Antifungal properties of volatile organic compounds produced byDaldinia eschscholtziiMFLUCC 19-0493 isolated fromBarleria prionitisleaves againstColletotrichum acutatumand its post-harvest infections on strawberry fruits

• DOI: 10.7717/peerj.11242
• Publication Date: 2021-04-16T09:37:34Z
• Authors: Sarunpron Khruengsai; Patcharee Pripdee...; Chutima Tanapicha...; Chanin Srisuwannapa; Priya Esilda D’Souza; Parinya Panuwet
• Keywords: Mechanisms of Plant Immune Response; 0301 basic medicine; Colletotrichum acutatum; QH301-705.5; Fungal endophyte; Plant Science; Horticulture; Antifungal; Strawberry; Microbiology; Agricultural and Biological Sciences; Food science; 03 medical and health sciences; Inoculation; Gas chromatography–mass spectrometry; Biochemistry, Genetics and Molecular Biology; 11. Sustainability; Colletotrichum; Anthracnose; Biology (General); Agricultural Science; Biology; Endophytic Fungi; Chromatography; 0303 health sciences; Mycelium; Mass spectrometry; R; Botany; Biocontrol; Life Sciences; Cell Biology; Antimicrobial Properties of Essential Oils in Foods; Chemistry; FOS: Biological sciences; Barleria prionitis; Medicine; Diversity and Evolution of Fungal Pathogens; Food Science

Fungal endophytes are microorganisms living symbiotically with a host plant. They can produce volatile organic compounds (VOCs) that have antimicrobial activity. This study aimed to isolate endophytic fungi fromBarleria prionitisplants grown in Thailand and to investigate the antifungal properties of their VOCs againstColletotrichum acutatum, a causal agent of anthracnose disease on post-harvest strawberry fruits. A total of 34 endophytic fungi were isolated from leaves ofB. prionitis. The VOCs produced from each individual isolate were screened for their antifungal activity againstC. acutatumusing a dual-culture plate method. From this in vitro screening experiment, the VOCs produced by the endophytic isolate BP11 were found to have the highest inhibition percentage (80.3%) against the mycelial growth ofC. acutatum. The endophytic isolate BP11 was molecularly identified asDaldinia eschscholtziiMFLUCC 19-0493. This strain was then selected for an in vivo experiment. Results from the in vivo experiment indicated that the VOCs produced byD. eschscholtziiMFLUCC 19-0493 were able to inhibit infections byC. acutatumon organic fresh strawberry fruits with an average inhibition percentage of 72.4%. The quality of the pathogen-inoculated strawberry fruits treated with VOCs produced byD. eschscholtziiMFLUCC 19-0493 was evaluated. Their fruit firmness, total soluble solids, and pH were found to be similar to the untreated strawberry fruits. Solid phase microextraction-gas chromatographic-mass spectrometric analysis of the VOCs produced byD. eschscholtziiMFLUCC 19-0493 led to the detection and identification of 60 compounds. The major compounds were elemicin (23.8%), benzaldehyde dimethyl acetal (8.5%), ethyl sorbate (6.8%), methyl geranate (6.5%), trans-sabinene hydrate (5.4%), and 3,5-dimethyl-4-heptanone (5.1%). Each major compound was tested for its antifungal activity againstC. acutatumusing the in vitro assay. While all these selected VOCs showed varying degrees of antifungal activity, elemicin was found to possess the strongest antifungal activity. This work suggests thatD. eschscholtziiMFLUCC 19-0493 could be a promising natural preservative for controllingC. acutatumassociated anthracnose disease in strawberry fruits during the post-harvest period.