Broccoli is a nutrient-dense vegetable rich in phytochemicals. However, it is highly perishable due to its high respiration rate and ethylene sensitivity, leading to rapid yellowing and nutrient loss. Maintaining both visual appearance and nutritional integrity remains a major challenge in the postharvest supply chain. This review comprehensively summarizes the physiological, biochemical, and molecular mechanisms involved in postharvest senescence of broccoli, focusing on chlorophyll catabolism, oxidative stress, and glucosinolate metabolism. It critically evaluates recent progress in preservation technologies, emphasizing their underlying regulatory mechanisms and impacts on quality attributes. Visual and nutritional decline in broccoli are mechanistically interconnected rather than parallel processes. Senescence drivers, including ethylene and phytohormone crosstalk, as well as reactive oxygen species (ROS), promote chlorophyll degradation by regulating chlorophyll catabolic enzymes (CCEs) and chlorophyll-degradation peroxidase (Chl-POX) and impairing chloroplast integrity via lipid peroxidation. They also disrupt cellular integrity, allowing glucosinolates to contact degrading enzymes and accelerate their degradation. Meanwhile, hormone crosstalk regulates glucosinolate metabolic genes, resulting in decreased glucosinolate content. Based on these insights, postharvest strategies can delay senescence and preserve quality by targeting these drivers, such as by inhibiting ethylene action, enhancing antioxidant systems, and regulating hormone crosstalk. Overall, this review highlights promising technologies to maintain the green color and nutritional value of broccoli, ensuring high-quality and residue-free produce.

Abstract Brassinazole-resistant1 (BZR1) and BRI1-EMS-suppressor1 (BES1) are phylogenetically closely related transcription factors that act as key components of brassinosteroid (BR) signaling. Although their individual roles in various plant developmental processes have been extensively reported in model plants such as Arabidopsis, their potential synergistic functions in regulating internode length and fruit shape in tomato, an important crop as well as a model system of fruit development, remain unclear. Here, we demonstrate that SlBZR1 and SlBES1 physically interact and modulate internode length and fruit shape in tomato through distinct mechanisms. Genetic analyses reveal that knockout of SlBZR1 or SlBES1 moderately reduces internode length, whereas the bzr1 bes1 double mutant exhibits severe dwarfism. SlBZR1 and SlBES1 promote internode elongation by directly targeting and repressing the expression of GA metabolic gene SlGA2ox10 while inducing that of gibberellin (GA) receptor gene SlGID1A. During fruit development, elongated fruit resulting from enhanced cell proliferation in the ovary wall was observed specifically in the bzr1 bes1 double mutant, but not in bzr1, bes1, BZR1-OE, BES1-OE, and wild-type plants, in a GA-independent manner. We identify the fruit shape regulator SlFS8.1 as a direct transcriptional target of SlBZR1 and SlBES1. Our work demonstrates that SlBZR1 and SlBES1 synergistically promote internode elongation via crosstalk with the GA pathway, while independently governing fruit shape through direct transcriptional activation of SlFS8.1.

The MADS-box gene family, particularly the ABCE-class genes, plays a pivotal role in regulating floral development and reproductive processes in angiosperms. Expansion of the MADS-box gene family through ancient whole-genome duplications and lineage-specific duplication events has generated extensive regulatory flexibility across flowering plants. This review summarizes current findings on the evolutionary expansion and functional diversification of MADS-box genes, with a focus on the evolution of the ABCE-class in ornamental plants. We highlight how differential gene retention, expression divergence, and functional specialization have shaped the remarkable morphological diversity of floral organs across flowering plants. Comparative analyses across angiosperms reveal a lineage-dependent distinction between phylogenetic A-class genes and the developmental A-function: while AP1 represents the canonical A-class gene in core eudicots, AGL6-like genes fulfill ancestral A-function roles in early-diverging angiosperms, magnoliids, and monocots. Lineage-specific expansion and rewiring of ABCE gene networks, as observed in Orchidaceae, Asteraceae, and Rosaceae, have enabled reassembly of MADS-box protein complexes and rebalancing of expression domains, driving innovative floral forms. Beyond floral development, numerous MADS-box genes have diversified to function in flowering-time regulation and environmental stress responses, highlighting their broader adaptive significance beyond reproduction. This review provides an integrated evolutionary and functional perspective on MADS-box genes plasticity, and offers valuable insights for ornamental plant breeding and horticultural improvement.

