Chickpea responsiveness to contrasting P fertilization reveals agro-physiological and genotypic variability in P use efficiency and rhizosphere microbial communities

Phosphorus (P) is crucial for grain legumes including chickpea, however P use efficiency (PUE) for both chickpea symbiosis and plant growth strongly relies on chickpea genotypic variability and responsiveness to contrasting P conditions including source, availability and application rate. In this study, three winter Moroccan chickpea ( Cicer arientinum L.) varieties (Arifi, Bochra and Taounate) were assessed for plant growth, PUE and rhizosphere soil-associated microbiome composition under both available “ortho-P” and unavailable P sources (rock-P) at increasing rates (0, 40, 80 and 120 kg P 2 O 5 ha − 1 ). Chickpea growth traits related to shoot dry weight (SDW), leaf area index (LAI), branches number and plant height were significantly enhanced under ortho-P (120 kg ha − 1 ). The highest pod DW (PDW) (108%) and Harvest Index (HI) (55%) were obtained under rock-P (120 kg ha − 1 ) as compared to unfertilized treatment, which is the case of Taounate variety that exhibited the highest PDW (2.33 g plant − 1 ), pod number (9.5 per plant), LAI (321), high PUE and P harvest index (PHI) as a consequence of improved root traits (biomass, length and surface-area). Meanwhile, Bochra variety responded more favorably to rock-P (40, 80 and 120 kg ha − 1 ) showing a higher PUE concomitantly to a lower root traits. Furthermore, chickpea varieties and P sources influenced the rhizosphere-associated microbial community with a notable abundance of Actinobacteria under rock-P in Bochra variety and Chytridiomycota phylum in Taounate variety under ortho-P, while Bochra and Arifi varieties had more Basidiomycota and Mortierellomycota under ortho-P. Findings revealed that ortho-P-fertilized Taounate and rock-P-fertilized Bochra exhibited high PUE and yielded superior agro-physiological performance concomitantly with specific rhizosphere microbial modifications. Such a genotype-P specific pattern indicates a differential responsiveness to P fertilization suggesting tight relationships between chickpea genotypic diversity, responsiveness to P and modulation of the rhizosphere microbiota that needs to be deciphered.