Molecular identification of fungi associated with avocado (<i>Persea americana</i> Mill.) fruits

Abstract

Avocado (Persea americana Mill.) is grown for its nutritious fruit. However, the quantity and quality of these fruits are threatened by some fungal organisms which can cause health complications when it is consumed by man. DNA extraction provides a unique tool for identification of organisms. This study was conducted to isolate and identify fungal species associated with avocado fruit using both morphological and molecular techniques. Fungal species were isolated from Persea americana purchased from Choba market, Port Harcourt, Rivers State, Nigeria using Potato Dextrose Agar (PDA) as a growth medium. The morphology of isolated fungi on PDA were cotton-like blackish grey spots, white villous colonies, greyish powdery spores and black spores for isolates 1 to 4 respectively. Extraction of DNA from fungal isolates was carried out using Zymo Fungal/Bacteria DNA Miniprep Kit. PCR amplification of the ITS1-2 regions of isolates was carried out using fungal universal primer pair; ITS4 and ITS5.PCR amplification of the ITS1-2 gene sequences yielded amplicons between 537-580 base pairs. PCR products were sequenced and the sequencing result after BLAST search revealed the identity of the four fungal species as follows: Lasiodiplodia theobromae, Fusarium proliferatum, Penicillium sp. and Aspergillus niger. This study will promote the knowledge of specific fungal species associated with Persea americanna and help plant pathologists to proffer preventive and control measures to enhance fruit protection and yield quality.