Regulation of gaseous signaling molecules on proline metabolism in plants

Proline accumulation plays an important role in the response and adaptation of plants to abiotic stress. Gaseous signaling molecules such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S) are involved in complicated events of cell signaling. However, the regulatory mechanisms of gaseous signaling molecules on proline synthesis and degradation are still unclear. This review summarized the biosynthesis and degradation of proline. The role of gaseous signaling molecules and their cross-talk on proline metabolic regulation in plants was discussed along with the future perspectives.