Genetic characterization of Phytophthora colocasiae isolates causing taro leaf blight (TLB) in the Sudanian climatic zone of Burkina Faso

Taro leaf blight, caused by the oomycete Phytophthora colocasiae, represents a significant constraint to taro production in the Sudanian climatic zone of Burkina Faso. Effective and sustainable management of this disease necessitates a thorough understanding of the genetic diversity of the pathogen. This study aimed to characterize the genetic diversity of Phytophthora colocasiae through morphological and molecular analyses of isolates collected from multiple locations. A total of 44 isolates were evaluated using four morphological markers and nine molecular markers. Morphological assessment identified six distinct morphotypes based on colony growth characteristics, with isolates further categorized into three growth-rate classes. Molecular characterization revealed low genetic diversity within the pathogen population, as indicated by a Shannon diversity index of 0.4. Analysis of molecular variance (AMOVA) showed that genetic variation was predominantly distributed within populations, with minimal differentiation and low genetic distances between groups. These findings offer essential insights into the population structure of Phytophthora colocasiae and provide a foundation for the development of targeted management strategies to mitigate taro leaf blight in Burkina Faso.