Oswald Pia, Rodríguez Ariel, Bourke Johara, Wagner Norman, de Buhr Nicole, Buschmann Holger, Köckritz-Blickwede Maren von, Pröhl Heike
Institute of Zoology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany.
Dis Aquat Organ. 2020 Dec 17;142:225-237. doi: 10.3354/dao03543.
The chytrid fungus Batrachochytrium dendrobatidis (Bd) infects numerous amphibian species worldwide and is suggested to drive population declines and extinction events. We report a study of Bd infection at the northernmost distribution of the European yellow-bellied toad Bombina variegata. A total of 577 individuals from ponds in 16 study sites were sampled for DNA and Bd throughout the breeding season. Microsatellite genotyping revealed 3 genetic clusters for the host B. variegata with an overall low genetic diversity. One of the clusters displayed a low microsatellite heterozygosity, a high inbreeding coefficient as well as high Bd infection prevalence and intensities. Multi-model estimates identified site, time of sampling, and heterozygosity to be important predictors of an individual's Bd infection status, and identified a strong effect of site on individual Bd infection intensity. The study site effects are suggestive of localized infection peaks, and the increase of individual Bd infection probabilities towards the end of the sampling period suggests cumulative infection during the breeding season. This study highlights the need for regular monitoring of Bd infection variables at multiple localities and times to gain insights into Bd dynamics. Due to the detected relationship between individual Bd infection status and heterozygosity, conservation measures should focus on the maintenance of high genetic diversity and connectivity within and among amphibian populations.
壶菌Batrachochytrium dendrobatidis（Bd）感染了全球众多两栖动物物种，并被认为是导致种群数量下降和灭绝事件的原因。我们报告了一项关于欧洲黄腹蟾蜍Bombina variegata最北分布区Bd感染情况的研究。在整个繁殖季节，从16个研究地点的池塘中总共采集了577只个体的DNA和Bd样本。微卫星基因分型显示宿主B. variegata有3个遗传簇，总体遗传多样性较低。其中一个簇显示出微卫星杂合度低、近亲繁殖系数高以及Bd感染率和感染强度高。多模型估计确定采样地点、采样时间和杂合度是个体Bd感染状况的重要预测因素，并确定了地点对个体Bd感染强度有强烈影响。研究地点的影响表明存在局部感染高峰，并且在采样期结束时个体Bd感染概率增加表明在繁殖季节存在累积感染。这项研究强调需要在多个地点和时间定期监测Bd感染变量，以深入了解Bd动态。由于检测到个体Bd感染状况与杂合度之间的关系，保护措施应侧重于维持两栖动物种群内部和之间的高遗传多样性和连通性。
