Biogeographical note on Antarctic microflorae: Endemism and cosmopolitanism
Biogeographical note on Antarctic microflorae: Endemism and cosmopolitanism
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DOI：
10.1016/j.gsf.2012.11.002
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发表时间：
2013-11
影响因子：
8.9
通讯作者：
W. Jadoon;R. Nakai;T. Naganuma
中科院分区：
文献类型：
--
作者：
W. Jadoon;R. Nakai;T. Naganuma
本文研究了南极微生物区系（南极是研究微生物区系的最佳模式）的地理分布，如蓝细菌和选择的嗜盐菌，特别强调变异盐单胞菌和地衣芽孢杆菌。已知嗜盐菌不仅能抵抗盐胁迫，还能抵抗极端温度、压力和干旱，它们能够在极地、深海栖息地和沙漠等恶劣环境中生存。已知许多微生物对恶劣的环境条件具有抵抗力，并且能够在恶劣的环境中存活。本课题组已从世界各地不同环境中分离到嗜盐菌28属444株。16 S rRNA基因序列分析表明，许多来自不同地理环境的分离菌株之间亲缘关系很近，有些菌株的16 S rRNA基因序列完全相同。具有诸如孢子形成等生存机制的生物通常是普遍存在的。盐单胞菌属以潜在的地方性菌株和普遍存在的变异盐单胞菌为代表，而孢子形成的地衣芽孢杆菌则呈世界性分布。东南极洲的Syowa站和西南极洲的Mario Zucchelli站报告了一种潜在的地方性（中度地方性，即区域和/或大陆分布）菌株，这两个站在地理上相隔3000 km。与地衣芽孢杆菌相似性为100%的15个菌株被认为是世界分布的。本研究结果支持了一些微生物具有中度地方性而另一些微生物具有世界性分布的中间模式。这些结果将有助于更好地了解微生物地理学，特别是南极洲。
This study deals with the biogeography of Antarctic microflora (Antarctica acts as best model to study microbial biogeography) such as cyanobacteria and selected halophiles with special emphasis onHalomonas variabilisandBacillus licheniformis. Halophiles are known to be resistant not only to salt stress, but also to extreme temperature, pressure, and aridity and they are capable of surviving in harsh environments such as polar regions, deep-sea habitats, and deserts. Many microbes are known to be resistant to hostile environmental conditions, and are capable of surviving in harsh environments. Our group has isolated 444 strains belonging to 28 genera of halophiles from various environments around the world. The 16S rRNA gene sequences revealed that many of the isolated strains from geographically distant habitats having different environmental conditions, were closely related to each other, with some strains possessing 100% identical sequences. Organisms possessing survival mechanism such as spore formation are usually ubiquitous. The genusHalomonasis represented by potentially endemic strains and the ubiquitousH. variabilis, while spore-formingB. licheniformisshowed cosmopolitan distribution. One potentially endemic (moderate endemicity that is regional and/or continental distribution) strain was reported from Syowa station, East Antarctica, and Mario Zucchelli station, West Antarctica, which are geographically separated by 3000 km. Moreover, 15 strains having 100% similarity withB. licheniformiswere considered cosmopolitans. The results of this work provide support for the middle-ground model that some microbes have moderate endemicity and others have cosmopolitan distribution. These results will contribute to a greater understanding of microbial biogeography with special emphasis on Antarctica.