Phylogeny And Renaming Of Cryptococcus Podzolicus And Related Strains

Objective: 1. To compare and analyze the stability and reliability of multilocus sequence typing(MLST) and Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry(MALDI-TOF-MS) methods in phylogeny of Cryptococcus. 2. To varify the recent taxonomic positions of Cryptococcus podzolicus and related strains proposed by F.Y. Bai and T. Boekhout. 3. To describe and rename four relevant novel strains by comprehensive phylogenic methods. Methods: 1.Twenty strains including Cryptococcus podzolicus and its adjacent strains were selected for the evaluation in this study; DNA was extracted and 5 genes(ITS,D1/D2,rpb1,rpb2,tef1) were amplified and sequenced. The phylogenetic tree was constructed by Bayesian, maximum parsimony and neighbor-joining analyses. The protein fingerprint acquisition parameters were collected by MALDI-TOF-MS method. 2. Both the results in this study and those of F.Y. Bai and T.Boekhout were compared and analyzed. 3. The comprehensively phylogenic analyses of four strains isolated from India were processed. Results: 1. Three clusters can be observed in the phylogenetic trees made by different molecular methods; all Cryptococcus podzolicus strains were classified into Cluster A, in which there was no apparent taxonomic diversity for the strains in the phylogenetic tree constructed by D1/D2, while the evolution distances among Cryptococcus podzolicus strains were easily identified by both MLST and MALDI-TOF-MS methods. 2. The taxonomic positions of studied type strains were correlated with those proposed in Bai’s report, and the strains’ scientific names were corrected according to the latest nomenclature proposal by Bai correspondingly. 3. Morphological, physiological, and chemotaxonomic characteristics supported these four strains to be placed into the genus Saitozyma.Conclusion: 1. Compared to physiological and biochemical characteritics and D1/D2 phylogenetic analysis, MLST and MALDI-TOF-MS methods can be more effectivefor identification and classification of Cryptococcus species. Moreover,MALDI-TOF-MS method is more efficient and accurate than other methods discussed in this study. 2. The accuracy and rationality of the taxonomic and nomenclative proposal suggested by F.Y. Bai and T. Boekhout is confirmed. 3. We propose to accommodate strains GP-26 = IFM 56699, VPCI 1367-A1, VPCI 1367-B1, and VPCI1367-C1 as a novel species, Saitozyma cassiae sp. nov.