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

Lead Research Organisation: University of Leeds
Department Name: Sch of Geography

Abstract

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.

Technical Summary

This project will use double-haploid lines of wheat derived from a mapping population of over 500 lines in which the parents have contrasting phenotype for arbuscular mycorrhiza (AM) competence, to determine the effect of wheat mycorrhiza on rhizosphere microbial populations, AM-inducible defences and soil quality (soil organic matter content, macroaggregate stability, soil porosity and water holding capacity). Intensive modern arable farming methods combined with selection of less AM-competent wheat is hypothesised to have contributed to the loss of soil structure and organic matter content that now is a major constraint on crop productivity, especially under conditions of inadequate or too much rainfall. AM fungi have been shown to be vital players in soil aggregate stability and contribute to soil organic matter storage but to date the possibility of actively selecting wheat varieties and agronomic management practices to synergistically harness the benefits of AM fungi and associated Plant Growth Promoting Rhizobacteria (PGPR) for sustainable soil quality has not been considered. We will resolve the basis of mycorrhiza inducible defences against major wheat fungal pathogens- take all and Septoria, and the potentialy synergistic interactions between mycorrhiza and PGPR. We will use wheat lines with contrasting mycorrhizal competence, but otherwise genetically very similar, selected from the mapping population. In the field we will establish a sequential trial of the wheat lines on plots under conventional tillage and no-tillage management, with and without addition of commercially available mycorrhizal inoculum. In addition a grass ley will be established and planted with the wheat lines after 3 years- to assess how this traditional way of rebuilding soil quality compares to the other management treatments. The work will quantify mycorrhizosphere carbon fluxes into aggregates using 14C and conduct metagenomic analyses of mycorrhizosphere communities.

Planned Impact

This project will resolve the fundamental role of soil microbes in sustainable wheat production, providing essential genetic and performance data that have the potential to underpin the development of new wheat varieties, optimised for sustainable low-input agriculture. The environmental benefits of the project include more sustainable agro-ecosystems with less dependence on chemical inputs that may have detrimental environmental impacts, and restoration of critical soil functions that have been degraded by conventional agriculture.

The societal benefits from the project include increased food security, enhanced farmer's incomes and reduced occupational exposure of farmers to fungicide/pesticides. In addition, as new varieties developed as a result of the outcomes of this project are likely to give greatest financial benefits under less intensive management, they will help to make sustainable agriculture increasingly economically attractive, and thereby help to promote biodiversity and improved quality of life and environment in rural areas. These core outcomes of the project directly influence 8 specific stakeholder groups (pre and post farmgate as well as policy makers): (i) Farmers, farm managers - benefit through new soil management practices (ii) Statutory agencies involved in water and soil conservation (E.g. Natural England, Syngenta Soil and Water Protection) (iii) Game and Wildlife Conservation (iv) Cereal Processors (v) Government policy makers (DEFRA) - innovation in agricultural industries (vi) Supermarkets (vii) The wider public (links with aims of GFS - improved productivity, sustainable crops), (viii) RAGT Seeds (one of Europe's largest cereal breeders) - new market opportunity as well as the principal route to commercialisation of data produced from this project in the form of new wheat varieties.
This project represent an industrial collaboration with international wheat breeder, RAGT Seeds Ltd., for the development and commercialisation of new cultivars of wheat that require reduced input in terms of pesticides and inorganic fertilisers by harnessing beneficial soil microbes. This provides a clear opportunity for commercialisation of our outputs.

To disseminate information and promote the benefits of MycoRhizaSoil research and ensure the relevant stakeholders are consulted throughout the project we will hold 3 events:

- A Launch event in September 2014 at the Hazelwood Hotel, close to the University of Leeds farm, to establish members of a user liaison group. Invitees will include Velcourt Farm Management, Harper Adams University, RAGT Seeds and the Game and Wildlife Trust Allerton Project)
- A 2-day project review and outreach planning meeting in April 2017 at the Allerton Project Visitor Centre at Loddington with selected external stakeholders.
- One day outreach meeting in the final year of the project at the Allerton Project Visitor Centre to demonstrate research outcomes and communicate findings to farmers and policy makers, following the successful model we used in a meeting co-hosted with the Organic Growers Alliance and facilitated by the Technology Strategy Board Environmental Sustainability Knowledge Transfer Network (see http://bit.ly/HNiOOs [ES-KTN site] & http://bit.ly/1cKLwND [OGA site]).

Publications


10 25 50
 
Description The work is still ongoing and the research has not been completed to a stage where we have firm conclusions. However,

There appears to be some effect of differing wheat varieties and mycorrhizal treatments on soil moisture and macropore structures.
Exploitation Route Application to farm management
Sectors Environment
 
Description The project is still ongoing - impacts will come in the future
 
Description BBC Radio York, Yorkshire Farming Science Special, October 2016 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact One hour BBC radio broadcast focused on the project, outlining the research aims, methods, teams, and findings and its regional and wider importance. The broadcast was recorded at the field site with different project team members.
Year(s) Of Engagement Activity 2016
 
Description Stakeholder advsiory meeting, May 2016 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Day long stakeholder advisory meeting with site visits. Involved industry and farm practitioners
Year(s) Of Engagement Activity 2016
 
Description Workshop with stakeholders 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Workshop with stakeholders to discuss project, show them the site, get feedback on the science and potential impacts
Year(s) Of Engagement Activity 2015