Morphology and phylogeny of ascomycetes associated with walnut trees (Juglans regia) in Sichuan province, China

In Sichuan province, walnuts, consisting of Juglans regia, Juglans sigillata, and the hybrid J. regia x J. sigillata, are commercially important edible nuts, and J. regia is the most widespread plant. To date, the diversity and distribution of fungi inhabiting on Juglans have not received enough attention, although there have been studies focusing on pathogens from fruit and stem. In order to update the checklist of fungi associated with Sichuan walnuts, a survey on fungi associated with the three Juglans species from 15 representative regions in Sichuan was conducted. In this article, ten fungi distributed in two classes of Ascomycota (Dothideomycetes and Sordariomycetes) were described based on morpho-molecular analyses, and two novel species, Neofusicoccum sichuanense and Sphaerulina juglandina, a known species of Ophiognomonia leptostyla, and seven new hosts or geographical records of Cladosporium tenuissimum, Diatrypella vulgaris, Helminthosporium juglandinum, Helminthosporium velutinum, Loculosulcatispora hongheensis, Periconia byssoides, and Rhytidhysteron subrufulum were included. Morphological descriptions and illustrations of these fungi are provided.

Automated summary

This study investigated the fungi associated with three walnut species in Sichuan province and identified ten fungi, including two new species. The findings contribute to updating the checklist of fungi associated with Sichuan walnuts and provide important insights.