The interaction among evolutionary forces in the pathogenic fungus Mycosphaerella graminicola

Zhan, Jiasui; McDonald, Bruce A.

doi:10.1016/j.fgb.2004.01.006

Cited by 76 publications

(64 citation statements)

References 52 publications

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“…This is in contrast to some of the Mycosphaerella pathogens on agricultural crops such as wheat (Zhan et al 2003;Zhan and McDonald 2004). However, in recent years, several polymorphic markers have been developed for important Teratosphaeria spp.…”

Section: Future Prospectsmentioning

confidence: 99%

Mycosphaerella and Teratosphaeria diseases of Eucalyptus; easily confused and with serious consequences

et al. 2011

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The Mycosphaerella complex accommodates thousands of taxa. Many of these species are economically important plant pathogens, notably on native and commercially propagated Eucalyptus species where they cause a wide range of disease symptoms including leaf spot, leaf blotch, shoot blight and stem cankers. Some of these diseases represent major impediments to sustainable Eucalyptus forestry in several countries where infection by Mycosphaerella and Teratosphaeria species can result in reduction of wood volume and in severe cases tree death.Extensive research has been conducted on these disease complexes over the past 40 years. The incorporation of DNA-based molecular techniques has made it possible to define and to better understand the differences between the Mycosphaerella and Teratosphaeria species occurring on Eucalyptus. These studies have also enabled refinement of anamorph and teleomorph generic concepts for the genera and thus facilitated the more accurate identification of species. They have also promoted a more lucid understanding of the biology, life cycles, population biology and epidemiology of the most important pathogens in the group.

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Section: Future Prospectsmentioning

confidence: 99%

Mycosphaerella and Teratosphaeria diseases of Eucalyptus; easily confused and with serious consequences

et al. 2011

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“…Our previous work also showed that M. graminicola has increased in population size while spreading around the world together with its wheat host (Banke and McDonald 2005;). In M. graminicola Zhan and McDonald (2004) previously estimated an N e of 25,000 using information from RFLP markers. This number is within the same range as the N e values estimated here for the ancestral Mycosphaerella species (Fig.…”

Section: à8mentioning

confidence: 99%

The making of a new pathogen: Insights from comparative population genomics of the domesticated wheat pathogenMycosphaerella graminicolaand its wild sister species

Stukenbrock¹,

Bataillon²,

Dutheil³

et al. 2011

Genome Res.

205

256

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The fungus Mycosphaerella graminicola emerged as a new pathogen of cultivated wheat during its domestication~11,000 yr ago. We assembled 12 high-quality full genome sequences to investigate the genetic footprints of selection in this wheat pathogen and closely related sister species that infect wild grasses. We demonstrate a strong effect of natural selection in shaping the pathogen genomes with only~3% of nonsynonymous mutations being effectively neutral. Forty percent of all fixed nonsynonymous substitutions, on the other hand, are driven by positive selection. Adaptive evolution has affected M. graminicola to the highest extent, consistent with recent host specialization. Positive selection has prominently altered genes encoding secreted proteins and putative pathogen effectors supporting the premise that molecular host-pathogen interaction is a strong driver of pathogen evolution. Recent divergence between pathogen sister species is attested by the high degree of incomplete lineage sorting (ILS) in their genomes. We exploit ILS to generate a genetic map of the species without any crossing data, document recent times of species divergence relative to genome divergence, and show that generich regions or regions with low recombination experience stronger effects of natural selection on neutral diversity. Emergence of a new agricultural host selected a highly specialized and fast-evolving pathogen with unique evolutionary patterns compared with its wild relatives. The strong impact of natural selection, we document, is at odds with the small effective population sizes estimated and suggest that population sizes were historically large but likely unstable.[Supplemental material is available for this article.]The ascomycete fungus Mycosphaerella graminicola is a major pathogen of wheat with a global distribution. M. graminicola originated in the Middle East ;11,000 yr ago from wild species infecting other grasses . Speciation was associated with adaptation to domesticated wheat and its associated agro-ecosystem. In a previous study, we characterized the two progenitor pathogen species Mycosphaerella S1 and Mycosphaerella S2 (hereafter called S1 and S2) endemic to the Middle East. S1 and S2 were isolated from three distantly related wild grass species: Elymus repens, Dactylis glomerata, and Lolium multiflorum. M. graminicola is mainly found on cultivated wheat but is able to infect other grass species (Seifbarghi et al. 2009). The recent divergence of M. graminicola, S1, and S2 implies that only a limited number of evolutionary changes are likely to have occurred. Here we use a population genomics approach to investigate the extent of genome divergence between M. graminicola, S1, and S2. We identify footprints of natural selection and study patterns of genome evolution. We compare the evolution of a pathogen species on a domesticated host with evolution on ''wild'' host species. In plants and animals, domestication is often associated with genome-wide increased rates of nonsynonymous mutations resulting from a rela...

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“…The pathogen is characterized by a mixed reproductive system, a large effective population size and substantial gene flow (Zhan & McDonald, 2004), providing significant potential for adaptation to both host resistance (Mundt et al, 1999;Mundt, 2002) and fungicides (Torriani et al, 2009a;Cools & Fraaije, 2013).…”

Section: Introductionmentioning

confidence: 99%

Emergence and early evolution of fungicide resistance in North American populations of Zymoseptoria tritici

et al. 2015

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Although fungicide resistance in crop pathogens is a global threat to food production, surprisingly little is known about the evolutionary processes associated with the emergence and spread of fungicide resistance. Early stages in the evolution of fungicide resistance were evaluated using the wheat pathogen Zymoseptoria tritici, taking advantage of an isolate collection spanning 20 years in Oregon, USA, and including two sites with differing intensity of fungicide use. Sequences of the mitochondrial cytb protein conferring single-mutation resistance to QoI fungicides and the nuclear CYP51 gene implicated in multiple-mutation resistance to azole fungicides were analysed. Mutations associated with resistance to both fungicides were absent in the 1992 isolates, but frequent in the 2012 collection, with higher frequencies of resistance alleles found at the field site with more intensive fungicide use. Results suggest that the QoI resistance evolved independently in several lineages, and resulted in significant mitochondrial genome bottlenecks. In contrast, the CYP51 gene showed signatures of diversifying selection and intragenic recombination among three phylogenetic clades. The findings support a recent emergence of resistance to the two fungicide classes in Oregon, facilitated by selection for mutations in the associated resistance genes.

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The interaction among evolutionary forces in the pathogenic fungus Mycosphaerella graminicola

Cited by 76 publications

References 52 publications

Mycosphaerella and Teratosphaeria diseases of Eucalyptus; easily confused and with serious consequences

Mycosphaerella and Teratosphaeria diseases of Eucalyptus; easily confused and with serious consequences

The making of a new pathogen: Insights from comparative population genomics of the domesticated wheat pathogenMycosphaerella graminicolaand its wild sister species

Emergence and early evolution of fungicide resistance in North American populations of Zymoseptoria tritici

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