Application of silver nanoparticles synthesized from the calli of Centella asiatica for the management of Meloidogyne arenaria infection in cowpea plants

Abstract

The green synthesis of AgNPs from the calli extract of Centella asiatica was confirmed by the detailed analysis of UV–Vis spectroscopy, Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR) which revealed the size, shape, chemical composition and functional groups involved in the AgNPs formation.The in-vitro raised cowpea plants were given root dip treatment in Murashige and Skoog (MS) suspension medium supplemented with LC50- 75 mg/mL AgNPs followed by their transfer to glass house conditions for acclimatization. To evaluate the efficiency of root dip treatment, the acclimatized plants were inoculated with 2000 J2s of M. arenaria and the plants were observed on weekly basis. A differential growth response was observed from the cowpea plants under glass house conditions. A treatment plan designed showed that P4 plants showed a significant defense response against the biotic stress of M. arenaria as indicated by the percentage response of several growth parameters such as- plant height of 49.22 ± 0.89 %, plant fresh mass of 46.12 ± 0.83 %, plant dry mass of 9.3 ± 0.17 % and nodule number of 38 ± 0.68 % were reported in P4 plants after 6 weeks of J2s inoculation.Confocal microscopy of root sections of P3 cowpea plants revealed the presence of M. arenaria J2s in the cortical and provascular regions, however, in case of P4 plants an intact cellular structure was maintained. The application of AgNP didn't show any toxic effect on the growth of plant.