SlABH15 Promotes Jasmonate-Mediated Lead Detoxification in Tomato: A Promising Target for Enhancing Phytoremediation...

Lead (Pb2+) toxicity disrupts cellular redox homeostasis and photosynthesis, highlighting the need to uncover the mechanisms underlying Pb2+ tolerance in phytoremediation. In this study, we characterized SlABH15, an α/β-hydrolase gene enhancing Pb2+ tolerance in tomato. SlABH15 was strongly Pb2+-induced (∼30-fold at 24 h) and was localized to the plasma membrane, acting as a methyl jasmonate esterase converting methyl jasmonate (MeJA) to jasmonic acid (JA). Co-immunoprecipitation (Co-IP) revealed that SlABH15 interacts with KAT2, a key peroxisomal enzyme in JA biosynthesis, and this interaction was strongly enhanced by Pb2+ and JA. SlABH15 overexpression improved Pb2+ tolerance, reduced ROS accumulation, sustained photosynthesis, and decreased tissue Pb2+ content. Conversely, silencing SlABH15 reduced JA levels, exacerbated oxidative damage, and repressed genes involved in JA and chlorophyll biosynthesis. Collectively, our results demonstrate that SlABH15 acts as a critical positive regulator integrating MeJA hydrolysis and JA biosynthesis to maintain plant defense and photosynthetic homeostasis under Pb2+ stress.