Genetic Diversity and Population Structure of Zymoseptoria Tritici Populations of Southern Ethiopia Using Ssr Markers
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Date
2020-09-28
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Addis Ababa University
Abstract
Septoria Tritici Blotch Caused By The Fungal Pathogen Zymoseptoria Tritici Is Considered To Be One The Major Threats To Wheat Production In Ethiopia And Elsewhere In The World. Understanding The Genetic Structure Of The Pathogen Has Great Importance In Designing And Implementing Suitable Management Strategies. Therefore, The Present Study Was Targeted To Explore The Genetic Structure Of 51 Z. Tritici Isolates Collected From Four Wheat Producing Zones Of South And Southwesten Parts Of Ethiopia Using Nine Microsatellite Marker Systems. Different Diversity Indices Were Computed. A Z. Tritici Specific Diagnostic Marker That Targets The ITS Rdna Had Amplified An Expected Fragment Size Of 345bp In All The Tested Isolates. All The Markers Were Found To Be Highly Polymorphic And Thus Useful Tools To Depict The Genetic Structure Of The Pathogen Populations. The Analysis Revealed A High Degree Of Genetic Diversity Within Populations With Number Of Alleles, Gene Diversity And Polymorphic Information Content Per Locus Ranging From 9 - 14, 0.80 - 0.88 And 0.70 - 0.87, Respectively. Analysis Of Molecular Variance (AMOVA) Confirmed A Moderate (0.14) Genetic Differentiation Where 86% Of The Total Genetic Variability (3.93) Resides Within Populations, And Only 14% Was Due To Among Populations‘ Difference. Dendrogram Produced UPGMA And Pcoa Also Showed A Moderate Population Clustering In Which The Populations Were Not Distinctly Clustered According To Their Areas Of Sampling Due To Presence Of High Gene Flow. Moreover, Bayesian Model-Based Population Structure Analysis Weakly Clustered The Population Into Five (ΔK) Sub-Groups With High Level Of Genetic Admixture. Among The Considered Populations, Populations Of Kembata -Tembaro Zone And Hadiya Zone Showed Relatively Higher Genetic Variability, And Thus Can Be Considered As STB Hot Spots For Further Studies On The Dynamics Of The Pathogen And Germplasm Screening And Host-Pathogen Interactions. Therefore, The Present Study Had Generated Useful Baseline Information For Wheat Breeders And Pathologists For Designing And Implementing Durable And Effective STB Control Strategies.
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Keywords
Genetic Structure, Microsatellites, Wheat