Volatomic differences among Vitis amurensis cultivars and its hybrids with V. vinifera revealed the effects of genotype, region, and vintage on grape aroma.

Vitis amurensis grape, an East Asian Vitis species, has excellent cold and disease resistance and exhibits high winemaking potential. In this study, the aroma compounds in grapes from five V. amurensis cultivars ('Beiguohong', 'Beiguolan', 'Shuangfeng', 'Shuanghong', 'Shuangyou') and three interspecific hybrids ('Beibinghong', 'Xuelanhong', 'Zuoyouhong') from two regions (Zuojia and Ji'an, Jilin, China) were identified via HS-SPME-GC/MS. The results showed that V. amurensis grapes had a greater concentration of aroma compounds than the interspecific hybrid berries. 'Beibinghong' was relatively rich in terpenes, although their concentrations were all lower than the threshold. 'Shuangfeng' contained more concentrations of free C6/C9 compounds, alcohols, aromatics and aldehydes/ketones than the other cultivars. The aroma characteristics of 'Beiguolan' and 'Shuanghong' were relatively similar. The grapes from the lower temperature and more fertile soil of Zuojia contained more C6/C9 compounds, norisoprenoids and alcohols, while aromatics were more abundant in the grapes from Ji'an, which was warmer than the Zuojia region. Herbaceous, floral, fruity and sweet were the main aroma series of V. amurensis grapes. Our study could provide a reference for the development and utilization of V. amurensis grapes and lay a foundation for the development of wild grape cultivars and the production of wines with characteristic styles.

De novo assembling a high-quality genome sequence of Amur grape (Vitis amurensis Rupr.) gives insight into Vitis divergence and sex determination.

To date, there has been no high-quality sequence for genomes of the East Asian grape species, hindering biological and breeding efforts to improve grape cultivars. This study presents ~522 Mb of the Vitis amurensis (Va) genome sequence containing 27 635 coding genes. Phylogenetic analysis indicated that Vitis riparia (Vr) may have first split from the other two species, Va and Vitis vinifera (Vv). Divergent numbers of duplicated genes reserved among grapes suggests that the core eudicot-common hexaploidy (ECH) and the subsequent genome instability still play a non-negligible role in species divergence and biological innovation. Prominent accumulation of sequence variants might have improved cold resistance in Va, resulting in a more robust network of regulatory cold resistance genes, explaining why it is extremely cold-tolerant compared with Vv and Vr. In contrast, Va has preserved many fewer nucleotide binding site (NBS) disease resistance genes than the other grapes. Notably, multi-omics analysis identified one trans-cinnamate 4-monooxygenase gene positively correlated to the resveratrol accumulated during Va berry development. A selective sweep analysis revealed a hypothetical Va sex-determination region (SDR). Besides, a PPR-containing protein-coding gene in the hypothetical SDR may be related to sex determination in Va. The content and arrangement order of genes in the putative SDR of female Va were similar to those of female Vv. However, the putative SDR of female Va has lost one flavin-containing monooxygenase (FMO) gene and contains one extra protein-coding gene uncharacterized so far. These findings will improve the understanding of Vitis biology and contribute to the improvement of grape breeding.

Study on the Effect of Different Concentrations of SO2 on the Volatile Aroma Components of 'Beibinghong' Ice Wine.

SO2 plays an important role in wine fermentation, and its effects on wine aroma are complex and diverse. In order to investigate the effects of different SO2 additions on the fermentation process, quality, and flavor of 'Beibinghong' ice wine, we fermented 'Beibinghong' picked in 2019. We examined the fermentation rate, basic physicochemical properties, and volatile aroma compound concentrations of 'Beibinghong' ice wine under different SO2 additions and constructed a fingerprint of volatile compounds in ice wine. The results showed that 44 typical volatile compounds in 'Beibinghong' ice wine were identified and quantified. The OAV and VIP values were calculated using the threshold values of each volatile compound, and t the effect of SO2 on the volatile compounds of 'Beibinghong' ice wine might be related to five aroma compounds: ethyl butyrate, ethyl propionate, ethyl 3-methyl butyrate-M, ethyl 3-methyl butyrate-D, and 3-methyl butyraldehyde. Tasting of 'Beibinghong' ice wine at different SO2 additions revealed that the overall flavor of 'Beibinghong' ice wine was the highest at an SO2 addition level of 30 mg/L. An SO2 addition level of 30 mg/L was the optimal addition level. The results of this study are of great significance for understanding the effect of SO2 on the fermentation of 'Beibinghong' ice wine.

Molecular mechanism of abscisic acid signaling response factor VcbZIP55 to promote anthocyanin biosynthesis in blueberry (Vaccinium corymbosum).

A high content of anthocyanin in blueberry (Vaccinium corymbosum) is an important indicator to evaluate fruit quality. Abscisic acid (ABA) can promote anthocyanin biosynthesis, but since the molecular mechanism is unclear, clarifying the mechanism will improve for blueberry breeding and cultivation regulation. VcbZIP55 regulating anthocyanin synthesis in blueberry were screened and mined using the published Isoform-sequencing, RNA-Seq and qRT-PCR at different fruit developmental stages. Blueberry genetic transformation and transgenic experiments confirmed that VcbZIP55 could promote anthocyanin biosynthesis in blueberry adventitious buds, tobacco leaves, blueberry leaves and blueberry fruit. VcbZIP55 responded to ABA signals and its expression was upregulated in blueberry fruit. In addition, using VcbZIP55 for Yeast one hybrid assay (Y1H) and transient expression in tobacco leaves demonstrated an interaction between VcbZIP55 and a G-Box motif on the VcMYB1 promoter to activate the expression of VcMYB1. This study will lay the theoretical foundation for the molecular mechanisms of phytohormone regulation responsible for anthocyanin synthesis and provide theoretical support for blueberry quality improvement.

Diversity of Endophytes of Actinidia arguta in Different Seasons.

The seasonal changes in environmental conditions can alter the growth states of host plants, thereby affecting the living environment of endophytes and forming different endophytic communities. This study employs Illumina MiSeq next-generation sequencing to analyze the 16SrRNA and ITS rDNA of endophytes in 24 samples of Actinidia arguta stem tissues across different seasons. The results revealed a high richness and diversity of endophytes in Actinidia arguta, with significant seasonal variations in microbial community richness. This study identified 897 genera across 36 phyla for bacteria and 251 genera across 8 phyla for fungi. Notably, 69 bacterial genera and 19 fungal genera significantly contributed to the differences in community structure across seasons. A distinctive feature of coexistence in the endophytic community, both specific and conservative across different seasons, was observed. The bacterial community in winter demonstrated significantly higher richness and diversity compared to the other seasons. Environmental factors likely influence the optimal timing for endophyte colonization. Solar radiation, temperature, precipitation, and relative humidity significantly impact the diversity of endophytic bacteria and fungi. In addition, seasonal variations show significant differences in the nutritional modes of fungal endophytes and the degradation, ligninolysis, and ureolysis functions of bacterial endophytes. This study elucidates the potential role of endophytes in assisting Actinidia arguta in adapting to seasonal changes and provides a theoretical basis for further exploration of functional microbial strains.