The role of TOR in response to chilling stress in the Solanum lycopersicum L

Tomato production in northern China is often susceptible to chilling stress, which seriously affects the growth and development, yield and quality of tomato. Recently, we found that the target of rapamycin (TOR) might be involved in the response to chilling of tomato. So we exogenously applied TOR inhibitor AZD8055 and activator MHY1485 to clarify the role of TOR signaling in tomato response to chilling stress. The research results showed that the damage caused by chilling stress was relieved due to the TOR signaling was inhibited by AZD8055. The development degree of seedlings and root activity increased compared with the control group, while the chilling injury index decreased. At the same time, after the AZD8055 treatment, the REC and MDA contents were significantly decreased, and membrane lipid damage was reduced. NBT and DAB staining results showed that the color was lighter, and the area was smaller under AZD8055 treatment while the contents of O₂⁻ and H₂O₂ increased. Under chilling stress, the application of AZD8055 increased the activity of the antioxidases SOD, CAT, POD, GR, and APX and improved the expression of the SOD, CAT, POD, GR, and APX antioxidase genes. Photosynthetic efficiency, chlorophyll content, energy dissipation and Fv/Fm also improved. The GSH content was reduced, and the GSSG content was increased. In addition, the contents of ASA and soluble protein also increased. Therefore, TOR signaling played a negative regulatory role in tomato response to chilling stress.