Astorga-Eló Marcia, Ramírez-Flandes Salvador, DeLong Edward F, Ulloa Osvaldo
1] Departamento de Oceanografía and Instituto Milenio de Oceanografía, Universidad de Concepción, Concepción, Chile [2] Programa de Magíster en Bioquímica y Bioinformática, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
1] Departamento de Oceanografía and Instituto Milenio de Oceanografía, Universidad de Concepción, Concepción, Chile [2] Programa de Doctorado en Ingeniería de Sistemas Complejos, Universidad Adolfo Ibáñez, Santiago, Chile.
ISME J. 2015 May;9(5):1264-7. doi: 10.1038/ismej.2015.21. Epub 2015 Feb 20.
Cyanobacteria of the genus Prochlorococcus are the most abundant photosynthetic marine organisms and key factors in the global carbon cycle. The understanding of their distribution and ecological importance in oligotrophic tropical and subtropical waters, and their differentiation into distinct ecotypes, is based on genetic and physiological information from several isolates. Currently, all available Prochlorococcus genomes show their incapacity for nitrate utilization. However, environmental sequence data suggest that some uncultivated lineages may have acquired this capacity. Here we report that uncultivated low-light-adapted Prochlorococcus from the nutrient-rich, low-light, anoxic marine zone (AMZ) of the eastern tropical South Pacific have the genetic potential for nitrate uptake and assimilation. All genes involved in this trait were found syntenic with those present in marine Synechococcus. Genomic and phylogenetic analyses also suggest that these genes have not been aquired recently, but perhaps were retained from a common ancestor, highlighting the basal characteristics of the AMZ lineages within Prochlorococcus.
原绿球藻属的蓝细菌是最丰富的光合海洋生物，也是全球碳循环的关键因素。对它们在贫营养的热带和亚热带水域中的分布、生态重要性以及分化为不同生态型的理解，是基于来自多个分离株的遗传和生理信息。目前，所有可用的原绿球藻基因组都显示它们无法利用硝酸盐。然而，环境序列数据表明，一些未培养的谱系可能已经获得了这种能力。在此我们报告，来自东热带南太平洋营养丰富、低光照、缺氧海洋区域（AMZ）的未培养的适应低光照的原绿球藻具有吸收和同化硝酸盐的遗传潜力。与该性状相关的所有基因都与海洋聚球藻中的基因同线排列。基因组和系统发育分析还表明，这些基因并非最近获得，而是可能从共同祖先那里保留下来的，这突出了原绿球藻中AMZ谱系的基础特征。
