Tobacco is an important economic crop grown primarily for its leaves, and the quality of flue-cured tobacco is strongly influenced by harvest maturity. To accurately determine the optimal harvest maturity of flue-cured tobacco leaves, this study examined the maturity of ‘Yunyan 87’ tobacco leaves across various harvest periods in Chongqing region. Our findings revealed that mature tobacco leaves enhanced both the appearance quality and the coordination of chemical composition in flue-cured tobacco. Metabolomics analysis showed that mature tobacco leaves had the highest levels of glucose, fructose, sucrose, and other sugars, while the flavonoid content was highest in over-mature leaves, and lowest in immature leaves. Transcriptomics analysis indicated that the gene expression pattern in mature tobacco leaves significantly differed from that in immature and over-mature leaves. DEGs were predominantly enriched in pathways associated with sugar, amino acid, and phenylpropanoid metabolism. The correlation analysis with metabolomics showed that compared with immature and over-mature tobacco leaves, mature tobacco leaves were more conducive to the accumulation of amino acids and the decrease of nicotine content. This experiment revealed the dynamic changes of aroma precursors and the potential mechanism of related genes in the key stages of curing of tobacco leaves with different maturity, and provided a valuable reference for the selection of suitable curing period for tobacco.

Phytoene synthase (PSY) is the primary rate-limiting enzyme in the carotenoid biosynthesis pathway and plays a crucial role in regulating carbon flux toward carotenoid production. The Orange (OR) protein functions as a molecular chaperone for PSY, increasing its activity and facilitating carotenoid accumulation. Notably, the mutation of OR to ORHis further amplifies this effect. However, the interaction dynamics between OR/ORHis and multiple PSY copies in plants remain unclear, particularly whether these proteins interact uniformly with all PSY variants or exhibit differential effects. We here cloned three BoaPSY homologs from Chinese kale and demonstrated that all identified BoaPSYs contribute to carotenoid accumulation in engineered bacterial systems and Chinese kale calli. Among them, BoaPSY1 exerted the most pronounced effect, followed by BoaPSY2 and BoaPSY3. Additionally, BoaOR/ORHis directly interacted with BoaPSYs, and the overexpression of BoaOR/ORHis–BoaPSYs complexes further enhanced carotenoid accumulation in Chinese kale calli, with the calli overexpressing BoaORHis-BoaPSY1/2 showing the highest carotenoid content. Binding energy analyses and α-galactosidase activity assays revealed that BoaORHis has the strongest binding affinity for BoaPSY2. Overexpression of the BoaORHis–BoaPSY2 complex in Chinese kale plants increased carotenoid and chlorophyll levels but reduced their degradation during postharvest storage. Our findings advance the understanding of carotenoid metabolic regulation and propose a novel strategy for improving both preharvest quality and postharvest shelf life of Chinese kale, thereby increasing its economic value and market potential.

Mustard (Brassica juncea) sprouts are recognized for their high nutritional and functional value. Here, the effects of ultrasound, trehalose, and their combined treatment on mustard metabolic traits were evaluated for improving sprout quality. Ultrasound promoted germination and increased soluble protein, flavonoid and glucosinolate levels. Trehalose primarily elevated soluble sugars, ascorbic acid and total phenolics. In contrast, the combined treatment reduced antioxidant capacity and decreased the glucosinolates content, indicating a metabolic trade-off. Transcriptome analysis revealed shifts in carbohydrate metabolism, diversion of phenylpropanoid flux towards flavonoid biosynthesis and suppression of glucosinolate biosynthetic genes. The transcription factors JUB1, ARF32 and NAC59 were identified as potential regulators. Overall, ultrasound was more effective than trehalose in enhancing functional nutrient quality, and single elicitors were preferable to combined application for targeted improvement of mustard sprout nutritional value.

