Limtong Savitree, Srisuk Nantana, Yongmanitchai Wichien, Yurimoto Hiroya, Nakase Takashi
Department of Microbiology, Faculty of Science, Kasetsart University, 50 Paholyothin Road, Bangkok 10900, Thailand.
Int J Syst Evol Microbiol. 2008 Jan;58(Pt 1):302-7. doi: 10.1099/ijs.0.65380-0.
Two thermotolerant, methylotrophic yeast strains, PT44(T) and S051(T), were respectively isolated from a tree exudate and soil collected in Thailand. They were categorized as thermotolerant strains on the basis of their good growth below 20 degrees C and up to a relatively high temperature (37 degrees C). The major characteristics of the two strains that place them in the genus Ogataea are the formation of four helmet- or hat-shaped ascospores in a deliquescent ascus that may be produced parthenogenetically or by conjugation between a cell and its bud or between independent cells; multilateral budding; assimilation of nitrate; the presence of ubiquinone Q7; negative for Diazonium blue B colour and urease reactions; and the absence of arthroconidia and ballistoconidia. Analysis of the D1/D2 domains of the large-subunit rDNA sequence revealed that strain PT44(T) was differentiated from the strain S051(T) by 25 nucleotide substitutions and 1 gap in 554 nt, which was sufficient to justify the description of two separate species. The closest recognized species in terms of pairwise sequences similarity to PT44(T) was Pichia (Ogataea) dorogensis, with 13 nucleotide substitutions and 1 gap in 554 nt. Strain S051(T) was closest to Pichia thermomethanolica, with 7 nucleotide substitutions in 566 nt. Phenotypic characteristics of strains PT44(T) and S051(T) allowed them to be differentiated from each other and from the closest related species. On the basis of the above finding, the two strains represent two novel species of the genus Ogataea, for which the names Ogataea chonburiensis sp. nov. (type strain PT44(T) =BCC 21227(T) =NBRC 101965(T) =CBS 10363(T)) and Ogataea nakhonphanomensis sp. nov. (type strain S051(T) =BCC 21228(T) =NBRC 101966(T) =CBS 10362(T)) are proposed. We also propose the transfer of two thermotolerant methylotrophic members of the genus Pichia described previously to the genus Ogataea: Pichia siamensis is renamed Ogataea siamensis (Limtong, Srisuk, Yongmanitchai, Kawasaki, Yurimoto, Nakase & Kato) Limtong, Srisuk, Yongmanitchai, Yurimoto & Nakase comb. nov. (type strain JCM 12264(T) =TISTR 5818(T)) and Pichia thermomethanolica is renamed Ogataea thermomethanolica (Limtong, Srisuk, Yongmanitchai, Yurimoto, Nakase & Kato) Limtong, Srisuk, Yongmanitchai, Yurimoto & Nakase comb. nov. (type strain CBS 10098(T) =JCM 12984(T) =BCC 16875(T)).
从泰国采集的树液和土壤中分别分离出两株耐热甲基营养型酵母菌株PT44(T)和S051(T)。根据它们在20℃以下直至相对较高温度（37℃）下生长良好的特性，将它们归类为耐热菌株。这两株菌株被归入Ogataea属的主要特征包括：在可能通过孤雌生殖产生或通过细胞与其芽体之间或独立细胞之间结合而形成的消解子囊中形成四个头盔状或帽状子囊孢子；多边芽殖；硝酸盐同化；存在泛醌Q7；重氮蓝B颜色反应和脲酶反应呈阴性；以及不存在节孢子和掷孢子。对大亚基rDNA序列的D1/D2结构域分析表明，菌株PT44(T)与菌株S051(T)在554个核苷酸中有25个核苷酸替换和1个缺口，这足以说明可描述为两个不同的物种。就成对序列相似性而言，与PT44(T)最接近的已识别物种是多罗格毕赤酵母（Ogataea），在554个核苷酸中有13个核苷酸替换和1个缺口。菌株S051(T)最接近嗜热甲醇毕赤酵母，在566个核苷酸中有7个核苷酸替换。菌株PT44(T)和S051(T)的表型特征使它们能够相互区分，也能与最接近的相关物种区分开来。基于上述发现，这两株菌株代表了Ogataea属的两个新物种，为此提出了新名称：春武里Ogataea（Ogataea chonburiensis）新种（模式菌株PT44(T)=BCC 21227(T)=NBRC 101965(T)=CBS 10363(T)）和那空拍侬Ogataea（Ogataea nakhonphanomensis）新种（模式菌株S051(T)=BCC 21228(T)=NBRC 101966(T)=CBS 10362(T)）。我们还提议将先前描述的毕赤酵母属的两个耐热甲基营养型成员转移到Ogataea属：暹罗毕赤酵母更名为暹罗Ogataea（Ogataea siamensis）（Limtong, Srisuk, Yongmanitchai, Kawasaki, Yurimoto, Nakase & Kato）Limtong, Srisuk, Yongmanitchai, Yurimoto & Nakase组合新名（模式菌株JCM 12264(T)=TISTR 5818(T)），嗜热甲醇毕赤酵母更名为嗜热甲醇Ogataea（Ogataea thermomethanolica）（Limtong, Srisuk, Yongmanitchai, Yurimoto, Nakase & Kato）Limtong, Srisuk, Yongmanitchai, Yurimoto & Nakase组合新名（模式菌株CBS 10098(T)=JCM 12984(T)=BCC 16875(T)）。
