Overexpression of IbSnRK1 enhances nitrogen uptake and carbon assimilation in transgenic sweetpotato

Nitrogen is an important nutrient for plant development. Nitrogen and carbon metabolisms are tightly linked to physiological functions in plants. In this study, we found that the IbSnRK1 gene was induced by Ca(NO3)2. Its overexpression enhanced nitrogen uptake and carbon assimilation in transgenic sweetpotato. After Ca(15NO3)2 treatment, the 15N atom excess, 15N and total N content and nitrogen uptake efficiency (NUE) were significantly increased in the roots, stems, and leaves of transgenic plants compared with wild type (WT) and empty vector control (VC). After Ca(NO3)2 treatment, the increased nitrate N content, nitrate reductase (NR) activity, free amino acid content, and soluble protein content were found in the roots or leaves of transgenic plants. The photosynthesis and carbon assimilation were enhanced. These results suggest that the IbSnRK1 gene play a important role in nitrogen uptake and carbon assimilation of sweetpotato. This gene has the potential to be used for improving the yield and quality of sweetpotato.