Fusarium and allied genera from cropland in Xizang, China

The Qinghai-Xizang Plateau is a globally renowned biodiversity epicentre which plays an important role in maintaining the ecological health of China and the Asian region. Understanding the distribution of phytopathogenic fungi in the major agricultural zones of Qinghai-Xizang Plateau is crucial for the agricultural management of major crops (e.g., highland barley) in the region. The genus Fusarium and its relatives in the family Nectriaceae (Ascomycota, Hypocreales) encompass a diverse array of species with pathogenic and ecological significance, but previous studies to the region have been very limited. This study aims to investigate the diversity and distribution of species belonging to Fusarium and allied genera in Xizang. A hitherto most intensive collection of diseased crops and samples of sediments, soils, and water from adjacent environments of cropland was carried out at 56 sites in Xizang, resulting in the isolation of 916 strains of fusarioid fungi. Using the FUSARIUM-ID v.3.0 and the FUSARIOID-ID databases, these strains were preliminarily classified into six genera: Cosmospora (4 strains), Fusarium (867 strains), Fusicolla (17 strains), Neocosmospora (21 strains), Neonectria (1 strain), and Thelonectria (6 strains). The representative strains were then subjected to multi-locus phylogenetic analyses, resulting in the identification of 46 species, including 17 new species described in this study and 8 new records for China. Our results provided preliminary insights into the species diversity and distribution of Fusarium and related genera in the Xizang region, and also suggested that cropland, including crop material, as well as neighboring ploughed and irrigated environments constitute a major reservoir for fungal pathogens.