Morphology and molecular phylogeny reveal new species and records of Diaporthales from Betula in Xinjiang, China

Xinjiang Uygur Autonomous Region (XUAR), located in the arid hinterland of northwest China, serves as important substrates for Betula species. As the most widely distributed floral genus of Betulaceae in Xinjiang, Betula serves as a vital pioneer species due to its stress tolerance and adaptation to extreme environments, playing an irreplaceable role in sustaining regional ecosystems. During disease surveys on Betula trees in the Tianshan and Altai Mountains of Xinjiang, we observed symptoms of stem and branch cankers.

A total of 37 fungal strains were isolated and identified, based on morphological characteristics and phylogenetic analyses. As a result, Cytospora altayensis sp. nov. was proposed and Coryneum lanciforme, Cryptosporella betulae, Cr. tomentella, Cy. tanaitica and Melanconis groenlandica are reported for the first time in China. In addition, Cytospora sophoriopsis is recorded for the first time on the host genus Betula.

This study identifies potential pathogenic fungi associated with Betula, providing a foundation for future disease management and forest health research.