gamma-Aminobutyric acid (GABA) is a nonprotein amino acid involved in plant stress responses and metabolic regulation. In this study, we investigated the effects of exogenous GABA on postharvest senescence in baby mustard stored at 20 degrees C. GABA treatment preserved external quality and delayed the loss of chlorophylls, ascorbic acid, and phenolics. Quasi-targeted metabolomics identified 195 differentially accumulated metabolites (DAMs) in the comparison between untreated and GABA-treated samples, including amino acids (e.g., threonine, phenylalanine), soluble sugars (e.g., trehalose), and phenylpropanoids (e.g., sinapine, astragalin). Transcriptomic profiling of the same comparison revealed 5,912 differentially expressed genes (DEGs). Many of these DEGs were enriched in phenylpropanoid biosynthesis and antioxidant pathways, with GABA upregulating antioxidant enzyme genes and contributing to redox stability. Moreover, GABA treatment suppressed ethylene signaling by downregulating ETR, CTR1, and 40 out of 42 ethylene-responsive (ERF) transcription factors, thereby repressing ethylene-responsive transcription. These integrated responses delayed oxidative damage and maintained nutritional stability. This study provides the first omics-based evidence of GABA-mediated alleviation of senescence in baby mustard, highlighting its potential as a postharvest preservation strategy for Brassica vegetables.

Baby mustard is rich in nutrients; however, it is prone to postharvest yellowing and wilting, which leads to the loss of nutritional components. Folic acid, an important water-soluble vitamin, exhibits substantial physiological antioxidant activity. This study explored the impact of folic acid immersion treatments on the visual quality and health-promoting compounds of baby mustard stored at 20 degrees C. The results showed that, compared with other concentrations, 5 mg L-1 folic acid treatment (F5) was the most effective in improving baby mustard storability. In terms of appearance and sensory acceptability, the F5 treatment was more effective than 0 mg L-1 folic acid treatment (CK), while the a* value was significantly lower than that of the control. In terms of pigments, chlorophyll and carotenoid contents were higher in the F5-treated samples than in the control, contributing to improved color retention during storage. In addition, the F5 treatment maintained glucosinolate content, especially by preserving aliphatic glucosinolates. This treatment also increased the ascorbic acid content of baby mustard, increased total phenolic content, and improved antioxidant activity. Overall, these findings indicate that the application of 5 mg L-1 folic acid is a promising strategy for improving the postharvest quality and commercial value of baby mustard, providing a theoretical basis and technical support for its preservation during room-temperature storage.

Brassica sprouts possess substantial nutritional value. In this study, the effects of pre-harvest MT and CaCl2 alone and MT+CaCl2 combined treatment on the quality of Chinese kale sprouts during low temperature storage were investigated. The results demonstrated that preharvest MT alone reduced weight loss, increased the content of soluble sugar, soluble protein, total chlorophylls, total carotenoids, total phenolics, flavonoids, ascorbic acid and total glucosinolates, which were 1.12, 1.04, 1.09, 1.09, 1.08, 1.06, 1.37, and 1.36 times those of CK, respectively. It also upregulated the expression of photosynthesis-related genes. Preharvest CaCl2 alone treatment can up-regulate the expression of genes related to phenylpropanoid and glucosinolate biosynthesis, and promoted the accumulation of phenolics and glucosinolates. Preharvest MT+CaCl2 combined treatment could increase the content of soluble sugar, ascorbic acid and total glucosinolates, which were 1.06, 1.87, and 1.26 times those of CK, respectively. In conclusion, preharvest MT and CaCl2 alone and MT+CaCl2 combined treatment can maintain postharvest quality of Chinese kale sprouts by specifically regulating nutritional components and bioactive substances, thereby providing a technical approach for postharvest preservation of sprouts.

Sprout vegetables have emerged as functional instant foods, with elevated concentrations of bioactive compounds compared with their mature counterparts. Chinese kale (Brassica oleracea var. alboglabra) is a cruciferous Brassica vegetable particularly rich in phenolic compounds, glucosinolates, and other nutrients, making it a suitable candidate for sprout production. This study aimed to explore the impact of melatonin (MT), calcium chloride (CaCl2), and their combination on the quality and functional metabolism of Chinese kale. The results showed that MT treatment alone led to significantly higher ferric-reducing antioxidant power and concentrations of chlorophylls, carotenoids, soluble sugar, soluble protein, flavonoid, total phenolic compounds, and glucosinolates than those under CaCl2 treatment alone. CaCl2 treatment alone increased ascorbic acid content by 30.5%, but had limited effects on protein accumulation and secondary metabolites. However, the combined treatment did not exert a synergistic effect on ascorbic acid content, which decreased by 19.8% compared with that under the control treatment, significantly (p < 0.05). Overall, MT treatment was effective in boosting nutrient levels, thereby elevating the functional quality of Chinese kale sprouts.

