Previous work in our laboratory demonstrated that exosomes derived from human amniotic epithelial cells (hAECs) accelerated wound healing by promoting the proliferation and migration of fibroblasts. It is reported that exosomes, which are carriers of the microRNAs (miRNAs) and proteins, play an important role in the regulation of cell-to-cell communication. However, it is still unclear precisely which molecule or which group of molecules carried within hAEC-derived exosomes (hAEC-Exos) mediated wound healing. Here, we explored purified hAEC-Exos together with either proteinase K (PROse) or RNase A on the effect of fibroblasts and cutaneous wound healing. Our experiments demonstrated that hAEC-Exos were positive for exosomal markers CD9, CD63, and CD81. Also, we found that hAEC-Exos could be internalized by fibroblasts and then stimulated cell migration and proliferation. However, the promotive effect of hAEC-Exos was abolished by pretreating hAEC-Exos with RNase A, not PROse. Importantly, in vivo wound healing assay showed that local injection of hAEC-Exos or PROse pretreated hAEC-Exos at skin wounds significantly accelerated wound healing. Our findings revealed an important role of exosomal miRNAs in wound healing.

Due to the relatively brief domestication history of sugar beet (Beta vulgaris ssp. vulgaris), our understanding of the genomic diversity and functional genes in its cultivars is limited, resulting in slow breeding progress. To address this issue, a total of 306 germplasm materials of major cultivars and breeding lines from China, the USA, and Europe were selected for genome resequencing. We investigated population structure and genetic diversity and performed selective scanning of genomic regions, identifying six novel genes associated with important agronomic traits: the candidate genes DFAX2 and P5CS for skin roughness; the candidate genes FRO5, GL24, and PPR91 for root yield and sugar yield, and the pleiotropic candidate gene POLX for flourishing growth vigour, plant height, crown size, flesh coarseness, and sugar yield. In addition, we constructed a protein–protein interaction network map and a phenotype-gene network map, which provide valuable information for identifying and characterizing functional genes affecting agronomic traits in sugar beet. Overall, our study sheds light on the future improvement of sugar beet agronomic traits at the molecular level.

Sugar beet is a nitrogen (N)-sensitive crop, and its N regulation and utilization are critical for enhancing productivity. Sugar beet seedlings at the two-true-leaf-pair stage were hydroponically grown in an artificial climate chamber. Leaves and roots from three seedlings per treatment were sampled at 10, 20, 25, and 30 days after exposure to N treatments (N5: 5 mmol/L, N10: 10 mmol/L, N15: 15 mmol/L, and N20: 20 mmol/L) to assess the effects of N supply level on growth, photosynthesis, and carbon and nitrogen metabolism. The results revealed a time-dependent dynamics in beet biomass accumulation, with N20 inducing chlorosis and necrosis symptoms by 10 days post-treatment (DPT), resulting in the lowest biomass. While N15 significantly promoted root biomass by 30 DPT, showing a 23.70% (root dry weight, RDW) increase over N20; chlorophyll content and gas exchange parameters-net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) exhibited significant N dependence, with N15 maintaining high chlorophyll level (0.78 mg/g) and photosynthetic rate (220.33 μmol/(m²·s). Nitrogen assimilation, as indicated by glutamine synthetase and glutamate synthetase activity (GS and GOGAT), was stronger under N15, promoting amino acid synthesis and root growth, whereas N20 inhibited enzyme activity. Carbon metabolism analysis revealed that N15-driven sucrose synthesis significantly increased root sucrose content, sucrose phosphate synthase and sucrose synthase activity (SPS and SS), optimizing source–sink allocation. Correlation analysis showed a positive relationship between leaf and root biomass (r = 0.91), and root sucrose content was positively correlated with GOGAT activity (r = 0.90), emphasizing the synergistic regulation of C/N metabolism. On the contrary, N20 led to disrupted C/N metabolic homeostasis, inhibited enzyme activity, and C/N distribution. These results indicated that the photosynthetic output, enzyme efficiency, and sucrose distribution were coordinated by nitrogen optimization, and the growth of sugar beet seedlings was optimized.

Freezing temperatures severely restrict plant growth and can cause serious damage or death to sugar beet seedlings in early spring. In this study, seedlings of two sugar beet genotypes, KWS1197 (K, freezing-tolerant) and SX1512 (S, freezing-sensitive), were subjected to RNA sequencing (RNA-seq) after exposure to −4 °C for 0, 1, 3, and 5 h. GO and KEGG enrichment and expression pattern analyses were performed to identify differentially expressed genes (DEGs) associated with freezing stress. The results showed that plant hormone signal transduction and the MAPK signaling pathway were the primary pathways involved in the freezing response in both genotypes. Notably, the galactose metabolism pathway may play an important role in freezing tolerance in KWS1197. Genes involved in galactose metabolism, including inositol 3-α-galactosyltransferase (GolS), raffinose synthase (RafS), invertase (INV), and α-galactosidase (GLA), were significantly up-regulated under freezing conditions, as confirmed by both RNA-seq and RT-qPCR analyses. These results suggest that rapid regulation of soluble sugar synthesis may represent an important mechanism contributing to freezing tolerance in sugar beet. Overall, this study provides a molecular basis for understanding freezing tolerance in sugar beet and identifies candidate genes for improving freezing resistance.