European Journal of Plant Pathology

, Volume 150, Issue 1, pp 139–148 | Cite as

Effect of host resistance on genetic structure of core and accessory chromosomes in Irish Zymoseptoria tritici populations

  • Thomas Welch
  • Angela Feechan
  • Steven KildeaEmail author


In agricultural pathosystems resistant cultivars are typically only temporarily effective, as widespread growth of said cultivars drives selection for pathogen genotypes capable of infecting them. A gene-for-gene interaction between Z. tritici and wheat has been demonstrated for one cultivar; however results of studies into the relevance of these interactions in the field remain inconsistent. Because genetic drift does not appear to occur between Z. tritici populations that are not widely geographically separated, according to neutral genetic theory if adaptation to different host cultivars is occurring, reduced genetic variation, and some differentiation between populations sourced from different cultivars should be observed. Selectively neutral microsatellite markers were used to genotype 260 isolates of Z. tritici taken from two naturally infected randomized block trials of four different cultivars, representing a spectrum of resistance to Z. tritici from susceptible to resistant. By calculating genetic parameters such as overall heterozygosity and FST from this genotypic data, the presented study aimed to determine if genetic drift or host selection is impacting on the genetic structure of the Irish Z. tritici population. Results indicated that diversity was distributed almost entirely within, rather than among populations, with little or no differentiation, and almost no clone isolates were present in the dataset. However this result was not reflected in the accessory chromosomes, where evidence of minor but significant genetic structure was found. This lack of structure in the core chromosomes and weak structure in the accessory chromosomes confirms that forces of genetic drift and selection are minor compared to sexual reproduction, in concurrence with multiple previous studies on other populations worldwide.


Host adaptation Microsatellites Zymoseptoria tritici Septoria tritici blotch Core chromosomes Accessory chromosomes 



The authors would like to thank Dr. Sinead Phelan for her assistance in collection establishment. This research has been funded by the Irish Department of Agriculture, Food and the Marine under their research stimulus fund, grant number 11S113.

Compliance with ethical standards

The authors declare no conflicts of interest.

Supplementary material

10658_2017_1259_MOESM1_ESM.pdf (512 kb)
ESM 1 (PDF 511 kb)


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Copyright information

© Koninklijke Nederlandse Planteziektenkundige Vereniging 2017

Authors and Affiliations

  1. 1.School of Agriculture and Food ScienceUniversity College DublinDublinIreland
  2. 2.Department of Crop Science, Teagasc Crops Environment and Land Use ProgrammeOak ParkIreland

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