Black Mountain Laboratories, GPO Box 1600, Canberra, ACT 2601, Australia.
Ecol Appl. 2012 Jan;22(1):35-52. doi: 10.1890/11-0341.1.
Increasingly, pathogen-resistant (PR) plants are being developed to reduce the agricultural impacts of disease. However PR plants also have the potential to result in increased invasiveness of nontarget host populations and so pose a potential threat to nontarget ecosystems. In this paper we use a new framework to investigate geographical variation in the potential risk associated with unintended release of genetically modified alfalfa mosaic virus (AMV)-resistant Trifolium repens (white clover) into nontarget host populations containing AMV, clover yellow vein virus (ClYVV), and white clover mosaic virus (WCIMV) in southeastern Australia. Surveys of 213 sites in 37 habitat types over a 300 000-km2 study region showed that T. repens is a significant weed of many high-conservation-value habitats in southeastern Australia and that AMV, ClYVV, and WClMV occur in 15-97% of nontarget host populations. However, T. repens abundance varied with site disturbance, habitat conservation value, and proximity to cropping, and all viral pathogens had distinct geographic distributions and infection patterns. Virus species frequently co-infected host plants and displayed nonindependent distributions within host populations, although co-infection patterns varied across the study region. Our results clearly illustrate the complexity of conducting environmental risk assessments that involve geographically widespread, invasive pasture species and demonstrate the general need for targeted, habitat- and pathosystem-specific studies prior to the process of tiered risk assessment.
越来越多的抗病原体（PR）植物被开发出来，以减少疾病对农业的影响。然而，PR 植物也有可能导致非目标宿主种群的入侵性增加，从而对非目标生态系统构成潜在威胁。在本文中，我们使用一个新的框架来调查在澳大利亚东南部，由于基因改造的紫花苜蓿花叶病毒（AMV）抗性三叶草（白车轴草）被意外释放到含有 AMV、三叶草黄脉病毒（ClYVV）和白车轴草花叶病毒（WCIMV）的非目标宿主种群中，与非预期释放相关的潜在风险的地理变异。在研究区域 300000 平方公里的范围内，对 37 种生境类型的 213 个地点进行了调查，结果表明，三叶草是澳大利亚东南部许多高保护价值生境中一种重要的杂草，而 AMV、ClYVV 和 WCIMV 存在于 15%-97%的非目标宿主种群中。然而，三叶草的丰度随地点的干扰、生境的保护价值和与种植的接近程度而变化，所有的病毒病原体都有独特的地理分布和感染模式。病毒物种经常共同感染宿主植物，并且在宿主种群内呈现出非独立的分布，尽管共同感染模式在整个研究区域有所不同。我们的研究结果清楚地说明了进行环境风险评估的复杂性，这些评估涉及到广泛分布、具有入侵性的牧场物种，并且需要在分层风险评估之前，针对特定的生境和病理系统进行有针对性的研究。
