Mycosynthesis of Silver Nanoparticles Using Screened Trichoderma Isolates and Their Antifungal Activity against Sclerotinia sclerotiorum.

Ali Athafah Tomah,Iman Sabah Abd Alamer,Bin Li,Jing-Ze Zhang

doi:10.3390/nano10101955

Abstract

To control the disease caused by Sclerotinia sclerotiorum, a total of 15 isolates of the Trichoderma species was screened for the biosynthesis of silver nanoparticles (AgNPs). Among them, the highest yield occurred in the synthesis of AgNPs using a cell-free aqueous filtrate of T.virens HZA14 producing gliotoxin. The synthetic AgNPs were charactered by SEM, EDS, TEM, XRD, and FTIR. Electron microscopy studies revealed that the size of AgNPs ranged from 5–50 nm and had spherical and oval shapes with smooth surfaces. Prepared AgNPs interacted with protein, carbohydrate and heterocyclic compound molecules, and especially, interaction patterns of AgNPs with the gliotoxin molecule were proposed. The antifungal activity assays demonstrated that percentage inhibition of the prepared AgNPs was 100, 93.8 and 100% against hyphal growth, sclerotial formation, and myceliogenic germination of sclerotia at a concentration of 200 μg/mL, respectively. The direct interaction between nanoparticles and fungal cells, including AgNPs’ contact, accumulation, lamellar fragment production and micropore or fissure formation on fungal cell walls, was revealed by SEM and EDS. These will extend our understanding of the mechanisms of AgNPs’ action for preventing diversified fungal disease.

Highlights

Sclerotinia sclerotiorum (Lib.) de Bary is a significant plant pathogenic fungus that leads to sclerotium disease on many crops and causes economical substantial losses throughout the world [1]
The experiment results showed that the color change markedly occurred from pale yellow to dark brown only in the reaction mixture produced by T. virens HZA14 among 15 isolates (Figure 1a,b), indicating the formation of maximum AgNPs after 120 h of incubation
The screened isolate HZA14 was used for the synthesis of AgNPs after different incubation times (24, 48, 72, 96 and 120 h)

Summary

Introduction

Sclerotinia sclerotiorum (Lib.) de Bary is a significant plant pathogenic fungus that leads to sclerotium disease on many crops and causes economical substantial losses throughout the world [1]. The pathogen infects the host plants to cause diseases including cottony rot, watery soft rot, drop, crown rot, blossom blight, and perhaps most common, Sclerotinia stem rot (SSR) or white mold, and so on [1]. This pathogen produces the melanized multicellular structure, known as sclerotia that can survive for years in the soil [3]. The emergence of S. sclerotiorum strains that are resistant to fungicides, such as carbendazim and benzimidazole in China, has been found [6]

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