ABSTRACT
Blast caused by Magnaporthe oryzae (syn. Pyricularia oryzae) pathotype Triticum (MoT) is today emerging as one of the most destructive diseases of wheat. Over the years, research groups have worked separately to understand the population biology and evolutionary history of the MoT fungus. Recent genomic evidences have indicated that the population dynamics and mechanisms for frequent mutation in MoT avirulence genes have led to the development of new pathotypes. It has been confirmed that unexpectedly high levels of gene flow and probabilistic chromosome painting have resulted in the introgression of chromosome segments from other host-specialised forms, leading to the emergence of wheat blast. Ecological and population biology studies conducted on the MoT fungus have pointed towards its highly variable genetic structure across different regions and have also confirmed that the MoT fungus is genetically distinct in pathogenicity from Pyricularia oryzae species associated with rice blast disease. In addition, various population genetic analysis and comparative genomics analysis have elucidated new insights into genome evolution, speciation and the origin of pathogenicity traits of the MoT fungus. Therefore, in this chapter, efforts have been made to summarise past and current knowledge regarding the population biology of the wheat blast fungus and highlight researchable gaps required for a complete understanding of its ecology and population biology for effective and timely management of the wheat blast disease.
