Ecosystem-dependent adaptive radiations of picocyanobacteria inferred from 16S rRNA and ITS-1 sequence analysis
Ecosystem-dependent adaptive radiations of picocyanobacteria inferred from 16S rRNA and ITS-1 sequence analysis
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DOI：
10.1099/mic.0.25475-0
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发表时间：
2003-01-01
期刊：
影响因子：
2.8
通讯作者：
Postius, C
中科院分区：
文献类型：
--
作者：
Ernst, A;Becker, S;Postius, C
以藻红蛋白或藻蓝蛋白为主要辅助色素的小球型和棒状聚藻球菌型蓝藻从几个大的温带湖泊和咸淡波罗的海分离出来。picocyanobacteria有两个核糖体操纵子，其中一个长内部转录间隔子（ITS-1）将16S rDNA和23S rDNA分开。基于16S rrna的系统发育分析将所有分离物归为浮游植物支系[sensu Urbach， E., Scanlan， D. J., Distel， D. L., Waterbury， J. B. & Chisholm， S. W.(1998)]。[J] .中华微生物学杂志，1999,18(1):1 -2,2 - 3。4-100% 16S rRNA序列鉴定。通过对ITS-1序列的分析，推断出5个对应的菌株簇。ITS-1的序列分化在最分化的23%和系统发育最保守的1%之间变化。ITS-1序列散度较低的聚类菌株通常来自同一地区的单一生态系统或水文特征相似的湖泊。它们代表了生理上不同的物种生态型，在其他表型变异中，它们的主要辅助色素，藻胆蛋白经常不同。不同谱系中色素性状的繁殖与16S rRNA或ITS-1序列推断的系统发育差异无关，而似乎与菌株分离的生态系统和栖息地特征有关。在不同的谱系和生态系统中出现的可比较的表型谱表明，不同的菌株群在独立的适应性辐射中发展出相似的生态型。
Small, coccoid and rod-shaped Synechococcus-type cyanobacteria with either phycoerythrin or phycocyanin as major accessory pigments were isolated from several large, temperate-zone lakes and the brackish Baltic Sea. The picocyanobacteria had two ribosomal operons with a long internal transcribed spacer (ITS-1) separating the 16S rDNA and 23S rDNA. A 16S rRNA-based phylogenetic analysis assigned all isolates to the picophytoplankton clade [sensu Urbach, E., Scanlan, D. J., Distel, D. L., Waterbury, J. B. & Chisholm, S. W. (11998). J Mol Evol 46, 188-201], which also comprises marine Synechococcus spp. and Prochlorococcus spp. The strains assorted to five paraphyletic clusters each containing two or more strains with 99(.)4-100% 16S rRNA sequence identity. Five corresponding strain clusters were deduced from analysis of ITS-1 sequences. Sequence divergence in ITS-1 varied between 23% in the most divergent and 1% in the phylogenetically most conserved cluster. Clustered strains with low sequence divergence in ITS-1 were frequently isolated from a single ecosystem or hydrographically comparable lakes in the same region. They represent physiologically distinct ecotypes of species which, among other phenotypic variations, frequently differed in their major accessory pigments, the phycobiliproteins. The reproduction of the various pigment traits in different lineages was not correlated with the phylogenetic divergence deduced from 16S rRNA or ITS-1 sequences but rather seemed to be related to characteristics of the ecosystem and habitat from which the strains were isolated. The occurrence of a comparable spectrum of phenotypes in different lineages and ecosystems indicates that different strain clusters developed similar ecotypes during independent adaptive radiations.