Nonribosomal peptide synthetase (NRPS) involved in the biosynthesis of the siderophore pseudomonine. Specifically adenylates L-threonine and loads it onto the peptidyl-carrier protein domain of the PmsG, via a thioester linkage to the phosphopanthetheine moiety. Activates proteinogenic L-Thr preferentially over L-allo-Thr or D-Thr. Then, the Cy2 condensation domain transfers a salicylic acyl group from PmsE to the L-threonyl moiety attached to PmsG, and the Cy1 condensation domain performs a cyclodehydration on the product, forming a salicylmethyloxazolinyl-PmsG intermediate. Finally, PmsD catalyzes the transfer of an N-hydroxyhistamine group to the salicylmethyloxazolinyl-PmsG intermediate, yielding pre-pseudomonine