Coello-Camba Alexandra, Diaz-Rua Ruben, Duarte Carlos M, Irigoien Xabier, Pearman John K, Alam Intikhab S, Agusti Susana
Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
AZTI - Marine Research, Pasaia, Spain.
Front Microbiol. 2020 Jun 3;11:1153. doi: 10.3389/fmicb.2020.01153. eCollection 2020.
and are pico-sized cyanobacteria that play a fundamental role in oceanic primary production, being particularly important in warm, nutrient-poor waters. Their potential response to nutrient enrichment is expected to be contrasting and to differ from larger phytoplankton species. Here, we used a metagenomic approach to characterize the responses to nutrient enrichment in the community of picocyanobacteria and to analyze the cyanophage response during a mesocosms experiment in the oligotrophic Red Sea. Natural picoplankton community was dominated by clade II, with marginal presence of (0.3% bacterial reads). Increased nutrient input triggered a fast bloom, with clade II being the dominant, with no response of growth. The largest bloom developed in the mesocosms receiving a single initial input of nutrients, instead of daily additions. The relative abundances of cyanophage sequences in cellular metagenomes increased during the experiment from 12.6% of total virus reads up to 40% in the treatment with the largest bloom. The subsequent collapse of the bloom pointed to a cyanophage infection on that reduced its competitive capacity, and was then followed by a diatom bloom. The cyanophage attack appears to have preferentially affected the most abundant clade II, increasing the evenness within the host population. Our results highlight the relevance of host-phage interactions on determining population dynamics and diversity of populations.
[具体名称1]和[具体名称2]是超微型蓝细菌，在海洋初级生产中发挥着重要作用，在温暖、营养贫乏的水域中尤为重要。预计它们对营养物质富集的反应会有所不同，且与较大的浮游植物种类不同。在这里，我们采用宏基因组学方法来描述超微型蓝细菌群落对营养物质富集的反应，并在贫营养的红海进行的中尺度实验中分析蓝噬菌体的反应。天然微微型浮游生物群落以[具体名称1]进化枝II为主，[具体名称2]的存在较少（细菌读数的0.3%）。增加营养输入引发了[具体名称1]的快速大量繁殖，进化枝II占主导地位，[具体名称2]的生长没有反应。最大的水华出现在接受单次初始营养输入而非每日添加营养的中尺度实验装置中。在实验过程中，细胞宏基因组中蓝噬菌体序列的相对丰度从病毒读数总数的12.6%增加到在[具体名称1]大量繁殖最大的处理组中的40%。随后水华的崩溃表明[具体名称1]受到蓝噬菌体感染，其竞争能力下降，随后是硅藻水华。蓝噬菌体攻击似乎优先影响了最丰富的[具体名称1]进化枝II，增加了宿主种群内的均匀度。我们的结果强调了宿主 - 噬菌体相互作用在决定[具体名称1]种群动态和多样性方面的相关性。
