Extracellular adenosine triphosphate (eATP) alleviates phytotoxicity of nanoplastics in maize (Zea mays L.) plants

The escalating use of plastic leads to a significant presence of nanoplastics in agricultural soil, directly impacting the growth and development of plants. However, the effective strategies to mitigate the accumulation of nanoplastic remains limited. The goal of this work was to explore the effect of extracellular ATP (eATP) on alleviating nanoplastic toxicity in maize plants. Here, seven-day-old maize seedlings were treated with PSNP (50 mg/L) and eATP (1 mM). Subsequently, the growth of maize (roots and shoots), accumulation of PSNP in roots, and various physiological indicators was analyzed. Additionally, transcriptome and metabolome analyses were conducted to examine the changes in differentially expressed genes and metabolites under these treatments. The results were as followed: foliar applied eATP markedly inhibited the accumulation of polystyrene nanoplastics (PSNP) in roots, thus alleviating the inhibitory effect of PSNP on maize plants growth. eATP application alleviated PSNP increases in malondialdehyde (MDA) content, and percent of electrolyte leakage, H₂O₂ and O₂^·- accumulation by activating antioxidant defense systems. eATP application significantly altered the expressions of aquaporin genes (ZmNIP4;1, ZmNIP1:2, etc.), resulting in the suppression of PSNP accumulation. In addition, eATP also triggered metabolic dynamics changes associated with Aminoacyl-tRNA biosynthesis, and ABC transporters in maizes treated with PSNP. In conclusion, the exogenous foliar application of 1 mM eATP alleviates the adverse effects of PSNP on maize by activating antioxidant defense systems and suppressing the expression of aquaporin genes, thereby reducing PSNP accumulation. This approach also holds promise as a strategy for alleviating the phytotoxic effects of PSNP in modern agriculture.