The effect of pulsed light treatment on the postharvest resistance and flavor quality of fresh tomato

Pulsed light (PL) is known to preserve postharvest fruit quality; however, its effects on flavor quality and the associated transcriptional mechanisms in fresh tomato remain unclear. This study investigated the impact of PL on postharvest resistance and flavor quality in tomato. PL treatment preserved fruit color, firmness, and total soluble solids (TSS) while reducing weight loss. RNA sequencing (RNA-seq) analysis revealed that PL maintained postharvest circadian rhythms by regulating light signaling genes. The upregulation of lignin biosynthesis genes led to the accumulation of compounds such as ferulic acid, trans-5- O -( p -coumaroyl) shikimate, sinapyl alcohol, and fumaric acid. Additionally, PL enhanced fruit defense by modulating plant hormone signal transduction genes and induced horizontal resistance by activating genes associated with plant-pathogen interactions. High TSS levels after PL were linked to the upregulation of glucose metabolism genes and the downregulation of acid metabolism genes. A total of 54 volatile organic compounds (VOCs) were identified, with lower levels of hexanal, 1-pentene-3-alcohol, and 1-pentene-3-one levels being correlated with reduced expression of alcohol dehydrogenase 1/1B (ADH1/1B) . In contrast, elevated levels of 2-phenylethanol were associated with increased expression of aromatic amino acid decarboxylase 1A/1B (AADC1A/1B) and phenylacetaldehyde reductase (PAR) . PL maintained the flavor profile of tomato fruit by preventing the reduction of aroma substances and the production of undesirable flavors. This study provides new insights into the transcriptional molecular mechanisms through which PL enhances tomato fruit resistance and preserves flavor quality.