Involved in the biosynthesis of pipecolate (Pip), a metabolite that orchestrates defense amplification, positive regulation of salicylic acid (SA) biosynthesis, and priming to guarantee effective local resistance induction and the establishment of systemic acquired resistance (SAR). Converts delta-(1)-piperideine-2-carboxylate (P2C) to Pip. Mediates reduction of P2C and biosynthesis of Pip in systemic tissue and contributes to SAR establishment (PubMed:27758894). Does not possess ornithine cyclodeaminase activity in vitro (PubMed:24237637). Induced by Pseudomonas syringae pv. maculicola (PubMed:27758894). Induced by low water potential stress and treatment with exogenous proline (PubMed:24237637). No visible phenotype under normal growth conditions (PubMed:24237637, PubMed:27758894). Mutant plants have compromised systemic acquired resistance (SAR) (PubMed:27758894). Mutant seedlings accumulate increased levels of proline (PubMed:24237637). Belongs to the ornithine cyclodeaminase/mu-crystallin family.