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

Warin Intana,Anurag Sunpapao,Suchawadee Kheawleng

doi:10.3390/jof7010046

Warin Intana, Anurag Sunpapao + Show 1 more

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https://doi.org/10.3390/jof7010046

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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.

Highlights

The muskmelon (Cucumis melo) is a species of melon that has been bred into several cultivated varieties worldwide
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
The dominant volatile compound released by T. asperellum T16-14, tentatively identified as phenylethyl alcohol (PEA) based on Solid-phase microextraction (SPME) gas chromatography spectrophotometry (GC/MS), was involved in antifungal activity against F. incarnatum (Figures 4 and 5)

Summary

Introduction

The muskmelon (Cucumis melo) is a species of melon that has been bred into several cultivated varieties worldwide. In Thailand, the cultivation of muskmelons has increased due to market demand, as observed by the Department of Agricultural Extension, Ministry of Agriculture and Cooperative, Thailand. Thailand is located in tropical and subtropical zones, in which the weather is favorable for pathogen germination and disease dispersal. The cultivation of muskmelons is complicated by several diseases that reduce both the quality and quantity of pre-harvest and postharvest production. Postharvest fruit rot is considered one of the most destructive diseases that negatively impact saleable stock. This disease has recently been reported to be caused by Fusarium incarnatum [1] in Thailand

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