Genetic Diversity and Population Structure of Wheat Stripe Rust Pathogen (Puccinia striiformis f. sp. tritici) in Turkey

Abstract

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases threatening wheat production both in Turkey and worldwide. However, the underlying genetic dynamics of Pst populations are not fully known in Turkey. To determine the population genetic structure and migration network among regional Pst populations, a total of 140 Pst isolates collected from six geographical regions of Turkey from 2018 to 2020 were sampled and genotyped using 21 simple sequence repeat (SSR) loci. A total of 70 multi-locus genotypes (MLGs) were identified and they were classified into the three major genetic groups by Bayesian assignment. The highest genotypic diversity was detected in Southeastern Anatolia (SA), showing its critical role as one of the source populations to trigger possible stripe rust epidemics. Analysis of molecular variance (AMOVA) revealed the highest variation (90.25%) within isolates. The migration network generated by number of effective migrants (Nm) showed that the highest migration (1.0) was determined between SA and CA, considerable levels of migration (>0.2) were determined among the other regions except for BS. Linkage equilibrium (P≥ 0.05) was detected for many geographical regions except for Marmara (MA) (P= 0.00) and Mediterranean (ME) (P= 0.03), suggesting that Pst populations are reproduced most likely sexual or mixed (sexual and clonal). To sum up, this is the first study on the genetic relationships and population genetic structure of Pst population in Turkey, and all these findings may provide a critical information to develop management strategies to wheat stripe rust.