Browsing by Author "Edema, Richard"

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    Inter-simple sequence repeat markers reveal a moderate genetic diversity among fusarium species causing common bean root rot in Uganda
    (Journal of Advances in Biology & Biotechnology, 2026-02-14) Erima, Samuel; Nyine, Moses; Edema, Richard; Nkuboye, Allan; Orodriyo, Harriet; Candiru, Agnes; Otim, Michael Hilary; Paparu, Pamela
    Aims: The present study aimed to determine the genetic diversity and population structure of Fusarium species causing common bean root rot in Uganda Study Design: The study used isolates from a previous disease survey in Uganda Place and Duration of Study: The isolates were collected from 6 different agro-ecological zones of Uganda. Isolation was conducted at the legumes pathology laboratory of the National Agricultural Research Organization at Namulonge, Kampala. The isolates were collected in 2019. Methodology: DNA was extracted from 101 Fusarium species isolates using a modification of the cetyltrimethylammonium bromide protocol. Seventeen inter-simple sequence repeat primers were used in the polymerase chain reaction. The bands were scored for presence and absence using 1 and 0, respectively. The genetic diversity and population structure were determined using parameters such as polymorphic information content, allele divergence frequency, Principal component analysis, and admixture analysis. Analysis of molecular variance was also conducted. Results: The average polymorphic information content of the isolates was 84%. The average Wright's fixation index (Fst) and expected heterozygosity were 0.2. The result of the analysis of molecular variance revealed that 0.2% of the variation was between the agro-ecological zones, while 99.8% of the variation was within agro-ecological zones. Admixture analysis showed that the isolates have an admixed ancestry. Conclusion: Since the isolates from the different agro-ecological zones were similar, released varieties may not face extreme variants when they are planted in agro-ecological zones where they were not screened.
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    Molecular characterisation of fusarium species causing common bean root rot in Uganda
    (MDPI, 2025-04-03) Erima, Samuel; Nyine, Moses; Edema, Richard; Nkuboye, Allan; Habiba, Nalule; Candiru, Agnes; Paparu, Pamela
    Recently, Fusarium root rot (FRR)-like symptoms were observed in Uganda’s agroecology zones, prompting the National Agricultural Organisation (NARO) to conduct a disease survey. The survey reports indicated FRR as the second most prevalent root rot disease of common bean in Uganda after Southern blight. Ninety nine Fusarium spp. strains were obtained from samples collected during the surveys. The strains were morphologically and pathogenically characterised and confirmed to cause Fusarium root rot as observed in the field. However, molecular characterization of the strains was not conducted. In this study, therefore, 80 of the strains were characterized using partial sequences of translation elongation factor 1-alpha (TEF-1α) gene, beta tubulin (β tubulin) gene and internal transcribed spacers (ITS) region of ribosomal RNA to determine species diversity. High-quality Sanger sequences from the target genes were compared to the sequences from Fusarium species available in the National Centre for Biotechnology Information coding sequences (NCBI-CDS) database to determine the most likely species the strains belonged. The sequences from our strains were deposited into the NCBI gene bank under ID#288420, 2883276, 2873058 for TEF-1α, β tubulin and ITS respectively. The Fusarium species identified included; F. oxysporum, F. solani, F. equiseti F. delphinoides, F. commune, F. subflagellisporum, F. fabacearum, F. falciforme, F. brevicaudatum, F. serpentimum, F. fredkrugeri and F. brachygibbosum. The diversity of these Fusarium species needs to be taken into consideration when developing breeding programs for management of the disease since currently there is no variety of common bean resistant to FRR in Uganda.