MycoRhizaSoil: Combining wheat genotypes with cultivation methods to facilitate mycorrhizosphere organisms improving soil quality and crop resilience

耕地耕作造成的土壤有机质含量和土壤大团聚体(碎屑)的损失降低了土壤的水分和养分保持能力，是作物产量和肥料有效利用的主要全球制约因素。在英国，由于遗传、环境和管理限制之间的相互作用，近20年来小麦产量没有增加。现代小麦育种侧重于抗病育种和提高籽粒产量和品质，而不考虑影响土壤质量的其他性状，最终影响土壤的长期可持续性。土壤侵蚀是一个主要的全球性问题，耕作加剧了土壤有机质的流失，以及土壤抵抗水和风蚀的大团聚体的流失。参与稳定土壤大团聚体和促进土壤有机质储存的最重要的生物功能群之一是被称为菌根的共生真菌，它们从植物根部接受糖分，以换取为植物提供养分和水分。我们最近表明，一些现代小麦品种形成菌根共生的能力有限或没有能力，我们联盟的成员是第一批表明传统耕作减少了这些共生体的多样性和功能的人之一。这些共生菌及其功能的丧失被认为是导致土壤质量损失的原因之一，这既是通过对土壤有机质和土壤结构的影响，也是通过减少对病原体的防御，这些病原体是由共生和促进植物生长的根际细菌诱导的，这些根际细菌被认为与菌根协同作用。菌根土壤将决定菌根和相关土壤微生物在维持土壤结构和有机质含量方面所起的关键作用，这是高产所必需的，并首次直接解决了选择小麦基因型和减少集约化管理的好处，以增强这些作物-微生物相互作用的功能效益，从而提供更低的投入、更具弹性和更具弹性的小麦生产。我们的方法结合了基于实验室和田间的研究，使用了在菌根形成能力上不同但在其他方面非常相似的小麦品系，选择了500多个小麦品系，这些品系来自两个菌根形成能力不同的亲本。这项基于实验室的研究将解决菌根诱导的对重要的根和地上部病原菌的系统防御的机制基础，这些病原菌导致英国和全球小麦的重大产量损失。在利用所选小麦品系进行的一系列田间试验中，我们将确定人工接种菌根真菌、暂时退耕还草(以恢复菌根)和采用免耕与传统耕作相比，土壤质量改善和作物对干旱、过量水分和本地疾病恢复沉默的程度。我们的议程设置研究计划为优化植物育种和可持续小麦生产的耕地管理确定了一套新的目标。我们雄心勃勃的最终目标是提供科学证据，评估同时减少耕作需求(对化石燃料要求最高的农业作业之一，也是对土壤保持和可持续性破坏最大的作业之一)和通过小麦基因选择增加有益土壤微生物的活动的益处。我们预测，这些方法结合在一起，将增加土壤表层有机碳的储存，有助于恢复水稳定的大团聚体，并提高作物对气候胁迫(水过多或过少)和疾病的适应能力。

Loss of soil organic matter content and soil macroaggregates (crumbs) as a result of arable cultivation reduces soil water and nutrient holding capacity and are major global constraints on crop yields and efficient use of fertilizer. In the UK wheat yield have not increased over nearly 20 years due to interactions between genetic, environment and management constraints. Modern wheat breeding has focussed on selection for disease resistance and increasing yield and quality of the grain, without consideration of other traits that can influence soil quality and ultimately, the long-term sustainabilty of soil. Soil erosion is a major global problem exacerbated by ploughing, loss of soil organic matter and the macroaggregates that hold soil together against water and wind erosion. One of the most important functional groups of organisms that are involved in stabilizing soil macroaggregates and contributing to soil organic matter storage are symbiotic fungi called mycorrhizas that receive sugars from plant roots in return for providing nutrients and water to the plants. We have recently shown that some modern wheat varieties have limited or no ability to form mycorrhizal symbiosis, and members of our consortium were amongst the first to show that conventional arable farming reduces the diversity and functioning of these symbionts. Loss of these symbionts and their functioning is thought to be contributory to loss of soil quality, both directly through effects on soil organic matter and soil structure, and indirectly though reductions in defences against pathogens which are induced by the symbiosis and plant growth promoting rhizobacteria that are thought to act synergistically with mycorrhizas.MycoRhizaSoil will determine the crucial roles mycorrhiza and co-associated soil microorganisms play in maintaining soil structure and organic matter content, which are required for high yields, and directly addresses for the first time the benefits of selecting wheat genotypes and less intensive management to enhance the functional benefits of these crop-microbe interactions to deliver lower input, more sustainable and resilient wheat production. Our approach combines laboratory and field based research using wheat lines that differ in mycorrhiza-forming capacity but are otherwise genetically very similar, selected over 500 lines of wheat bred from two parents that differed in mycorrhiza-forming ability. The laboratory-based research will resolve the mechanistic basis of mycorrhiza-induced systemic defenses to important root and shoot pathogens that cause major yield losses of wheat in the UK and globally. In a series of sequential field trials using the selected wheat lines we will determine the extent to which artificial inoculation with mycorrhizal fungi, the temporary conversion of crop land to grassland (to restore mycorrhiza) and adoption of no-tillage leads to improvements in soil quality and crop resilence to drought, excess water and native diseases compared to wheat grown conventionally with annual tillage. Our agenda-setting research programme identifies a new set of targets for optimising plant breeding and arable management for sustainable wheat production. Our ambitious ultimate goal is to provide the scientific evidence to evaluate the benefits of simultaneously reducing the need for ploughing (one of the most fossil-fuel demanding farm operations and one of the most damaging to soil conservation and sustainability) and increasing the activities of beneficial soil microorganisms through wheat genotype selection. In combination we predict these approaches will increase the storage of soil organic carbon in the surface soil, help restore water-stable macroaggregates and increase crop resilience to climate stress (too much and too little water) and diseases.