UPMC-Université Paris 06, Station Biologique, 29682 Roscoff cedex, France.
Ann Rev Mar Sci. 2010;2:305-31. doi: 10.1146/annurev-marine-120308-081034.
Prochlorococcus is the key phytoplanktonic organism of tropical gyres, large ocean regions that are depleted of the essential macronutrients needed for photosynthesis and cell growth. This cyanobacterium has adapted itself to oligotrophy by minimizing the resources necessary for life through a drastic reduction of cell and genome sizes. This rarely observed strategy in free-living organisms has conferred on Prochlorococcus a considerable advantage over other phototrophs, including its closest relative Synechococcus, for life in this vast yet little variable ecosystem. However, this strategy seems to reach its limits in the upper layer of the S Pacific gyre, the most oligotrophic region of the world ocean. By losing some important genes and/or functions during evolution, Prochlorococcus has seemingly become dependent on co-occurring microorganisms. In this review, we present some of the recent advances in the ecology, biology, and evolution of Prochlorococcus, which because of its ecological importance and tiny genome is rapidly imposing itself as a model organism in environmental microbiology.
聚球藻是热带环流系统中关键的浮游植物生物，该海洋区域缺乏光合作用和细胞生长所需的基本大量营养素。这种蓝细菌通过极大地减少细胞和基因组的大小，将生命所必需的资源最小化，从而使自身适应贫营养环境。这种在自由生活的生物体中很少观察到的策略，使聚球藻在这个广阔而变化不大的生态系统中，与其他光合生物（包括其最亲近的亲缘种——聚球藻）相比具有相当大的优势。然而，这种策略在南太平洋环流系统的上层似乎已经达到了极限，该区域是世界海洋中最贫营养化的区域。通过在进化过程中丢失一些重要的基因和/或功能，聚球藻似乎已经变得依赖于共生微生物。在这篇综述中，我们介绍了聚球藻的生态学、生物学和进化方面的一些最新进展，由于其生态重要性和微小的基因组，聚球藻正在迅速成为环境微生物学中的一种模式生物。
