Rep-PCR Genomic Fingerprinting Revealed Genetic Diversity and Population Structure among Ethiopian Isolates of Pseudocercospora griseola Pathogen of the Common Bean (Phaseolus vulgaris L.)

Angular leaf spot (Pseudocercospora griseola) is one of the most devastating diseases affecting common bean production in most parts of Ethiopia. Thus, use of common bean varieties with durable resistance is the most effective and economical control measure. Knowledge about the genetic variability and population structure of the pathogen populations is important for a successful common bean improvement program. The objective of this study was to determine the genomic diversity existing among and between P. griseola isolates which were obtained from the field survey collection of diverse common-bean growing areas of Ethiopia. The study used the repetitive extragenic palindromic elements-polymerase chain reaction protocol to fingerprinting DNA sequence diversity. To study the genetic diversity, we analysed molecular data from 79 single-spore isolates of the P. griseola pathogen. Hence, Molecular Analysis of Variance (AMOVA) and cluster analysis revealed the existence of high genetic diversity within and among P. griseola isolates. ERIC PCR produced 21 different patterns of clusters, whereas, REP-PCR and BOX PCR produced 11 and 5 different patterns of clusters respectively. This is because of some isolates that shared the same BOX patterns could be distinguished by the ERIC and REP finger printing patterns. The ERIC-, BOX- and REP-PCR combined fingerprinting patterns discriminated 25 different patterns among the 79 monosporic P. griseola isolates were produced at cut-off 77% genetic similarity matrix. These discriminated clusters revealed the existence of genetic diversity within and among the isolates of P. griseola collected from the diverse common bean growing regions of Ethiopia