Different Stress Tolerances of Juveniles of the Coral Acropora tenuis Associated with Clades C1 and D Symbiodinium.
Different Stress Tolerances of Juveniles of the Coral Acropora tenuis Associated with Clades C1 and D Symbiodinium.
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DOI：
10.6620/zs.2016.55-19
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发表时间：
2016
影响因子：
1.6
通讯作者：
I. Yuyama;Takashi Nakamura;T. Higuchi;M. Hidaka
中科院分区：
文献类型：
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作者：
I. Yuyama;Takashi Nakamura;T. Higuchi;M. Hidaka
Ikuko Yuyama, Takashi Nakamura， Tomihiko Higuchi和Michio Hidaka（2016）造礁珊瑚通常与共生鞭毛藻共生枝（Symbiodinium spp.）有关，共生枝的相对组成可以改变宿主珊瑚的系统发育特性（例如，胁迫响应性，生长速度）。共生枝属包含9个分支，其中一些分支对强光和/或温度胁迫的反应不同，例如，共生枝D是耐热的。然而，以前的研究是基于现场存在的珊瑚，并且在以前的实验中使用的珊瑚可能不包含单一的共生枝。为了准确评估每个共生枝对宿主热胁迫抗性的影响，将C1枝和D枝的单克隆培养物接种到非共生稚虫中。两个支系的光合效率（最大量子产率：F v /F m）在30°C下均比在25°C下下降。共生体进化枝C1比进化枝D表现出更高的rETRmax，波动幅度更大，在热胁迫处理下幼鱼存活率更低。在强光照射下，含C1支的珊瑚在3小时后的F v /F m下降幅度更大（-74%），而含D支的珊瑚则下降幅度更大（-50%）。这是第一次评估与单克隆共生枝C和D相关的幼珊瑚的耐应力性的研究，我们的结果表明，与D相关的珊瑚对强光（500 μmol m-2 s-1）的耐受性更强。然而，高温胁迫对珊瑚-藻类共生的影响很难从光合活性上确定。在高温下，C1共生枝表现出较高的光合活性，但与D共生枝相关的珊瑚寄主存活率更高。由于C1枝在高温下具有较高的光合活性，因此与D枝相比，C1枝在高温下的共生可能对珊瑚产生负面影响。
Ikuko Yuyama, Takashi Nakamura, Tomihiko Higuchi, and Michio Hidaka (2016) Reef-building corals are often associated with multiple clades of symbiotic dinoflagellate Symbiodinium spp., where the relative composition of Symbiodinium can alter the phylogenetic properties (e.g., stress responsiveness, growth rate) of the host coral. The genus Symbiodinium contains nine clades, some of which behave differently in response to strong light and/or temperature stresses, for example, clade D Symbiodinium are thermally tolerant. However, previous studies are based on corals present in the field, and it is possible that the corals used in previous experiments did not contain single Symbiodinium clades. For an accurate assessment of the effects of each Symbiodinium clade on host thermal stress resistance, monoclonal cultures of clades C1 and D were inoculated into aposymbiotic juvenile polyps. Photosynthetic efficiency (maximum quantum yield: F v /F m) showed a decline at 30°C than at 25°C in both clades. Symbiodinium clade C1 showed a consistently higher rETRmax with larger fluctuations than clade D, with a lower survival rate of juveniles during thermal stress treatment. Under strong light exposure, corals containing clade C1 showed a greater decline in F v /F m (-74%), compared to decline in corals associated with clade D (-50%) after 3 hours. This is the first study to assess stress tolerances of juvenile corals in association with the monoclonal Symbiodinium clades C and D, and our results indicated greater tolerance of corals associated with clade D to strong light (500 μmol m-2 s-1). However, it is difficult to determine the impact of high-temperature stress on coral-algae symbiosis from photosynthetic activity. At high temperatures, clade C1 Symbiodinium exhibited high photosynthetic activity, but host survival rates were higher in corals associated with clade D Symbiodinium. Since clade C1 has a relatively high photosynthetic activity under high temperatures, clade C1 symbiosis at high temperatures might have a negative impact on corals compared with clade D.