Morphological and Physiological Features of Cryptococcus yokohamensis: A First Report from Eucalyptus Trees in Southern China

This study conducted a systematic investigation of fungal diversity in eucalyptus plantation areas in Guangxi, China. A total of 2000 environmental samples from eucalyptus forests were collected, leading to the isolation and identification of 28 yeast-like fungal species belonging to 20 genera. Several rare fungi were identified, including Cryptococcus yokohamensis , Syzygospora spp., Cryptotrichosporon brontae , Tremella basidiomaticola , and Colacogloea terpenoidalis . Notably, C.yokohamensis —a capsulated yeast-like fungus first reported in Japan—was successfully isolated in this study, with 30 strains obtained at an isolation rate of 1.5%. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis provided its characteristic mass spectral profile. Based on internal transcribed spacer (ITS) sequencing, two newly identified fungal sequences were found to exhibit 100% identity with the type strains JCM16990 and JCM16989, respectively. Phylogenetic analysis classified the strain within the genus Tremella . In vitro antifungal susceptibility testing revealed that the susceptibility profiles of these isolates closely aligned with the epidemiological cutoff values (ECVs) established for the Cryptococcus gattii species complex. This study represents the second global report and the first environmental isolation of C. yokohamensis from eucalyptus forests in China, following its initial description in Japan. These findings provide valuable data for research on fungal resources and assessment of potential pathogenic fungi distribution in eucalyptus plantation ecosystems in China.