Temporal and spatial infection dynamics indicate recognition events in the early hours of a dinoflagellate/coral symbiosis
Temporal and spatial infection dynamics indicate recognition events in the early hours of a dinoflagellate/coral symbiosis
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DOI：
10.1007/s00227-006-0272-x
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发表时间：
2006-07-01
期刊：
影响因子：
2.4
通讯作者：
Weis, Virginia M.
中科院分区：
文献类型：
--
作者：
Rodriguez-Lanetty, Mauricio;Wood-Charlson, Elisha M.;Weis, Virginia M.
鞭毛藻、共生藻和造礁珊瑚之间的专性共生关系在每一代寄主中重新建立。独居珊瑚真菌scutaria Lamarck 1801在成年期含有一种单一的藻类菌株，共生菌ITS2型Clf（同源菌株）。先前的研究表明，C枝中不同的藻类ITS2类型在幼虫期共生开始时与F. scutaria-Symbiodinium特异性相关。本研究通过观察不同类型共生菌攻毒后黄褐飞虱幼虫与共生菌的侵染动态，探讨了黄褐飞虱幼虫与共生菌共生发生的早期特异性事件。结果表明，共生开始时的特异性是由吞噬前初始共生体-宿主物理接触期间的识别事件和共生体并入宿主细胞后的后续细胞事件介导的。此外，同源和异源共生菌在幼虫体内的定位模式不相同。当幼虫被同源共生体（Clf）感染时，在接种21 h后，在幼虫的口端和口端之间的赤道区发现了约70%的获得藻类。而异源共生体侵染后的幼虫在藻类定位上无空间差异。这一结果提供了幼虫发育过程中胃真皮细胞功能差异的证据。幼虫赤道的细胞具有营养吞噬细胞的功能，并且在黄鳞飞虱中似乎也是增强共生体获取的区域。
The obligate symbiotic relationship between dinoflagellates, Symbiodinium spp. and reef building corals is re-established each host generation. The solitary coral Fungia scutaria Lamarck 1801 harbors a single algal strain, Symbiodinium ITS2 type Clf (homologous strain) during adulthood. Previous studies have shown that distinct algal ITS2 types in clade C correlate with F. scutaria-Symbiodinium specificity during the onset of symbiosis in the larval stage. The present study examined the early specificity events in the onset of symbiosis between F. scutaria larvae and Symbiodinium spp., by looking at the temporal and spatial infection dynamics of larvae challenged with different symbiont types. The results show that specificity at the onset of symbiosis was mediated by recognition events during the initial symbiont-host physical contact before phagocytosis, and by subsequent cellular events after the symbionts were incorporated into host cells. Moreover, homologous and heterologous Symbiodinium sp. strains did not exhibit the same pattern of localization within larvae. When larvae were infected with homologous symbionts (Clf), similar to 70% of the total acquired algae were found in the equatorial area of the larvae, between the oral and aboral ends, 21 h after inoculation. In contrast, no spatial difference in algal localization was observed in larvae infected with heterologous symbionts. This result provides evidence of functional differences among gastrodermal cells, during development of the larvae. The cells in the larval equator function as nutritive phagocytes, and also appear to function as a region of enhanced symbiont acquisition in F. scutaria.