Efficiency assessment of the antifungal metabolites from Sclerotium cepivorum against onion white rot disease

Abstract

The inhibitory effects of secondary metabolites of Sclerotium cepivorum against itself were studied both in vitro and in vivo. The highest inhibition of fungal growth and a 98.6 % reduction in the number of sclerotia was obtained with 50 % culture filtrate. No sclerotial germination was observed on media amended with culture filtrates at 10, 25 and 50 %. Methanol extract of mycelia and sclerotia, and ethyl acetate extract of culture filtrate both exhibited over 90 % inhibition of S. cepivorum growth at 1200 ppm. A chloroform extract of culture filtrate resulted in 71.1 % inhibition at 1200 ppm. All extracts completely suppressed the formation and germination of sclerotia at 400, 800 and 1200 ppm. In greenhouse experiments, no disease was observed with the ethyl acetate extract when onion seedlings were dipped in the extract for 4 or 8 h. The GC-MS analysis revealed 28 compounds in the methanol extract. The methanol extract contained mainly hexadecanoic acid methyl ester (31.16 %), whereas 5-hydroxymethylfurfural, HMF, (36.40 %) was the main constituent of the ethyl acetate extract. These results suggest that the secondary metabolites of S. cepivorum are potential and promising antifungal agents for the control of onion white rot. These results can be also applied to reduce the incidence and severity of other diseases in different crops.

Fungicidal properties of the medium from SCOBY microorganism cultivation in saturated wood against Coniophora puteana fungus

“…The fungicidal properties of hexadecanoic acid were demonstrated by Bukhari et al (2020). The fungicidal effectiveness of 5-hydroxymethylfurfural was positively assessed by Elsherbiny et al (2015). Yuniarto et al (2016) reports that the factor inhibiting the growth activity of microorganisms is, among others, acetic acid, produced during the fermentation process conducted by kombucha microorganisms.…”

Effect of Inoculum Density of <i>Stromatinia cepivora</i> on the Ability of Sclerotial Mycoparasites to Suppress White Rot in Garlic

“…Fungal mass of garlic isolate S. cepivora (Sc8) for soil infestation in greenhouse experiments was obtained by growing the isolate on a sand-barley medium [14]. This medium was prepared by mixing 50g barley grains, 50 g sand and 40 mL water; then the mixture in glass bottles (500 mL capacity) with cotton plugs was sterilized at 121°C for 30 min.…”

<i>In vitro </i>technique for selecting onion for white rot disease resistance

“…Various chemical, biological, and physical measures have been examined for the control of the disease, including fungicides (Zewide et al, 2007a), soil amendments (Brewster, 2008), soil solarisation (Melero-Vara et al, 2000), composts (Smolinska, 2000;Coventry et al, 2005) and biological control agents (Clarkson et al, 2002;Coventry et al, 2006;Zhang et al, 2013;Elsherbiny et al, 2015;Mahdizadehnaraghi et al, 2015). In addition, a number of studies have attempted to mimic the natural phenomenon of sclerotia germination with chemicals (Davis et al, 2007).…”