Characterization and Synergistic Effect of Antifungal Volatile Organic Compounds Emitted by the Geotrichum candidum PF005, an Endophytic Fungus from the Eggplant

Abstract

Plant-associated endophytes are recognized as sources of novel bioactive molecules having diverse applications. In this study, an endophytic yeast-like fungal strain was isolated from the fruit of eggplant (Solanum melongena) and identified as Geotrichum candidum through phenotypic and genotypic characterizations. This endophytic G. candidum isolate PF005 was found to emit fruity scented volatiles. The compositional profiling of volatile organic compounds (VOCs) revealed the presence of 3-methyl-1-butanol, ethyl 3-methylbutanoate, 2-phenylethanol, isopentyl acetate, naphthalene, and isobutyl acetate in significant proportion when analyzed on a time-course basis. The VOCs from G. candidum exhibited significant mycelial growth inhibition (54%) of phytopathogen Rhizoctonia solani, besides having mild antifungal activity against a few other fungi. The source of carbon as a nutrient was found to be an important factor for the enhanced biosynthesis of antifungal VOCs. The antifungal activity against phytopathogen R. solani was improved up to 91% by feeding the G. candidum with selective precursors of alcohol and ester volatiles. Furthermore, the antifungal activity of VOCs was enhanced synergistically up to 92% upon the exogenous addition of naphthalene (1.0 mg/plate). This is the first report of G. candidum as an endophyte emitting antifungal VOCs, wherein 2-penylethanol, isopentyl acetate, and naphthalene were identified as important contributors to its antifungal activity. Possible utilization of G. candidum PF005 as a mycofumigant has been discussed based upon its antifungal activity and the qualified presumption of safety status.

Changes of volatile organic compounds and bioactivity of Alternaria brassicae GL07 in different ages

“…Healthy Ginkgo leaves were washed under running tap water, cut into 3 mm × 3 mm pieces with a scalpel, surface sterilized by immersion in 75% ethanol for 60 s, 2% NaClO solution for 180 s, and rinsed with sterile distilled water for three times between solutions and at the end. All steps were carried out under aseptic conditions and finally dried . Four pieces were placed onto potato dextrose agar (PDA) supplemented with an antibiotic (chloramphenicol; 250 mg/L).…”

Volatile Organic Compounds from Rice Rhizosphere Bacteria Inhibit Growth of the Pathogen Rhizoctonia solani

“…showed 100% inhibition of R. solani growth (Figure 1). In comparison, Mookherjee et al found that the endophyte Geotrichum candidum utilized different carbon sources to varying extents [23], and the antifungal activity of its VOCs against phytopathogen R. solani changed with each carbon source, with the maximum mean growth inhibition of about 62% observed with glucose. Elkahoui et al (2015) found 25 VOCs producing strains inhibited (by 27-50%) the growth of R. solani [24].…”

Volatile Organic Compounds (VOCs) Produced By The Rhizosphere Actinobacteria Streptomyces Sp. and Amycolatopsis Sp. Strains and Their Antifungal Activity Against Colletotrichum Musae

“…Compound`s identification was done by comparison of the mass spectra obtained for each compound with the one reported in mass spectral libraries [30], including NIST 05 and NIST 27 (National Institute of Standards and Technology, Gaithersburg, USA). Additionally, Kovats index was calculated for each compound using a mixture of saturated n-alkanes C7-C30 (Sigma-Aldrich ® ), followed by comparison with literature data [30,31,32].…”

“…The relative concentrations of the constituents are represented in the loadings graph (Figure 6b) by circles with three different colors, where red, dark blue and light blue are associated to the highest concentration constituents from the actinobacteria (ACTB-77), C. musae and co-culture, respectively. Figure 6b shows 3-methyl-butan-1-ol (1), 2-methyl-butan-1-ol (2), α-phellandrene (12), β-phellandrene (15), phenylethyl alcohol (24), p-mentha-1,5-dien-8-ol (29), menthol (31) and aristolochene (59) as constituents from the C. musae group with the highest relatively concentrations. Among them, compounds 1, 12, 15, 24 and 59 represent ca.…”