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

利用自然细菌来保护作物和维持农业我们研究的目的是建立以有效、安全和环境非持久性的方式使用自然产生的植物保护细菌所需的基本科学知识。目前的农业依赖于使用化学杀虫剂来保护作物免受致病微生物的攻击。其中一种名为立枯病的疾病是农作物发芽时死亡的主要问题。为了养活不断增长的世界人口，我们需要加强农业，增加更多的化学杀虫剂来保护农作物。我们不能持续大量使用杀虫剂，特别是在它们破坏环境和人类健康的情况下。必须开发可持续的替代方法，天然细菌生物杀虫剂提供了一个有吸引力的解决方案，以加强未来的农业和保护作物免受疾病的侵袭。BURKHOLDERIA AMBIFARIA-一种天然的植物保护细菌-几种天然细菌与植物生活得非常密切，并提供对致病微生物的保护。一组细菌，伯克霍尔德氏菌(B.ambiaria)，当作为种衣剂使用时，可以很好地保护萌发中的作物免受真菌的致命攻击。这导致它们在美国作为生物杀虫剂的安全使用一直持续到1999年，但在20世纪90年代，一组相关的伯克霍尔德氏菌被发现会导致囊性纤维症患者的肺部感染。由于当时还不能完全确定新生物杀虫剂的安全性，因此决定在新的生物杀虫剂被证明对健康没有风险之前，不允许对其进行登记。虽然注册的伯克霍尔德氏菌生物农药产品仍然可以使用，但农业已经停止使用它们，并扩大了化学杀虫剂的使用以维持农业。为了了解伯克霍尔德氏菌如何保护植物并确保它是安全和环保的，我们利用现代研究技术，发现布氏杆菌的植物保护能力是由于细菌用来制造一种名为洋葱的抗真菌分子的一组基因。当制造洋葱素的基因被移除时，细菌种皮就失去了植物保护。通过对B.ambiaria细菌中所有基因的测序，我们还发现了多个新基因，这些基因使天然产品有可能被用作生物杀虫剂分子、抗生素或精细化学品。这些新的发现使我们能够制定一项研究计划，以重新将斑潜蝇作为生物杀虫剂，这将作为以下四个研究目标进行：1.我们将绘制斑潜蝇保护植物免受病原体攻击的所有分子和途径，特别是识别当细菌在作物种子萌发释放的分泌物上生长时被开启的那些分子和途径。我们将设计洋葱素途径，使其能够转移到其他生物技术细菌中，并探索它如何能够制造这种生物杀虫分子的不同寻常的化学结构。我们将通过识别它用来致病的基因，并探索不同的策略来移除这些基因，从而提高白僵菌的安全性。当特定基因被移除时，感染性活细菌可以被用作疫苗，同样的方法将被用来制造安全的生物检测。我们将探索将斑潜蝇作为种衣剂放置在土壤中时会发生什么，以及它如何影响其他土壤微生物，以便我们了解它在环境中的持久性。总体而言，这一综合研究计划将寻求提供一种有效、安全和对环境无持久性的斑潜蝇生物杀虫剂，它可以显著提高和维持农业生产，而不需要使用化学农药。

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.