Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0202, USA.
ISME J. 2013 Jun;7(6):1139-49. doi: 10.1038/ismej.2012.175. Epub 2013 Jan 24.
Highly variable regions called genomic islands are found in the genomes of marine picocyanobacteria, and have been predicted to be involved in niche adaptation and the ecological success of these microbes. These picocyanobacteria are typically highly sensitive to copper stress and thus, increased copper tolerance could confer a selective advantage under some conditions seen in the marine environment. Through targeted gene inactivation of genomic island genes that were known to be upregulated in response to copper stress in Synechococcus sp. strain CC9311, we found two genes (sync_1495 and sync_1217) conferred tolerance to both methyl viologen and copper stress in culture. The prevalence of one gene, sync_1495, was then investigated in natural samples, and had a predictable temporal variability in abundance at a coastal monitoring site with higher abundance in winter months. Together, this shows that genomic island genes can confer an adaptive advantage to specific stresses in marine Synechococcus, and may help structure their population diversity.
高度可变区域称为基因组岛，在海洋蓝藻的基因组中被发现，并且已经预测它们参与了小生境适应和这些微生物的生态成功。这些海洋蓝藻通常对铜胁迫高度敏感，因此，在海洋环境中某些条件下，增加铜耐受性可能会带来选择性优势。通过对已知在铜胁迫下在聚球藻 sp. 菌株 CC9311 中上调的基因组岛基因进行靶向基因失活，我们发现两个基因（sync_1495 和 sync_1217）在培养物中赋予了对甲基紫精和铜胁迫的耐受性。然后在自然样本中调查了一个基因 sync_1495 的流行程度，在一个沿海监测点，其丰度具有可预测的时间变异性，冬季月份的丰度更高。总之，这表明基因组岛基因可以赋予海洋聚球藻特定胁迫的适应性优势，并可能有助于构建它们的种群多样性。
