The wheat TaGBF1 gene is involved in the blue-light response and salt tolerance.

Summary Light and abiotic stress both strongly modulate plant growth and development. However, the effect of light-responsive factors on growth and abiotic stress responses in wheat (Triticum aestivum) is unknown. G–box binding factors (GBFs) are blue light-specific components, but their function in abiotic stress responses has not been studied. Here we identified a wheat GBF1 gene that mediated both the blue light- and abiotic stress-responsive signaling pathways. TaGBF1 was inducible by blue light, salt and exposure to abscisic acid (ABA). TaGBF1 interacted with a G–box light-responsive element in vitro and promoted a blue-light response in wheat and Aradidopsis thaliana. Both TaGBF1 over-expression in wheat and its heterologous expression in A. thaliana heighten sensitivity to salinity and ABA, but its knockdown in wheat conferred resistance to high salinity and ABA. The expression of AtABI5, a key component of the ABA signaling pathway in A. thaliana, and its homolog Wabi5 in wheat was increased by transgenic expression of TaGBF1. The hypersensitivity to salt and ABA caused by TaGBF1 was not observed in the abi5 mutant background, showing that ABI5 is the mediator in TaGBF1-induced abiotic stress responses. However, the hypersensitivity to salt conferred by TaGBF1 is not dependent on light. This suggests that TaGBF1 is a common component of blue light- and abiotic stress-responsive signaling pathways.