Soybean mitogen-activated protein kinase GmMPK6 enhances drought tolerance.

Soybeans are a critical crop that provides both protein and oil. In response to environmental stresses, mitogen-activated protein kinases (MPKs) play a key role in transmitting stress signals to the nucleus to initiate stress-responsive actions. Drought stress reduces plant development and productivity but the specific MPK responsible for drought stress responses has not been previously identified. In this study, we demonstrate that GmMPK6, a soybean MPK, responds to drought stress and enhances drought tolerance. GmMPK6 is activated in drought conditions through post-translational modifications. Inhibition of GmMPK6 activity leads to reduced drought resistance and a decrease in GmRD19A expression. Additionally, GmMPK6 activation is modulated by calcium signaling, highlighting GmMPK6 as a positive regulator of drought stress resistance in soybean. This study presents the first report of an MPK conferring drought tolerance in soybean.