The 13‐lipoxygenase <scp> <i>GmLOX6</i> </scp> is involved in <scp>JA</scp> biosynthesis and serves as a positive regulator of salt stress tolerance in soybean

Abstract

SUMMARY Salinity represents a major abiotic stressor that significantly impairs soybean growth and yield. Although jasmonic acid (JA) has been firmly established as a key regulator of plant defense against salt stress, the precise functions of lipoxygenase ( LOX ) genes responsible for initiating JA biosynthesis remain poorly defined. Here, a comprehensive genome‐wide analysis of the soybean LOX gene family was performed, and a detailed functional characterization of GmLOX6 was carried out. Subcellular localization confirmed that GmLOX6 is targeted to chloroplasts, while enzymatic assays demonstrated that it acts as a 13‐LOX enzyme with a strong preference for α‐linolenic acid as substrate. To clarify its role under salt stress, we generated both overexpression and CRISPR/Cas9‐mediated knockout lines of soybean. Phenotypic and molecular evaluations revealed that GmLOX6 facilitates JA production under salt stress, thereby contributing to enhanced JA accumulation. This elevation in JA levels was associated with improved salt tolerance through multiple physiological adaptations, including the activation of antioxidant enzymes for the detoxification of reactive oxygen species (ROS), enhanced Na + extrusion to preserve ionic balance, and reinforced membrane stability. Moreover, GmRWP‐RK11 was identified as a transcriptional repressor of GmLOX6 . Functional disruption of GmRWP‐RK11 via CRISPR/Cas9 conferred greater salt tolerance, further supporting its negative regulatory role. Collectively, these findings uncover a novel regulatory axis in which GmLOX6 ‐mediated JA biosynthesis enhances soybean resistance to salinity through modulation of ROS homeostasis and Na + transport. These insights provide an expanded understanding of the transcriptional and biochemical mechanisms underpinning JA‐driven stress adaptation in soybean.

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