淡水球状绿藻一新种——汾河麦可藻  

Mychonastes fenhensis sp.nov.:A Novel Species of Freshwater Coccoid Green Algae

作　　者：李艳晖[1] 张瑶 李砧[1] LI Yanhui;ZHANG Yao;LI Zhen(Taiyuan Normal University,Jinzhong Shanxi 030619,China)

机构地区：[1]太原师范学院,山西晋中030619

出　　处：《西北植物学报》2023年第5期867-876,共10页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金项目(51709197);山西省基础研究计划项目(自由探索类)(20210302124302);太原师范学院研究生教育创新项目(SYYJSJC-2163)。

摘　　要：麦可属(Mychonastes)是一种分布广泛的超微型球状绿藻,是微藻能源生产、水质净化方面的潜力藻种。该研究对采自山西省太原市汾河公园的水样分离得到的一株球状绿藻(FHGY-19)进行藻株形态显微观察,并进行18S rDNA系统发育与ITS2二级结构分析鉴定,以明确FHGY-19的分类位置以及生态利用潜力。结果表明:(1)FHGY-19藻株为单细胞,球形,直径1.5~2.5μm,无黏质被膜,杯状叶绿体1个,周生,不具蛋白核,以2~4个似亲孢子进行繁殖,常见2个似亲孢子包被于母细胞壁内。(2)18S rDNA系统发育分析表明,藻株FHGY-19位于麦可属分支内部,与麦可属内的其他成员共同形成环藻目内一独立的单系分支,且FHGY-19与麦可属分支中的Mychonastes sp.5C3和Mychonastes sp.2C1亲缘关系较近,表明藻株FHGY-19为麦可属一成员。(3)ITS2 rDNA系统发育分析表明,FHGY-19与同是单细胞类型的Mychonastes frigidus、同球麦可藻(M.homosphaera)、M.pusillus、M.rotundus和M.ovahimbae聚为一支,且FHGY-19与5个藻种在ITS2二级结构上的总CBCs(碱基补偿替换)和保守区域HelixⅢ上的CBCs数分别为16个/7个、13个/6个、12个/4个、11个/4个和14个/5个,但藻株FHGY-19与系统发育树另一支的6个物种在ITS2序列长度、二级结构中总CBCs及HelixⅢ上的CBCs数均不同,表明FHGY-19的ITS2二级结构不同于已描述的11个种,为麦可属一新种。研究鉴定确认FHGY-19藻株为麦可属一新种,命名为汾河麦可藻(Mychonastes fenhensis sp.nov.)。FHGY-19藻株保存于太原师范学院淡水藻种库。The genus Mychonastes is a coccoid green picoalgae with wide distribution,also as potential species in energy production and water purification.In this study,a strain(numbered FHGY-19)of coccoid green alga,which isolated from water samples collected from the Fenhe Park,Taiyuan City,Shanxi Province,was observed by microscopic morphology.18S rDNA phylogeny and ITS2 secondary structure analysis were also performed to identify the taxonomic position and ecological utilization potential of FHGY-19.The results showed that:(1)cells of the algal strain FHGY-19 are solitary,spherical with a diameter of 1.5-2.5μm,without mucilaginous envelope,a parietal,cup-shaped chloroplast without pyrenoid,asexual reproduction by two or four autospores,and usually two autospores are wrapped in the mother cell wall.(2)Phylogenetic analysis of 18S rDNA showed that the algal strain FHGY-19 was located in the clade of the genus Mychonastes and formed an independent monophyletic clade of Sphaeropleales together with other members of the genus Mychonastes,and FHGY-19 was closely related to Mychonastes sp.5C3 and Mychonastes sp.2C1.The results indicated that FHGY-19 was a member of the genus Mychonastes.(3)Phylogenetic analysis of ITS2 rDNA showed that FHGY-19 formed a clade with unicellular Mychonastes frigidus,M.homosphaera,M.pusillus,M.rotundus,and M.ovahimbae,total CBCs(compensatory base changes)between FHGY-19 and these five species on ITS2 secondary structure and the number of CBCs on the conservative region HelixⅢwere 16/7,13/6,12/4,11/4 and 14/5,respectively.However,the length of ITS2 sequences,the total CBCs on secondary structure and the number of CBCs on HelixⅢwere different between FHGY-19 and 6 species from another branch of phylogenetic tree,indicated that the ITS2 secondary structure of FHGY-19 was different from that of 11 described species,and it was a new species of the genus Mychonastes.FHGY-19 was identified as a new species of the genus Mychonastes,named Mychonastes fenhensis sp.nov.The strain FHGY-19 was preserved at

关 键 词：球状绿藻 汾河麦可藻 系统发育 ITS2二级结构 CBCs 

分 类 号：Q949.21[生物学—植物学]