Foliar Application of Nanoselenium: A Novel Strategy to Enhance Tuber Quality, Yield, and Nitrogen Use Efficiency in Potato

Excessive nitrogen application reduces nitrogen use efficiency (NUE) and exacerbates environmental risks. Nanoselenium (nano-Se) has been shown to enhance plant nitrogen uptake efficiency. This study investigated nano-Se influences potato (Solanum tuberosum L.) tuber yield, quality, rhizosphere soil enzyme activity, and inorganic nitrogen content under different nitrogen application levels, integrating metabolomic, metagenomic, and soil metabolomic analyses. Results showed that the N₂ + Se treatment matched the yield of the N₃ + Se treatment but notably boosted vitamin C (Vc), starch content, and NUE. Metabolomic analysis showed that nano-Se promoted the accumulation of d-glucose-1-phosphate (a starch precursor) and amino acids (raw materials for protein) in tubers. Multiomics data indicated that nano-Se recruited beneficial rhizobacteria such as Flavobacterium and Pseudoxanthomonas by exuding l-tyrosine, l-valine, and 4-oxoproline. In addition, It promoted nitrate assimilation genes (narB and nirB) and suppressed nitrification genes (amoA and hao), reducing nitrogen losses.