Molecular cloning and functional characterization of TaIRI9 gene in wheat (Triticum aestivum L.)

The vernalization of wheat is one of the important factors that determine the planting region, introduction and cultivation techniques of wheat. However, the known vernalization genes (molecular marker) cannot precisely distinguish the vernalization requirement of winter wheat cultivars. Therefore, it is important to explore new vernalization genes and elucidate the mechanism of vernalization regulation. To explore the gene network in the vernalization pathway, we screened TaIRI9 (ice recrystallization inhibitor protein) gene associated with the expression profile of vernalization treatment of winter wheat Jing 841. Overexpression of TaIRI9 in wild type wheat resulted in reduced plant height, increased tiller number and delayed heading days. After 4 °C vernalization treatment for 30, 35, 45 or 50 days, TaIRI9 overexpression lines showed increased vernalization requirement and delayed heading time than wild type, indicating that TaIRI9 may affect vernalization process of wheat. In addition, the expression of the TaIRI9 genes were analyzed in winter Jing 841, strong winter wheat cultivar Xindong 18 and ten recombinant inbred lines (RILs, Hussar × Yanzhan1). The data showed that the expression of TaIRI9 was positively associated with the requirement of vernalization. These results indicated that TaIRI9 regulates heading and flowering time in wheat by promoting VRN2 and inhibiting flowering promoter VRN1 and VRN3 and may be involved in wheat vernalization regulation pathway.