Trichoderma asperellum T76-14 Released Volatile Organic Compounds against Postharvest Fruit Rot in Muskmelons (Cucumis melo) Caused by Fusarium incarnatum

Abstract

Postharvest fruit rot caused by Fusarium incarnatum is a destructive postharvest disease of muskmelon (Cucumis melo). Biocontrol by antagonistic microorganisms is considered an alternative to synthetic fungicide application. The aim of this study was to investigate the mechanisms of action involved in the biocontrol of postharvest fruit rot in muskmelons by Trichoderma species. Seven Trichoderma spp. isolates were selected for in vitro testing against F. incarnatum in potato dextrose agar (PDA) by dual culture assay. In other relevant works, Trichoderma asperellum T76-14 showed a significantly higher percentage of inhibition (81%) than other isolates. Through the sealed plate method, volatile organic compounds (VOCs) emitted from T. asperellum T76-14 proved effective at inhibiting the fungal growth of F. incarnatum by 62.5%. Solid-phase microextraction GC/MS analysis revealed several VOCs emitted from T. asperellum T76-14, whereas the dominant compound was tentatively identified as phenylethyl alcohol (PEA). We have tested commercial volatile (PEA) against in vitro growth of F. incarnatum; the result showed PEA at a concentration of 1.5 mg mL−1 suppressed fungal growth with 56% inhibition. Both VOCs and PEA caused abnormal changes in the fungal mycelia. In vivo testing showed that the lesion size of muskmelons exposed to VOCs from T. asperellum T76-14 was significantly smaller than that of the control. Muskmelons exposed to VOCs from T. asperellum T76-14 showed no fruit rot after incubation at seven days compared to fruit rot in the control. This study demonstrated the ability of T. asperellum T76-14 to produce volatile antifungal compounds, showing that it can be a major mechanism involved in and responsible for the successful inhibition of F. incarnatum and control of postharvest fruit rot in muskmelons.

Inhibitory Effect of Trichoderma asperellum Isolate against Ralstonia solanacearum Causing Brinjal Wilt

“…Heavy sporulation against the R. solanacearum bacterium was recorded in the present dual culture plate during the qualitative antagonistic bioassay. This observation was similar to previous studies (Hermosa et al, 2000;Patel and Saraf, 2017;Kilonzi et al, 2020;Intana et al, 2021), where fast growth and profuse sporulation of Trichoderma were observed against many plant pathogens (2018) recorded mycoparasitism of T. asperellum (isolate Ray1715) as it completely overgrew on Phytophthora nicotianae (Phytophthora foot and root rot of citrus). Additionally, the faster growth of T. asperellum T76-14 in the dual-culture assay against F. incarnatum on PDA suggested a competition mechanism (Intana et al, 2021).…”

“…This observation was similar to previous studies (Hermosa et al, 2000;Patel and Saraf, 2017;Kilonzi et al, 2020;Intana et al, 2021), where fast growth and profuse sporulation of Trichoderma were observed against many plant pathogens (2018) recorded mycoparasitism of T. asperellum (isolate Ray1715) as it completely overgrew on Phytophthora nicotianae (Phytophthora foot and root rot of citrus). Additionally, the faster growth of T. asperellum T76-14 in the dual-culture assay against F. incarnatum on PDA suggested a competition mechanism (Intana et al, 2021). According to Jiang et al (2016) T. asperellum was able to collapse the mycelium of the colonies of the pathogen through dual culture tests by breaking down the pathogenic hyphae into fragments.…”

Trichoderma strains selection for biological control of Fusarium nygamai in sorghum (Sorghum bicolor L. Moench)

“…All seedlings that were infected with F. nygamai (F4 and F5) in vivo under laboratory conditions evidenced wilt as disease symptoms, except those that were treated with T. asperellum (T6), where 50 % did not develop disease symptoms. Intana, Kheawleng, and Sunpapao (2021) found that volatile organic compounds emitted from T. asperellum, with phenylethyl alcohol as the principal compound, were able to inhibit mycelial growth of F. incanatum in vitro and smaller lesions of muskmelons were obtained in in vivo assays.…”

Debaryomyces hansenii, Stenotrophomonas rhizophila, and Ulvan as Biocontrol Agents of Fruit Rot Disease in Muskmelon (Cucumis melo L.)

“…Previous studies have shown that biological control by applying microbial antagonists, such as Bacillus subtilis [9], Burkholderia sp. [10], and Pseudomonas graminis [11], or by applying secondary metabolites such as phenylethyl alcohol from Trichoderma asperellum [12] and lactic acid from Lactobacillus plantarum [13], is a promising method for managing decay in harvested muskmelon.…”