Biogenic Synthesis of Silver Nanoparticles Using Phyllanthus emblica Fruit Extract and Its Inhibitory Action Against the Pathogen Acidovorax oryzae Strain RS-2 of Rice Bacterial Brown Stripe

Abstract

Biogenic synthesis of silver nanoparticles (AgNPs) using plants has become a promising substitute to the conventional chemical synthesis method. In this study, we report low-cost, green synthesis of AgNPs using fresh fruit extract of Phyllanthus emblica . The biosynthesized AgNPs was confirmed and characterized by analysis of spectroscopy profile of the UV-visible and Energy dispersive spectrophotometer, Fourier transform infrared, X-ray diffraction pattern, and electron microscopy images examination. UV-visible spectra showed a surface resonance peak of 430 nm corresponding to the formation of AgNPs, and FTIR spectra confirmed the involvement of biological molecules in AgNPs synthesis. In spherical AgNPs, the particle size ranged from 19.8 to 92.8 nm and the average diameter was 39 nm. Synthesized nanoparticles at 20 μg/ml showed remarkable antimicrobial activity in vitro against the pathogen Acidovorax oryzae strain RS-2 of rice bacterial brown stripe, while 62.41% reduction in OD 600 value was observed compared to the control. Moreover, the inhibitory efficiency of AgNPs increased with the increase of incubation time. Furthermore, AgNPs not only disturbed biofilm formation and swarming ability but also increased the secretion of effector Hcp in strain RS-2, resulting from damage to the cell membrane, which was substantiated by TEM images and live/dead cell staining result. Overall, this study suggested that AgNPs can be an attractive and eco-friendly candidate to control rice bacterial disease.

Biosynthesis of silver nanoparticle from pomelo (Citrus Maxima) and their antibacterial activity against acidovorax oryzae RS-2

“…The fresh fruit extract of pomelo was prepared according procedure reported by [25] with minor modification. Briefly, the fresh fruits were thoroughly washed with ddH 2 O and then sliced into small pieces.…”

“…Synthesis of AgNPs was performed based on the method of [25] with minor modification. Briefly, 100 ml of 2 mM and 4 mM silver nitrate solution was prepared in conical flask.…”

“…The formation of AgNPs was confirmed by UV-vis spectra analysis according to the method used by [25]. The absorption was recorded by UV-visible spectrophotometer 2550 (Shimadzu Corporation, Kyoto, Japan) at a resolution of 1 nm in the wavelengths range 200-800 nm.…”

“…In order to assess the structure and composition of synthesized AgNPs we performed crystallographic analyses using x-ray diffraction (Siemens D5000, Germany) according to the method used by 25. In addition, the presence of Nano silver elements was confirmed by energy dispersive spectroscopy (EDS, Oxford Instruments, Oxford, UK) at 20 keV as described by [25].…”

“…Surface structure and surface morphology of AgNPs were analysed by SEM (SU8010, Hitachi, Japan) according to the method used by [25]. The size and morphology of AgNPs was characterized by TEM (JEOL JEM 100CX II) as described by.…”