Worldwide genetic structure elucidates the eurasian origin and invasion pathways of dothistroma septosporum, causal agent of dothistroma needle blight
Mullett, Martin S.; Drenkhan, Rein; Adamson, Kalev; BoroN, Piotr; Lenart-Boron, Anna; Barnes, Irene; Tomsovsky, Michal; Janosíkova, Zuzana; Adamcikov, Katarina; Ondruskova, Emilia; Queloz, Valentin; Piskur, Barbara; Musolin, Dmitry L.; Davydenko, Kateryna; Georgieva, Margarita; Schmitz, Sophie; Kacergius, Audrius; Ghelardini, Luisa; Orlovic, Jelena Kranjec; Muller, Michael; Oskay, Funda; Hauptman, Tine; Halasz, Agnes; Markovskaja, Svetlana; Solheim, Halvor; Vuorinen, Martti; Heinzelmann, Renate; Hamelin, Richard C.; Konecny, Adam
Date:
2021-02-03
Abstract:
Dothistroma septosporum, the primary causal agent of Dothistroma needle blight, is one of
the most significant foliar pathogens of pine worldwide. Its wide host and environmental ranges have
led to its global success as a pathogen and severe economic damage to pine forests in many regions.
This comprehensive global population study elucidated the historical migration pathways of the
pathogen to reveal the Eurasian origin of the fungus. When over 3800 isolates were examined, three
major population clusters were revealed: North America, Western Europe, and Eastern Europe, with
distinct subclusters in the highly diverse Eastern European cluster. Modeling of historical scenarios
using approximate Bayesian computation revealed the North American cluster was derived from an
ancestral population in Eurasia. The Northeastern European subcluster was shown to be ancestral to
all other European clusters and subclusters. The Turkish subcluster diverged first, followed by the
Central European subcluster, then theWestern European cluster, which has subsequently spread to
much of the Southern Hemisphere. All clusters and subclusters contained both mating-types of the
fungus, indicating the potential for sexual reproduction, although asexual reproduction remained
the primary mode of reproduction. The study strongly suggests the native range of D. septosporum to
be in Eastern Europe (i.e., the Baltic and Western Russia) and Western Asia.
Description:
Figure S1: Delta K plot of the STRUCTURE analysis, showing K = 3 as the best
clustering of individuals, Figure S2: Bayesian clustering of D. septosporum multilocus haplotypes
inferred using the program STRUCTURE at K = 6, K = 7 and K = 8 (a) and K = 9, K = 10 and K = 11 (b).
Each multilocus haplotype is represented by a vertical line partitioned into colored sections that
represent the isolate’s estimated membership fractions in each cluster. Black lines separate isolates
from different population groups, Figure S3: Plot of the Bayesian information criterion (BIC) vs. the
number of clusters from k-means clustering showing a break at K = 3, indicating three clusters best
describe the dataset for DAPC analysis, Figure S4: Bayesian clustering of only the North American
D. septosporum multilocus haplotypes inferred using the program STRUCTURE at K = 2, K = 3 and
K = 4. Each multilocus haplotype is represented by a vertical line partitioned into colored sections
that represent the isolate’s estimated membership fractions in each cluster. Black lines separate
isolates from different population groups. The inset shows a graph of delta K, Figure S5: Graphical
representation of the winning scenarios of demographic history for each of the eight DIYABC analyses.
Abbreviations used on time scales refer to time parameters used during simulations, Figure S6: Model checking of the winning DIYABC scenarios for each of the eight conducted analyses, Table S1: Details
of D. septosporum isolates used in this study including the host, geographic location, population group,
microsatellite allele calls and mating-types, Table S2: Scenario descriptions, posterior probabilities
with 95% credibility intervals of each scenario, and posterior predictive error of models, Table
S3: Pairwise population FST (below the diagonal) and Nm, the estimated number of migrants
per generation (above the diagonal) for the D. septosporum population groups, Table S4: Posterior
distributions of parameters for winning scenarios of DIYABC analyses 1 to 8.
