The interaction of plant and soil microbiome is a source of ecosystem complexity with implications for plant adaptation to environmental stress. However, the three-fold interaction between plant genotype, soil microbiome, and environment remains largely unexplored. In legumes the interactions involve rhizobia in soil and plant nodules. This study used a plasticity perspective to investigate the rhizosphere soil and legume nodule microbiome in a factorial combining four contrasting chickpea (Cicer arientinium L.) genotypes and five rainfed field environments spanning a 10-fold range of plant productivity primarily associated with drought stress. We quantified the rhizosphere effect (RE) as the normalised difference in diversity of microbial communities between bulk soil and rhizosphere, and its plasticity in response to environment. Rhizosphere effect was genotypedependent and varied with bacterial and fungal communities. Two genotypes maintained a stable RE regardless of conditions, and two genotypes enhanced recruitment of bacterial communities under increasing stress. Genotypic ability to modulate the rhizosphere bacteriome was negatively correlated with their N fixation under harsh conditions (r = -0.7). Fungal RE showed a non-linear relationship with environmental stress, peaking at moderate stress in all chickpea genotypes. In the nodules, symbiotic rhizobia consistently dominated (similar to 95% abundance) across all environments and genotypes, resulting in a low plasticity of nodulation effect on microbial recruitment. We identified and isolated four non-rhizobial bacterial strains (Burkholderia spp. and Pseudomonas spp.) that stably colonised nodules. Three of these strains promoted nodulation and N fixation through production of indole-3-acetic acid. In an agronomically relevant, large-scale field setting, we provide novel insights into the role of plant microbiome plasticity with implications for legume productivity in drylands.