Russian populations of Puccinia triticina in distant regions are not differentiated for virulence and molecular genotype

Abstract

The objective of this study was to determine whether genetically distinct groups of Puccinia triticina are present in four regions of the Russian Federation. Collections of P. triticina were obtained from the Central, North Caucasus, Volga and West Siberia regions from 2006 to 2010. Ninety‐nine single uredinial isolates were tested for virulence phenotype with 20 Thatcher near‐isogenic lines of wheat. Forty‐one virulence phenotypes were found in the four regions, with eight in common between the widely separated Central and West Siberia regions. A total of 72 isolates were tested for molecular genotype with 23 simple sequence repeat (SSR) primer pairs, and 66 isolates were used for further analysis after clone correction for virulence and molecular genotype. Analysis of variation showed no overall differentiation of SSR genotypes or virulence phenotypes based on region of origin. Linkage disequilibria for SSR genotypes were high across the entire population. The regional populations had higher than expected levels of allelic heterozygosity that indicated clonal reproduction. Based on cluster analysis of SSR genotypes there were two groups of P. triticina isolates that were widely distributed across Russia. The two SSR groups also differed significantly for virulence. Puccinia triticina may be dispersed from a common source of inoculum in the European or Caucasus regions of Russia. The Russian P. triticina populations were highly differentiated for SSR genotype from populations in Tajikistan, Kyrgyzstan, Uzbekistan, Armenia, Georgia and Azerbaijan and more similar to populations from southern Kazakhstan and northern Kazakhstan.

Regional and temporal differentiation of virulence phenotypes of Puccinia triticina from common wheat in Russia during the period 2001–2018

“…Our results confirm the findings of Kolmer et al . (2015) that the regional populations of P . triticina in Russia share many virulence phenotypes.…”

“…However, in their recent research Kolmer et al . (2015) stated that there was no differentiation among regional populations of P . triticina ; in particular, they could not distinguish between the pathogen in the European and Asian parts of Russia.…”

“…All the above‐mentioned results of virulence data analyses raise concern regarding the main statement of Kolmer et al . (2015) that a single population of P . triticina exists in Russia and indicate that it cannot be accepted.…”

“…We assume that the small sample size of around 100 isolates tested by Kolmer et al . (2015) was not sufficient to reveal pathogen differentiation between the two giant regions of the European and West Asian parts of Russia, and much larger sampling efforts are generally required to disclose relatively subtle differences. Moreover, our recent results, obtained with SSR profiles of 226 isolates of P .…”

“…triticina was recently analysed with virulence and simple‐sequence repeat (SSR) markers by Kolmer et al . (2015). Using a relatively small sample of the European and Asian isolates collected in 2006–2010, it was stated that there was no differentiation among regional populations of P .…”