Wohlrab Sylke, Tillmann Urban, Cembella Allan, John Uwe
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Section Ecological Chemistry, Bremerhaven, Germany.
ISME J. 2016 Nov;10(11):2658-2668. doi: 10.1038/ismej.2016.57. Epub 2016 Apr 19.
Populations of the toxigenic marine dinoflagellate Alexandrium are composed of multiple genotypes that display phenotypic variation for traits known to influence top-down processes, such as the ability to lyse co-occurring competitors and prospective grazers. We performed a detailed molecular analysis of species interactions to determine how different genotypes perceive and respond to other species. In a controlled laboratory culture study, we exposed two A. fundyense strains that differ in their capacity to produce lytic compounds to the dinoflagellate grazer Polykrikos kofoidii, and analyzed transcriptomic changes during this interaction. Approximately 5% of all analyzed genes were differentially expressed between the two Alexandrium strains under control conditions (without grazer presence) with fold-change differences that were proportionally higher than those observed in grazer treatments. Species interactions led to the genotype-specific expression of genes involved in endocytotic processes, cell cycle control and outer membrane properties, and signal transduction and gene expression regulatory processes followed similar patterns for both genotypes. The genotype-specific trait changes observed in this study exemplify the complex responses to chemically mediated species interactions within the plankton and their regulation at the gene level.
产毒海洋甲藻亚历山大藻的种群由多种基因型组成，这些基因型在影响自上而下过程的性状上表现出表型变异，例如裂解共生竞争者和潜在捕食者的能力。我们对物种间相互作用进行了详细的分子分析，以确定不同基因型如何感知并对其他物种作出反应。在一项受控的实验室培养研究中，我们将两种产生裂解化合物能力不同的A. fundyense菌株暴露于甲藻捕食者多环旋沟藻中，并分析了这种相互作用过程中的转录组变化。在对照条件下（无捕食者存在），两种亚历山大藻菌株之间约5%的所有分析基因存在差异表达，其倍数变化差异按比例高于在捕食者处理中观察到的差异。物种间相互作用导致参与内吞过程、细胞周期控制和外膜特性的基因出现基因型特异性表达，信号转导和基因表达调控过程在两种基因型中遵循相似模式。本研究中观察到的基因型特异性性状变化例证了浮游生物内对化学介导的物种间相互作用的复杂反应及其在基因水平上的调控。