Fruit color is a key quality trait in cherry tomato (Solanum lycopersicum) and an important factor influencing consumer purchasing decisions. Various pigments, including flavonoids, carotenoids, and chlorophylls, form the biochemical basis of fruit coloration, imparting vivid colors such as red, yellow, orange, and green. Flavonoids and carotenoids are also essential nutritional components in cherry tomato, directly influencing their commercial value, while chlorophylls are crucial for photosynthesis and fruit development. However, conventional tomato varieties typically contain insufficient flavonoid levels to meet human dietary requirements. In this study, we quantified flavonoids, carotenoids, and chlorophyll a and b in ten high-flavonoid cherry tomato cultivars and investigated the relationships between fruit color and pigment content. The results revealed that red and orange tomato varieties contained higher flavonoid and carotenoid levels than yellow varieties, while green tomatoes exhibited elevated chlorophyll content. Yellow varieties showed the maximum L* (lightness) value. Flavonoid and carotenoid contents were significantly positively correlated with a* (red-green axis) and a*/b* (yellow-blue axis) values but negatively correlated with hue angle, whereas chlorophyll content showed no significant correlations with color parameters. Our findings provide guidance for evaluating the nutritional value of cherry tomatoes based on pigmentation.

Carotenoids and flavonoids are two principal classes of secondary metabolites in tomato fruit, jointly contributing to pigmentation and nutritional quality. Here, we identified SlWRKY14 as a novel regulator of both these two pathways. slwrky14 lines result in redder fruits enriched in carotenoids, whereas fruit-specific overexpression lines produce orange-yellow fruits with reduced carotenoids but elevated flavonoids. SlWRKY14 directly binds to the promoter of carotenoid biosynthetic genes (SlDXS1 and SlPSY1) and represses their transcription by recruiting histone deacetylase SlHDA1, which functions in decreased histone acetylation to inhibit gene expression. Further genetic evidence verifies the role of the SlWRKY14-SlHDA1 module in suppressing carotenoid accumulation. In contrast, SlWRKY14 activates the flavonoid biosynthetic gene SlPALA to promote flavonoid accumulation. Our findings demonstrate SlWRKY14 as a regulatory node of carotenoid and flavonoid biosynthesis, providing a strategy for coloration regulation and quality improvement without penalty of yield in tomato.

WRKY transcription factors (TFs) have been widely investigated for their roles in stress responses and plant development. Nevertheless, recent studies have revealed that WRKY TFs also exert important functions in the regulation of plant secondary metabolic networks, which are closely associated with crop resistance and quality. In this review, we comprehensively summarize how WRKYs are activated by various developmental and environmental cues to mediate distinct regulatory responses that control the biosynthesis of secondary metabolites such as flavonoids, carotenoids, and glucosinolates. We also examine the multi-layered modulation mediated by WRKYs, focusing on epigenetic regulation and post-translational modifications and highlighting their roles as regulatory hubs in secondary metabolism. Finally, we propose future research directions and discuss potential agricultural applications.

With rising living standards, consumers' demand for color diversity and nutritional quality in tomato products has increased. Flavonoids are a key determinant of peel color and nutritional value in tomato fruit, where their biosynthesis is controlled by various phytohormones, including brassinosteroids (BRs). However, the underlying mechanism by which BR regulates flavonoid biosynthesis remains unclear. Here, we show that exogenous BRs suppress flavonoid accumulation, whereas reduced endogenous BR levels in RNAi lines of SlCYP90B3, a rate-limiting BR biosynthetic gene, result in increased flavonoid content in the fruit peel. We further demonstrate that BRI1-EMS-suppressor1 (SlBES1), a basic helix-loop-helix transcription factor essential for BR signaling, not only regulates fruit firmness but also represses flavonoid accumulation by directly binding to the promoters of the flavonoid biosynthetic genes SlCHS1, SlCHS2, and SlF3'H. Additionally, SlBES1 modulates a hierarchical transcriptional cascade by repressing the expression of SlMYB12, further suppressing flavonoid biosynthesis. Moreover, the homologous transcription factor brassinazole-resistant1 (SlBZR1) enhances SlBES1-mediated repression of flavonoid accumulation. Specifically, SlBES1 predominantly inhibits flavonoid biosynthesis, whereas SlBZR1 primarily enhances carotenoid pathway activity. Notably, variation in SlBES1 is correlated with flavonoid content during tomato domestication. Collectively, these results highlight a novel role for SlBES1 as a negative regulator of flavonoid biosynthesis, offering potential strategies for flavonoid biofortification in tomato.

