Micropropagation assisted by biosynthesized zinc oxide nanoparticles in Agave applanata

Abstract

Nanoparticles in plant biotechnology are recognized for their ability to enhance regeneration, induce callus formation, and control microorganisms. Agave applanata, an endemic Mexican species of ecological and economic importance, has propagation difficulties due to its limited natural reproduction. This study evaluated its in vitro multiplication in a culture medium supplemented with biosynthesized zinc oxide nanoparticles (ZnONPs). The ZnONPs, obtained using the cell-free filtrate of Mucor fragilis as a reducing agent, showed an average size of 87 ± 14 nm and a semi-spherical morphology. After 45 days of culture, the number and average length of shoots were evaluated. The main factors and their interactions had significant effects, indicating that regeneration was influenced by the combined action of growth regulators and ZnONPs. The center-point treatments produced the highest proliferation, with 25.6 ± 1.67 shoots per explant, whereas the combination of 0.025 mg L⁻¹ 2,4-dichlorophenoxyacetic acid and 5.0 mg L⁻¹ 6-benzylaminopurine promoted the greatest elongation, reaching 2.94 ± 0.11 cm. In addition, treatments with ZnONPs also reduced microbial contamination. These results highlight the biostimulant and antimicrobial potential of biosynthesized ZnONPs for improving the micropropagation of endemic agaves.