Vitis amurensis is a cold-hardy wild grape species and represents valuable germplasm for breeding cold-tolerant grapevines. In this study, we identified a highly expressed gene (VaTPS9) in one-year-old shoots of V. amurensis ‘Shuangfeng’ during overwintering, but its biological function remained unclear. Temporal and spatial expression analyses revealed distinct expression patterns of VaTPS9 among different tissues from June to November, with the highest transcript abundance detected in one-year-old shoots in November. Gene cloning and sequence alignment showed that VaTPS9 encoded a type II trehalose-6-phosphate synthase (TPS) and was designated as VaTPS9. Functional analyses demonstrated that overexpression of VaTPS9 enhanced cold tolerance in yeast, Arabidopsis thaliana, and V. amurensis callus tissues. Conversely, virus-induced gene silencing (VIGS) of VaTPS9 in grapevine plantlets markedly increased cold sensitivity under low-temperature stress. These reciprocal gain- and loss-of-function phenotypes indicate that VaTPS9 positively regulates cold tolerance, likely by modulating trehalose metabolism and associated physiological responses, including reactive oxygen species (ROS) homeostasis. Collectively, our findings provide new insights into the molecular basis of cold adaptation in wild grape species and highlight VaTPS9 as a promising candidate gene for improving cold tolerance in cultivated grapevine.

Actinidia arguta is a dioecious plant, and the selection of superior male germplasm is crucial for ensuring effective pollination of female cultivars, maximizing their economic traits, and achieving high-quality yields. This study evaluated 30 male germplasms for pollen quantity, germination capacity, storage characteristics, and ultrastructural features. Results revealed significant variation in pollen germination rates (1.56–96.57%) among germplasms, with ‘Lvwang’, ‘TL20083’, and ‘TG06023’ performing best (all >90% germination). The storage characteristics study demonstrated that −80 °C is the optimal temperature for long-term pollen storage in A. arguta. Significant variations were observed in storage tolerance among different germplasms. Among them, Lvwang exhibited the best performance, maintaining a germination rate of 97.40% after 12 months of storage at −80 °C with no significant difference from the initial value, followed by TT07063. Pollen morphology was closely correlated with fertility. High-fertility pollen grains typically exhibited standard prolate or ultra-prolate shapes, featuring a tri-lobed polar view and an elliptical equatorial view, with neat germination furrows and clean surfaces. In contrast, low-fertility pollen grains frequently appeared shrunken and deformed, with widened germination furrows and visible exudates. Based on these findings, the following recommendations are proposed: ① Prioritize the use of germplasms with pollen germination rates >80% as pollinizers; ② Establish a rapid screening system based on pollen morphological characteristics. This study provides important scientific basis for both male germplasm selection and efficient cultivation practices in A. arguta (kiwiberry).

Heterogeneity among grape berries directly affects wine quality and restricts the wine grape industry’s development. To study the heterogeneous development of Vitis amurensis berries, the morphology and physiology of three different types—large berry, medium berry, and live green ovary (LGO)—in the same clusters of wine-making cultivar ‘Shuangfeng’ were monitored at different growth stages from June to September. External differences in berry development were distinguishable at 12 days after full bloom (DAF). The pedicel, berry size, fresh weight, and seed length of the medium berries were intermediate between those of large berries and LGOs. Seeds are crucial for fruit set and normal berry development. The activity levels of soluble acid invertase and cell-wall-bound acid invertase in large berries increased earlier, at 18 DAF, than the accumulation of sugar. Abscisic acid concentrations in medium berries and LGOs were greater than that in large berries at 18 DAF. The greater endogenous indole-3-acetic acid concentration in the medium berries compared with LGOs might protect the former from abscission.