Abstract: Objective To sequence the intergenic sequence region 1 （IGS1） of 5 clinical isolates of Trichosporon asahii, and to analyze intraspecies polymorphism of IGS1 gene in T. asahii isolates. Methods Nuclear DNA was extracted from the 5 isolates of T. asahii by using a method of glass pearls. IGS1and internal transcribed spacer region （ITS） were amplified using specific primers by PCR. The products of IGS1 were cloned and sequenced using the ABI377 nucleotide sequenator. The resulted sequence of IGS1 was blasted against Genbank and aligned with CLUSTAL X 1.83 software. The restricted fragment length polymorphism （RFLP） analysis of IGS1 was performed using restricted endonucleases HapⅡ, MboⅠ, HhaⅠand AluⅠ. Results PCR yielded amplicons of ITS and IGS1 genes at the expected sizes of 540 bp and 643 bp, respectively, from all T. asahii isolates, with the sequence homology of IGS1 being 98% - 99% among the isolates. All isolates shared common RFLP profile after digestion of IGS1 amplicons with endonuclease MboⅠor AluⅠ, whereas the HapⅡ digestion profile of strain BZP07003 and HhaⅠdigestion profile of strain BZP07004 were distinct from that of other isolates. Conclusions HhaⅠand HapⅡ can be used to analyse the intraspecies polymorphism of T. asahii. Three RFLP profiles were achieved from these 5 T. asahii isolates by digestion with HhaⅠ and HapⅡ, suggesting that there is an intraspecies polymorphism and genetic heterogeneity within clinical isolates of T. asahii.

Key words: Trichosporon asahii, IGS1, Clone, RFLP