Veterinary Medical Research Institute, P.O. Box 18, Budapest, 1143, Hungary.
Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Budapest, 1143, Hungary.
Mycopathologia. 2022 Aug;187(4):333-343. doi: 10.1007/s11046-022-00640-x. Epub 2022 Jun 11.
Revealing the phylogenetic relationships of Candida krusei strains (sexual form Pichia kudriavzevii) is a prerequisite for understanding the evolution of its virulence-associated mechanisms and ecological lifestyles. Molecular phylogenetic analyses based on entire internal transcribed spacer region (ITS) and multilocus sequence typing (MLST) data were carried out with sequences available in public databases and Hungarian isolates from animals obtained for the study. The ITS haplotype network yielded a high frequency haplotype at the centre of the network (H1; n = 204) indicating that various selective pressure might resulted in population expansion from H1. MLST analysis identified three new genotypes among animal-derived isolates, therefore overall 203 sequence types were investigated to determine the population structure of C. krusei. The most commonly encountered sequence types were ST 17 and ST 67. Phylogenetic analyses showed diverse genetic construction of C. krusei population. Evidence of potential recombination events were also observed that might play some role in high intraspecies genetic variability among strains, however, the limited data of C. krusei genotypes from different countries prevented us to identify accurate evolutionary routes of commensal and pathogenic strains or species-specific lineages. Further expansion of C. krusei MLST database may promote the better understanding of the mixed evolutionary history of this species.
揭示克鲁氏假丝酵母（毕赤酵母的有性形式）菌株的系统发育关系是理解其毒力相关机制和生态生活方式进化的前提。本研究基于公共数据库中可用的序列和从动物中获得的匈牙利分离株，进行了基于整个内部转录间隔区（ITS）和多位点序列分型（MLST）数据的分子系统发育分析。ITS 单倍型网络在网络中心产生了一个高频单倍型（H1；n=204），表明各种选择压力可能导致 H1 从种群中扩张。MLST 分析在动物来源的分离株中鉴定出三种新的基因型，因此总共研究了 203 种序列类型，以确定克鲁氏假丝酵母的种群结构。最常见的序列类型是 ST17 和 ST67。系统发育分析显示克鲁氏假丝酵母种群具有多样化的遗传结构。还观察到潜在重组事件的证据，这些证据可能在菌株间的高种内遗传变异性中发挥作用，然而，来自不同国家的克鲁氏假丝酵母基因型的有限数据阻止了我们确定共生和病原菌株或种特异性谱系的准确进化途径。进一步扩展克鲁氏假丝酵母 MLST 数据库可能有助于更好地理解该物种的混合进化历史。
