Understanding and Exploiting Biological Nitrogen Fixation for Improvement of Brazilian Agriculture

Lead Research Organisation: John Innes Centre
Department Name: Molecular Microbiology

Abstract

After water, available nitrogen is the most limiting nutrient for plant growth. Although the demand for fixed nitrogen can be met by the use of chemical fertilisers, their use in agriculture has resulted in major environmental and economic impacts. At present less than half of the nitrogen used by farmers is assimilated by crops. Excess nitrogen leaks into the environment, leading to significant effects on soil and water quality, biodiversity, and atmospheric pollution. However, some bacteria can perform a process known as biological nitrogen fixation, which converts nitrogen gas from the atmosphere into ammonia, a source of nitrogen that can be assimilated by animals and plants. This provides a more sustainable alternative to the use of synthetic fertilisers.

Although soil-dwelling nitrogen fixing bacteria can associate with food and energy crops, they do not readily release their fixed nitrogen for the benefit of the plant, although they can have beneficial effects on plant growth. In Brazil, significant increases in crop yield have been observed in response to inoculation with nitrogen fixing bacteria, some of which have an endophytic lifestyle and can gain access to intercellular spaces in plant roots and shoots. This provides an opportunity to engineer closer associations between nitrogen-fixing bacteria and food and energy crops, in which fixed nitrogen is delivered more effectively to the plant. This proposal for a Virtual Joint Centre (VJC) brings together a team of Brazilian and UK investigators focused towards understanding and exploiting plant-diazotroph interactions as a means to enhance agricultural productivity in Brazil. Using fundamental knowledge of nitrogen regulation in endophytic nitrogen fixing bacteria, we will engineer strains, which excrete ammonium to benefit crop growth, and examine the potential of these modified strains as inoculants. We will also design selection strategies to isolate associative diazotrophs that are competitive in the rhizosphere in relation to plant varieties that respond well and have a growth advantage in the presence of these endophytes. We will identify genes required for efficient plant-microbe interactions and quantitate the level of biological, nitrogen fixation in relation to crop yield. Finally, we will we examine the potential for the use of native and engineered strains as inoculants. To achieve these objectives, we will exploit strong synergies and world-leading expertise of UK and Brazilian researchers in biological nitrogen fixation, microbial population dynamics, bacterial and plant genetics, genomics and synthetic biology, in order to engineer efficient cultivar-endophyte combinations and develop improved inoculant technologies. Enhancing nitrogen fixation in our target crops promises substantial benefits for Brazilian agriculture, while decreasing the use and environmental impact of industrial nitrogen fertilisers.

Planned Impact

Application of chemical fertilisers has maintained high crop yields in many countries, but has resulted in severe perturbation of the global biogeochemical nitrogen cycle, resulting in greenhouse gas emissions and consequent acute damage to human health and ecosystem services. We are faced with the dilemma of reducing chemical nitrogen input into agriculture but at same time increasing yields to feed the growing world population and maintain global food security. Biological nitrogen fixation provides a more sustainable route to supply nitrogen to crops and as we propose here, can be exploited to enhance crop productivity while mitigating the consequences of reactive nitrogen release. This promises enormous benefit for humanity through the reduction of greenhouse gas emissions and development of sustainable agriculture. The impacts of this research will be global in the long term, benefiting not only academia, industry and the farming community, but also substantial socio-economic benefits on an international scale.

The academic sector will benefit in the short to medium term as the proposed research will provide publications, knowledge, expertise and materials of direct relevance to biological nitrogen fixation and agriculture on an international, multidisciplinary level.

We intend to communicate our research activities to a range of audiences including those in schools and cafe scientific environments to help raise the underlying issues and to illustrate biotechnological solutions to worldwide challenges to achieve a sustainable planet.

The farming community and the agro-industrial sector will benefit in the medium to long-term from the development of biofertiliser strains identified by the VJC, which will be validated in field trials and evaluated to control the quality and the development of new commercial inoculants, which will be disseminated to farmers and representatives of the biofertiliser industry in Brazil.

Tackling the nitrogen problem with sustainable biotechnological solutions such as those proposed here is likely to yield enormous economic, social and ecosystem impacts, through reduced costs of nitrogen inputs in agriculture together with the added benefit of decreased greenhouse gas emissions.
 
