Cold stress-induced biochemical and molecular responses in Safflower (Carthamus tinctorious L.)

Cold stress causes substantial losses in global agricultural productivity. When exposed to cold stress, plants usually exhibit a variety of cold-induced physiological, biochemical, and molecular responses. Safflower is one of the oldest, marginalized, neglected and domesticated multipurpose oilseed crops which is uniquely affected by cold stress at different growth stages. Because of lack of systematic research on cold signalling pathways and gene regulatory networks, the underlying biochemical and molecular mechanisms of cold signal transduction in different developmental stages of safflower are poorly understood. Therefore, this study sought to detect biochemical response and identify cold responsive safflower genes expressed at the rosette and bolling stages to provide novel insight about the growth stage’s differential responses to cold stress. The results demonstrated that pseudo-marker snap genes CtAH10T0001700.1 and CtAH10T0001500.1 are the E3 ligase genes with RING finger domain while CtAH10T0000500 matched the GRAS family genes. These genes successfully exhibited similar cold responses as per their respective family. Overexpression of some E3 genes like CIP8 and HOS 1 could be associated with the cold susceptibility of plants in the bolling stage of safflower. Additionally, CtAH10T0001700.1 expression was found to be positively correlated with electrolyte leakage and proline content at the rosette stage. Meanwhile CtAH10T0001500.1, a negative cold regulator significantly correlated with electrolyte leakage and proline content. While CtAH10T0000500, a positive cold regulator significantly correlated with electrolyte leakage and proline at the rosette stage, but negatively associated with the two parameters at bolling stage. Overall, the genes were found to play a significant role in cold responsiveness of safflower plants at different growth stages.