Root-microbiome synergy drives phosphorus acquisition in cotton: Genotype-specific recruitment of beneficial taxa under low phosphorus stress

Phosphorus (P) scarcity is a major constraint to crop productivity due to its low bioavailability in soils. Although plant-microbe interactions are crucial for enhancing P acquisition, their underlying mechanisms, especially in economically significant crops such as cotton, remain elusive. This study explored the adaptive strategies of low-P-tolerant (BX014) and sensitive (DLNTDH) cotton genotypes to P deficiency, focusing on their modifications in root morphology, exudation patterns, and rhizosphere microbiota for optimizing P utilization. A 60-day pot experiment with four P levels was performed to evaluate agronomic performance, root traits, organic acid anions (OAA) exudation, soil enzyme activity, and bacterial community dynamics, employing 16S rRNA sequencing and structural equation modeling (SEM). The results indicated that under low-P stress (P0), BX014 exhibited superior root plasticity, elevated OAA exudation (formic, malic, lactic, acetic acid), and enhanced soil enzyme activity (soil-acid phosphatases (S_ACP), soil-catalases (S_CAT), soil leucine aminopeptidases (S_LAP), and soil-urease (S_UR)). These adaptations promoted the recruitment of beneficial microbial taxa ( Proteobacteria , Actinobacteria) , resulting in a 48.3 % higher P-use efficiency (PUE) in BX014 than in DLNTDH. SEM analysis confirmed that root exudates, microbial biomass, and soil enzyme activity contributed to PUE, accounting for 91 % of the biomass variation in BX014. These findings underscore genotype-specific strategies for mitigating P limitation via root-microbe interactions. Harnessing these natural synergies could advance sustainable agriculture by decreasing fertilizer dependency and enhancing resilience in nutrient-deficient soils. • BX014 superior low-P adaptation through enhanced root plasticity and OAA. • BX014 achieves higher PUE than DLNTDH under low-P stress. • Revealed genotype-specific microbial recruitment under low-P stress. • Highlighted root exudates and microbial biomass significantly impact PUE.