Nanoscale phosphorus-based agrochemicals enhance tomato and rice growth via positively modulating the growth-associated gene expression and endophytic microbial community†

Abstract

Nano-hydroxyapatite (nHA) has attracted increasing attention as a potential novel fertilizer. The present study investigated the effects of root exposure to nHAs (20 nm-nHA, 60 nm-nHA, 1% Cu-nHA, and 10% Cu-nHA) at 50 mg kg⁻¹ on the growth and development of tomato (Solanum lycopersicum L.) and rice (Oryza sativa L.) seedlings for 50 days. Compared with the control, different types of 50 mg kg⁻¹ nHA increased the biomass of seedlings by 10.7–30.9%; for example, 20 nHA significantly increased the fresh weight of the two plant species by 17.2% and 29.2%, respectively. Additionally, 20 nm-nHA and 1% Cu-nHA altered the diversity of plant endophytic microbial communities and increased the abundance of plant-associated beneficial microorganisms, including Glomeromycotina, Funneliformis, and Blastocladiomycota. Transcriptomic analysis suggests that 20 nm-nHA and 1% Cu-nHA induced transcriptional reprogramming in exposed seedlings. KEGG pathway analysis shows that root exposure to 20 nm-nHA and 1% Cu-nHA promoted plant hormone signal transduction pathways in both tomato and rice roots; and, 1% Cu-nHA promoted photosynthesis and amino acid metabolism. Overall, this work demonstrates that root exposure to 50 mg kg⁻¹ 20 nm-nHA significantly improves crop growth, and provides valuable insight into the development of novel nanoscale phosphorus fertilizers as a sustainable path for precision agriculture.