Mn3O4 nanozymes increased cotton salt tolerance by recruiting S-adenosylmethionine synthase to reduce DNA methylation level

Land salinization threatens agricultural sustainability worldwide. Foliar delivery of nanotherapeutics is emerging as a tool for improving crop stress tolerance in diverse soils. Herein, we report that poly(acrylic) acid coated Mn 3 O 4 nanoparticles (PMO) applied to leaves enhance cotton growth (up to 31.6%) and yield (up to 47.3%) in three saline lands with different soil types. We elucidated the molecular mechanisms by which PMO improve cotton salinity stress tolerance by reducing DNA methylation (up to 24.6%). The S-adenosylmethionine synthase 2 (SAMS2) enzyme involved in DNA methylation is a major component of the PMO protein corona in vivo. The interaction between PMO and SAMS2 results in the change of protein alpha helix (12.3% decrease) and beta-sheets (13.7% increase), with a consequent reduction in enzymatic V max (10.7%). Overall, PMO can be a biocompatible nanotherapeutic tool to improve crop salt tolerance by a targeted interaction with DNA methylation enzymes for sustainable agriculture.