Background Agro-food production and consumption impact climate change and human health. Bioactive secondary metabolites in horticulture crops make them an indispensable part of environmentally sustainable and healthy diet. Among them, apocarotenoids from carotenoid degradation are promising in promoting a preference for plant-based foods over other metabolites. Aim of Review In horticulture crops, carotenoids are vital for photosynthesis and antioxidant defense, but their enzymatic or oxidative metabolites, apocarotenoids, offer greater structural diversity and biological functions. They serve as pigments, scents, signaling molecules, and growth regulators in crop growth and development and provide antioxidant, nutraceutical, and pharmaceutical benefits to human health. The carotenoids as bioactive compounds are well understood. By contrast, much less is explored and reviewed about apocarotenoids. Key Scientific Concepts of Review Recently identified metabolic pathways and components of apocarotenoids are reviewed. Their significance for quality formation in horticulture crops, including the regulation of pigmentation, aroma, flavor, architecture, nutrition value, and broader ecological interactions is discussed. Additionally, this review specifically highlights two representative apocarotenoids, retinal and abscisic acid (ABA), that exhibit conserved yet distinct regulatory functions across plant and animal kingdoms. Comprehensive dissection of apocarotenoid metabolism and their regulatory mechanisms will enhance apocarotenoid biofortification and subsequent biotechnological exploitation in horticultural commodities. We put forward the perspective that apocarotenoids could enhance horticultural crop quality and then promote sensory- and health-driven dietary choices which will in turn increase consumption and production of horticultural plants and promote both human and ecosystem health.

Chinese kale (Brassica oleracea var. alboglabra), a native Chinese vegetable, is usually grown for its bolting stems as the common edible part. However, the tender leaves of the vegetable have higher nutritional value. To investigate the effects of cultivation seasons on the nutritional substances in leafy Chinese kale, we conducted a pilot trial to analyze the differences in the content of nutritional substances, including glucosinolates, in five varieties of leafy Chinese kale (JLYC-01, JLYC-02, JLYC-03, JLYC-04, JLYC-05) cultured in fall, winter, and spring. The plant weight was 27.2 g–40.4 g in spring, 20.0 g–38.6 g in winter, and 20.3 g–34.0 g in fall, and the JLYC-05 variety showed superiority among the varieties, with weights of 34.0 g in fall, 38.6 g in winter, and 39.7 g in winter. Overall, the nutritional substance content in leafy Chinese kale cultivated in spring and fall was better than that of those cultivated in winter, providing a key reference for leafy Chinese kale planting. Among the five varieties, JLYC-04 and JLYC-05 are excellent candidates for future breeding programs, since JLYC-04 has a higher content of total phenols (10.1 mg GAE g−1 DW–10.7 mg GAE g−1 DW) and glucosinolates (5.8 μmol g−1 DW–7.1 μmol g−1 DW), exhibiting strong antioxidant capacity, while JLYC-05 contains more chlorophyll (157 mg 100 g−1 FW–214 mg 100 g−1 FW) and carotenoids (31.8 mg 100 g−1 FW–39.1 mg 100 g−1 FW).

Disease resistance is one of the most important target traits for sugarcane genetic improvement. Sugarcane brown stripe (SBS) caused by Helminthosporium stenospilum is one of the most destructive foliar diseases, which not only reduces harvest cane yield but also sugar content. This study aimed to identify quantitative trait loci (QTL) and candidate genes associated with SBS resistance. Here, the phenotypic investigation in six field habitats showed a continuous normal distribution, revealing that the SBS resistance trait is a quantitative trait. Two high-density linkage maps based on the single-dose markers calling from the Axiom Sugarcane100K SNP chip were constructed for the dominant sugarcane cultivars YT93-159 (SBS-resistant) and ROC22 (SBS-susceptible) with a density of 2.53 cM and 2.54 cM per SNP marker, and mapped on 87 linkage groups (LGs) and 80 LGs covering 3069.45 cM and 1490.34 cM of genetic distance, respectively. A total of 32 QTL associated with SBS resistance were detected by QTL mapping, which explained 3.73–11.64% of the phenotypic variation, and the total phenotypic variance explained (PVE) in YT93-159 and ROC22 was 107.44% and 79.09%, respectively. Among these QTL, four repeatedly detected QTL (qSBS-Y38-1, qSBS-Y38-2, qSBS-R8, and qSBS-R46) were considered stable QTL. Meanwhile, two major QTL, qSBS-Y38 and qSBS-R46, could account for 11.47% and 11.64% of the PVE, respectively. Twenty-five disease resistance candidate genes were screened by searching these four stable QTL regions in their corresponding intervals, of which Soffic.01G0010840-3C (PR3) and Soffic.09G0017520-1P (DND2) were significantly up-regulated in YT93-159 by qRT-PCR, while Soffic.01G0040620-1P (EDR2) was significantly up-regulated in ROC22. These results will provide valuable insights for future studies on sugarcane breeding in combating this disease.

