Heterocyte glycolipids indicate polyphyly of stigonematalean cyanobacteria
Heterocyte glycolipids indicate polyphyly of stigonematalean cyanobacteria
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DOI：
10.1016/j.phytochem.2019.112059
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发表时间：
2019-10-01
期刊：
影响因子：
3.8
通讯作者：
Schwark, Lorenz
中科院分区：
文献类型：
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作者：
Bauersachs, Thorsten;Miller, Scott R.;Schwark, Lorenz
蓝藻门目前分为五个亚门（I-V），后两个亚门包含无分支或假分支（nostocalean）和真分支（stigonematalean）蓝藻。虽然形态特征（如细胞分裂和二级分支）明确区分两种类型的异细胞蓝藻，分子证据表明，stigonematalean蓝藻（第五小节）不形成一个单系群，而是穿插和嵌套在nostocalean蓝藻（第四小节）。为了进一步解决异细胞蓝藻的发生，我们在这里分析了异细胞糖脂（HG）的分布在真正的分支蓝藻Stigonema ocellatum SAG 48.90（模式属的亚组V），并将其与其他stigonematalean和nostocalean蓝藻HG库存。S. ocellatum SAG 48.90为1-（O-己糖）-27-酮基-3，25-二十八烷二醇（HG（28）酮二醇）和1-（O-己糖）-3，25，27-二十八烷三醇（HG（28）三醇），它们共同构成了约200个氨基酸。94%的HGS。此外，1-（O-己糖）-3-酮基-27-二十八烷醇（HG（28）酮醇）、1-（O-己糖）-3，27-二十八烷二醇（HG（28）二醇）、1-（O-己糖）-3-酮基-27，29-三十烷醇（HG（38）酮二醇）和1-（O-己糖）-3，27，29-三十烷三醇（HG（30）三醇）以少量存在。以前报道的stigonematalean蓝细菌特有的杂细胞糖脂，即1-（O-己糖）-3，29，31-三十二烷三醇（HG（32）triols）和1-（O-己糖）-3-酮基-29，31-三十二烷二醇（HG（32）keto-diols），在S. ocellatum SAG 48.90.通过与其他异细胞蓝藻的分布模式比较，表明该藻是一种典型的蓝藻。ocellatum SAG 48.90与念珠藻科Rivulariaceae和Scytonemataceae的亲缘关系最近，与重建的16 S rRNA基因序列互补。因此，我们的HG为基础的数据提供了证据stigonematalean蓝藻的多系性，独立于分子方法，并指出需要一个关键的重新评估目前的分类异细胞蓝藻。
The cyanobacterial phylum is currently divided into five subsections (I-V), with the latter two containing no or false-branching (nostocalean) and true-branching (stigonematalean) cyanobacteria. Although morphological traits (such as cellular division and secondary branches) clearly separate both types of heterocytous cyanobacteria, molecular evidence indicates that stigonematalean cyanobacteria (Subsection V) do not form a monophyletic group but instead are interspersed and nested within the nostocalean cyanobacteria (Subsection IV). To further resolve the phylogeny of heterocytous cyanobacteria, we here analyzed the distribution of heterocyte glycolipids (HGs) in the true-branching cyanobacterium Stigonema ocellatum SAG 48.90 (type genus of Subsection V) and compared it with the HG inventory of other stigonematalean and nostocalean cyanobacteria. The most dominant HGs in S. ocellatum SAG 48.90 were 1-(O-hexose)-27-keto-3,25-octacosanediol (HG(28 )ketodiol) and 1-(O-hexose)-3,25,27-octacosanetriol (HG(28 ) triol), which together constituted ca. 94% of all HGs. In addition, 1-(O-hexose)-3-keto-27-octacosanols (HG(28 ) keto-ols), 1-(O-hexose)-3,27-octacosanediols (HG(28 ) dios), 1-(O-hexose)-3-keto-27,29-triacontanediol (HG(38) keto-diol) and 1-(O-hexose)-3,27,29-triacontanetriol (HG(30) triol) occurred in minor abundances. Heterocyte glycolipids previously reported to be unique for stigonematalean cyanobacteria, i.e. 1-(O-hexose)-3,29,31-dotriacontanetriols (HG(32) triols) and 1-(O-hexose)-3-keto-29,31-dotriacontanediols (HG(32) keto-diols), were not detected in S. ocellatum SAG 48.90. Comparison of the HG distribution pattern with those of other heterocytous cyanobacteria indicated that S. ocellatum SAG 48.90 is most closely related to the nostocalean families Rivulariaceae and Scytonemataceae, which is complementary to reconstructed 16S rRNA gene sequence phylogenies. Our HG-based data thus provides evidence for the polyphyly of stigonematalean cyanobacteria, independent from molecular approaches, and points to the need for a critical re-evaluation of the current taxonomy of heterocytous cyanobacteria.