Isolation of fungal pathogens from eggs of the endangered sea turtle species Chelonia mydas in Ascension Island
Isolation of fungal pathogens from eggs of the endangered sea turtle species Chelonia mydas in Ascension Island
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从阿森松岛濒危海龟种海龟卵中分离真菌病原体
DOI：
10.1017/s0025315416001478
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发表时间：
2016
影响因子：
1.2
通讯作者：
J. Diéguez
中科院分区：
文献类型：
--
作者：
J. M. Sarmiento;J. Sim;P. van West;J. Diéguez
真菌新出现的病原体是全球生物多样性的主要威胁之一。海龟似乎也不例外，最近对全球重要筑巢区域的研究表明，两种真菌病原体，即镰状镰刀菌和角化镰刀菌，与海龟物种巢穴的孵化成功率较低有关。尽管在阿森松岛已检测到这两种病原体的存在，但尚未调查这两种病原体在岛上主要筑巢海滩的分布情况。在这项研究中，我们分析了来自阿森松岛四个筑巢区的 109 个海龟蛋壳。我们已分离并鉴定出总共 46 种真菌分离株。对 ITS nrDNA 区域的系统发育分析以及茄病镰孢菌种复合体的许多参考序列表明，其中 23 个分离株对应于病原体 F. keratoplasum。对分离频率的分析，包括之前获得的其他分离株，即 11 种 F. keratoplasum 和 1 种 F. falciforme，结果表明 F. keratoplase 是阿森松岛最常分离到的物种，在所有筑巢海滩都发现了它，而 F. falciforme 仅在泛美海滩分离到。与全球其他筑巢区域相比，镰状镰刀菌上的角化镰刀菌的丰度高于任何其他测试的筑巢区域。这些发现对于评估这种病原体对阿森松岛海龟种群巢穴的潜在威胁并制定未来的控制策略非常重要。
Fungal emerging pathogens are one of the main threats for global biodiversity. Sea turtles do not seem to be an exemption, and recent studies on important nesting areas worldwide have shown that two fungal pathogens, i.e. Fusarium falciforme and Fusarium keratoplasticum, are involved in low hatching success in nests of sea turtle species. Although the presence of these pathogens has been detected in Ascension Island, there are no investigations on the distribution of these two pathogens in main nesting beaches in the island. In this study, we analysed 109 eggshells of the species Chelonia mydas from four nesting areas in Ascension Island. We have isolated and identified a total of 46 fungal isolates. A phylogenetic analysis, of the ITS nrDNA region, with a number of reference sequences of the Fusarium solani species complex, showed that 23 of these isolates corresponded to the pathogen F. keratoplasticum. The analyses on isolation frequency, that included other previously obtained isolates, i.e. 11 F. keratoplasticum and one F. falciforme, showed that F. keratoplasticum was the species most frequently isolated in Ascension Island and it was found in all nesting beaches, while F. falciforme was only isolated from Pan Am beach. When compared with other nesting areas worldwide, the abundance of F. keratoplasticum over F. falciforme was higher than any other nesting region tested. These findings are important in order to evaluate the potential threat of this pathogen to nests of the sea turtle population of Ascension Island, and to develop future control strategies.