Anthocyanin accumulation is acknowledged as a phenotypic indicator of phosphate (Pi) starvation. However, negative regulators of this process and their molecular mechanisms remain largely unexplored. In this study, we demonstrate that WRKY33 acts as a negative regulator of phosphorus -status -dependent anthocyanin biosynthesis. WRKY33 regulates the expression of the gene encoding dihydroflavonol 4-reductase (DFR), a rate -limiting enzyme in anthocyanin production, both directly and indirectly. WRKY33 binds directly to the DFR promoter to repress its expression and also interferes with the MBW complex through interacting with PAP1 to indirectly influence DFR transcriptional activation. Under - Pi conditions, PHR1 interacts with WRKY33, and the protein level of WRKY33 decreases; the repression of DFR expression by WRKY33 is thus attenuated, leading to anthocyanin accumulation in Arabidopsis . Further genetic and biochemical assays suggest that PHR1 is also involved in regulating factors that affect WRKY33 protein turnover. Taken together, our findings reveal that Pi starvation represses WRKY33, a repressor of anthocyanin biosynthesis, to finely tune anthocyanin biosynthesis. This "double -negative logic"regulation of phosphorus -status -dependent anthocyanin biosynthesis is required for the maintenance of plant metabolic homeostasis during acclimation to Pi starvation.

Variations in the concentration of glucoraphanin (GRA) and glucoerucin (GER), as well as the corresponding breakdown products, isothiocyanates (ITCs) and nitriles, were investigated during the growth of broccoli sprouts. The concentrations of GRA and GER decreased sharply from 33.66 µmol/g to 11.48 µmol/g and 12.98 µmol/g to 8.23 µmol/g, respectively, after seed germination. From the third to the seventh day, both GRA and GER were maintained as relatively stable. The highest concentrations of sulforaphane (17.16 µmol/g) and erucin (12.26 µmol/g) were observed on the first day. Hereafter, the concentrations of nitrile hydrolyzed from GRA or GER were higher than those of the corresponding ITCs. Moreover, the ratio of sulforaphane to sulforaphane nitrile decreased from 1.35 to 0.164 from 1 d to 5 d, with a similar trend exhibited for erucin/erucin nitrile after 2 d. RNA-seq analysis showed that BolMYB28 and BolCYP83A1, involved in aliphatic glucosinolate (GSL) biosynthesis, remained largely unexpressed until the third day. In contrast, the genes operating within the GSL-myrosinase hydrolysis pathway were highly expressed right from the beginning, with their expression levels increasing significantly after the third day. Additionally, we identified two BolESPs and six BolNSPs that might play important roles in promoting the production of nitriles during the development of broccoli sprouts.

In this study, a new composite with combination of chitosan oligosaccharide (COS) and zinc oxide nanoparticles (ZnO NPs), termed Chitosan Oligosaccharide-Zinc Oxide Nanocomposites (COS-ZnO NC), was designed to enhance the quality of tomato fruits during postharvest storage. SEM analysis showed a uniform distribution of COS-ZnO NC films on tomato surfaces, indicating high biocompatibility, while the FTIR spectrum confirmed the interaction of COS and ZnO NPs via hydrogen bonds. The COS-ZnO NC exerts positive effects on post-harvest quality of tomato fruits, including significantly reduced water loss, fewer skin wrinkles, increased sugar-acid ratio, and enhanced vitamin C and carotenoids accumulation. Furthermore, COS-ZnO NC induces transcription of carotenoid biosynthesis genes and promotes carotenoids storage in the chromoplast. These results suggest that the COS-ZnO NC film can significantly improve the quality traits of tomato fruits, and therefore is potential in post-harvest storage of tomato fruits.

