African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12484

Full Length Research Paper

Pathogenic and molecular characterization of Pseudocercospora griseola, the causal agent of angular leaf spot of common bean, in Eastern Democratic Republic of Congo (DRC)

Kijana Ruhebuza
  • Kijana Ruhebuza
  • Institut National Pour l’Etude et la Recherche Agronomiques (INERA) MULUNGU, D/S Bukavu, Democratic Republic of the Congo.
  • Google Scholar
Mathew Abang
  • Mathew Abang
  • Centro International for Tropical Agriculturale (CIAT) NARL Kawanda, Kampala P. O. Box 6247, Uganda.
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Richard Edema
  • Richard Edema
  • Makerere University, Kampala P. O. Box 7062, Uganda.
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Clare Mukankusi
  • Clare Mukankusi
  • Centro International for Tropical Agriculturale (CIAT) NARL Kawanda, Kampala P. O. Box 6247, Uganda.
  • Google Scholar
Fred Kato
  • Fred Kato
  • Centro International for Tropical Agriculturale (CIAT) NARL Kawanda, Kampala P. O. Box 6247, Uganda.
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Robin Buruchara
  • Robin Buruchara
  • Centro International for Tropical Agriculturale (CIAT), Africa Regional Hub, Nairobi, Kenya.
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  •  Received: 20 June 2023
  •  Accepted: 30 August 2023
  •  Published: 31 May 2024

Abstract

Angular leaf spot (ALS) caused by Pseudocercospora griseola is the most economically damaging common bean (Phaseolus vulgaris L.) foliar disease in Democratic Republic of Congo (DRC) and elsewhere in Eastern and Central Africa. Information regarding pathotypes distribution and genetic structure that would enable development of appropriate control measures is still lacking in DRC. The study aimed to investigate the pathogenic and genetic structure of P. griseola isolates from two agro-ecological zones of eastern DRC. Virulence analysis of 59 P. griseola isolates, using differential cultivars, identified 35 pathotypes groups. Most virulent pathotypes were discerned in sub-humid highlands area: Repetitive PCR primers, BOXAIR and REP used to elucidate genetic diversity revealed high level of polymorphism (95.5%), influence of agro-ecology and host genotypes on P. griseola population structure; with moderate genetic differentiation, respectively (GST= 19% and GST= 12%). Low genetic diversity(DST) value revealed that most of the genetic  variability was within subpopulations (96%), with little variability between P. griseola sub populations from the host genotypes (4%). The cluster analysis using UPGMA method identified two main clusters at 65% genetic similarities. The study confirmed that P. griseola populations from eastern DRC, can be broadly grouped into two structured host genotype groups and co-evolution process. This implies that screening for ALS resistance should consider this high diversity for an appropriate breeding program and durable disease management strategies development.

 

Key words: Pathotypes, agro-ecology, common bean, genetic distance, durable resistance.