Catabolic capabilities of bacterial endophytes

每年约有1500种新的人造化学品被引入世界，10万种这样的化学品已经在工业和自然生态系统中流通。在加拿大，其中整整5000人甚至没有得到适当的评估。我们依靠微生物为我们消除这些化学物质。降解菌是我们的市政和工业废物处理系统的核心，我们希望它们能通过抵御农药残留来保护农作物和土壤。我们对能够破坏这些化学物质的微生物了解得越多越好。*虽然人们对生活在土壤中的特定污染物降解菌以及它们使用哪些基因进行清理知之甚少，但仍有一些细菌的来源没有得到充分的探索。某些细菌被称为内生菌，几乎在所有植物中都能找到--近年来，它们在许多方面对植物健康有益。其中一个好处是分解从受污染的土壤和大气中吸收的毒素，如泄漏的石油成分、杀虫剂和工业污染物。这项建议中描述的研究将调查细菌内生细菌中污染物降解基因的性质，以及它们是如何获得的。*一项研究将检查生长在自然历史石油渗漏区的植物的内生菌--草本植物生长在被浮油覆盖的土壤中，显示出对碳氢化合物毒性的显著适应程度。另一项研究将调查暴露在高水平杀虫剂下的咖啡树的细菌伙伴。几个项目将深入研究一组特定的植物相关细菌，这些细菌是从世界各地分离出来的，可以分解与杀虫剂和多氯联苯有关的氯化芳香化合物。这个集合的一个代表携带最近描述的遗传元素(TRIO或RIT元素中的重组酶)，该基因元素在数据库中的其他植物相关菌株中也很常见。我们怀疑这种RIT元件可能在许多细菌获得新的有用基因方面发挥作用。拟议的研究将涉及在现有收集和其他内生降解菌株中寻找RITs及其相关性。这将阐明RITS在开发新的有益途径以分解毒素和其他有用特征方面的重要性。*我们发现的东西对于清理植物修复等技术以及我们农作物的健康都将是重要的。这项工作将集中在寻找植物组织中的新型降解菌。随着加拿大面临更多的化学品、更多的泄漏和不断变化的气候，扩大对细菌内生菌可用的降解工具的理解，以及它们重新排列基因以实现有益效果的机制，将是有价值的。

About 1500 new man-made chemicals are introduced to the world each year and 100,000 such chemicals already circulate in industrial and natural ecosystems. In Canada, a full 5,000 of these are not even properly assessed. We depend on microorganisms to eliminate these chemicals for us. Degradative bacteria are central to our municipal and industrial waste treatment systems, and we expect them to protect agricultural crops and soils by fending off pesticide residues. The more we can learn about microbes that can destroy these chemicals, the better. ***While much is known about particular contaminant-degrading bacteria that live in soil and which genes they use to do this clean up, there are sources of bacteria that are not fully explored. Certain bacteria, known as endophytes, are found in virtually all plants -where they benefit plant health in many ways that have come to light in recent years. One such benefit is the breakdown of toxins absorbed from polluted soils and atmospheres, such as spilled oil components, pesticides and industrial contaminants. The research described in this proposal will investigate the nature of contaminant degradation genes in bacterial endophytes, and the means by which they were acquired.***One study will examine the endophytes of plants growing in natural historical oil seeps areas - where herbaceous plants grow in soils covered by oil slicks, showing a remarkable degree of adaptation to hydrocarbon toxicity. Another will investigate the bacterial partners of coffee trees that are exposed to high levels of pesticides. Several projects will delve into a specific collection of a specific group of plant-associated bacteria, isolated from different places around the world, that can break down chlorinated aromatic compounds related to pesticides and polychlorinated biphenyls. A representative of this collection carries a recently described genetic element (recombinase in trio or RIT element) that is also common in other plant associated strains in the database. We suspect this RIT element may play a role in the acquisition of new useful genes by many bacteria. The proposed research will involve a search for RITs and their associations in the existing collection and in other endophytic degradative strains. This will shed light on the importance of RITS to the development of new beneficial pathways for toxin breakdown and other useful traits. ***The things we find will be important to clean up technologies such as phytoremediation and to the health of our crops alike. This work will concentrate of looking for novel degradative bacteria inside plant tissues. An expanded understanding of the degradative tools available to bacterial endophytes, and the mechanisms they have to rearrange genes for beneficial effects will be valuable as Canada faces more chemicals, more spills and a changing climate.