The active corporation of root bacteria and Arabidopsis promotes P nutrition and plant growth

Plants are known to interact dynamically with root-associated bacteria during phosphate malnutrition, but it remains unknown whether and how plants can actively engage bacteria for phosphorous acquisition and growth. Here we show that ~20% root-associated bacteria are capable of alleviating the phosphate starvation response (PSR) and promoting growth of Arabidopsis seedlings by utilizing an insoluble inorganic phosphate. A close examination of a growth-promoting Acinetobacter guillouiae showed that roots actively recruit this bacterium during phosphate malnutrition through the Arabidopsis STOP1-ALMT1 pathway. Synthetic community experiments suggest A. guillouiae cooperates with other root bacteria to promote plant phosphorous nutrition and growth. In addition, phosphate-starved roots stimulated the expression of genes controlling phosphate homeostasis in A. guillouiae, suggesting that Arabidopsis plants actively coordinate with root commensal bacteria to utilize otherwise inaccessible phosphate.