Engineering wheat rhizoplane microbiomes with niche-conserved bacterial consortia to enhance phosphorus acquisition and plant growth

Aims Bacterial consortia (BC) are gaining increasing interest as agricultural bio-inputs due to their agroecological potential to sustain crop production. This study investigates the potential of BC constructed, using a niche-conserved approach, with microbes isolated from the wheat rhizoplane to enhance phosphorus (P) acquisition and plant growth. Methods Geographic bioprospection, conducted across 24 zones within six agricultural regions of Morocco, employed a niche-conserved approach to construct 24 niche-conserved (BC₁-BC₂₄), six intra-regional (BC_R1-BC_R6) and one inter-regional (BC_RG) BC. Constructed BC were evaluated for their ability to solubilize Rock phosphate (RP) and enhance wheat growth and P uptake under RP-based conditions across in-vitro, soil amendment, and in-planta settings. Results Phylogenetic diversity of bacterial species highlighted the dominance of readily culturable Bacillus and Pseudomonas genera in the wheat rhizoplane. Bacterial diversity showed regional variability, with some exhibiting greater richness (Sidi Kacem, Beni Mellal, and Azilal) compared to others. Niche-conserved BC, especially BC₁₉, BC₂₀, and BC₃, emerged as top-performing BC, consistently displaying superior performance in P solubilization and acid phosphatase (APase) activities under low P conditions across diverse experimental settings, including TCP- and RP-supplemented NBRIP media, RP-amended soil, and the rhizosphere of 30- and 70-day-old plants. Additionally, inoculation with these BC maintain top performance in enhancing above- and below-ground plant parameters including root morphological traits of 30- and 70-day-old plants. Conclusions The effect of niche-conserved BC (BC₁₉, BC₂₀, and BC₃) outperforms intra- and the inter-regional BC, underlining the efficacy of the niche-conserved strategy in constructing plant-beneficial BC that enhance P availability, biomass and root development of wheat.