Expression and analysis of StNR and StNiRs, key enzyme genes of nitrogen assimilation in potato (Solanum tuberosum L.) with different nitrogen efficiencies

The potato is a pivotal food crop on a global scale. Nitrate reductase (NR) and nitrite reductase (NiR) are the key enzymes in nitrogen assimilation. In previous research, we found that the nitrogen assimilation process was effectively regulated by StNR and StNiRs in potato and that there were significant differences in nitrogen utilisation efficiency between different potato varieties. In this study, three potato variants with different nitrogen use efficiency (NUE) were subjected to various nitrogen supply levels and photoperiod treatments. The results indicated that the relative expression levels of <i>StNR</i> and <i>StNiRs</i> in their leaves and roots, along with the enzyme activity of NR and NiR, were proportional to the nitrogen supply levels and photoperiod. This study further clarified the expression patterns of <i>StNR</i> and <i>StNiRs</i>, as well as the enzyme activity changes of NR and NiR in leaves and roots under different nitrogen supply levels and different photoperiod treatments. This provides a theoretical basis for further in-depth exploration of the specific functions related to nitrogen absorption and assimilation efficiency in potato.