Beisser Daniela, Bock Christina, Hahn Martin W, Vos Matthijs, Sures Bernd, Rahmann Sven, Boenigk Jens
Biodiversity, University of Duisburg-Essen, Essen, Germany.
Research Institute for Limnology, University of Innsbruck, Mondsee, Austria.
Front Microbiol. 2019 Jul 9;10:1498. doi: 10.3389/fmicb.2019.01498. eCollection 2019.
We studied the impact of protist grazing and exudation on the growth and transcriptomic response of the prokaryotic prey species . Different single- and multi-species communities of chrysophytes were used to determine a species-specific response to the predators and the effect of chrysophyte diversity. We sequenced the mRNA of in communities with three single chrysophyte species ( and ) and all combinations. The molecular responses of significantly changed in the presence of predators with different trophic modes and combinations of species. In the single-species samples we observed significant differences related to the relative importance of grazing and exudation in the protist-bacteria interaction, i.e., to the presence of either the heterotrophic or the mixotrophic . When grazing dominates the interaction, as in the presence of , genes acting in stress response are up-regulated. Further genes associated with transcription and translation are down-regulated indicating a reduced growth of . In contrast, when the potential use of algal exudates dominates the interaction, genes affiliated with iron transport are up-regulated. Rapid phototrophic growth of chrysophytes, with a high demand on soluble iron, could thus lead to iron-limitation and cause changes in the iron metabolism of . Additionally, we observe a benefit for from a more diverse protistan community, which could be due to shifts in the relative importance of phototrophy in the mixotrophic chrysophytes when competing for food with other species. Our study highlights the importance of biotic interactions and the specificity of such interactions, in particular the differential effect of grazing and algal exudation in the interaction of bacteria with mixotrophic protists.
我们研究了原生生物捕食和分泌物对原核猎物物种生长和转录组反应的影响。使用不同的金藻单物种和多物种群落来确定对捕食者的物种特异性反应以及金藻多样性的影响。我们对具有三种金藻单物种（和）及其所有组合的群落中的mRNA进行了测序。在存在不同营养模式和物种组合的捕食者的情况下，的分子反应发生了显著变化。在单物种样本中，我们观察到与原生生物 - 细菌相互作用中捕食和分泌物的相对重要性相关的显著差异，即与异养的或混合营养的的存在有关。当捕食在相互作用中占主导时，如在存在的情况下，参与应激反应的基因上调。进一步与转录和翻译相关的基因下调，表明的生长减少。相反，当藻类分泌物的潜在利用在相互作用中占主导时，与铁运输相关的基因上调。金藻快速的光合生长对可溶性铁有很高的需求，因此可能导致铁限制并引起的铁代谢变化。此外，我们观察到来自更多样化的原生生物群落对有好处，这可能是由于混合营养金藻在与其他物种竞争食物时光合作用相对重要性的转变。我们的研究强调了生物相互作用的重要性以及这种相互作用的特异性，特别是在细菌与混合营养原生生物相互作用中捕食和藻类分泌物的不同影响。