Description Although we are only midway through the grant period, we have made considerable progress on each of the work packages. Diazotrophic bacteria of importance to Brazilian agriculture have been manipulated to excrete ammonia and a rhizopine biosensor has been designed to enable plant-inducible nitrogen fixation in Azospirillum brasilense. Field trails have been initiated with Pennisetum and sugar cane to assess the influence of inoculation with diazotrophic bacteria on crop yield. We are also evaluating a recently isolated diazotrophic endophyte, Azoarcus olearius DQS-4, for plant growth promotion and the role of nitrogen fixation. Preliminary analysis of RNA-seq data on sugar cane, suggests that plant nitrogen metabolism is reprogrammed when beneficial plant-microbe associations are established.
Exploitation Route Strains engineered to excrete ammonium may provide substantial nitrogen to plants and when used as inoculants may provide a more sustainable alternative to the use of synthetic fertilisers
Sectors Agriculture, Food and Drink,Manufacturing, including Industrial Biotechology

 
Description We have used the Newton grant to promote and explain the sustainable development concept and the importance of biological nitrogen fixaiton in agriculture to schools, colleges, and farmers in Brazil and the UK. The University of Parana have announced a public call to grant commercial rights to the biofertiliser industry to exploit some of the most efficient inoculant strains developed during the course of this project. This has the potential to translate our research findings to benefit crop productivity and hence enhance the environmental, social and economic potential of Brazil.
First Year Of Impact 2017
Sector Agriculture, Food and Drink,Education,Manufacturing, including Industrial Biotechology
Impact Types Societal,Economic

 
Description Annual UBNFC Meeting 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The annual UBNFC meeting is an opportunity for the scientists within the UK and Brazil partnership to meet and formally discuss progress within their research. The two day meeting (held in Brazil, 2016/17) has worked successfully using a format of individual PL talks, breakout sessions to discuss specific work packages and an admin and engagement session. As well as the PL's, attendee's have included post-doctoral researchers who have also been given the chance to talk about their involvement in the research. The annual meeting is an essential event to determine the future direction of the research and provides an opportunity for direct communication between the two international partners and renewed emphasis on areas that require work.
Year(s) Of Engagement Activity 2016,2017
URL http://ubnfc.org/?page_id=74
 
Description Attending UBNFC Annual Meeting in Brazil, Nov 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact Meeting of all collaborators on an international project or annual meeting
Year(s) Of Engagement Activity 2017
URL https://rhizosphere.org/lab-news/
 
Description JIC 50 Open day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Open Day to celebrate 50 years of the John Innes Centre in Norwich, where we exhibited a stand to show isolation of microbes from soil and their influence on plant growth.
Year(s) Of Engagement Activity 2017
 
Description Joint meeting of the UBNFC and NUCLEUS Virtual Joint Centres 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact In the first meeting of its kind 24 leading experts from the UK and Brazil came together to find practical, low cost solutions that make more effective use of nitrogen (N) in agriculture, while attempting to decrease N pollution losses to the environment either to the atmosphere or through the soil.
UBNFC led by Ray Dixon, Professor of Molecular Microbiology at the John Innes Centre and NUCLEUS led by Sacha Mooney, Professor of Soil Physics in the School of Biosciences at the University of Nottingham focus on improving nitrogen use efficiency from both the agronomic and biological perspectives.The meeting revealed the overlapping goals of the two research centres and identified several opportunities for collaboration that will develop the scientific and practical outcomes for the benefit of Brazilian and UK agriculture.
Professor Dixon said: "We are very grateful to the BBSRC for supporting this meeting to explore synergies between the two UK-Brazil virtual joint centres on agricultural nitrogen. The outcome of our discussions has uncovered exciting new opportunities to mitigate the impact of nitrogen fertilisers on the environment and increase agricultural productivity in Brazil through enhanced use of biological nitrogen fixation and improved agronomic practices."
Professor Mooney said: "While our two centres are following different approaches, the potential synergies are clear. In NUCLEUS we have shown that combinations of natural soil amendments and leguminous trees planted between crops have the capacity to provide similar quantities of nitrogen to that from artificial fertilizers. For important non-leguminous crops like maize and rice, UBNFC are isolating second generation bacterial inoculants that have great potential for supplying fixed N to plants when added to soil - although this is yet to be tested in the field."
"We have developed new plans to exchange ideas and scientists in the coming year to test this combination of approaches. We are all really excited by the potential this offers."
Explaining the problem of managing nitrogen in Brazil, Professor Ciro Rosolem from São Paulo State University said: "Most tropical, weathered soils have low mineral N, and the introduction of legumes in crop rotation is one way to naturally increase soil N. However, heavy rainfall on fragile, tropical soils can lead to significant losses of N by leaching through the soil. The NUCLEUS project is seeking to understand which crop species are best at scavenging N from deeper in the soil and recycle it for the next crop, thus reducing the need for fertilizer inputs and improving nitrogen use efficiency".
UBNFC is pioneering an alternative approach - biological nitrogen fixation (BNF). Professor Emanuel de Souza from the Federal University of Paraná said: "We are using nitrogen-fixing bacteria as a sustainable source of fixed N. We believe this approach also has the potential to significantly reduce the input of chemical fertilisers in agriculture and mitigate the environmental and economic impacts of reactive nitrogen pollution."
Year(s) Of Engagement Activity 2017
URL http://ubnfc.org/?page_id=74
 
