenic lines (TaCRG1-B-OE) under Fielder background, respectively. We found that the tiller number of Tacrg1-2 was significantly lower while TaCRG1-B-OE1 were significantly higher than that in wild type when they planted in autumn.

However, there were no significant differences in tiller number of these TaCRG1 transgenic plants planted in spring. Moreover, we also found that the freezing survival rate was significantly higher in TaCRG1-B-OE plants while lower in Tacrg1-2 plants compared with that in the wild type, demonstrating that TaCRG1 also promotes cold tolerance of wheat.

In order to further understand the molecular mechanism of TaCRG1 in regulating tiller number and cold tolerance of wheat, the TaCRG1 interacting protein TaCRG1IP1 was screened by yeast two-hybrid assay and interaction was further verified by using double luciferase complementary assay.

Further illustrating the molecular mechanism of TaCRG1 will be helpful to breed wheat cultivars with ideal plant architecture and cold tolerance.