Researchers have discovered
sixteen new species of fungus living unnoticed inside garden and wild flowers across northern Thailand, more than quintupling the number of such fungi known to occur in the country.
The fungi belong to Aureobasidium, a genus of dark, yeast-like organisms found almost everywhere on Earth, from human skin to glacial ice. Several members of the group are already prized in industry for producing useful enzymes, fighting plant disease and even breaking down plastic. Yet despite their familiarity, little was known about the diversity within Thailand's tropical flowers.
Researchers from
Chiang Mai University and
Kasetsart University collected 54 fungal strains from 31 species of flower during a 2024 survey, among them bougainvillea, butter daisy, and periwinkle. Using a combination of DNA analysis across five gene regions, microscopy and growth trials, the team distinguished sixteen entirely new species, alongside five already known species (four of which had never before been recorded in Thailand).
“Our team was motivated to study Aureobasidium because it was one of the most frequently isolated fungal genera from our flower samples,” said Professor Nakarin Suwannarach of Chiang Mai University. “We observed considerable variation among the isolates in colony morphology and other phenotypic characteristics, which suggested that there might be much greater species diversity than previously recognised.”
Distinguishing the new species was far from straightforward. Many looked almost identical under the microscope, and the DNA markers usually relied upon proved unable to tell them apart. “This highlighted the limitations of relying on morphology alone, as well as on commonly used molecular markers,” Professor Suwannarach explained. “By integrating multiple loci with morphological, physiological and growth-temperature data, we were able to distinguish closely related species more accurately. This was particularly surprising because Aureobasidium is a well-known fungal genus, yet our results revealed substantial previously unrecognised diversity in Thailand.”
Most of the new species take their names from the flowers in which they were found, including Aureobasidium bougainvilleae, A. catharanthi and A. plumeriae, while others honour the northern Thai locations where they were collected. Two species, A. saisamorniae and A. savitreeae, were named in tribute to two of Thailand's leading mycologists, Professor Saisamorn Lumyong and Professor Savitree Limtong. “We wanted the names to tell a story, either about where these fungi came from or about the people who have helped advance mycological research in Thailand,” said Professor Suwannarach.
Beyond the taxonomy, the team says the findings matter for the future. A small number of Aureobasidium species have been linked to opportunistic infections, so having an accurate record of which species occur naturally will help scientists spot and respond to any change in their behaviour over time. "This study demonstrates that multilocus phylogenetic analysis is not simply a tool for naming new species," Professor Suwannarach added. "It can reveal hidden fungal diversity and provide essential baseline information for understanding and monitoring fungal populations in the future."