JAR1 — Arabidopsis thaliana

Summary

AT2G46370 (JAR1, also known as FIN219 and AtGH3.11) on chromosome 2 of Arabidopsis thaliana encodes a jasmonoyl-amino acid synthetase (EC 6.3.2.52) that conjugates jasmonic acid to isoleucine, producing the bioactive hormone JA-Ile. The protein belongs to the GH3 family and possesses adenylyltransferase and amino-acid binding activities. JAR1 is associated with jasmonate signaling and pathogen defense, with mutants showing susceptibility to Fusarium graminearum and resistance to Botrytis cinerea. The gene is linked to shade-induced hypocotyl elongation, far-red light sensitivity, and responses to serotonin and quercetin. Associations extend to grain yield, panicle number, flower diameter, leaf chlorophyll content, photosynthetic ability, submergence tolerance, and bacterial and viral disease responses. The protein localizes to the cytoplasm, nucleus, vacuole, and plasma membrane, and is connected to phytochrome A activation and COP1 complex formation.