Abstract

The current scientific evidence shows a synergistic role between phosphorus use efficiency (PUE) and water use efficiency (WUE). However, the interactions between plants and soil microorganisms that stimulate phosphorus (P) and water uptake could exhibit variation at the cultivar level. This manuscript aims to evaluate the influence of different wheat cultivars on soil microbial activities and functional diversity and how their interaction could affect plant performance in terms of PUE and WUE. Three wheat cultivars (Fritz, Chevignon, and Rancofen) differing in their ability to use P and water were grown under controlled conditions on an Andisol with background soil P-concentration of 4 mg P kg(-1) (-P), which was enriched to 30 mg P kg(-1) (+P). Water management was applied at two levels: well-watered (+W) and 30% of the water applied to + W (water stress, -W). Soil microbial activities were assayed at the anthesis stage, but wheat was harvested at the end of its phenological cycle. Phosphorus scarcity and water deficit stress negatively affected growth traits, P cquisition, and grain yield of wheat cultivars. The P concentration affected the acid phosphatase (APs)a and dehydrogenase activity (DHA) more than water management. The community-level physiological profile (CLPP) was modulated by the cultivar, water management, and P concentration. The main drivers determining microorganisms' catabolic activity were water deficit stress and high P concentration in the soil. The P addition to plants facing water limitation increased by about 84% the CO2 production by soil microorganisms. Finally, the differences observed among cultivars and the soil microbial activities affected PUE and WUE performance, being Fritz the most efficient cultivar in both components in all conditions evaluated. Our data suggest that an assembly between cultivars and microorganisms affects the plant performance in terms of PUE and WUE.