Molecular and phenotypic characterization of a VGII genotype Cryptococcus gattii XH91 isolated in China

Abstract:

Abstract: [Objective] To characterize the molecular and phenotypic traits of the VGII genotype of Cryptococcus gattii isolate XH91 firstly isolated in China. [Methods] The serotype was identified by molecular method; multi-locus sequence typing (MLST) was performed based on 16 gene fragments both of nuclear and mitochondria genomes; the abilities of haploid fruiting, same-sex mating and opposite sex mating were all evaluated; the phenotypic traits including melanin production, capsule size, and growth at 37℃ were characterized. [Results] The isolate XH91 firstly isolated in China was serotype B. The isolate shared the same MLST genotype with the minor outbreak genotype VGIIb from Vancouver islands. Strain XH91 could mate with the reference strain of opposite mating type and produced basidiospores, but could not mate with the reference strain of same mating type and had no ability of haploid fruiting. We did not observe obvious difference between XH91 and reference strains for melanin production, capsule size, and growth at 37℃. [Conclusion] Based on the results from MLST and phenotypic analysis, the Cryptococcus gattii strain XH91 is identical with the minor outbreak genotype VGIIb from Vancouver islands. This study will be critical to gain further insight into the emergence and molecular epidemiology of the VGII genotype of Cryptococcus gattii from China.

Key words:Keywords: Cryptococcus gattii; genotype; sequence analysis; mating; phenotype