Comparing phenotypic plasticity in bacterial prey traits and ecological consequences by using specialist vs. generalist strains and organic aggregates as model systems

通过使用专业菌株和通才菌株和有机聚集体作为模型系统，比较细菌猎物特征的表型可塑性和生态后果

• 批准号: 257346203
• 负责人: Professor Dr. Hans-Peter Grossart
• 金额: --
• 依托单位: Abteilung 3: Plankton- und mikrobielle Ökologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/257346203?language=en
• 关键词: Comparing; phenotypic; plasticity; bacterial; prey

Changes in bacterial cell size, microcolony formation and attachment to particle/aggregate surfaces can be regarded as key traits of aquatic bacteria to counteract protozoan grazing and changes in environmental conditions, e.g. the availability of nutrients and organic matter. Thereby, specialist with a low phenotypic plasticity (non-plastic, either free or surface attached) can be distinguished from generalists with a high phenotypic plasticity (plastic, switching between free and surface-attached life stages). Trait plasticity can be induced (phenotypic plasticity; generalists) or inherited (rapid evolution; specialists). Theoretically changes of specialists with a low phenotypic plasticity (either free or attached) lead to pronounced predator-prey cycles, whereas generalists with a high phenotypic plasticity dampens these oscillations and hence stabilize the system. Models predict that generalists are favored by fluctuations in environmental parameters, e.g. ecosystem disturbances, but that their stabilizing effect leads to a preference of specialists. Yet, such differences in bacterial lifestyle have not been taken into account when experimentally analyzing predator-prey interactions and dynamics. Our proposal addresses the core question of DynaTrait, i.e. by which mechanisms the existing trait variation at the prey/predator levels influences the dynamics at both trophic levels, which then feeds back on the maintenance of trait variation. We will combine experimental and modelling enterprises to examine the (combined) effects of rapid evolution and phenotypic plasticity of antipredatory defense on predator-prey dynamics in chemostats. Instead of using only one predator with high phenotypic plasticity, we will use 2 predators with a narrow plasticity (a predator grazing free bacteria and a second predator feeding on surface-attached bacteria).Our work focus on the different bacterial lifestyles and hence physiological traits of specialist and generalist prey bacteria. We propose that generalist prey dampens predator prey cycles and thus stabilize the system. Stable environmental conditions should lead to dominance of non-plastic specialist prey (small trait range), whereas changing environments should favor plastic generalist prey (high trait range). Phenotypically plastic prey thus determines coexistence of 2 different specialist predators and changes in specialist to generalist bacteria ratio affect organic matter cycling efficiency and ecosystem functioning. The tight inter-linkage of chemostat experiments and modeling enterprises allows us to elucidating ecological and evolutionary patterns for generalization of interactions between microorganisms. In a second step we aim to link these patterns to organic matter cycling in the system. Thus we will use the trait based approach to better define to which extent phenotypic plasticity on the microorganism level feeds back to biodiversity and ecosystem function.

细菌细胞大小，微菌落形成和粒子/聚集体表面的附着的变化被视为水生细菌的关键特征，以抵消原生动物​​放牧和环境条件的变化，例如营养和有机物的可用性。因此，可以将具有较低表型可塑性（非塑料，自由或表面附着的非塑性）的专家与具有高表型可塑性（塑料，自由和表面连接的生活阶段切换）的通才区分开。可以诱导特质可塑性（表型可塑性；通才）或遗传（快速进化；专家）。从理论上讲，专家的表型可塑性（自由或附着）的变化导致明显的捕食者弹性周期，而具有较高表型可塑性的通才会抑制这些振荡，从而稳定系统。模型预测，通才受到环境参数的波动的青睐，例如生态系统障碍，但它们的稳定效应会导致专家的偏好。然而，在实验分析捕食者 - 挑战相互作用和动态时，尚未考虑细菌生活方式的这种差异。我们的提议解决了Dynatrait的核心问题，即通过哪种机制来捕食/捕食者水平的现有性状变化影响两个营养水平的动态，然后以性状变化的维持反馈。我们将结合实验性和建模企业，以检查抗逆转防御对化学稳定剂中捕食者 - 纯化动力学的快速进化和表型可塑性的（组合）影响。我们将不使用一个具有高表型可塑性的捕食者，而是使用2种具有狭窄塑性的捕食者（捕食者放牧的游离细菌和第二个以表面附着的细菌为食）。我们的工作专注于不同的细菌生活方式，因此，专门的和普通的宠物的生理特征。我们提出，通才猎物会抑制捕食者捕食循环，从而稳定系统。稳定的环境条件应导致非塑料专家猎物（小特质范围）的主导地位，而不断变化的环境应有利于塑料通用猎物（高性状范围）。因此，表型塑料猎物决定了2种不同的专业捕食者的共存，并且专家与通才细菌比率的变化会影响有机物循环效率和生态系统功能。化学稳定实验和建模企业的紧密联系使我们能够阐明生态和进化模式，以概括微生物之间的相互作用。在第二步中，我们旨在将这些模式与系统中的有机物循环联系起来。因此，我们将使用基于性状的方法来更好地定义微生物水平上表型可塑性在多大程度上回馈生物多样性和生态系统功能。