Discovering genus-specific mycoparasites against plant pathogens

近十年来，由于化学农药对环境的危害作用，植物病害的生物防治日益受到重视。几种微生物利用各种机制有效保护植物免受病原体侵害，真菌高寄生虫或支寄生虫被视为控制种子和根腐病病原体（如赤霉病/赤霉病（G/F））暴发的生态解决方案。到目前为止，只有少数基于木霉和胶粘菌的高寄生虫产品已经上市。虽然几种生物可以在受控条件下控制病原体种群，但最近的研究表明，在原位使用这些支寄生虫存在根本问题。它们是多面手，强烈依赖于环境条件和兼性坏死性微生物，通常会对非目标微生物产生不利影响。因此，本研究的目标是找到更有效的生物替代品，基于生物营养菌比一般的坏死性菌更可预测的假设。它们是宿主特异性的，因此仅限于特定的真菌分类群，包括致病性G/F。它们似乎主要依赖于病原体-宿主种群的分散，因此可能是主要的生物防治候选者。目前，对其生物学、多样性和宿主相互作用的了解甚少，有待进一步研究。具体目标是：1)通过原位调查构建与植物致病性G/F种群相关的关键属特异性高寄生生物的生物图谱；2)了解生物营养性高寄生生物的进化和专门化。这些G/F物种的支寄生虫将使用形态学和分子方法，培养依赖性和非培养依赖性检测来评估它们对疾病发展的影响。研究结果将为在可持续农业和森林生产生态系统中生物防治应用方面具有很高潜力的一组生物提供新的知识体系。对这些生物营养性高寄生虫的了解将有助于有效和安全地控制土传植物致病性和种子传真菌毒素产生的G/F菌群。总之，本项目为加拿大植物病原生物防治提供了一个新的方向。

Over the last decade, biological control of plant diseases has received increasing attention due the environmental hazard effects of chemical pesticides.  Several microorganisms use various mechanisms to effectively protect plants against pathogens, and fungal hyperparasites or mycoparasites are seen as an ecological solution to control outbreaks of seed and root-rot pathogens such as Giberella/Fusarium (G/F).  Only a handful of hyperparasite products based on Trichoderma and Gliocladium have been marketed so far.  While several organisms may control pathogen populations under controlled conditions, recent studies showed fundamental problems in using these mycoparasites in situ.  They are generalists that strongly depend on environmental conditions and facultative necrotrophs that often detrimentally affect non-target microbes.  The goal of this research is therefore to find more efficient biological alternatives, based on the hypothesis that biotrophic mycoparasites would be more predictable than general necrotrophs.  They are host specific and thus restricted to particular fungal taxa including pathogenic G/F.  They seem to depend mainly on the dispersion of pathogen-host population and thus would be prime biocontrol candidates.  Currently, little is known about their biology, diversity and host-interaction which need to be clarified.  Specific goals are: 1) to construct the bioprofile of key genus-specific hyperparasitic organisms associated with plant pathogenic G/F populations through an in situ survey, and 2) to understand biotrophic hyperparasites evolution and specialisation.  These mycoparasites of G/F species will be examined using morphological and molecular approaches, culture dependent and culture-independent assays to assess their impact on disease development.  The results will provide a new body of knowledge on a group of organisms with high potential for biocontrol applications in sustainable agricultural and forest production ecosystems.  Knowledge on these biotrophic hyperparasites will lead to an effective and safe control of soilborne plant pathogenic and seedborne mycotoxin producing G/F consortia.  Overall, this project offers a new dimension for Canadian biocontrol against plant pathogens.