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A senescence-induced gene named CsNRT1.7 was cloned from a cucumber cultivar with high capacity for low-N tolerance using a homologous cloning technique based on bioinformatics analysis and cucumber genome information. The full-length cDNA of CsNRT1.7 was 1803 bp with an open reading frame encoding 601 amino acids. Homology analysis showed that CsNRT1.7 had high homology (74%) to the Arabidopsis nitrate transporter gene NRT1.7. Phylogenetic analysis indicated that CsNRT1.7 had a close relationship with NRT1.7 among different nitrate transporters in Arabidopsis. Quantitative RT-PCR and CsNRT1.7pro:GUS reporter analysis showed that CsNRT1.7 was a senescence-induced gene, whose transcription was much stronger in old leaf, followed by mature leaf and young leaf of cucumber plants. CsNRT1.7 could also be induced by low-nitrogen treatment. The transient expression of CsNRT1.7:EGFP in onion epidermal cells indicated that CsNRT1.7 was localized in the plasma membrane. Further functional analysis revealed that 35S:CsNRT1.7/nrt1.7-2 transgenic Arabidopsis plants showed lower nitrate content and larger leaf size than nrt1.7-2 T-DNA insertion Arabidopsis plants. These results provide new clues to further understand the function of CsNRT1.7 regarding senescence-regulated low-nitrogen tolerance in cucumber. [ABSTRACT FROM AUTHOR]