Molecular Characterization of Pyricularia oryzae Through Randomly Amplified Polymorphic DNA Marker

Abstract

Rice blast is not only one of the earliest known plant diseases but also one of the most widely distributed diseases, occurring in every region of the world where rice is grown. Assessment of the genetic diversity of pathogenic fungi provides a basis for the development of future resistant crop varieties. An experiment was conducted during the period from September 2020 to December 2021 in the Plant Protection Laboratory of Agrotechnology Discipline, Khulna University, Khulna, to determine the genetic variability among nineteen isolates of Pyricularia oryzae. The isolates were obtained from infected rice blast samples collected from different locations of the southwestern rice-growing regions of Bangladesh. A total of ten arbitrary RAPD primers were used, which generated clearly visible banding patterns. Only four primers (OPA-02, OPA-03, UBC-155, and UBC-173) produced a low number of bands in isolate PO-16. The other primers did not produce any bands in PO-16, indicating that this isolate was genetically distinct from the remaining isolates. Cluster analysis revealed two distinct clusters. Cluster I contained only one isolate, PO-16, which originated from AEZ-13. Cluster II consisted of eighteen isolates collected from different locations and showed up to 94% genetic similarity. The highest genetic diversity was observed between isolates PO-16 and PO-03, both originating from AEZ-13, with a genetic distance of 79%. This finding indicates that there is no direct relationship between genetic diversity and geographical origin. Principal Component Analysis (PCA) supported the results of the cluster analysis and further confirmed that PO-16 was a genetically distinct isolate.