This study aimed to develop a bio-based intelligent packaging film using mustard (Brassica juncea) as a single-crop resource, integrating leaf-derived anthocyanins as pH-responsive indicators and seed-derived glucosinolate-rich extracts as multifunctional additives in an alginate-starch matrix. Glucosinolate incorporation enhanced ultraviolet shielding, antioxidant activity, and intermolecular interactions, resulting in improved barrier and mechanical properties. Among the formulations, the film containing 6 wt% glucosinolates exhibited optimal performance, achieving a tensile strength of 15.47 MPa, elongation at break of 29.09%, and reduced water-vapor and oxygen permeability. This optimized film effectively delayed increases in pH, total volatile basic nitrogen, and microbial growth in chilled salmon. Moreover, film color variation displayed strong correlations with freshness indicators, enabling visual monitoring and extending shelf life to 6 days. These findings show that mustard-derived anthocyanin-glucosinolate films provide a sustainable strategy for intelligent packaging with simultaneous freshness indication and preservation functions.

Carotenoid isomerase (CRTISO) is an important enzyme in carotenoid biosynthesis, and it catalyzes the conversion of lycopene precursors to lycopene in several plant species. However, the role of CRTISO in other biochemical processes during plant growth and development remains unclear. Here, we showed that Chinese kale boacrtiso mutants have distinctive characteristics, including a yellow-green hue and glossy appearance, and this contrasts with the dark green and glaucous traits observed in wild-type (WT) plants. Analysis of pigments in mutants revealed that the reduction in the content of carotenoids and chlorophylls contributed to the yellow-green coloration observed in mutants. An examination of cuticular waxes in Chinese kale indicated that there was a decrease in both the total wax content and the content of individual waxes in boacrtiso mutants (bearing a mutation of BoaCRTISO), which may be caused by the decrease of abscisic acid (ABA) content. The expression of carotenoid, chlorophyll, ABA, and wax biosynthesis genes was down-regulated in boacrtiso mutants. This finding confirms that BoaCRTISO regulates the biosynthesis of pigments, ABA, and cuticular waxes in Chinese kale. Our results provide new insights into the interplay between plant pigment and cuticular wax metabolic pathways in Brassica vegetables.

The potential of mustard (Brassica juncea) leaves as a raw material for herbal tea remains unexplored. This study aimed to evaluate the suitability of mustard leaves for tea production and optimize processing and formulation. Four mustard varieties were evaluated using traditional green tea processing techniques, demonstrating that purple-leaf mustard is an excellent raw material for herbal tea, both in terms of sensory properties and bioactive compounds. Next, eight processing methods for purple-leaf mustard were employed. The mustard leaf tea, processed using a combination of steaming fixation, rolling, and vacuum freeze-drying technology, demonstrated effective preservation of health-promoting compounds while maintaining a desirable flavor profile. Blending mustard leaf tea with Maofeng green tea or Tieguanyin oolong tea further enhanced its aroma and taste. This study developed a novel herbal tea using purple-leaf mustard and provides a reference for producing high-quality herbal teas with a unique flavor profile and health-promoting compounds.

Mulberry is a representative economic tree species valued for both poverty alleviation and medicinal use. To advance the understanding of mulberry genomics and demography, we assembled high-quality haploid genomes of two widely cultivated mulberry varieties NS14 and QS1, and analysed 376 accessions from 12 countries, including 39 ancient trees to investigate their origin and spreading. Population genetic analyses revealed that mulberry originated in the Yunnan-Guizhou Plateau (YGP) and subsequently spread northward from South China to North China. This migration resulted in significant genetic differentiation between northern and southern populations, with the southern populations exhibiting higher genetic diversity. A total of 37 traits related to development and immunity were analysed in 203 accessions, and a genome-wide association study (GWAS) was used to identify 204 associated loci. Five causal gene haplotypes were pinpointed for key production traits of mulberry trees, including branch pitch, branch length, budburst timing, leaf thickness, and leaf size (leaf area, leaf width, and leaf length). To further explore loci related to disease resistance, we examined the resistance of 538 F1 hybrids derived from NS14 (resistant) and QS1 (susceptible). Through bulked segregant analysis and GWAS, we identified a G-type RLK (receptor-like kinase) tandem gene cluster. Transcriptomic analyses revealed opposite expression trends of these RLK genes in NS14 and QS1, further supporting their role in mulberry blight resistance. Our findings provide valuable genomic and demographic insights for future multi-purpose breeding efforts in mulberry.

