Search Results (4)

Photosynthetic characteristics are critical for grape growth and development. Drought conditions in arid regions significantly affect these characteristics. To identify grape varieties better suited for cultivation in arid environments, this study evaluated the leaf phenotypes and photosynthetic characteristics of 27 table grape varieties in Hotan Prefecture, China. Results revealed significant variations in leaf phenotypes and chlorophyll content (SPAD) among varieties under Hotan’s drought conditions. ‘Kyoho’ exhibited the largest leaf area (254.34 cm²), while ‘Munage’ had the smallest (112.43 cm²), and ‘Manaizi’ showed the highest chlorophyll content (SPAD = 44.21). ‘Munage’ and ‘Flame Seedless’ recorded the highest net photosynthetic rates (P_Nmax = 16.24 and 16.23 μmol·m⁻²·s⁻¹, respectively), while ‘Thompson Seedless’ had the lowest respiratory loss (R_D = 1.15 μmol·m⁻²·s⁻¹) and light compensation point (I_c = 22.41 μmol·m⁻²·s⁻¹), with a highly significant positive correlation between R_D and I_c. ‘Crimson Seedless’ exhibited the highest light saturation point (I_sat = 2745.15 μmol·m⁻²·s⁻¹). Chlorophyll fluorescence analysis indicated that ‘Autumn Black’ had the highest PSII photochemical yield (F_v/F_m = 0.84), while ‘Zicuiwuhe’ showed high energy transfer indices (PI_abs = 1.78, PI_total = 1.66) and electron transfer efficiency (φ_Eo = 0.39). PIabs was significantly correlated with F_v/F_m, F_v/F_o, and energy flux parameters. ‘Molixiang’ demonstrated superior energy utilization, with the highest light absorption (ABS/CSm = 2440.8) and electron transfer flux (ETo/CSm = 874) and the lowest energy dissipation (DIo/CSm = 455.8), supported by a negative correlation between energy dissipation (DIo/CSm) and photochemical efficiency (φ_Eo). Principal component analysis revealed that ‘Molixiang’ had the highest comprehensive photosynthetic adaptability score (0.97), followed by ‘Zicuiwuhe’ (0.79) and ‘Hetianhong’ (0.73), under Hotan’s drought stress conditions. These findings provide valuable insights for selecting and breeding grape varieties adapted to arid environments and climate change. Full article

This study aimed to investigate the impact of Botrytis cinerea (B. cinerea) on the post-harvest quality of ‘Munage’ grapes and their molecular mechanism. The results showed that B. cinerea significantly reduced the post-harvest quality of ‘Munage’ grapes, which was manifested by an increase in incidence and rot rate, a significant increase in weight loss rate and fruit color difference, and a significant decrease in fruit firmness. In addition, B. cinerea infection significantly changed the reactive oxygen species and antioxidant enzyme activities of ‘Munage’ grapes, including increasing the H₂O₂ content and O₂⁻ generation rate as well as changing the superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), and peroxidase (POD) activities. B. cinerea also significantly changed the wax structure and content of ‘Munage’ grapes, causing the wax to completely dissolve and disappear and reducing the relative content of wax components. Through RNA-seq analysis, it was found that after B. cinerea infection, 49 differentially expressed genes (DEGs) related to fatty acid synthesis, extension, cutin and wax synthesis, and wax transport showed up-regulation or down-regulation, and 12 different transcription factors (TFs) also showed significant differential expression. These TFs were correlated with DEGs related to wax synthesis and metabolism, indicating that they may play an important role in the epidermal wax changes in ‘Munage’ grapes caused by B. cinerea. This study revealed the impact of B. cinerea on the post-harvest quality of ‘Munage’ grapes and their molecular mechanism and provided a scientific basis for grape disease prevention and quality maintenance. Full article

Postharvest grapes exhibit a limited shelf life due to susceptibility to rot and deterioration, significantly reducing their nutritional and economic value. Sulfur dioxide (SO₂) is a widely recognized preservative for extending grape storage life. This study performed a detailed analysis of ‘Munage’ table grapes treated with SO₂ fumigation, employing transcriptomic and metabolomic approaches. Results indicate that SO₂ fumigation significantly extends the shelf life of grapes, as demonstrated by improved visual quality, reduced decay rates, and increased fruit firmness. We identified 309 differentially accumulated metabolites (DAMs) and 1906 differentially expressed genes (DEGs), including 135 transcription factors (TFs). Both DEGs and DAMs showed significant enrichment of flavonoid-related metabolism compared with the control, and the relative content of four flavonoid metabolites (Wogonin-7-O-glucuronide, Acacetin-7-O-glucuronide, Apigenin-7-O-glucuronide, and Baicalein 7-O-glucuronide) were significantly increased in grapes upon SO₂ treatment, suggesting that SO₂ treatment had a substantial regulatory effect on grape flavonoid metabolism. Importantly, we constructed complex regulatory networks by screening key enzyme genes (e.g., PAL, 4CLs, CHS, CHI2, and UGT88F3) related to the metabolism of target flavonoid, as well as potential regulatory transcription factors (TFs). Overall, our findings offer new insights into the regulatory mechanisms by which SO₂ maintains the postharvest quality of table grapes. Full article

To enhance comprehension of the impact of mixed fermentation using Torulaspora delbrueckii Bio-119667 (TD) on the aroma composition of Munage grape base-wine (MGBW), we analysed the aroma composition of MGBW using HS-SPME-GC-MS widely targeted metabolomics. The levels of volatile aroma components, including terpenes, higher alcohols, aldehydes, heterocyclic compounds, and esters, were significantly higher in MGBW produced by mixed fermentation compared to the pure Saccharomyces yeast control fermentation. The study found that the content of esters increased by 26.3% after mixed fermentation, indicating the contribution of TD to the formation of ester flavour components during the fermentation of MGBW. After analysing aroma activity values, we discovered that 49 out of 115 esters (25.5% of the total) significantly contributed to the aroma profile of MGBW (rOAV > 1). Of these esters, 16 were identified as key aroma compounds (rOAV > 1, VIP > 1) produced by mixed fermentation with the participation of TD. This finding further supports the contribution of TD to the improvement of MGBW’s aroma composition. This study reveals the role of non-Saccharomyces yeast strain Torulaspora delbrueckii Bio-119667 in improving the aroma composition of MGBW produced by mixed culture fermentation and the biosynthetic pathways of key aroma components therein. Full article