Geographical distribution of vegetative compatibility and mating types of Cryphonectria parasitica in İzmir, Manisa and Denizli provinces in western Turkey

Abstract

To extend our knowledge of population structure of Cryphonectria parasitica in the Aegean region, 264 isolates obtained from eight subpopulations in Izmir, Manisa and Denizli provinces were studied. Only three vegetative compatibility (vc) types, EU‐1, EU‐12 and EU‐2, were identified. EU‐1 (59%) was dominant and was found in all eight subpopulations. EU‐12 (32%) was detected in six subpopulations and was highly dominant (71%) in the Ödemiş subpopulation (İzmir province). EU‐2 was restricted to only one subpopulation, Tire, but, there, had the highest frequency (50%). This is the first reported occurrence of EU‐2 in western Turkey. Regarding sexual compatibility, both MAT1‐1 and MAT1‐2 were detected in all subpopulations; however, 85% of the isolates were MAT1‐1 and no perithecia were found in any of the subpopulations. Multilocus linkage disequilibrium analysis determined that all subpopulations were clonal. Indicator co‐kriging representations showed that vc types and mating types were spatially aggregated. In combination, these results indicate that the dispersal of the pathogen most likely occurs via localized short‐distance transport of rain‐splashed asexual conidia, rather than the long‐distance dispersal of wind‐borne ascospores. Because of the presence four polymorphic vegetative incompatibility (vic) loci in certain subpopulations, C. parasitica has the potential to generate new vc types in the future.

The potential diversity of vegetative compatibility types in the population of Cryphonectria parasitica in Turkey

“…Lack of perithecia on the bark samples supports the hypothesis that C. parasitica population is clonal in western Turkey. In the past, low vc type diversity in the C. parasitica population in western Turkey was mostly associated with the lack of sexual reproduction (Daldal et al., 2018; Erincik et al., 2008, 2011). In our study, even though both MAT‐1 and MAT‐2 were found in all the five sampled sites, chi‐square values in four sites indicated that the mating‐type ratio significantly deviated from 1:1.…”

“…EU1/MAT1 and EU12/MAT2 were not used since EU12/MAT2 was a rare genotype in western Turkey. Crosses were conducted on autoclaved pieces of chestnut wood embedded in potato dextrose agar (Figure 1) (Cortesi & Milgroom, 1998; Daldal et al., 2018). To prepare media, chestnut wood pieces, about 2–3 cm in diameter and 5 cm in length, were split equally longitudinally and the bark side of each piece was scraped lengthwise with a razor blade to create 5–6 parallel scrapes before autoclaving.…”

“…The two different chestnut‐growing regions of Turkey, the Aegean region and the East Black Sea region, were chosen to evaluate the potential of C. parasitica for increasing vc type diversity in nature. These two regions were in our interest since it has been known that C. parasitica had different population dynamic and structure in each region (Çeliker & Onoğur, 2001; Akıllı et al., 2009; Daldal et al., 2018; Erincik et al., 2011; Mangil & Erincik, 2018). C. parasitica has had a clonal population with low genetic diversity in the Aegean region so far; however, this may not be long‐lasting since EU‐1 and EU‐12 isolates from opposite mating types coexist nearby at several chestnut sites (Erincik et al., 2011, Daldal et al.…”

“…C. parasitica has had a clonal population with low genetic diversity in the Aegean region so far; however, this may not be long‐lasting since EU‐1 and EU‐12 isolates from opposite mating types coexist nearby at several chestnut sites (Erincik et al., 2011, Daldal et al. 2018). In the East Black Sea region, it is known that sexual reproduction is common in C. parasitica and contributes to the increase of vc type diversity (Mangil & Erincik, 2018).…”

“…These two regions were in our interest since it has been known that C. parasitica had different population dynamic and structure in each region (Çeliker & Onoğur, 2001;Akıllı et al, 2009;Daldal et al, 2018;Erincik et al, 2011;. C. parasitica has had a clonal population with low genetic diversity in the Aegean region so far; however, this may not be long-lasting since EU-1 and EU-12 isolates from opposite mating types coexist nearby at several chestnut sites (Erincik et al, 2011, Daldal et al 2018. In the East Black Sea region, it is known that sexual reproduction is common in C. parasitica and contributes to the increase of vc type diversity .…”