School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia.
FASEB J. 2010 Jun;24(6):1935-46. doi: 10.1096/fj.09-152447. Epub 2010 Feb 2.
Immunity is a key life history trait that may explain hierarchies in the susceptibility of corals to disease and thermal bleaching, two of the greatest current threats to coral health and the persistence of tropical reefs. Despite their ongoing and rapid global decline, there have been few investigations into the immunity mechanisms of reef-building corals. Variables commonly associated with invertebrate immunity, including the presence of melanin, size of melanin-containing granular cells, and phenoloxidase (PO) activity, as well as concentrations of fluorescent proteins (FPs), were investigated in hard (Scleractinia) and soft (Alcyonacea) corals spanning 10 families from the Great Barrier Reef. Detectable levels of these indicators were present in all corals investigated, although relative investment differed among coral taxa. Overall levels of investment were inversely correlated to thermal bleaching and disease susceptibility. In addition, PO activity, melanin-containing granular cell size, and FP concentration were each found to be significant predictors of susceptibility and thus may play key roles in coral immunity. Correlative evidence that taxonomic (family-level) variation in the levels of these constituent immunity parameters underpins susceptibility to both thermal bleaching and disease indicates that baseline immunity underlies the vulnerability of corals to these two threats. This reinforces the necessity of a holistic approach to understanding bleaching and disease in order to accurately determine the resilience of coral reefs.
免疫是一个关键的生活史特征，它可以解释珊瑚对疾病和热白化的易感性的层次结构，这是当前对珊瑚健康和热带珊瑚礁持续存在的最大威胁之一。尽管珊瑚正在迅速全球衰退，但对造礁珊瑚的免疫机制的研究很少。通常与无脊椎动物免疫有关的变量，包括黑色素的存在、含黑色素的颗粒细胞的大小以及酚氧化酶（PO）活性以及荧光蛋白（FP）的浓度，在大堡礁的 10 个科的硬珊瑚（Scleractinia）和软珊瑚（Alcyonacea）中进行了调查。在所调查的所有珊瑚中都存在这些指标的可检测水平，尽管珊瑚类群之间的相对投资有所不同。总体投资水平与热白化和疾病易感性呈负相关。此外，PO 活性、含黑色素的颗粒细胞大小和 FP 浓度都被发现是易感性的重要预测因子，因此可能在珊瑚免疫中发挥关键作用。相关性证据表明，这些组成免疫参数的水平在分类学（科级）上的变化支持了对热白化和疾病的易感性，这表明基线免疫是珊瑚对这两种威胁的脆弱性的基础。这强化了采用整体方法来理解白化病和疾病的必要性，以便准确确定珊瑚礁的恢复力。
