A Maize Calmodulin-like 3 Gene Positively Regulates Drought Tolerance in Maize and Arabidopsis

Drought stress is one of the important abiotic stresses that affects maize production. As an important Ca2+ sensor, calmodulin-like proteins (CMLs) play key roles in plant growth, development, and stress response, but there are a limited number of studies regarding CMLs in response to drought stress. In this study, a Calmodulin-like gene, namely ZmCML3, was isolated from maize (Zea mays L.). The coding sequence (CDS) of ZmCML3 was 474 bp and a protein of 158 aa which contains three EF-hand motifs. ZmCML3 was localized within the nucleus and plasma membrane. The expression of ZmCML3 was induced by polyethylene glycol (PEG) 6000, NaCl, methyl jasmonate (MeJA), and abscisic acid (ABA). Overexpression of ZmCML3 resulted in enhanced drought tolerance in maize through increasing proline (Pro) content and the activity of peroxide (POD) and superoxide dismutase (SOD). Meanwhile, ZmCML3 also positively regulated the expression of drought stress-responsive genes in maize under drought stress treatment. Taken together, ZmCML3 acts as a positive regulator in maize response to drought stress. These results will provide theoretical basis for breeding drought tolerance maize variety.