Streptomyces bacteria: antibiotic production in the wheat endosphere

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Increasing food production to feed a growing world population is essential for the future survival of the human race. Our proposal focuses on wheat, one of the most important crops in the world, and a genus of antimicrobial-producing bacteria called Streptomyces that are abundant inside wheat roots. Streptomyces bacteria make numerous specialised metabolites (SMs), many of which have antimicrobial activity, and they also form mutually beneficial symbioses with insects, marine invertebrates and plants, which exchange food and housing for antimicrobials, to protect themselves against disease. We are interested in exploiting Streptomyces bacteria as biological fungicides to protect wheat against disease and we are also interested in unlocking the biosynthesis of the estimated 90% of their SMs that are encoded but not produced under laboratory conditions. Their SMs already account for 50% of all known antibiotics and genome sequencing has indicated there are many more waiting to be discovered.

We have shown streptomycetes are highly enriched in the endosphere of wheat variety Paragon grown in Church Farm soil (Norfolk) relative to the rhizosphere and surrounding soil. Some Streptomyces strains have beneficial effects on wheat plants, including protection against the Take-all fungus and we have also shown that the wheat root exudate molecule IAA can increase the antimicrobial activity of a Streptomyces endophyte strain. Here we will determine which root exudate molecules attract and feed streptomycetes and test whether they induce production of SMs not made under laboratory conditions. We will also genome sequence 10 streptomycetes isolated from wheat roots which inhibit the growth of the Take-all fungus and determine if the fungus or plant can activate production of their antifungal molecules and whether these strains can be used as seed coatings to protect wheat plants against fungal disease.

The proposed work will generate significant impacts for a broad range of end users, and we describe below who will benefit and the mechanisms in place to show how that impact will be achieved.

1. TRAINING. This project will offer excellent training and career opportunities to the PDRAs we appoint. Training will be provided in microbiology, plant growth, bioinformatics, GCMS and metabolomics. The project will lead to high quality publications and they will be encouraged to present at national and international academic conferences and take part in public engagement events, including at least one big public exhibition during this project plus SAW Trust workshops in local schools. The UEA technician will also be offered broad training as will visitors to the lab, including A-level students, undergraduates and Masters students who regularly volunteer to gain work experience or carry out research projects as part of their degrees.

2. DISSEMINATION TO SCIENTISTS AND THE GENERAL PUBLIC. It has long been known that soils can be disease suppressive and this is due to the prevalence of antibiotic-producing bacteria in those soils which presumably colonise and protect plant roots. Research has largely focused on plant symbiotic pseudomonads and bacilli and their antifungal compounds and streptomycetes have been largely ignored, probably because they are challenging to work with. Our project will be of general interest to groups working on Streptomyces bacteria and on plant root microbiomes. There is a lot of interest in this area amongst academic groups and industrial scientists as high throughput sequencing techniques have enabled advances in understanding the core root microbiomes of many plants. We will share our results freely with scientists through publication in high quality open access journals, dissemination at academic conferences and more widely through Twitter (@matthutchings10) and press releases and on our group websites. Hutchings has a strong track record in public engagement in schools, through public lectures and at major public science events including the Royal Society Summer Science Exhibition 2014, the BBSRC Great British Bioscience Festival 2014, Big Bang Science Fair 2015 and Norwich Science festival 2016 and 2018. He won a UEA award in 2015 for his outstanding contribution to public and community engagement and the Microbiology Society Public engagement award in 2019. He will continue to engage widely with the public through all available avenues to talk about their work on Streptomyces natural product antibiotics and their role in protective symbioses.

3. ECONOMIC - NEW TOOLS. Materials, strains and knowledge developed during this project will be made freely available to academics and industrial scientists (subject to MTA) to stimulate and assist efforts to promote beneficial root microbiome formation. As the project progresses, we will engage with seed companies to explore the possibility of including Streptomyces spores in seed coatings. Companies interested in developing plant root synthetic communities (syncomms) include AgBiome, Syngenta, BioAg and Bayer AG and, if necessary, we will use our links with TSL and JIC to contact these companies. Intellectual property arising from this work will be protected and licensed by UEA's Research and Innovation office.