Bidochka M J, Walsh S R, Ramos M E, St Leger R J, Silver J C, Roberts D W
Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY 14853, USA.
Proc Natl Acad Sci U S A. 1996 Jan 23;93(2):918-21. doi: 10.1073/pnas.93.2.918.
In North America there are two generally recognized pathotypes (pathotypes 1 and 2) of the fungus Entomophaga grylli which show host-preferential infection of grasshopper subfamilies. Pathotype 3, discovered in Australia, has a broader grasshopper host range and was considered to be a good biocontrol agent. Between 1989 and 1991 pathotype 3 was introduced at two field sites in North Dakota. Since resting spores are morphologically indistinguishable among pathotypes, we used pathotype-specific DNA probes to confirm pathotype identification in E. grylli-infected grasshoppers collected at the release sites in 1992, 1993, and 1994. In 1992, up to 23% of E. grylli-infected grasshoppers of the subfamilies Melanoplinae, Oedipodinae, and Gomphocerinae were infected by pathotype 3, with no infections > 1 km from the release sites. In 1993, pathotype 3 infections declined to 1.7%. In 1994 grasshopper populations were low and no pathotype 3 infections were found. The frequency of pathotype 3 infection has declined to levels where its long-term survival in North America is questionable. Analyses of biocontrol releases are critical to evaluating the environmental risks associated with these ecological manipulations, and molecular probes are powerful tools for monitoring biocontrol releases.
在北美，真菌蝗虫噬虫霉（Entomophaga grylli）有两种普遍认可的致病型（致病型1和致病型2），它们对蝗虫亚科表现出宿主偏好性感染。在澳大利亚发现的致病型3，其蝗虫宿主范围更广，被认为是一种优良的生物防治剂。1989年至1991年期间，致病型3被引入北达科他州的两个野外地点。由于静止孢子在形态上无法区分致病型，我们使用致病型特异性DNA探针来确认1992年、1993年和1994年在释放地点采集的感染蝗虫噬虫霉的蝗虫中的致病型鉴定。1992年，黑蝗亚科、斑翅蝗亚科和槌角蝗亚科中感染蝗虫噬虫霉的蝗虫中，高达23%被致病型3感染，在距离释放地点1公里以外未发现感染情况。1993年，致病型3感染率降至1.7%。1994年蝗虫数量较少，未发现致病型3感染情况。致病型3的感染频率已降至其在北美的长期生存令人质疑的水平。生物防治释放分析对于评估与这些生态操纵相关的环境风险至关重要，分子探针是监测生物防治释放的有力工具。
