Taxonomy and biological properties of Ascomycota on Bidens pilosa and Chromolaena odorata in Northern Thailand with a global checklist

Abstract

Bidens pilosa and Chromolaena odorata are widespread weeds in Asteraceae, recognized as invasive species in many regions worldwide. Comparative research on fungal diversity across Asteraceae weeds remain limited, with only a few studies conducted on the diversity of saprobic fungi on these weeds. Further research is necessary to discover the potential ecological or biotechnological benefits of these taxa. In this study, saprobic fungi collected from Bidens pilosa and Chromolaena odorata in northern Thailand comprises 44 species, distributed across 30 genera, 20 families, and six orders within Dothideomycetes and Sordariomycetes. Among them, 17 species are identified as novel (Albifimbria bidentis, Austropleospora chromolaenae, Bahusandhika bidentis, Dothiorella asteracearum, D. chromolaenae, Diaporthe asteracearum, D. chromolaenicola, Forliomyces bidentis, Fusarium bidentis, F. chromolaenae, Kalmusia thailandica, Pseudothyridariella asteracearum, Ps. thailandica, Pseudolophiostoma chromolaenae, Pseudoneoconiothyrium chromolaenae, Pseudo. thailandicum, Sarocladium bidentis). In addition, 20 new host records (Acrocalymma pterocarpi, Bahusandhika indica, Colletotrichum gigasporum, C. truncatum, Diaporthe biconispora, Dictyocheirospora nabanheensis, Dendryphion hydei, Fusarium hainanense, Lasiodiplodia henanica, L. theobromae, Leptospora thailandica, Montagnula chromolaenae, Neodendryphiella mali, Neoroussoella entadae, Periconia byssoides, Pseudopithomyces chartarum, Remotididymella anthropophila, R. fici-microcarpae, Torula canangae, and T. mackenziei) are documented. The species boundaries were delineated based on morphology and multi-gene phylogenetic approaches. Additionally, the preliminary assays revealed antibacterial activity in 36 species against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus, highlighting their biotechnological potential. Furthermore, a global checklist documented 76 fungal taxa on Bidens pilosa and 161 fungal taxa on Chromolaena odorata, highlighting their roles as reservoirs of fungal diversity. This study expands the taxonomic and ecological understanding of microfungi associated with invasive Asteraceae weeds in Thailand and the host-fungal relationships in a global context by encouraging future mycological and ecological research efforts.