Simulating phenolic acid input enhances rice phosphorus uptake by increasing the relative abundance of Diversispora

Introduction Phenolic acids are allelopathic substances that mediate plant-fungal interactions. However, the regulatory effects of phenolic acids on soil microbiota and crop phosphorus (P) uptake remain unclear. Thus, this study aimed to investigate the effects of continuous addition of cumalic acid (CA) on soil microbial communities and P uptake of rice. Methods We continuously added different concentrations of CA to the rhizosphere during the rice growth to investigate its effects on soil fungal communities and P uptake of rice. Results The addition of 5 and 10 μmol kg −1 CA significantly increased P uptake in rice by 51.4% and 63.8%, respectively. In addition, the 10 μmol kg −1 CA treatment significantly increased soil Olsen P content. Exogenous addition of CA altered the diversity and composition of soil microbial communities. The application of 5 and 10 μmol kg −1 CA significantly elevated the relative abundance of Diversisporales from 46.3% to 68.7% and 67.1%, respectively; while suppressing Eurotiales from 15.8% to 2.6% and 5.7%, respectively. At the genus level, the treatment enhanced Diversispora (from 46.3% to 68.7% and 67.0%) and reduced Penicillium (from 9.0% to 1.2% and 2.2%). Notably, the relative abundance of Diversispora was significantly and positively correlated with P uptake of rice, whereas Penicillium was negatively correlated with P uptake. Conclusion CA stimulated the P uptake of rice by shaping keystone fungal taxa. Our results suggest that the indirect microbial-mediated mechanism dominated P uptake improvement of rice. This study provides critical insights into the potential application of allelopathic substances in agricultural production.