Morphological and Molecular Characterisation of Three Fungi, Antagonistic to Plant Pathogens

Aims: This study characterized three antagonistic fungi viz Trichoderma sp, Penicillium sp and a Putative Metarhizium sp. Morphological and Molecular characterization were conducted on the three antagonistic fungi for proper identification to the species level. Study Design: The study employed an experimental laboratory design combining morphological and molecular techniques to isolate, characterize, and identify potential antagonistic fungi (Trichoderma, Penicillium, and a putative Metarhizium) obtained from soil and culture collections. Place and Duration of Study: Department of Crop and Soil Sciences, KNUST, Kumasi and Cocoa Research Institute of Ghana (CRIG) Akyem New Tafo, Ghana, between February 2022 and May 2023. Methodology: For morphological characterization of the three antagonistic fungi, a single spore of the antagonistic fungi was centrally placed on PDA plate (three replicate plates per fungi) and grown on a laboratory bench in a room with approx. 8 h photo period at approx. 28 ºC. Colony diameters were measured from the underside of the plates with a meter rule from day 1 to day 7 (for the penicillium sp. and the putative Metarhizium sp.) and for day 1 to day 4 for Trichoderma sp. Fungal reproductive structures were studied using a modified slide culture technique. Measurement of the various structures of each organism were measured using an Amscope microscope. Colony coloration was described using the pantone colour chart. Genomic DNA was extracted using the CTAB method. PCR, Gel electrophoresis and DNA sequencing were done at the functional Biosciences, WI Madison, USA. Results: Molecular determinations conducted on the three antagonistic fungi conclusively, identified the Trichoderma sp. as T. asperellum, the Penicillium sp. as P. citrinum and the putative Metarhizium as Myxotrichum stiputatum. Conclusion: With proper identification using molecular approaches, the three antagonistic fungi were found to be Trichoderma asperellum, Penicillium citrinum, and Myxotrichum stipitatum. When then three antagonistic fungi were tested against all the seven plant pathogens for biocontrol potential using the dual culture technique, T. asperellum exhibited the strongest antagonistic activity against all seven plant pathogens.