Promoter of Cassava Responds to Diverse Abiotic Stresses and Hormone Signals in Transgenic .

The AT-hook motif nuclear-localized () family is pivotal for the abiotic stress response in plants. However, the function of the cassava genes has not been elucidated. Promoters, as important regulatory elements of gene expression, play a crucial role in stress resistance. In this study, the promoter of the cassava gene was cloned. The MeAHL31 protein was localized to the cytoplasm and the nucleus. qRT-PCR analysis revealed that the gene was expressed in almost all tissues tested, and the expression in tuber roots was 321.3 times higher than that in petioles. Promoter analysis showed that the promoter contains drought, methyl jasmonate (MeJA), abscisic acid (ABA), and gibberellin (GA) -acting elements. Expression analysis indicated that the gene is dramatically affected by treatments with salt, drought, MeJA, ABA, and GA3. Histochemical staining in the transgenic corroborated that the GUS staining was found in most tissues and organs, excluding seeds. Beta-glucuronidase (GUS) activity assays showed that the activities in the transgenic were enhanced by different concentrations of NaCl, mannitol (for simulating drought), and MeJA treatments. The integrated findings suggest that the promoter responds to the abiotic stresses of salt and drought, and its activity is regulated by the MeJA hormone signal.