Natural variation of nitrate uptake and nitrogen use efficiency in Arabidopsis thaliana cultivated with limiting and ample nitrogen supply

Eighteen accessions of Arabidopsis thaliana were grown with low (N-)and high (N+)nitrogen supply. N uptake was monitored by feeding plants with 15N-enriched nutritive solution over 24 h. Biomass [fresh matter (FM)and dry matter (DM)], N concentration (N per cent, and 15N content were monitored and computed to determine the nitrogen use efficiency (NUE)and nitrogen uptake efficiency (NupE). NUE has been estimated as the ratio between biomass and N concentration (DM/N per cent)and NupE as the concentration of 15N in plants [mg (g21 DM)]. Accession traits were analysed to detect common and individual genotype features. The genetic variation in NUE at high N input was mainly explained by variation in N uptake. Even though plants managed N uptake and N metabolism differently under N+ and N-, NUE was similar in these two conditions, showing that NUE was exclusively genetically determined. Hierarchical classification revealed that the physiological classes arising were similar under N- and N+. Both wasteful and efficient genotypes were detected. Three extreme genotypes, Col-0, Bur-0, and Tsu-0, were noted. Bur-0 and Tsu-0 exhibited high NUE and large biomass. Col-0 showed the reverse: low NUE and low biomass. Bur-0 appeared poorly tolerant of a high N supply. The present data will facilitate the choice of Arabidopsis accessions as parents of recombinant inbred line populations suitable for the mapping of quantitiative trait loci related to NUE, NupE, and N storage capacity.