Discovering genus-specific mycoparasites against plant pathogens

近十年来，由于化学农药对环境的危害，植物病害的生物防治受到越来越多的关注。 几种微生物利用各种机制来有效地保护植物免受病原体的侵害，真菌超寄生虫或真菌寄生虫被视为控制种子和根腐病原体如Giberella/Fusarium（G/F）爆发的生态解决方案。 到目前为止，只有少数基于木霉和粘帚霉的重寄生虫产品已经上市。 虽然几种生物体可以控制在受控条件下的病原体种群，最近的研究表明，在使用这些真菌寄生虫在原位的根本问题。 它们是多面手，强烈依赖于环境条件和兼性坏死营养菌，经常间接影响非目标微生物。 因此，本研究的目标是找到更有效的生物替代品，基于活体营养型真菌寄生虫比一般的坏死营养型更可预测的假设。 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-宿主种群的扩散，因此将是主要的生防候选者。 目前，对它们的生物学、多样性和宿主相互作用知之甚少，需要加以澄清。 具体目标是：1）通过原位调查构建与植物病原G/F种群相关的关键属特异性重寄生生物的生物概况，以及2）了解生物营养重寄生虫的进化和专门化。 将使用形态学和分子方法、培养物依赖性和非培养物依赖性试验对这些G/F种属的真菌寄生虫进行检查，以评估其对疾病发展的影响。 研究结果将为一组在可持续农业和林业生产生态系统中具有生物控制应用潜力的生物体提供新的知识体系。 这些生物营养重寄生虫的知识将导致一个有效的和安全的控制土传植物病原菌和种传真菌毒素生产G/F财团。 总体而言，该项目为加拿大植物病原体生物防治提供了一个新的层面。

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.