melatonin-regulation
Melatonin regulation in plants refers to the biosynthesis, signaling, and functional roles of melatonin (N-acetyl-5-methoxytryptamine) as an endogenous molecule across plant tissues and developmental stages. Though long associated with animal circadian rhythms, melatonin in plants acts as a versatile regulator of growth, stress responses, and defense mechanisms. Understanding its regulation offers insights into how plants coordinate responses to environmental challenges such as drought, temperature extremes, and pathogen attack.
open_in_new WikipediaPubMed · 2026-05-01
Scientists discovered a two-gene switch in tomatoes that controls how much melatonin the plant retains. Keeping melatonin levels high — by editing out the enzyme that breaks it down — made tomato seedlings more salt-tolerant and produced fruit richer in beneficial pigments like carotenoids.
CRISPR knockout of SlASDAC caused substantial melatonin accumulation, enhancing leaf pigmentation, trichome density, and carotenoid accumulation in tomato fruit.
SlASDAC knockout seedlings showed significantly improved salt tolerance during germination and early growth, while SlASDAC overexpression compromised salt tolerance — an effect fully rescued by applying external melatonin.
The transcription factor SlWRKY75 directly binds W-box elements in the SlASDAC promoter to repress its expression, establishing a SlWRKY75→SlASDAC regulatory axis that governs melatonin catabolism.
