Involved in the biosynthesis of the siderophore pyochelin (PubMed:9846750, PubMed:11208777). Accepts salicylate activated by PchD at the first peptidyl carrier domain (ArCP), and activates and fixes one molecule of cysteine at the second peptidyl carrier domain (PCP1) via a thioester linkage to the phosphopanthetheine moiety (By similarity). Then catalyzes the condensation reaction between the salicylate bound to the first site and the cysteine bound to the second site, and the cyclization of the cysteine to form the salicyl-thiazolinyl-S-PCP1 intermediate at the second site (By similarity). When this intermediate is released by the action of a thioesterase, it produces the antifungal antibiotic dihydroaeruginoic acid (Dha or hydroxyphenyl-thiazolinyl-carboxylate) (PubMed:11208777). ATP + holo-[peptidyl-carrier protein] + L-cysteine = AMP + diphosphate + L-cysteinyl-[peptidyl-carrier protein] Siderophore biosynthesis. Antifungal biosynthesis. Expression of the pchEF operon is strictly dependent on the PchR regulator and is induced by extracellular pyochelin, the end product of the pathway. Repressed by Fur and iron. Modular protein that contains an aryl carrier protein (ArCP) domain which bears a phosphopantetheinyl arm to attach the activated salicylic acid, a condensation/cyclization domain involved in the cyclization of the cysteine, an adenylation domain which activates the cysteine residue into an aminoacyl-AMP ester and a peptidyl carrier protein (PCP1) domain which bears a phosphopantetheinyl arm to attach the activated cysteine. Deletion of the gene completely abolishes the formation of both Dha and pyochelin and results in salicylate accumulation. Belongs to the NRP synthetase family.