Do Nodule Phosphatase and Phytase Link with the Phosphorus Use Efficiency for N2-Dependent Growth in Phaseolus vulgaris ?

Grain legumes can contribute to cropping systems through their ability to fix atmospheric N2 in their root-nodules. However, the symbiotic nitrogen fixation process requires additional phosphorus. Thus, the production of grain legumes, particularly common bean, is limited by P-deficiency in many soils, mostly in tropical and Mediterranean areas. Recombinant inbred lines (RILs – F8) from a cross of common bean parents BAT477 with DOR364 were selected for improved phosphorus-use efficiency and N2dependent growth in glasshouse hydro-aeroponic culture and tested in farmers’ field. The present work with Phaseolus vulgaris as a model grain legume shows a significant difference in the overall phosphatase activity in nodules, including a relatively high level of phytase activity, between two recombinant inbred lines that contrast in their efficiency in utilization of P for symbiotic nitrogen fixation.