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Pyrenophora Species Associated with Barley and Wheat in Japan

Summary

Scientists in Japan discovered that wheat and barley plants showing yellow spot disease were infected by a different fungus than previously thought. Using genetic testing, they found that isolates labeled as Pyrenophora tritici-repentis were actually Pyrenophora trichostoma. This discovery is important because it means scientists need to update their understanding of which fungi cause this crop disease in Japan and worldwide.

Background

Pyrenophora species are fungal pathogens that cause significant disease on barley and wheat worldwide. Pyrenophora tritici-repentis has long been recognized as the causal agent of yellow spot disease in wheat in Japan. However, preliminary molecular data suggested the involvement of additional Pyrenophora species.

Objective

To clarify the species diversity and phylogenetic relationships of Pyrenophora species on Poaceae plants in Japan using multi-locus molecular analysis. The study aimed to confirm the identification of fungi causing yellow spot disease observed in wheat fields converted from rice paddies in Mie, Japan.

Results

All examined Japanese isolates previously labeled as Pyrenophora tritici-repentis were identified as Pyrenophora trichostoma. Japanese isolates shared a toxin-producing gene (ToxA24 haplotype). Several Japanese isolates required taxonomic label corrections, indicating greater Pyrenophora diversity than previously reported in Japan.

Conclusion

The study reveals greater diversity of Pyrenophora species in Japan than previously recognized, with Pyrenophora trichostoma being the actual causal agent of yellow spot disease rather than P. tritici-repentis. These findings highlight the need to revise the taxonomy of Pyrenophora species worldwide, particularly regarding differentiation between P. tritici-repentis and P. trichostoma on wheat and barley.
  • Published in:Mycobiology,
  • Study Type:Molecular Phylogenetic Study,
  • Source: 10.1080/12298093.2025.2604407, PMID: 41509588
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