Lichens are a well-known symbiosis between a host mycobiont and eukaryote algal or cyanobacterial photobiont partner(s). Recent studies have indicated that terrestrial lichens can also contain other cryptic photobionts that increase the lichens’ ecological fitness in response to varying environmental conditions. Marine lichens live in distinct ecosystems compared with their terrestrial counterparts because of regular submersion in seawater and are much less studied. We performed bacteria 16S and eukaryote 18S rRNA gene metabarcoding surveys to assess total photobiont diversity within the marine lichen Lichina pygmaea (Lightf.) C. Agardh, which is widespread throughout the intertidal zone of Atlantic coastlines. We found that in addition to the established cyanobacterial photobiont Rivularia, L. pygmaea is also apparently host to a range of other marine and freshwater cyanobacteria, as well as marine eukaryote algae in the family Ulvophyceae (Chlorophyta). We propose that symbiosis with multiple freshwater and marine cyanobacteria and eukaryote photobionts may contribute to the ability of L. pygmaea to survive the harsh fluctuating environmental conditions of the intertidal zone.

中文翻译：

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海洋地衣Lichina pygmaea中的复杂光生物多样性

地衣是宿主真菌生物和真核生物藻类或蓝细菌光生物伙伴之间众所周知的共生关系。最近的研究表明，陆地地衣还可以包含其他神秘的光生物，这些光生物可以增加地衣的生态适应度以响应不同的环境条件。与陆地对应物相比，海洋地衣生活在不同的生态系统中，因为它们经常浸没在海水中，而且研究较少。我们进行了细菌 16S 和真核生物 18S rRNA 基因元条形码调查，以评估海洋地衣内的总光生物多样性地榆(Lightf.) C. Agardh，广泛分布于大西洋海岸线的潮间带。我们发现，除了已建立的蓝藻光生物河豚,L. pygmaea显然也是一系列其他海洋和淡水蓝藻的宿主，以及 Ulvophyceae (Chlorophyta) 中的海洋真核藻类。我们提出与多种淡水和海洋蓝细菌以及真核生物光生物的共生可能有助于L. pygmaea在潮间带恶劣的波动环境条件下生存。