Actinomycetes as natural fungicide on infected green leafy vegetables

Fungal diseases in green leafy vegetables are commonly under-esteemed but, the application of agrochemical fungicide has raised multiple drawbacks such as the higher amount of chemical residues and intensified microbial community stress. There is an urgent need to establish a bio-control antifungal agent with minimal toxicity threat, which sourced from natural environment. This study targeted to isolate and identify soil-borne fungi species in green leafy vegetables by molecular identification and investigated the antifungal potential of actinomycete strains on isolated fungi strain. Fungi were isolated from 3 soils collected underneath the infected green leafy vegetables. Actinomycete strains and synthetic compounds were screened for antifungal potential against selected fungi strains using agar plug diffusion assay. The isolated fungi were identified by 16S rDNA analysis. In this study, 41 fungal strains were isolated from soil samples. Actinomycetes strain C.D 6.5 exhibited the largest inhibition zone on 5 selected fungal strains, whereas actinomycetes strain C.KSJ 13.3 produced the broadest spectrum of antifungal activities. Synthetic compounds tend to form distinct and bigger inhibition zone compared to actinomycetes strain due to presence of methanol solvent. Isolated fungi were not identified due to low quality of genomic DNA that affects the PCR amplification results. The role of liquid nitrogen was proven in the fungal genomic DNA extraction as it reduced DNA degradation under the absence of cell wall. It can be concluded that actinomycetes strain have significant antagonistic activity against fungi and pure antifungal component can be extracted as an effective and environmental friendly bio-control agent on plant fungi.