A Game of Russian Roulette for a Generalist Dinoflagellate Parasitoid: Host Susceptibility Is the Key to Success.
A Game of Russian Roulette for a Generalist Dinoflagellate Parasitoid: Host Susceptibility Is the Key to Success.
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DOI：
10.3389/fmicb.2016.00769
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发表时间：
2016
影响因子：
5.2
通讯作者：
Garcés E
中科院分区：
文献类型：
--
作者：
Alacid E;Park MG;Turon M;Petrou K;Garcés E
海洋微生物与真核生物及其寄生虫的相互作用在浮游植物群落结构的形成中起着重要作用。这些相互作用可能会改变主要宿主的种群密度，这反过来又可能对其他共存物种产生影响。通性寄生蜂对群落的影响很大程度上取决于寄主特异性的程度。小萤光虫（Parvilucifera sinensis）是一种多面手寄生蜂，能侵染多种甲藻，包括毒水华形成种。密度依赖性化学线索已被确定为激活感染阶段的触发器。这些特性使Parvilucifera甲藻主机一个很好的模型来调查的程度的特异性的一个通才寄生虫，和潜在的影响，它可以在社区水平上。在这里，我们提出的第一次，一个多面手甲藻寄生虫的策略，寻找它的主机，并确定它是否表现出主机的喜好，突出在确定感染的关键因素。我们的研究结果表明，在其感染阶段，中华疟原虫能够感知潜在的宿主，但不会主动选择它们。相反，寄生蜂随机接触宿主，由遭遇概率率决定，一旦遭遇，穿透宿主细胞内部并发展感染的机会强烈取决于宿主易感性的程度。因此，他们的持久性策略更像是俄罗斯轮盘赌游戏，生存的机会取决于宿主的易感性。我们的研究确定P. sinavirata作为一个潜在的关键球员在社区生态学，在混合甲藻群落组成的主机是非常容易感染，寄生虫的偏好可能会调解宿主物种之间的共存，降低优势的上级竞争对手。或者，它可能会增加竞争，导致物种排斥。然而，如果高度敏感的主机是缺席的社会，寄生虫种群可能会遭受稀释效应维持较低的寄生虫密度。因此，宿主群落结构和宿主易感性将决定田间的感染性。
Marine microbial interactions involving eukaryotes and their parasites play an important role in shaping the structure of phytoplankton communities. These interactions may alter population densities of the main host, which in turn may have consequences for the other concurrent species. The effect generalist parasitoids exert on a community is strongly dependent on the degree of host specificity. Parvilucifera sinerae is a generalist parasitoid able to infect a wide range of dinoflagellates, including toxic-bloom-forming species. A density-dependent chemical cue has been identified as the trigger for the activation of the infective stage. Together these traits make Parvilucifera-dinoflagellate hosts a good model to investigate the degree of specificity of a generalist parasitoid, and the potential effects that it could have at the community level. Here, we present for the first time, the strategy by which a generalist dinoflagellate parasitoid seeks out its host and determine whether it exhibits host preferences, highlighting key factors in determining infection. Our results demonstrate that in its infective stage, P. sinerae is able to sense potential hosts, but does not actively select among them. Instead, the parasitoids contact the host at random, governed by the encounter probability rate and once encountered, the chance to penetrate inside the host cell and develop the infection strongly depends on the degree of host susceptibility. As such, their strategy for persistence is more of a game of Russian roulette, where the chance of survival is dependent on the susceptibility of the host. Our study identifies P. sinerae as a potential key player in community ecology, where in mixed dinoflagellate communities consisting of hosts that are highly susceptible to infection, parasitoid preferences may mediate coexistence between host species, reducing the dominance of the superior competitor. Alternatively, it may increase competition, leading to species exclusion. If, however, highly susceptible hosts are absent from the community, the parasitoid population could suffer a dilution effect maintaining a lower parasitoid density. Therefore, both host community structure and host susceptibility will determine infectivity in the field.