Fig. 9

The proposed transcription model of RsWRKY40 coordinates cold stress response via RsSPS1-mediated sucrose accumulation and CBF-dependent pathway in radish. RsWRKY40 could regulate RsSPS1, RsCBF1 and RsCBF2 expression as well as its own transcription under normal growth conditions. RsWRKY40 is rapidly accumulated in the presence of cold stress. RsWRKY40 promotes the RsSPS1 expression to facilitate sucrose synthesis, thereby balancing cell osmotic pressure and enhancing cold tolerance. In parallel, RsWRKY40 directly activates the expression of RsCBF1/2 to elevate the cold tolerance in radish. RsWRKY40 also enhances its own transcription, thus forming a self-regulating loop to coordinate cold stress response