Brassinazole resistant 1 (BZR1), a brassinosteroid (BR) signaling component, plays a pivotal role in regulating numerous specific developmental processes. Our study demonstrated that exogenous treatment with 2,4-epibrassinolide (EBR) significantly enhanced the accumulation of carotenoids and chlorophylls in Chinese kale (Brassica oleracea var. alboglabra). The underlying mechanism was deciphered through yeast one-hybrid (Y1H) and dual-luciferase (LUC) assays, whereby BoaBZR1.1 directly interacts with the promoters of BoaCRTISO and BoaPSY2, activating their expression. This effect was further validated through overexpression of BoaBZR1.1 in Chinese kale calli and plants, both of which exhibited increased carotenoid accumulation. Additionally, qPCR analysis unveiled upregulation of carotenoid and chlorophyll biosynthetic genes in the T1 generation of BoaBZR1.1-overexpressing plants. These findings underscored the significance of BoaBZR1.1-mediated BR signaling in regulating carotenoid accumulation in Chinese kale and suggested the potential for enhancing the nutritional quality of Chinese kale through genetic engineering of BoaBZR1.1.

Saline-alkali stress is an important abiotic stress factor affecting tomato (Solanum lycopersicum L.) plant growth. Although the involvement of the tomato SlWRKY gene family in responses to saline-alkali stress has been well established, the mechanism underlying resistance to saline-alkali stress remains unclear. In this study, we investigated the role of SlWRKY81 in conferring saline-alkali stress resistance by using overexpression and knockout tomato seedlings obtained via genetic modification. We demonstrated that SlWRKY81 improves the ability of tomato to withstand saline-alkali stress by enhancing antioxidant capacity, root activity, and proline content while reducing malondialdehyde levels. Saline-alkali stress induces an increase in jasmonic acid (JA) content in tomato seedlings, and the SlWRKY81 promoter responds to JA signaling, leading to an increase in SlWRKY81 expression. Furthermore, the interaction between SlJAZ1 and SlWRKY81 represses the expression of SlWRKY81. SlWRKY81 binds to W-box motifs in the promoter regions of SlSPDS2 and SlNHX4, thereby positively regulating their expression. This regulation results in increased spermidine (Spd) content and enhanced potassium (K+) absorption and sodium (Na+) efflux, which contribute to the resistance of tomato to saline-alkali stress. However, JA and SlJAZ1 exhibit antagonistic effects. Elevated JA content reduces the inhibitory effect of SlJAZ1 on SlWRKY81, leading to the release of additional SlWRKY81 protein and further augmenting the resistance of tomato to saline-alkali stress. In summary, the modulation of Spd synthesis and Na+/K+ homeostasis mediated by the interaction between SlWRKY81 and SlJAZ1 represents a novel pathway underlying tomato response to saline-alkali stress.

Cruciferous sprout is a new form of vegetable product rich in bioactive compounds, especially glucosinolates. Previous studies have focused on increasing the accumulation of glucosinolates in cruciferous sprouts by applying different chemical regulators, with a particular focus on their contribution to nutritional quality and health benefits. Nevertheless, the effects of melatonin and UV-B irradiation on glucosinolate biosynthesis remain unclear. In this study, it was found that changes in melatonin concentrations significantly affected the contents of individual as well as total aliphatic and indolic glucosinolates. The 5 μmol · L-1melatonin was decided as the optimum concentration that could increase the content of beneficial glucosinolates including glucoraphanin and 4-methoxy glucobrassicin in Chinese kale sprouts. Notably, the enhancement of glucosinolate accumulation by melatonin treatment could be further amplified by UV-B irradiation. Furthermore, our results showed that R2R3-MYB transcription factor BoaMYB28 and BoaMYB51, which are central regulators of aliphatic and indolic glucosinolate biosynthesis respectively, were both involved in the regulation of glucosinolate biosynthesis by melatonin and UV-B irradiation. Additionally,the expression of glucosinolate biosynthetic genes, including BoaCYP79F1, BoaCYP83A1, BoaSUR1, BoaUGT74B1, BoaCYP79B2, BoaCYP79B3, and BoaCYP83B1 participated in the formation of core structures and BoaFMOGS-OX5, BoaAOP2, BoaCYP81F2, and BoaIGMT1 involved in the sidechain modification of aliphatic and indolic glucosinolate, was regulated by melatonin or UV-B irradiation. Taken together, these findings provide a potential strategy for improving the nutritional quality and resistance of Chinese kale sprouts.