Glutathione (GSH) has a beneficial effect on the response of plants to cadmium (Cd) stress. The physiological and molecular processes by which glutathione influences Cd tolerance in purple flowering stalks (a Brassica vegetable) remain unclear. The aim of this study was to investigate the role of exogenous GSH in alleviating Cd toxicity in purple flowering stalks. On day 10 of the Cd stress treatment, spraying of GSH resulted in an increase in the net photosynthetic rate by 18.48%; enhanced antioxidant enzyme activities and the endogenous GSH and ascorbic acid contents; reduced the malondialdehyde and proline content 32.45% and 24.65%, respectively; and reduced the Cd content in the roots by 2.93%. On day 5, the transcriptome analysis showed that the application of GSH up-regulated the expression of 27 genes in the photosynthetic pathway. In contrast, GSH application led to the down-regulation of most genes involved in GSH metabolism, sulfur metabolism, and arginine and proline metabolism. These findings will aid future studies of the response of purple flowering stalks to Cd stress.

Mustard sprouts are rich in bioactive compounds and have significant nutritional effects. This experiment investigated the effects of melatonin and sucrose separately and in combination on mustard sprout growth, antioxidant capacity, and nutritional value. The results indicated that melatonin successfully mitigated the reduction of chlorophyll and carotenoids content in mustard sprouts induced by sucrose and mannitol. Sucrose significantly promoted the growth of mustard sprouts, with plant height and fresh weight increasing by 53.22 % and 22.31 %, respectively, compared to the control. In contrast, mannitol treatment did not significantly enhance mustard sprout growth. Both sucrose and mannitol treatments increased the accumulation of ascorbic acid, total phenolics, glucosinolates, and antioxidant capacity, with sucrose showing a more pronounced effect. Moreover, the combined treatment of sucrose and melatonin further stimulated sprout growth and increased the contents of soluble protein, soluble sugar, ascorbic acid, total phenolics, glucosinolates, and antioxidant capacity. Notably, the total glucosinolates content increased by 42.25 % compared to the control. In summary, the combination of sucrose and melatonin can significantly improve the yield and nutritional quality of mustard sprouts, which provides an effective strategy for improving the production of high-quality mustard sprouts.

Brassica sprouts are rich in bioactive compounds and have significant nutritional value. In this study, the effects of sole and combined sucrose and melatonin treatment on the growth, nutritional quality, and antioxidant capacity of Chinese kale sprouts were evaluated. Melatonin effectively alleviated the growth retardation of Chinese kale sprouts caused by sucrose and mannitol and the decrease in the chlorophyll and carotenoid content, thereby increasing the biomass of sprouts. Transcriptome analysis showed that sucrose promoted the accumulation of soluble sugars and anthocyanins by enhancing starch and sucrose metabolism and anthocyanin biosynthesis. The combined treatment of sucrose and melatonin promoted the accumulation of antioxidants and glucosinolates by enhancing phenylpropanoid metabolism and glucosinolate biosynthesis. Metabolomics analysis showed that sucrose significantly up-regulated most sugars and amino acids in sprouts. When biomass was taken into account, the accumulation of antioxidant substances and glucosinolates was highest in the combined sucrose and melatonin treatment.

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).

