Nanoscale Hydroxyapatites Reprogram Phyllosphere Microbiomes and Disease Resistance-Related Phytohormone Biosynthesis...

Phyllosphere-microbe-plant interactions underlying nanoscale hydroxyapatite (nHAP)-mediated disease control remain poorly understood. Here, foliar application of nHAP (100-400 mg/L) was evaluated for controlling rice blast caused by Magnaporthe oryzae under greenhouse conditions. The optimal treatment (200 mg/L) reduced disease severity by 42.6% and outperformed ionic Ca and P controls, as well as a commercial fungicide. Mechanistically, nHAP exhibited superior foliar retention (6.88%), enhancing local Ca and P bioavailability, and reshaping the phyllosphere microbiome by enriching beneficial and phosphate-solubilizing bacteria. These shifts were associated with a 23.5% increase in salicylic acid biosynthesis relative to that of the infected control and activation of systemic acquired resistance. Metabolomic analysis further revealed an enhanced energy metabolism and secondary metabolite biosynthesis. In addition, nHAP increased grain yield by 51.9% and improved grain nutritional quality (e.g., starch and protein) by 40.5-63.0%. These findings support nHAP as a promising strategy for sustainable crop-disease management and food production.