Adaptations to photoautotrophy associated with seasonal ice cover in a large lake revealed by metatranscriptome analysis of a winter diatom bloom
Adaptations to photoautotrophy associated with seasonal ice cover in a large lake revealed by metatranscriptome analysis of a winter diatom bloom
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DOI：
10.1016/j.jglr.2016.07.025
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发表时间：
2016-10-01
影响因子：
2.2
通讯作者：
McKay, R. M. L.
中科院分区：
文献类型：
--
作者：
Edgar, R. E.;Morris, P. F.;McKay, R. M. L.
人们越来越认识到，冬季是冰雪覆盖的淡水环境中光合自养生物生长的重要季节。伊利湖冰下大量丝状硅藻就是一个例证。在这里，我们描述了一个metatranscriptome从浮游植物群落占主导地位的丝状硅藻。如预期的，在国家生物技术信息中心数据库中与核苷酸或蛋白质具有BLAST命中的高百分比（>73%）的序列与光合藻类相关，其中大多数是硅藻，主要是Aulacoseira spp.和冠盘藻属（Stephanodiscus spp.）通过18 S rRNA基因转录本分析和显微镜检查证实了这一点。与冬季生长环境相一致，观察到嗜冷和弱光适应。在对寒冷的适应中，最突出的是参与不饱和脂肪酸生物合成的基因的转录本，这与预期的低温下膜流动性增加是一致的。反映低冬季日照和高光衰减的组合效应的是捕光天线的读取的丰富补充，主要是编码岩藻黄素叶绿素a/c蛋白的基因。来自卵菌的毒力因子的存在为伊利湖冬季硅藻水华最终衰退的新假设提供了支持。尽管真菌通过元转录组和显微镜鉴定，但检测到真菌的dsRNA病毒，其可间接对抗真菌感染。这项研究证明了环境组学方法的实用性，以产生潜在的光养生命以及整个微生物群落在极端环境中的相互作用的见解。(C)2016年国际五大湖研究协会。Elsevier B. V.出版，保留所有权利。
There is growing recognition that winter is an important season for growth of photoautotrophs in ice-covered freshwater environments. Exemplifying this are expansive under-ice blooms of filamentous diatoms in Lake Erie. Here we describe a metatranscriptome constructed from a phytoplankton community dominated by filamentous diatoms. As expected, a high percentage (>73%) of the sequences with BLAST hits to nucleotides or proteins in National Center for Biotechnology Information databases were associated with photosynthetic algae of which the majority were diatoms, mainly Aulacoseira spp. and Stephanodiscus spp. which was confirmed by analysis of 18S rRNA gene transcripts and microscopy. Consistent with the winter growth environment, psychrophilic and low light adaptations were observed. Prominent among adaptations to cold were transcripts for genes involved in biosynthesis of unsaturated fatty acids, which were consistent with expected increased membrane fluidity at low temperatures. Reflecting the combined effect of low winter insolation and high light attenuation were an abundant complement of reads for light-harvesting antennae, mainly genes encoding fucoxanthin chlorophyll a/c proteins. The presence of virulence factors originating from oomycetes offers support for new hypotheses into the eventual decline of Lake Erie's winter diatom bloom. Whereas fungi were identified both through the metatranscriptome and by microscopy, dsRNA viruses of fungi were detected that may indirectly counter against fungal infection. This study demonstrates the utility of an environmental omics approach to yield insights underlying phototrophic life as well as the interactions of the entire microbial community in an extreme environment. (C) 2016 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.