Genetic Diversity And Population Structure of Zymoseptoria Tritici Populations of Southern Ethiopia Using SSR Markers

Abstract The fungal disease Zymoseptoria tritici causes Septoria tritici blotch, which is one of the most serious challenges to wheat production in Ethiopia and around the world. Understanding the pathogen's genetic structure is critical for developing and implementing effective management methods. Therefore, the present study targeted to explore the genetic structure of 51 Z. tritici isolates collected from four wheat producing zones of South and Southwestern parts of Ethiopia using nine microsatellite markers. In all of the examined isolates, a Z. tritici specific diagnostic marker that targets the ITS rDNA had amplified a predicted fragment size of 345bp. The number of alleles, gene diversity, and polymorphic information content per locus ranged from 9 to 14, 0.80 to 0.88, and 0.70 to 0.87, respectively, indicating a significant degree of genetic variety within populations. The results of an analysis AMOVA revealed a moderate (0.14) genetic differentiation, with 86 percent of total genetic variability (3.93) occurring within populations. Due to the existence of considerable gene flow, the dendrogram produced by UPGMA and PCoA also revealed a moderate population clustering in which the populations were not clearly clustered according to their sample areas. Furthermore, population structure analysis using a Bayesian model loosely grouped the population into five (K) sub-groups with substantial genetic mixing. The populations of the Kembata-Tembar and Hadiya zone have higher genetic variability than the other populations studied, and hence can be considered STB hot sites for future research on pathogen dynamics, germplasm screening, and host-pathogen interactions.