Comprehensive metabolomics-based analysis of sugar composition and content in berries of 18 grape varieties.

Xinjiang is the largest grape-producing region in China and the main grape cultivation area in the world. The Eurasian grape resources grown in Xinjiang are very rich in diversity. The sugar composition and content are the main factors that determine the quality of berries. However, there are currently no systematic reports on the types and contents of sugars in grapes grown in Xinjiang region. In this research, we evaluated the appearance and fruit maturity indicators of 18 grape varieties during fruit ripening and determined their sugar content using GC-MS. All cultivars primarily contained glucose, D-fructose, and sucrose. The glucose content in varieties varied from 42.13% to 46.80% of the total sugar, whereas the fructose and sucrose contents varied from 42.68% to 50.95% and 6.17% to 12.69%, respectively. The content of trace sugar identified in grape varieties varied from 0.6 to 2.3 mg/g. The comprehensive assessment by principal component analysis revealed strong positive correlations between some sugar components. A comprehensive study on the content and types of sugar will provide the foundation to determine the quality of grape cultivars and effective ways to utilize resources to improve sugar content through breeding.

Transcriptome and metabolome reveal the effects of three canopy types on the flavonoids and phenolic acids in 'Merlot' (Vitis vinifera L.) berry pericarp.

The flavonoids and phenolic acids in grape berries greatly influence the quality of wine. Various methods are used to shape and prune grapevines, but their effects on the flavonoids and phenolic acids remain unclear. The flavonoids and phenolic acids in the berry pericarps from grapevines pruned using three types of leaf canopy, namely, V-shaped, T-shaped, and vertical shoot-positioned (VSP) canopies, were compared in this study. Results showed that the V-shaped canopy was more favorable for the accumulation of flavonoids and phenolic acids. Transcriptome and metabolome analyses revealed that the differentially expressed genes (DEGs) and differentially regulated metabolites (DRMs) were significantly enriched in the flavonoid and phenylpropanoid biosynthesis pathways. A total of 96 flavonoids and 32 phenolic acids were detected among the DRMs. Their contents were higher in the V-shaped canopy than in the T-shaped and VSP canopies. Conjoint analysis of transcriptome and metabolome showed that nine DEGs (e.g., cytochrome P450 98A9 and 98A2) were significantly correlated to nine phenolic acids (e.g., gentisic acid and neochlorogenic acid) and three genes (i.e., chalcone isomerase, UDP-glycosyltransferase 88A1, and caffeoyl-CoA O-methyltransferase) significantly correlated to 15 flavonoids (e.g., baimaside and tricin-7-O-rutinoside). These genes may be involved in the regulation of various flavonoids and phenolic acids in grape berries, but their functions need validation. This study provides novel insights into the effects of leaf canopy on flavonoids and phenolic acids in the skin of grape berries and reveals the potential regulatory networks involved in this phenomenon.

Metabolomic and transcriptomic analyses reveal the effects of self- and hetero-grafting on anthocyanin biosynthesis in grapevine.

Grafting, which joins a scion from a cultivar with the stem of a rootstock from a grapevine wild relative, is commonly used in viticulture. Grafting has crucial effects on various phenotypes of the cultivar, including its phenology, biotic and abiotic resistance, berry metabolome, and coloration, but the underlying genetics and regulatory mechanisms are largely unexplored. In this study, we investigated the phenotypic, metabolomic, and transcriptomic profiles at three developmental stages (45, 75, and 105 days after flowering) of the Crimson Seedless cultivar (Vitis vinifera) grafted onto four rootstocks (three heterografts, CS/101-14, CS/SO4, and CS/110R and one self-graft, CS/CS) with own-rooted graft-free Crimson Seedless (CS) as the control. All the heterografts had a significant effect on berry reddening as early as ~45 days after flowering. The grafting of rootstocks promoted anthocyanin biosynthesis and accumulation in grape berries. The metabolomic features showed that cyanidin 3-O-glucoside, delphinidin 3-O-glucoside, malvidin 3-O-glucoside, peonidin 3-O-glucoside, and petunidin 3-O-glucoside were the pigments responsible for the purplish-red peel color. Transcriptomic analyses revealed that anthocyanin biosynthesis-related genes, from upstream (phenylalanine ammonia-lyase) to downstream (anthocyanidin 3-O-glucosyltransferase and anthocyanidin synthase), were upregulated with the accumulation of anthocyanins in the heterografted plants. At the same time, all these genes were also highly expressed and more anthocyanin was accumulated in self-grafted CS/CS samples compared with own-rooted graft-free CS samples, suggesting that self-grafting may also have promoted berry reddening in grapevine. Our results reveal global transcriptomic and metabolomic features in berry color regulation under different grafting conditions that may be useful for improving berry quality in viticulture.

Grafting with rootstocks promotes phenolic compound accumulation in grape berry skin during development based on integrative multi-omics analysis.

In viticulture, grafting has been practiced widely and influences grape development as well as berry and wine quality. However, there is limited understanding of the effects of rootstocks on grape phenolic compounds, which are located primarily in the berry skin and contribute to certain sensory attributes of wine. In this study, scion-rootstock interactions were investigated at the green-berry stage and the veraison stage when grapevines were hetero-grafted with three commonly used rootstock genotypes (5BB, 101-14MG, and SO4). Physiological investigations showed that hetero-grafts, especially CS/5BB, contained higher concentrations of total proanthocyanidins (PAs) and various PA components in berry skins compared with the auto-grafted grapevines. Further metabolomics analysis identified 105 differentially accumulated flavonoid compounds, the majority of which, including anthocyanins, PAs, and flavonols, were significantly increased in the berry skins of hetero-grafted grapevines compared with auto-grafted controls. In addition, transcriptomic analysis of the same samples identified several thousand differentially expressed genes between hetero-grafted and auto-grafted vines. The three rootstocks not only increased the transcript levels of stilbene, anthocyanin, PA, and flavonol synthesis genes but also affected the expression of numerous transcription factor genes. Taken together, our results suggest that hetero-grafting can promote phenolic compound accumulation in grape berry skin during development. These findings provide new insights for improving the application value of grafting by enhancing the accumulation of nutritious phenolic components in grape.

