Mechanisms of SNP and melatonin effects on antioxidant and chlorophyll metabolism in postharvest okra.

Okra fruit rapidly undergoes chemical deterioration after harvest, necessitating effective preservation strategies. This study represents the first comprehensive investigation combining transcriptomic analysis with biochemical assessment to elucidate how SNPs and MT affect antioxidant capacity and chlorophyll metabolism in okra. MT + SNP treatment most effectively preserved fruit quality by reducing weight loss, maintaining color parameters, decreasing oxidative stress markers (HO, MDA), and enhancing antioxidant enzyme activities (SOD, CAT, POD, APX). This treatment stabilized chlorophyll content by modulating degrading enzymes (CLH, PPH, MDcase). Transcriptome analysis revealed 1927 differentially expressed genes associated with antioxidant defense and chlorophyll metabolism. Key antioxidant genes (PODs, GSTs, MDHARs) were upregulated, while chlorophyll metabolism genes (POR, PAO, Lhcbs) showed coordinated expression, maintaining pigment stability. Network analysis identified transcription factors (NAC86, ERF4, MYB24) linking these pathways. This study provides molecular insights for developing postharvest technologies that extend shelf life while maintaining nutritional quality and reducing food waste.