Cyanobacteria Affect Fitness and Genetic Structure of Experimental Daphnia Populations
Cyanobacteria Affect Fitness and Genetic Structure of Experimental Daphnia Populations
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DOI：
10.1021/acs.est.5b05973
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发表时间：
2016-04-05
影响因子：
11.4
通讯作者：
Pomati, Francesco
中科院分区：
文献类型：
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作者：
Druga, Bogdan;Turko, Patrick;Pomati, Francesco
浮游动物群落可能受到蓝藻水华的强烈影响，特别是水蚤属物种，它们是湖泊生态系统中的关键物种。在这里，我们探讨了产生微囊藻毒素/非微囊藻毒素（MC/non-MC）的蓝藻对由八种基因型组成的实验性帽状水蚤种群的饮食的影响。我们使用从 10 至 60 岁的 ephippia 孵化的 D. galeata 克隆，首先在单一培养物中进行测试，然后作为混合群体暴露于由绿藻与能够/不能产生 MC 的蓝细菌组合组成的三种食物处理中 10 周。我们测量了可能与水蚤适应蓝细菌有关的 9 个基因的表达：6 个蛋白酶基因、1 个泛素结合酶基因和 2 个 rRNA 基因，然后我们跟踪了混合群体中基因型的动态。一种蛋白酶和泛素结合酶基因的表达模式与蓝藻存在下竞争克隆的适应性增加呈正相关，表明其具有生理可塑性。混合群体中的基因型动态仅部分与单一栽培中克隆的生长速率相关，并且随食物变化很大。我们的结果揭示了 D. galeata 克隆对其饮食中产生 MC/不产生 MC 的蓝藻的耐受性存在强烈的种内差异，这表明微进化效应。
Zooplankton communities can be strongly affected by cyanobacterial blooms, especially species of genus Daphnia, which are key-species in lake ecosystems. Here, we explored the effect of microcystin/nonmicrocystin (MC/non-MC) producing cyanobacteria in the diet of experimental Daphnia galeata populations composed of eight genotypes. We used D. galeata clones hatched from ephippia 10 to 60 years old, which were first tested in monocultures, and then exposed for 10 weeks as mixed populations to three food treatments consisting of green algae combined with cyanobacteria able/unable of producing MC. We measured the expression of nine genes potentially involved in Daphnia acclimation to cyanobacteria: six protease genes, one ubiquitin-conjugating enzyme gene, and two rRNA genes, and then we tracked the dynamics of the genotypes in mixed populations. The expression pattern of one protease and the ubiquitin-conjugating enzyme genes was positively correlated with the increased fitness of competing clones in the presence of cyanobacteria, suggesting physiological plasticity. The genotype dynamics in mixed populations was only partially related to the growth rates of clones in monocultures and varied strongly with the food. Our results revealed strong intraspecific differences in the tolerance of D. galeata clones to MC/non-MC-producing cyanobacteria in their diet, suggesting microevolutionary effects.