Response of two species of Indo-Pacific corals, Porites cylindrica and Stylophora pistillata, to short-term thermal stress: The host does matter in determining the tolerance of corals to bleaching
Response of two species of Indo-Pacific corals, Porites cylindrica and Stylophora pistillata, to short-term thermal stress: The host does matter in determining the tolerance of corals to bleaching
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DOI：
10.1016/j.jembe.2009.03.011
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发表时间：
2009-05-31
影响因子：
2
通讯作者：
Lesser, M. P.
中科院分区：
文献类型：
--
作者：
Fitt, W. K.;Gates, R. D.;Lesser, M. P.
研究了寄主和甲藻共生体在造礁珊瑚对光照下温度胁迫的反应中所起的作用。来自GBR的复制的海鞘和柱状珊瑚小块暴露在28摄氏度(对照组)或32摄氏度的环境中5天，然后返回到环境珊瑚礁温度(28摄氏度)。Pistillata含有共生菌C1型或C8a型，而圆柱藻的基因分型为C15型。对圆柱藻共生体的光系统II荧光量子产率的分析表明，C15共生体的光诱导激发压力显著低于C_1/C_8a共生体，中午的光系统II荧光的稳态量子产率(F/Fm‘)大于C_1/C_8a共生体。来自S.pistillata。受热胁迫后，雌蕊共生藻中PS II D1蛋白的免疫印迹显著低于柱状共生藻。实验前圆柱藻的热应激蛋白(HSP)70和超氧化物歧化酶(SOD)等生化标志物显著高于实验前，两种珊瑚在暴露于热胁迫时都增加了HSP 70和SOD的生物合成。在这些实验中，MAAs、甘油和脂类的浓度并没有受到热应激的显著影响，但与圆柱藻相比，热应激对DNA的损伤更大。珊瑚粘液最少，占珊瑚总能量收支的一半，为入侵的微生物提供第一层防御，与柱状螺旋藻相比，入侵微生物是在热胁迫后产生的。结果表明，圆柱藻含有一种耐热的C15共生菌，关键寄主蛋白的浓度高于雌蕊假单胞菌，它们的结合提供了更好的保护，使其免受高温光漂白条件的影响。(C)2009爱思唯尔B.V.保留所有权利。
The role of both host and dinoflagellate symbionts was investigated in the response of reef-building corals to thermal stress in the light. Replicate coral nubbins of Stylophora pistillata and Porites cylindrica from the GBR were exposed to either 28 degrees C (control) or 32 degrees C for 5 days before being returned to an ambient reef temperature (28 degrees C). S. pistillata was found to contain either Symbiodinium genotype C1 or C8a, while P cylindrica had type C15 based on ITS genotyping. Analysis of the quantum yield of photosystem (PS) II fluorescence of the symbionts in P. cylindrica showed that light-induced excitation pressure on the C15 Symbiodinium was significantly less, and the steady state quantum yield of PSII fluorescence at noon (Delta F/Fm') greater, than that measured in C1/C8a Symbiodinium sp. from S. pistillata. Immunoblots of the PS II D1 protein were significantly lower in Symbiodinium from S. pistillata compared to those in P. cylindrica after exposure to thermal stress. The biochemical markers, heat-stress protein (HSP) 70 and superoxide dismutase (SOD), were significantly greater in P. cylindrica before the experiments and both species of coral increased their biosynthesis of HSP 70 and SOD when exposed to thermal stress. Concentrations of MAAs, glycerol, and lipids were not significantly affected by thermal stress in these experiments, but DNA damage was greater in heat-stressed S. pistillata compared to R cylindrica. There was minimal coral mucus, which accounts for up to half of the total energy budget of a coral and provides the first layer of defense for invading microbes, produced by S. pistillata after heat stress compared to P. cylindrica. It is concluded that P. cylindrica contains a heat resistant C15 Symbiodinium and critical host proteins are present at higher concentrations than observed for S. pistillata, the combination of which provides greater protection from bleaching conditions of high temperature in the light. (C) 2009 Elsevier B.V. All rights reserved.