The rhizosphere harbors intricate microbial networks that influence plant health and productivity. Understanding the structure and dynamics of these networks is crucial for developing microbiome-based strategies to enhance crop performance. In this study we examined rhizosphere bacterial communities across Brassica napus developmental stages, aiming to (1) identify indicator genera and infer functional traits, (2) determine bacterial genera driving community assembly, (3) assess growth-stage-specific driver genera, and (4) identify core-hub microbial communities shaping community structure. Network analysis revealed a highly complex rhizosphere microbiome, with microbial network complexity peaking at the flowering stage, which exhibited the highest network connectivity (up to 179 exclusive edges). This suggests a strong influence of plant developmental stage on microbial community assembly. We identified 40 driver genera forming novel associations across growth stage transitions, including 10 conserved driver genera present throughout development and stage-specific driver genera during vegetative-flowering (5) and flowering-maturity (20) transitions. Despite dynamic shifts, core-hub communities remained stable across growth stages, suggesting an early-established, conserved microbial foundation. Indicator taxa and predicted functions showed stage-specific enrichment of nitrogen and carbon cycling traits, including early-stage dominance of nitrification and nitrogen fixation functions and late-stage shifts toward carbon degradation. These functional shifts likely reflect plant nutrient requirements, root exudation and responses to fertilization. Together, these findings highlight both stability and plasticity in bacterial taxa of rhizosphere microbiomes and offer valuable targets for further microbial assembly process dissection for microbiome-informed crop improvement strategies.
Taye et al. (Fri,) studied this question.