A comparison of wild and cultivated strawberries for nitrogen uptake and reduction

The strawberry (Fragaria x ananassa) requires substantial amounts of nitrogen to produce reasonable yields. Wild strawberries (e.g. F. virginiana) grow in soils in the absence of supplemental nitrogen and may possess desirable genes, alleles or expression patterns that support efficient nitrogen uptake and assimilation. The F. virginiana accessions and cultivated materials were used to monitor the accumulation kinetics of five nitrate responsive genes (nitrate transporter, NRT1.1; nitrate reductase, NIA1; nitrite reductase, NiR; ferredoxin NADP reductase, FNR; and transketolase, TK) along with nitrate reductase activity. The results revealed expression patterns that were reminiscent of those observed in Arabidopsis. Wild strawberries exhibited higher transcript accumulation for all genes examined except the nitrate transporter, compared to cultivated materials. Nitrate reductase activity (NRA) did not change in roots but increased in leaves in response to nitrate. Most wild genotypes had higher NRA in aerial tissues compared to cultivated materials. Comparisons of enzyme activity to transcript accumulation kinetics suggest that available nitrate reductase is activated and not likely synthesized de novo, suggesting that some wild accessions may possess enhanced nitrogen assimilation mechanisms. These attributes may be useful to breeding programs in the design of elite plants that may make more efficient use of fertilizers.