School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
Mar Pollut Bull. 2018 Sep;134:94-98. doi: 10.1016/j.marpolbul.2017.08.032. Epub 2017 Aug 23.
Seagrass meadows suffered large-scale declines in the past century. The 'wasting disease', pathognomonically associated with Labyrinthula zosterae, reduced populations of Zostera marina on both sides of the North Atlantic in, and since, the 1930s, coinciding with intensive agricultural use of artificial fertilizers and herbicides. This study tests the long-standing hypothesis that nutrient enrichment and a herbicide increases vulnerability to pathogens. Z. marina shoots from the Thames Estuary grown in elevated nitrate concentrations had significantly higher rates of infection by L. zosterae than controls, but not by Aplanochytrium sp., another slime-mould like protist. Z. marina shoots grown in 2μg·l Diuron solutions and infected separately by L. zosterae and Aplanochytrium sp. had significantly higher wasting indices than controls. The results identified Aplanochytrium sp. as another opportunistic pathogen causing a seagrass wasting-type disease and support the hypothesis that pollution by herbicides and nitrate increases the susceptibility of Z. marina to infections.
过去一个世纪以来，海草草甸大规模减少。“消瘦病”与具缘毛藻属（Labyrinthula zosterae）有着明确的关联，自 20 世纪 30 年代以来，北大西洋两岸的大西洋海枣种群数量减少，这与化肥和除草剂的大量农业使用同时发生。本研究检验了一个长期存在的假设，即营养富集和除草剂会增加对病原体的易感性。在升高的硝酸盐浓度下，来自泰晤士河口的海洋草苗的感染率显著高于对照组，但对另一种类似粘菌的原生动物 Aplanochytrium sp. 的感染率没有显著增加。在 2μg·l 的 Diuron 溶液中生长并分别感染具缘毛藻属和 Aplanochytrium sp. 的海洋草苗的消瘦指数显著高于对照组。结果表明，Aplanochytrium sp. 是另一种导致海草消瘦型疾病的机会性病原体，并支持了这样一种假设，即除草剂和硝酸盐污染会增加海洋草对感染的敏感性。