Tobacco is a widely cultivated economic crop globally, with the quality of flue-cured tobacco being closely linked to the curing process. In this study, we improved the curing process parameters for Yunyan 87 tobacco leaves and explored the effects of these treatments on tobacco curing. The improved curing process enhanced the visual and chemical quality of flue-cured tobacco leaves. Metabolomics and proteomics analyses revealed that the treatment upregulated the expression of proteins such as glycogen phosphorylase (PYG), alpha-amylase (AMY), and acid invertase (INV) in the tobacco leaves during the key stages of the curing process, which promoted the accumulation of sugars like glucose and fructose. Additionally, the treatment regulated the expression of key enzymes such as triosephosphate isomerase (TIM), fructose bisphosphate aldolase (ALDO), glutamine synthetase (glnA), and arogenate dehydratase (ADT) involved in glycolysis, the TCA cycle, and amino acid metabolism, fostering the synthesis of amino acids including L-glutamine, 4-aminobutyric acid, and L-phenylalanine. The flavonoid levels in flue-cured tobacco were correlated with protein expression in the biosynthesis of phenylpropanoids and flavonoids at the 42°C stage. This regulation of flavonoid synthesis and degradation was accompanied by the upregulation of carotenoid epsilon hydroxylase (LUT1) and zeaxanthin epoxide enzyme (ZEP), which increased carotenoid content. Our findings indicate that the treatment curing process enhance aroma precursors such as sugars, amino acids, flavonoids, and carotenoids in flue-cured tobacco. This process holds significant potential for the development of tobacco production and offers a theoretical foundation for optimizing both the tobacco curing process and tobacco quality.

In this study, we analyzed the nutritional components and antioxidant capacity of 17 leaf mustard cultivars, including 13 cultivars from Leshan, 2 from Ya’an, and 2 from Yibin. Significant variations were observed among the cultivars in terms of their nutritional composition and antioxidant properties. Our findings revealed that cultivar LS12 exhibited the highest levels of total chlorophyll, total anthocyanidin, flavonoids, total phenolics, and ferric-reducing antioxidant power (FRAP). Cultivar YB2 showed higher contents of soluble sugar, soluble protein, ABTS antioxidant capacity, and total glucosinolates. On a regional basis, the cultivars from Leshan had higher total phenolics compared to those from Ya’an and Yibin, while cultivars from Yibin exhibited the highest total glucosinolate content. Additionally, purple-leaf mustard demonstrated superior flavonoid and total phenolic contents, as well as higher FRAP values, compared to the cultivars of green-leaf mustard. However, green-leaf mustard contained higher levels of total glucosinolates than their purple counterpart. Based on a comprehensive evaluation using a membership function analysis, LS12 was identified as the cultivar with the best nutritional quality and antioxidant capacity. This study provides valuable insights into the nutritional attributes and antioxidant capacity of different leaf mustard cultivars and offers guidance for selecting varieties to promote a healthy diet.

Humic acids (HAs), tea polyphenols (TPs), and fulvic acids (FAs) are bioactive substances known for their antimicrobial, antioxidant, and plant growth-promoting properties. However, the chemical structures and molecular mechanisms underlying their growth-promoting effects remain unclear. Solid-state 13C nuclear magnetic resonance analysis reveals that FA has the most aromatic and oxygen-containing groups, followed by HA and TP, with a molecular weight ranking of HA > TP > FA. Transcriptomic and metabolomic analyses reveal that these biostimulants unregulated genes related to IAA, C and N metabolism, and pathogen resistance, leading to enhanced synthesis of amino acids, lipids, vitamins, and sugars while improving N and P utilization efficiency. Small molecular weight and aromatic compounds with carboxyl groups and phenolic hydroxyl (especially those with high O/C or (O + H)/C ratios) are crucial for stimulating hormone synthesis and nutrient uptake. These findings provide valuable insights into developing novel fertilizers and artificially regulating humic substances.

This study mainly explored the effects of different concentrations of AgNPs on the growth and quality of mustard sprouts. The results demonstrated that treatment with 50 mg L- 1 AgNPs significantly increased the edible fresh weight, soluble protein, ascorbic acid, total phenolics, chlorophylls, carotenoids, and glucosinolates content of mustard sprouts, with the values being 1.11, 1.40, 1.05, 1.04, 1.16, 1.12, and 1.14-fold those of the control, respectively. Similarly, treatment with 100 mg L- 1 AgNPs significantly elevated the soluble sugar, flavonoids content, with values 1.26-fold and 1.24-fold higher than those in the control, respectively. The treatment with 200 mg L- 1 AgNPs increased the glucosinolates content to 1.14-fold that of the control. A comprehensive evaluation of the membership function across all treatments revealed that the optimal AgNPs concentration was 50 mg L- 1, yielding an average membership function value of 0.82. In conclusion, the 50 mg L- 1 AgNPs treatment significantly enhanced both the productivity and nutritional quality of mustard sprouts. It provides an effective method for improving the efficient and high quality production of mustard sprouts.