An in vitro study of the antifungal activity of Trichoderma virens 7b and a profile of its non-polar antifungal components released against Ganoderma boninense

Abstract

Ganoderma boninense is the causal agent of a devastating disease affecting oil palm in Southeast Asian countries. Basal stem rot (BSR) disease slowly rots the base of palms, which radically reduces productive lifespan of this lucrative crop. Previous reports have indicated the successful use of Trichoderma as biological control agent (BCA) against G. boninense and isolate T. virens 7b was selected based on its initial screening. This study attempts to decipher the mechanisms responsible for the inhibition of G. boninense by identifying and characterizing the chemical compounds as well as the physical mechanisms by T. virens 7b. Hexane extract of the isolate gave 62.60% ± 6.41 inhibition against G. boninense and observation under scanning electron microscope (SEM) detected severe mycelial deformation of the pathogen at the region of inhibition. Similar mycelia deformation of G. boninense was observed with a fungicide treatment, Benlate indicating comparable fungicidal effect by T. virens 7b. Fraction 4 and 5 of hexane active fractions through preparative thin layer chromatography (P-TLC) was identified giving the best inhibition of the pathogen. These fractions comprised of ketones, alcohols, aldehydes, lactones, sesquiterpenes, monoterpenes, sulphides, and free fatty acids profiled through gas chromatography mass spectrometry detector (GC/MSD). A novel antifungal compound discovery of phenylethyl alcohol (PEA) by T. virens 7b is reported through this study. T. virens 7b also proved to be an active siderophore producer through chrome azurol S (CAS) agar assay. The study demonstrated the possible mechanisms involved and responsible in the successful inhibition of G. boninense.

Impact of Seed Treatments with Fungal Biocontrol Agents on Enzymatic Activities and Phenolic Content of Soybean under Greenhouse and Field Conditions

“…An increase of phenolic contents was also observed in soybean when seeds were treated with T. virens (Yusnawan et al 2019). Trichoderma species have been studied for decades as effective bio-control agents against many pathogens through various modes of action (Inayati et al 2020) and these Trichoderma spp., can induce systemic resistance in various plant species and pathogens (Angel et al 2016;Małolepsza et al 2017). The study of Dubey et al (2018) showed that there were upregulated expression of some defense-related genes and catalase in response to the presence of T. virens and R. solani.…”

New Antimicrobial Phenyl Alkenoic Acids Isolated from an Oil Palm Rhizosphere-Associated Actinomycete, Streptomyces palmae CMU-AB204T

“…racemosus IFO 4581, and A. niger ATCC 6275, while AB204-E (5) and F (6) displayed a positive degree of activity against Gram-positive bacteria, B. subtilis ATCC 6633, K. rhizophila ATCC 9341, M. smegmatis ATCC 607, and S. aureus ATCC 6538p. New antifungal compounds, AB204-A (1) and B (2), possessed similar structures to phenylethyl alcohol (PEA), an antifungal aromatic compound that was obtained from Trichoderma virens 7b, which had significant potential as a biological control agent for BSR [43]. These compounds may exhibit a mechanism in inhibiting fungi similar to PEA which inhibits protein, DNA, RNA, and aminoacyl tRNA syntheses of fungi [44,45].…”

Antagonistic effect of volatile and non-volatile compounds from Streptomyces strains on cultures of several phytopathogenic fungi

“…isobutyl isothiocyanate, dimethyl disulfide, and 2-(methylthio) ethanol, among others), which are highly produced by other antagonistic microorganisms (i.e. Pseudomonas stutzeri E25, Stenotrophomonas maltophilia CR71, and T. virens) (Angel et al, 2016;Rojas-Solís et al, 2018).…”