Title: Detection of virulence-associated genes of Fusarium oxysporum and Geotrichum candidum strains in tomato cultivars from Nigeria

Authors: Olalekan Ajibolade Ogunoye; Ayodele Adegboyega Sobowale; Odunayo Joseph Olawuyi

Addresses: Department of Crop, Soil and Pest Management Technology, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria; Department of Botany, University of Ibadan, Ibadan, Oyo State, Nigeria ' Department of Crop, Soil and Pest Management Technology, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria; Department of Botany, University of Ibadan, Ibadan, Oyo State, Nigeria ' Department of Crop, Soil and Pest Management Technology, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria; Department of Botany, University of Ibadan, Ibadan, Oyo State, Nigeria

Abstract: Tomato can be contaminated with fungal species, which is deadly for human and animal's consumption, as some of them produce mycotoxins. Fusarium oxysporum and Geotrichum candidum diseases still cause massive damages in greenhouses and open fields. The objectives of this study were to detect virulent genes (fmk1, endoPG {pg1}, and xyl3-genes) and ascertain pathogenic strains in F. oxysporum and G. candidum isolated from two tomato cultivars obtained from Nigeria. Isolation of the two fungal pathogens from the tomato cultivars were done on acidified Potato Dextrose Agar (APDA) plates at the Plant Pathology/Mycology laboratory, Department of Botany, University of Ibadan following standard procedures. DNA extraction from pure cultures of the pathogens was done at the Centre Laboratory of University of Ibadan. Molecular investigations of fmk1, pg1 and xyl3-coding gene in the fungal isolates were by PCR reaction. Genetic relationships among the pathogens were also estimated by constructing a Dendrogram through UPGMA using the Mega6 Software. Five strains of F. oxysporum and seven strains of G. candidum were identified. A positive amplification of the ITS region of the fungal pathogens was given by agarose gel electrophoresis on PCR reaction. Percentage similarity of the pathogens with those in GenBank was 99.17%100.00% for F. oxysporum and 98.48%100.00% for G. candidum. Gel image indicated a negative amplification for the virulence-associated gene flk1, pg1 and xyl3-gene in all the fungal strains. More studies should be carried out to investigate the gene responsible for virulence and diverse expression of virulence genes upon infection on tomato fruit should also be investigated. This is to ascertain the possibility of more genes coding for pathogenicity in these fungi.

Keywords: Fusarium oxysporum; Geotrichum candidum; pathogens; mycotoxins; virulence.

DOI: 10.1504/IJBT.2023.138738

International Journal of Biotechnology, 2023 Vol.14 No.4, pp.303 - 320

Received: 20 Jul 2023
Accepted: 25 Mar 2024
Published online: 29 May 2024 *

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