Establishing the Efficacy, Safety and Persistence of biopesticides based on naturally occurring beneficial bacteria

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HARNESSING NATURAL BACTERIA TO PROTECT CROPS AND SUSTAIN AGRICULTUREThe aim of our research is to establish the fundamental scientific knowledge required to use naturally occuring plant protective bacteria in an effective, safe and environmentally non-persistent manner. Current agriculture is reliant on the use of chemical pesticides to protect crops from attack by disease-causing microorganisms. One such disease, known as damping off, is a major problem killing crop plants as they germinate. To feed the growing world population we will need to intensify agriculture and adding more chemical pesticides to protect crops. We cannot sustain high usage of pesticides, especially when they damage the environment and human health. Alternative approaches which are sustainable must be developed and natural bacterial biopesticides offer an attractive solution to enhance future agriculture and protect crops from disease.BURKHOLDERIA AMBIFARIA - A NATURALLY PLANT PROTECTIVE BACTERIASeveral natural bacteria live very closely with plants and provide protection against disease causing microbes. One group of bacteria, Burkholderia ambifaria (B. ambifaria), when applied as a seed coat are very good at protecting germinating crops from lethal attack by damping off fungi. This led to their safe use as biopesticides up to 1999 in the US, but during the 1990s, a related group of Burkholderia bacteria were found to cause lung infections in people with cystic fibrosis. At the time, the safety of B. ambifaria could not be fully defined, it was decided that registration of new biopesticides would not be permitted until they were demonstrated to have no health risks. Although the registered Burkholderia biopesticide products could still be used, the agricultural industry moved away from using them and expanded their use of chemical pesticides to sustain agriculture.UNDERSTANDING HOW BURKHOLDERIA AMBIFARIA PROTECTS PLANTS AND ENSURING IT IS SAFE AND ENVIRONMENTALLY NON-PERSISTENTUsing modern research techniques, we found B. ambifaria's plant protective ability was due to a set of genes that the bacterium uses to make an antifungal molecule called cepacin. When the cepacin-making genes were removed, plant protection was lost from the bacterial seed coat. By sequencing all the genes in B. ambifaria bacteria we also identified multiple new genes that make natural products potentially exploitable as biopesticide molecules, antibiotics or fine chemicals. These new findings have allowed us to map out a research program to re-purpose B. ambifaria as a biopesticide which will be carried out as the following four research objectives: 1. We will map all the molecules and pathways B. ambifaria uses to protect plants from attack by pathogens, specifically identifying those which are switched on when the bacteria grow on the exudates released by germinating crop seeds.2. We will engineer the cepacin pathway allowing it to be moved into other biotechnological bacteria and also exploring how it is able to make the unusual chemical structure of this biopesticidal molecule.3. We will improve the safety of B. ambifaria by identifying the genes it uses to cause disease and exploring different strategies to remove these genes. Infectious live bacteria can be used as vaccines when specific genes are removed, and the same approach will be exploited to make a safe biopesticide.4. We will explore what happens to B. ambifaria when it is placed in the soil as a seed coat and how it affects other soil microorganisms, so that we understand it's environmental persistence.Overall this integrated research programme will seek to deliver an effective, safe and environmentally non-persistent B. ambifaria biopesticide, which can significantly enhance and sustain agricultural production without the need to use chemical pesticides.