Soil biodiversity and suppressiveness of soil against plant diseases and insect pests

由于其特殊的生物群落，土壤对作物植物病原真菌引起的根系疾病的抑制作用各不相同。然而，土壤生物多样性与抑制作用之间的联系以及受这一机制控制的有害生物范围的特征尚不明确。该项目旨在综合了解土壤生物多样性与作物保护之间的关系，在全球变化的背景下，利用几个国家具有不同抑制地位的土壤，使作物和病原体/害虫的重要性发生变化。将采取两种办法：(i)对已知具有抑制或有益作用的标志性土壤进行比较（瑞士和法国可获得此类土壤），以及（ii）对不同农业管理策略下的土壤进行比较（例如，旨在增强土壤生物多样性的基于土壤有机质的管理实践，包括在长期实验中），这些策略可能导致不同程度的抑制（德国已对此类条件进行了调查）。首先，将填补目前关于抑制性的知识空白，这将基于(i)土壤色谱分析（评估土壤有机质质量，这可能是抑制性的潜在指标），（ii）与作物植物生理和防御状态相关的疾病抑制性评估，（iii）微生物分类生物多样性的元条形码，以及（iv）受控条件下微生物功能群的分子监测。其次，将通过评估(i)新兴作物的疾病抑制程度（重点是小麦），（ii）对害虫的抑制可能性，以及（iii）丛枝菌根真菌（迄今为止在此背景下被忽视的共生伙伴）对疾病抑制的贡献，来表征全球变化下抑制的重要性。第三，将根据具体监测(i)植物病原体和（ii）害虫种群、（iii）作物代谢组学分析和（iv）田间根际微生物群分析，确定项目结果对田间农艺条件的适用性。该项目涉及由3个国家的6个合作伙伴组成的多学科联盟，从著名的学术研究团体到实地推广专家，以促进与农业社区和其他利益攸关方的联系。该项目有望产生关于植物保护和生物多样性在抑制中的重要性的新知识。这些知识对于开发新的土壤质量生物多样性指标，以及确定管理策略，以改善土壤中较差或没有抑制特性并面临全球变化挑战的作物健康将是重要的。

Thanks to their particular biotic community, soils vary in their suppressiveness towards root diseases caused by phytopathogenic fungi on crop plants. However, the link between soil biodiversity and suppressiveness and the range of deleterious organisms that are controlled by this mechanism are poorly characterized. This project aims at developing an integrated understanding of the relation between soil biodiversity and crop protection, using soils of contrasting suppressiveness status in several countries, in a context of global change materialized by changes in crops and in pathogen/pest importance. Two approaches will be followed: (i) the comparison of emblematic soils known to be suppressive or conducive (such soils are available in Switzerland and France), and (ii) the comparison of soils under different agricultural management strategies (e.g. with soil organic matter-based management practices aiming at enhancing soil biodiversity, including in long-term experiments), which have the potential to result in different levels of suppressiveness (such conditions have been investigated in Germany). First, current knowledge gaps on suppressiveness will be filled, based on (i) chromatographic profiling of soil (to assess soil organic matter quality, which might represent a potential indicator of suppressiveness), (ii) assessment of disease suppressiveness in relation to crop plant physiology and defense status, (iii) metabarcoding of microbial taxonomic biodiversity, and (iv) molecular monitoring of microbial functional groups under controlled conditions. Second, the significance of suppressiveness under global change will be characterized, by assessing (i) the extent of disease suppressiveness on emerging crops (with a focus on wheat), (ii) the possibility of suppressiveness towards insect pests, and (iii) the contribution of arbuscular mycorrhizal fungi, a symbiotic partner neglected so far in this context, to disease suppressiveness. Third, the applicability of project findings to agronomic field conditions will be determined, based on specific monitoring of (i) phytopathogens and (ii) insect pest populations, (iii) metabolomic profiling of crops, and (iv) the analysis of the rhizosphere microbiota in fields. The project involves a multidisciplinary consortium of 6 partners in 3 countries, ranging from prominent academic research groups to field extension specialists to facilitate outreach to the farming community and other stakeholders. This project is expected to generate new knowledge on phytoprotection and the importance of biodiversity in suppressiveness. This knowledge will be important to develop novel biodiversity indicators of soil quality, and to define management strategies to improve crop health in soils with poor or no suppressiveness properties and facing the challenge of global change.