Signal crosstalk of phytomelatonin during salinity stress tolerance in plants

Melatonin (MT, an indoleamine, N-acetyl-5-methoxytryptamine) is distributed broadly in distant life forms and is responsible for multiple functions in plants. Phytomelatonin functions as an antioxidant, and now its role as a phytohormone-candidate is well established. Current understanding advocates phytomelatonin as a regulator for plant growth, development, and an effective molecule for stress-alleviation. Among various types of stresses, salinity largely influences plant productivity and causes significant crop loss. Phytomelatonin production is significantly stimulated under salt stress, which mitigates the salinity effect by either serving as an antioxidant or suppressing the salinity-induced undesired features. Phytomelatonin interacts with other signals (e.g., SA, ET, H₂S, ABA, NO, etc.) during this function, responsible for salt mitigation. The current review expands on the role of phytomelatonin in salinity and its interactions with other signaling molecules. Further, the review identifies some missing links, which are essential to carry this research ahead and provides relevant discussion to formulate further prospects in phytomelatonin-mediated salinity tolerance in crops.