Tomato fruit consumption is influenced by flavor and nutrient quality. In the present study, we investigate the impact of water saving irrigation (WSI) as a pre-harvest management on flavor and nutrient quality of tomato fruit. Our results demonstrate that WSI-treated tomato fruit exhibited improved sensory scores as assessed by a taste panel, accompanied by elevated levels of SlGLK2 expression, sugars, acids, and carotenoid contents compared to non-treated fruit. Notably, WSI treatment significantly enhanced the development of chloroplast and plastoglobulus in chromoplast, which served as carotenoid storage sites and upregulated the expression of carotenoid biosynthetic genes. Furthermore, integrated transcriptome and metabolome analysis revealed heightened expression of sugar and flavonoid metabolism pathways in WSI-treated tomato fruit. Remarkably, the master regulator SlMYB12 displayed a substantially increased expression due to WSI. These findings suggest that WSI is an effective and sustainable approach to enhance the pigments metabolism and storage capacity as well as the organoleptic characteristics and nutritional value of tomato fruit, offering a win-win solution for both water conservation and quality improvement in agro-food production.

Different lighting time affects the content of bioactive substances in postharvest kale sprouts. The contents of glucosinolates, vitamin C, total polyphenols, chlorophyll, carotenoids, and total antioxidant capacity in Chinese kale sprouts were analyzed during postharvest storage at room temperature after different treatments including shading treatment group（0 h light/24 h darkness, 8 h light/16 h darkness and 12 h light/12 h darkness） and supplementary light treatment group（24 h light/0 h darkness）, and the natural photoperiod（16 h light/8 h darkness） was used as control. The results showed that total glucosinolates content in shading treatment T1（0 h light/24 h dark） increased significantly by27.96% and 19.73% respectively when stored for 2 d and 3 d compared with the control, and the shading treatment T2（8 h light/16 h dark） increased remarkably by 27.70% and 10.88%, respectively. In addition, shading treatment effectively maintained the contents of chlorophyll and carotenoids in Chinese kale sprouts during storage. The postharvest light time had no significant effect on the total polyphenol content and antioxidant capacity. The research results provide a theoretical basis for setting the light time reasonably to postpone the decrease of Chinese kale sprouts after harvest, which is potential in maintaining the quality of Chinese kale sprouts during the postharvest period.

番茄八氢番茄红素合成酶(SlPSY1)作为类胡萝卜素生物合成途径的关键限速酶,直接影响果实中类胡萝卜素的积累.为探究SlPSY1基因的转录调控机制,通过克隆SlPSY1基因启动子序列,构建pSlPSY1pro-AbAi诱饵载体,并将诱饵载体转化至酵母细胞中获得诱饵酵母菌株.利用番茄混合组织酵母杂交cDNA文库进行酵母单杂交筛库试验,筛选得到AP2/ERF家族转录因子SlJERF1和10个未知功能蛋白.后续克隆SlJERF1基因序列,构建pGADT7-SlJERF1重组载体,通过酵母单杂交点对点对SlJERF1进行分子验证,结果显示在金担子素(AbA)浓度为150 ng·mL-1的条件下,对照组酵母不能正常生长,而试验组酵母能正常生长,表明SlJERF1与SlPSY1基因启动子存在互作.这一结果为进一步拓展类胡萝卜素合成调控网络提供了重要的理论依据.

Chitosan oligosaccharide (COS), a degradation product of chitosan, is easily accessible, highly bioactive, non-toxic, and well-soluble in water. The effects of COS on the qualitative attributes of tomato fruits were investigated in the current study. COS was administered to tomato plants (Solanum lycopersicum cv. Ruixinghongniu) by foliar spray and root irrigation in alternate cycles at concentrations of 0.5 g·L−1 and 0.16 g·L−1, respectively. The experimental outcomes revealed that COS treatment promoted the coloring and softening of tomato fruits. Lycopene, vitamin C, fructose, and glucose levels increased by 49.0%, 25.4%, 30.2%, and 33.4%, respectively, in COS-treated ripe fruits compared to controls. The volatile metabolome showed that COS application also increased the release of ten volatiles correlated with consumer preference (1-penten-3-one, (E)-2-pentenal, (E)-3-hexen-1-ol, (E)-2-heptenal, 2-isobutylthiazole, phenylacetaldehyde, 2-phenylethanol, 6-methyl-5-hepten-2-one, 6-methyl-5-hepten-2-ol, and β-ionone), contributing to an improved tomato flavor. Moreover, increased transcript levels of genes participating in ethylene biosynthesis, perception, and response along with enhanced ethylene production were observed in COS-treated fruits, suggesting that COS may regulate tomato fruit quality via the ethylene pathway. Taken together, our results indicated that the pre-harvest application of COS could improve tomato fruit quality attributes.