Fig. 4: TaSG-D1 and TaSG-D1^E286K have different effects on TaPIF4 protein stability.

a TaSG-D1^E286K enhances TaPIF4 stability compared to TaSG-D1 in response to heat stress. TaPIF4 was detected with anti-Myc antibody (top panel). TaSG-D1/TaSG-D1^E286K was detected with anti-GFP antibody (middle panel). Actin was detected with anti-Actin antibody as a loading control (bottom panel). The relative abundances of TaPIF4 and TaSG-D1/TaSG-D1^E286K were quantified using ImageJ software (v1.52i). The relative protein levels of TaPIF4/TaSG-D1/TaSG-D1^E286K at 0 h were defined as 1.00. Three independent experiments were performed. b TaSG-D1^E286K attenuates TaPIF4 degradation in a cell-free degradation assay. TaPIF4 abundance was examined with anti-GST antibody. TaSG-D1/TaSG-D1^E286K were detected with anti-GFP antibody. Actin was detected with anti-Actin antibody as a loading control. The relative protein abundance of TaPIF4 was quantified using ImageJ software. The relative protein level of TaPIF4 at 0 h was defined as 1.00. Three independent experiments were performed. c A working model for the role of the TaSG-D1/TaSG-D1^E286K-TaPIF4 signaling pathway in the response of wheat to heat stress (Created with BioRender.com). In hot areas of India and Pakistan, the protein of TaSG-D1^E286K is stable, which then stabilizes TaPIF4 via strong phosphorylation and leads to improved heat tolerance of T. sphaerococcum. Under normal conditions, the protein of TaSG-D1 is unstable, which results in moderate degradation of TaPIF4 due to decreased phosphorylation, and causes reduced heat tolerance. Source data are provided as a Source Data file.