Discovering novel microbial tools to mitigate the global phosphorus crisis: Identification of unique phosphatases in abundant rhizobacteria

点击翻译按钮获取中文摘要

The demand to provide sufficient food for a rising global population in the face of several emerging global issues, such as climate change and depletion of natural resources, has resulted in an urgent need to explore novel ways of generating sustainable agricultural practices. For example, currently, agriculture massively relies on the intensive application of rock phosphate fertiliser to maintain sufficient crop yields. Unfortunately, predictions suggest that we could run out of rock phosphate, which is only produced through geological processes, within the next 50-200 years. In addition, only 10-30% of rock phosphate, applied as fertiliser, is taken up by the plant for growth. This inefficiency leads to problems such as eutrophication, which has negative effects on our environment and wildlife. Most soils are actually saturated with numerous forms of inorganic and organic phosphorus (oP) that are unfortunately unavailable to plants without prior transformation to an available form, orthophosphate. Plants have a limited ability to mobilise phosphorus locked up in these various forms. Therefore, plants heavily rely on their associations with various microorganisms to assist them in acquiring bioavailable orthophosphate from various complex inorganic and organic forms. One of the major microbial mechanisms involved in transforming various soil oP complexes into orthophosphate is the production of extracellular phosphatases. Despite advances in understanding the role of microorganisms in mobilising soil oP, a complete and holistic understanding of this process remains unknown. Therefore, our ability to use microorganisms as a means of alleviating our reliance on rock phosphate is inadequate.I recently discovered that a group of abundant bacteria related to the genus Flavobacterium, that inhabit the rhizosphere of Oil Seed Rape, the UK's 3rd most economically important crop, exhibited both strong and constitutive phosphatase activity. This phenotype appears to be both unique to Flavobacterium and potentially beneficial for plants. However, the specific enzymes responsible for this interesting and unique phenotype remain unknown. The phylum Bacteroidetes (predominantly Flavobacteria), can constitute up to 65% of the plant microbiome and are major components of the human and marine microbiomes. Therefore, they likely have a major role in regulating environmental phosphorus dynamics. The major aim of this project is to therefore identify and characterise the novel unidentified phosphatases produced by these under-studied but interesting Flavobacteria. The two major outcomes of this project are 1) the discovery of novel microbial enzymes with potential agritech application 2) the discovery of new components in the soil oP cycle. Both of these outcomes will improve our knowledge regarding the global phosphorus cycle and sustainable agricultural practices, through increasing the efficiency by which plants utilise natural phosphorus resources locked up in soils.I will undertake this Fellowship in the Department of Animal and Plant Sciences at the University of Sheffield using the lab of Prof. Tim Daniell as a host. The Daniell lab is based in the state-of-the-art Arthur Willis Environmental Centre, home of the Plant Protection and Production (P3) Centre, which unifies a diverse set of plant and soil scientists. The University of Sheffield was placed in the top 10% of research excellence in the UK (2014 Research Excellence Framework) and 99% of research at Sheffield that is internationally recognised with 48% of research in Biological Sciences classed as 4* world leading. Therefore, undertaking this prestigious Fellowship at Sheffield will provide me with the best opportunities to embark on a career in academia and tackle the emerging issues related to food security.