To elucidate the function of the cold resistance regulatory gene FmNAC1 from Fraxinus mandshurica, this study identified the role that the overexpression of the FmNAC1 gene plays in tobacco growth and cold stress regulation. The cloned FmNAC1 gene from F. mandshurica is 891 bp in length and encodes 296 amino acids. Our subcellular localization analysis confirmed that FmNAC1 is primarily located in the nucleus and functions as a transcription factor. FmNAC1 is responsive to cold and NaCl stress, as well as to the induction of IAA, GA, and ABA hormone signals. To further elucidate its function in cold resistance, four transgenic tobacco lines of FmNAC1 overexpression（FmNAC1-OE）were generated through tissue culture after the agrobacterium-mediated transformation of wild-type (WT) tobacco. These FmNAC1-OE plants exhibited accelerated growth after transplantation. When exposed to low-temperature conditions at -5°C for 24 hours, the rates of wilting and yellowing of the FmNAC1-OE plants were significantly lower than those of the WT tobacco plants. Additionally, the membrane integrity, osmotic regulation, and reactive oxygen species (ROS)-scavenging abilities of the FmNAC1-OE tobacco lines were better than those of the WT plants, indicating the potential of the FmNAC1 gene to improve plant cold resistance. The gene expression results further revealed that the FmNAC1 transcription factor exhibits regulatory interactions with growth-related genes such as IAA and AUX1; cold resistance-related genes such as ICE, DREB, and CBF1; and genes involved in the clearance of reactive oxygen species (ROS), such as CAT and SOD. All of this evidence shows that the FmNAC1 transcription factor from F. mandshurica plays a key role in contributing to the enhancement of growth, cold resistance, and ROS clearance in transgenic tobacco plants.

Group A rotaviruses (RVA) have been identified as the leading cause of neonatal calf diarrhea (NCD) In Yunnan, China, despite the limited documentation on this issue within the country. Given the significant impact on animal health and welfare, further attention is warranted to comprehend the prevalence and epidemiology of this disease. In this study, we isolated RVA strains from NCD clinical samples to support RVA epidemic study and further disease control in Yunnan. Material and Methods: Ten fecal samples were obtained from calves with a single episode of neonate calf diarrhea from a farmer during a severe NCD outbreak. For the diagnosis of Group A rotavirus (RVA) infection, fecal reverse transcription-polymerase chain reaction (RT-PCR) was employed as the primary method. Subsequently, RVA isolation was conducted on MA104 cells, with inoculates being pretreated with trypsin TPCK to enhance viral infectivity. The isolated RVA strain was further confirmed through RT-PCR and immunofluorescence assay. Results: RVA virus was isolated from clinical samples following six passages depended on trypsin treatment of inoculates. The sign of CPE detected consisted of increased cell granularity, obscure cell boundaries, cell rounding, and eventual degeneration and detachment of cells. Analysis of sequencing revealed that field isolates was of group A serotype. Phylogenetic analysis based on the ORF sequences of the VP4 and VP7 sequences segments indicated that the isolate was classified as the P[1] genotype. VP4 gene of strain YN-1 shares 75.2%-99.7% nucleotide identity of and 81.6%–99.7% amino acid identity with the complete VP4 sequences of the P[1]. The complete VP7 gene of YN-1 is 981 nucleotide long and encode 326 amino acids. The RotaC v2.0 analysis classified the sequence as the G8 genotype. The VP7 gene of strain YN-1 shares 88.5%-97.7% nucleotide identity and 94.2%-99.1% amino acid identity. Conclusion: This is the first study in China which reports the circulation of Group A NCD on cattle farms in the field. Our study constitutes a crucial and a necessary step allowing preventive and veterinary medicine to support RVA disease controls in Yunnan province, China.