Synthesis of biocompatible Fe3O4 and MnO2 nanoparticles for enhanced tuberization in potato (Solanum tuberosum L.)

Abstract

Iron oxide (Fe3O4) and manganese dioxide (MnO2) Nanoparticles (NPs) were synthesized via green synthesis approach using beetroot (Beta vulgaris) leaf extract and evaluated as nanofertilizer for studies of In-vitro microtuberization of potato. Successfully biogenesis of NPs were demonstrated through UV–visible spectroscopy, FTIR, XRD, SEM-EDX, and TEM analysis. In-vitro micortuberization analysis, single nodal explants of potato were placed on media (MurashigeSkoog plant growth medium devoid of original Fe and Mn salt) added with different concentrations of metal oxide-NPs, and physiological, biochemical and molecular changes were observed via using standard methods. The interaction of the NPs with the nodal explants significantly induced early tuber induction and tuber growth upon application of Fe3O4NPs (4.0 mg L-1) and MnO2NPs (1.0 mg L-1) in comparison to untreated potato tissues. Molecular analysis of potato tissues revealed enhanced expression of primary tuber inducing genes viz. Calcium-Dependent Protein Kinases (StCDPK), Calmodulin (StCaM1), and Lipoxygenase (StLOX) enzyme activity show a positive correlation of tuber induction with added NPs. Further elemental analysis via EDX exhibited that the addition of biocompatible metal oxide NPs in the growth media induced the cytosolic Ca+2 burst leading to enhanced expression of major tuber induction pathway genes resulting in early and enhanced potato tuberization. Absorption of metal-oxide NPs in microtubers was evaluated by FTIR and EDX mapping. This study is the first report on the molecular mechanism involved in regulating NPs induced the potato tuberization under In-vitro conditions. The study also indicated that application of the metal-oxide NPs as nano-nutrient to enhanced potato microtuber production.