Description NUCLEUS UBNFC (VJC meeting) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A joint meeting of two VJCs who are working in UK and Brazil, held in Brazil, Nov 2017
Year(s) Of Engagement Activity 2017
URL https://rhizosphere.org/lab-news/
 
Description Organised Nitrogen Network Workshop, June 2017 
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 Nitrogen Network wa a one-day meeting for researchers interested in common themes
Year(s) Of Engagement Activity 2017
URL https://rhizosphere.org/lab-news/
 
Description Science Engagement at St. Michaels Junior School, Norwich (08/06/2017) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact During a science week at St. Michael's Junior School a team member was invited to speak to three classes about 'What is a scientist?'. The classes consisted of ~30 year 4 children (aged 8/9 years). The talk was based around images on a powerpoint but was largely unscripted so that the children felt able to ask questions and spark discussion. The children were introduced to the idea that there are different types of scientists, investigating all areas of the biology, chemistry and physics. This progressed onto the career of a scientist and how scientists share their knowledge locally and internationally which naturally led to speaking about how the UBNFC's work is beneficial to sustainable agriculture, economy and the environment. The clear outcome was that it gave the children an opportunity to think about science as an interesting subject to learn more about and that a science related career was accessible option to all.
Year(s) Of Engagement Activity 2017
URL http://ubnfc.org/?page_id=74
 
Description Science Media Training for group member (Training course organised by the BBSRC, training carried out by members of the BBC) 
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 Member attended an official BBSRC Media Training course for scientists. This one-day course gave background on how interviews are conducted on TV and Radio. Techniques for answering questions were given and excellent practical sessions were included. The course is designed to prepare scientists in the event that the research attracting media attention.
Year(s) Of Engagement Activity 2017
 
Description Science, Art and Writing workshop for West Earlham Junior School, Norwich (10/10/17) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact As part of the impact activities of the UBNFC, we liaised with the SAW initiative to provide a one-day practical workshop for year 4 children at a local school. SAW provided an artist and a writer who used their skills to highlight and enhance the scientific concepts given to the children. We began with a simple talk explaining the science concepts behind the practical activities; what bacteria are and the importance of nitrogen to living organisms. This talk also included a brief mention of the international nature of science, exemplified by our UK-Brazil virtual joint centre; with researchers working together on a single project but being physically located in different parts of the world. The children worked their way through three key practicals including making soil plates (so they could study the bacterial growth post workshop), using junior microscopes to investigate root nodules and pre-grown bacterial colonies and playing an educational game teaching them about symbiosis. The science principles learnt in the morning were then applied in the art and writing sessions in the afternoon. The workshop provided a legacy for the teachers to build on provided by information on the day and the bacterial cultures that developed on the agar plates in the following weeks.
Year(s) Of Engagement Activity 2017
URL http://ubnfc.org/?page_id=74
 
Description UBNFC Information Leaflet 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A full colour and professionally printed information leaflet has been produced. The leaflet contains information about our research background, aims and outcomes as well as contact information. The purpose of the leaflet is to promote the work carried out by our network to colleagues, general public and schools.
Year(s) Of Engagement Activity 2016,2017,2018
 
Description UK-Brazil Nitrogen Fixation Centre Website 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The website is an important platform for colleagues, the general public and other interested parties to learn about the research carried out by the UBNFC. The content provides information about network members, background to the science, published papers and a news section used to highlight impact and events. The website is a focal point for the virtual joint centre and offers a space where contact details can be found.
Year(s) Of Engagement Activity 2017,2018
URL http://ubnfc.org/