Bittner Tonya D, Hajek Ann E, Liebhold Andrew M, Thistle Harold
Cornell University, Department of Entomology, Ithaca, New York, USA
Cornell University, Department of Entomology, Ithaca, New York, USA.
Appl Environ Microbiol. 2017 Aug 17;83(17). doi: 10.1128/AEM.00724-17. Print 2017 Sep 1.
The goal of this study was to develop effective and practical field sampling methods for quantification of aerial deposition of airborne conidia of over space and time. This important fungal pathogen is a major cause of larval death in invasive gypsy moth () populations in the United States. Airborne conidia of this pathogen are relatively large (similar in size to pollen), with unusual characteristics, and require specialized methods for collection and quantification. Initially, dry sampling (settling of spores from the air onto a dry surface) was used to confirm the detectability of at field sites with deaths caused by , using quantitative PCR (qPCR) methods. We then measured the signal degradation of conidial DNA on dry surfaces under field conditions, ultimately rejecting dry sampling as a reliable method due to rapid DNA degradation. We modified a chamber-style trap commonly used in palynology to capture settling spores in buffer. We tested this wet-trapping method in a large-scale (137-km) spore-trapping survey across gypsy moth outbreak regions in Pennsylvania undergoing epizootics, in the summer of 2016. Using 4-day collection periods during the period of late instar and pupal development, we detected variable amounts of target DNA settling from the air. The amounts declined over the season and with distance from the nearest defoliated area, indicating airborne spore dispersal from outbreak areas. We report on a method for trapping and quantifying airborne spores of , an important fungal pathogen affecting gypsy moth () populations. This method can be used to track dispersal of from epizootic areas and ultimately to provide critical understanding of the spatial dynamics of gypsy moth-pathogen interactions.
本研究的目标是开发有效且实用的野外采样方法，用于在空间和时间上对空气中传播的分生孢子的空中沉降进行定量分析。这种重要的真菌病原体是美国入侵性舞毒蛾（）幼虫死亡的主要原因。该病原体的空气传播分生孢子相对较大（大小与花粉相似），具有独特的特征，需要专门的收集和定量方法。最初，采用干采样（孢子从空气中沉降到干燥表面），利用定量聚合酶链反应（qPCR）方法，在因感染而出现死亡情况的野外地点确认是否可检测到。然后，我们测量了野外条件下分生孢子DNA在干燥表面上的信号降解情况，最终由于DNA快速降解而摒弃干采样作为一种可靠方法。我们对孢粉学中常用的一种腔式诱捕器进行了改进，以在缓冲液中捕获沉降的孢子。2016年夏天，我们在宾夕法尼亚州舞毒蛾疫情爆发地区进行了一次大规模（137公里）的孢子诱捕调查，对这种湿捕方法进行了测试。在末龄幼虫和蛹发育阶段，采用4天的收集期，我们检测到从空气中沉降下来的目标DNA数量各不相同。这些数量在整个季节中以及随着与最近落叶区域距离的增加而下降，表明空气中的孢子从疫情爆发区域扩散开来。我们报告了一种捕获和定量空气中传播的孢子的方法，是一种影响舞毒蛾（）种群的重要真菌病原体。这种方法可用于追踪从疫情流行区域的扩散情况，并最终提供对舞毒蛾与病原体相互作用空间动态的关键理解。
