Exploration of the Inconspicuous Xylarialean Fungal Flora (Xylariomycetidae) in Northern Thailand
Milan C. Samarakoon1*, Kevin D. Hyde2, Saisamorn Lumyong3, 4, 5
1Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand
2Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
3Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
4Center of Excellence in Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
5Academy of Science, The Royal Society of Thailand, Bangkok 10300, Thailand
Deviation from conventional fungal niches for exploring hidden fungal diversity is an aspect to consider when estimating global fungal numbers and their consequences for estimations of diversity. The Xylariomycetidae (Sordariomycetes: Ascomycota; referred to as xylarialean taxa) includes species that vary greatly in their stromatic characteristics, either in conspicuous or inconspicuous forms. Since 2017, our research has focused on the taxonomy, phylogeny, evolution, and secondary metabolites of xylarialean taxa in northern Thailand. In the provinces of Chiang Mai, Chiang Rai, Lampang, Nan, Phayao, and Phrae, we have introduced 20 new species and five new genera (Magnostiolata, Melanostictus, Neoamphisphaeria, Nigropunctata, and Paravamsapriya) until 2022. The majority of novel species were discovered between July and September (during the rainy season) on the substrates of senescent plants or attached to hosts in less disturbed locations. In our recent investigations, we have discovered more than 15 inconspicuous xylarialean fungal flora, considering time, geography, and substrates. Five of them are described as new species, i.e., Xenoanthostomella parvispora (Gyrotrichaceae), Muscodor brunneascosporus, M. lamphunensis (Xylariaceae), Nigropunctata lamphunensis, and N. saccata (Incertae sedis), based on ITS-LSU-rpb2-tub2 multigene phylogeny and morphology. Senescence or plant substrates that are attached to the host serve as potential sampling sites to focus on the collection of unidentified and hidden, inconspicuous xylarialean taxa. The endophytic mode during the dry season may be related to the emergence of saprobic forms during the rainy season. Therefore, it would be worthwhile to concentrate future research on the impact of seasonal fluctuations on nutritional mode changes. Furthermore, numerous endophytic isolate sequences that resemble inconspicuous xylarialeans are available in public databases and are required for the linking of endophytic and saprobic modes.