Enhancing phosphorus-solubilizing microorganism potential for alleviating plant phosphorus limitation through amino acid co-application

Phosphorus-solubilizing microorganisms (PSMs) are recognized as a sustainable ecological strategy to mitigate plant phosphorus (P) limitation. However, their efficacy in real-world production scenarios is not as consistent as observed in controlled laboratory conditions. To deepen our comprehension of PSMs in mitigating plant P limitation and evaluate the efficacy of combined amino acids (AA) and PSMs application in optimizing plant nutritional environments, we conducted a study, aiming to preliminary delineate the model of plant-microbe-soil interactions facilitated by this joint approach. Phyllostachys edulis seedlings were cultivated in phosphorus-limited soil with or without AA and PSMs application. We assessed treatment impacts on plant growth and soil nutrient conditions through plant biomass, root morphology, tissue nitrogen (N) and P content, soil N and P contents, rhizosphere microbial communities, and soil enzyme activities. Application of AA and PSMs significantly enhanced shoot growth of P. edulis seedlings, reduced root ratio, modified root morphology, increased N and P content in plant tissues, facilitated conversion of soil insoluble P to active forms, and raised total soil N, alkali-hydrolysable N, ammonium N, and nitrate content. Moreover, it influenced the structure and function of the soil microbial community. Notably, soil enzyme activities under the combined application exhibited distinctions from individual applications, demonstrating greater similarity to the treatment without AA and PSMs, which received no additional amendments. Our findings underscored the significant positive impact of the combined AA and PSMs application on P. edulis seedling growth, improving soil nutrient status, enriching plant growth-promoting rhizobacteria, and reducing soil diseases. However, plant-soil-microbe interactions induced by the combined application might differ from those observed with individual applications, necessitating further experimentation for a comprehensive understanding.