Generation and utilization of chemical-resistant mutants in <i>Pyrenophora tritici-repentis</i>, the causal agent of tan spot of wheat

McCallum, Brent D.; Bernier, C. C.; Lamari, L.

doi:10.1139/b94-014

Cited by 4 publications

(1 citation statement)

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“…Although Ptr is a homothallic fungus, outcrossing (heterothallic capability) of differentially marked antibiotic-resistant isolates in the laboratory has been shown to occur at low frequency (L. Ciuffetti and J. Gaventa, unpublished data; McCallum et al 1994); however, the extent of outcrossing that occurs in nature remains unknown. In the absence of outcrossing, nuclear transfer could take place through hyphal fusion (data not shown) or conidial anastomosis (Figure 4).…”

Section: Resultsmentioning

confidence: 99%

Comparative Genomics of a Plant-Pathogenic Fungus,Pyrenophora tritici-repentis, Reveals Transduplication and the Impact of Repeat Elements on Pathogenicity and Population Divergence

Manning

Pandelova

Dhillon

et al. 2013

G3 Genes|Genomes|Genetics

155

146

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Pyrenophora tritici-repentis is a necrotrophic fungus causal to the disease tan spot of wheat, whose contribution to crop loss has increased significantly during the last few decades. Pathogenicity by this fungus is attributed to the production of host-selective toxins (HST), which are recognized by their host in a genotype-specific manner. To better understand the mechanisms that have led to the increase in disease incidence related to this pathogen, we sequenced the genomes of three P. tritici-repentis isolates. A pathogenic isolate that produces two known HSTs was used to assemble a reference nuclear genome of approximately 40 Mb composed of 11 chromosomes that encode 12,141 predicted genes. Comparison of the reference genome with those of a pathogenic isolate that produces a third HST, and a nonpathogenic isolate, showed the nonpathogen genome to be more diverged than those of the two pathogens. Examination of gene-coding regions has provided candidate pathogen-specific proteins and revealed gene families that may play a role in a necrotrophic lifestyle. Analysis of transposable elements suggests that their presence in the genome of pathogenic isolates contributes to the creation of novel genes, effector diversification, possible horizontal gene transfer events, identified copy number variation, and the first example of transduplication by DNA transposable elements in fungi. Overall, comparative analysis of these genomes provides evidence that pathogenicity in this species arose through an influx of transposable elements, which created a genetically flexible landscape that can easily respond to environmental changes.

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Section: Resultsmentioning

confidence: 99%