Find in Library

Abscisic acid (ABA)-, stress-, and ripening-induced (ASR) proteins are reported to be involved in drought stress responses. However, the function of maize <i>ASR</i> genes in enhancing drought tolerance is not known. Here, nine maize <i>ASR</i> members were cloned, and the molecular features of these genes were analyzed. Phenotype results of overexpression of maize <i>ZmASR3</i> gene in <i>Arabidopsis</i> showed lower malondialdehyde (MDA) levels and higher relative water content (RWC) and proline content than the wild type under drought conditions, demonstrating that <i>ZmASR3</i> can improve drought tolerance. Further experiments showed that <i>ZmASR3-</i>overexpressing transgenic lines displayed increased stomatal closure and reduced reactive oxygen species (ROS) accumulation by increasing the enzyme activities of superoxide dismutase (SOD) and catalase (CAT) under drought conditions. Moreover, overexpression of <i>ZmASR3</i> in <i>Arabidopsis</i> increased ABA content and reduced sensitivity to exogenous ABA in both the germination and post-germination stages. In addition, the ROS-related, stress-responsive, and ABA-dependent pathway genes were activated in transgenic lines under drought stress. Taken together, these results suggest that <i>ZmASR3</i> acts as a positive regulator of drought tolerance in plants.