Figure 3.

Regulation of gene expression in response to drought, salt, and cold: involvement of ABA-dependent and ABA-independent pathways. Cis-acting elements are shown in boxes and transcription factors are in ovals. Pathways I, II, and V are ABA dependent and based on ABRE or MYBR/MYCR cis-acting elements. Pathways III, IV, VI, and VII are ABA independent and based on DRE/CRT or still unidentified cis-acting sequences. Both types of pathways are implemented in drought, salt, and cold signaling. Some transcription factors like ABFs and DREB2s are stress activated to induce gene expression, whereas others, like CBFs, require biosynthesis first.