Dynamic Changes in Anthocyanin Accumulation and Cellular Antioxidant Activities in Two Varieties of Grape Berries during Fruit Maturation under Different Climates.

As popularly consumed fruit berries, grapes are widely planted and processed into products, such as raisins and wine. In order to identify the influences of different climatic conditions on grape coloring and quality formation, we selected two common varieties of grape berries, 'Red Globe' and 'Xin Yu', for investigation. Grapes were separately grown in different climates, such as a temperate continental arid climate and a temperate continental desert climate, in Urumqi and Turpan, China, for five developmental stages. As measured, the average daily temperature and light intensity were lower in Urumqi. Urumqi grape berries had a lower brightness value (L*) and a higher red-green value (a*) when compared to Turpan's. A RT-qPCR analysis revealed higher transcriptions of key genes related to anthocyanin biosynthesis in Urumqi grape berries, which was consistent with the more abundant phenolic substances, especially anthocyanins. The maximum antioxidant activity in vitro and cellular antioxidant activity of grape berries were also observed in Urumqi grape berries. These findings enclosed the influence of climate on anthocyanin accumulation and the antioxidant capacity of grapes, which might enlarge our knowledge on the quality formation of grape berries and might also be helpful for cultivating grapes with higher nutritional value.

Effects of fruit tree canopy shading on grain filling of intercropping winter wheat.

Fruit tree-wheat intercropping system is the main agricultural production pattern in sou-thern Xinjiang. In this study, almond (Amygdalus communis)-winter wheat (Xindong 20 (Triticum aestivum, var. Xindong 20) intercropping system was used as the research object. Four tree forms of delayed open-central shape (DC), open-center shape (OC), high stem-shape (HS), and semicircle small-canopy shape (SC) and three intercropping distances (wheat intercropping area respectively 1.5, 2.5 and 3.5 m from the tree trunk) were set to create tree canopy shading treatments, with monoculture wheat as the control. The environmental factors and the grain filling characteristic of winter wheat under different treatment conditions were measured, and the correlation between grain filling characteristics and 1000-grain weight and environmental factors was established to provide information for selecting the best management standards and optimizing the intercropping system. The results showed that under the almond tree-winter wheat intercropping system, the PAR, red/far-red light (R/FR), and temperature above the wheat canopy were significantly decreased due to canopy shading, resulting in a significant increase in humidity. The degree of variation was affected by tree form and distance. The PAR decrease degree of the four treatments was DC＞OC/HS＞SC, except for HS. The PAR decrease of the other tree form treatments was 1.5 m＞2.5 m＞3.5 m. The PAR decrease was distributed in the range of 35.5%-86.6%. A cubic polynomial equation represented the grain filling process, and the specific property of grain filling and 1000-grain weight was assessed using the correlation analysis. The decrease in the 1000-grain weight in the intercropping system was closely associated with the decreases in average grain-filling rate (V), maximum grain-filling rate (Vmax), effective grain-filling duration (Se), and effective grain-filling duration (Vs). The shortening of Se and the reduction in the grain filling rate were related with the reduction in the PAR incidence above the wheat canopy. In the fruit tree-winter wheat intercropping system, the reduction of PAR, dry matter accumulation after flowering, and Se were reduced by tree canopy shading consequently for the decrease in the 1000-grain weight of the intercropping wheat. When the distance between the intercropping area and the tree trunk was greater than 75% of tree height, and shading intensity was less than 35.5% of the natural light intensity, the intercropping with the almond tree could increase the 1000-grain weight of wheat by increasing the effective grain-filling duration.

Comparative phenotypic and transcriptomic analysis of Victoria and flame seedless grape cultivars during berry ripening.

Grape berry development is a highly coordinated and intricate process. Herein, we analyzed the phenotypic and transcriptomic patterns of Victoria (VT) and Flame Seedless (FS) grape varieties during berry development. Physiological analysis and transcriptomic sequencing were performed at four berry developmental phases. VT berry size was comparatively larger to the FS variety. At maturity, 80 days postanthesis (DPA), the FS soluble solids were 61.8% higher than VT. Further, 4889 and 2802 differentially expressed genes were identified from VT and FS 40 DPA to 80 DPA development stages, respectively. VvSWEET15, VvHXK, and MYB44 genes were up-regulated during the postanthesis period, while bHLH14, linked to glucose metabolism, was gradually down-regulated during berry development. These genes may have significant roles in berry development, ripening, and sugar accumulation.

Two Unusual Cases of Human Immunodeficiency Virus-Negative Patients with Talaromyces marneffei Infection.

Talaromyces marneffei (formerly known as Penicillium marneffei) is a dimorphic fungus endemic in south and southeast Asia. It is not only commonly found in human immunodeficiency virus (HIV)-infected patients, but also among HIV-negative immunocompromised patients. The infection caused by this pathogen can disseminate hematogenously to other locations. Herein, we report for the first time two cases complicated with a rare disease or involving a rare site: in the first case, T. marneffei infection was complicated by Langerhans cell histiocytosis, whereas the second case showed clear etiological evidence of pleural nodules and pleural effusion caused by T. marneffei and diagnosed by thoracoscopic pleural biopsy.