Diversity and function of plant microbiomes

越来越多的人认识到，植物和包括人类在内的动物一样，不是自给自足的有机体，而是由多种多样的微生物居住的，包括真菌、细菌和古细菌。这些微生物中的许多为宿主提供了宝贵的好处，例如氮和磷等营养物质的循环，并提供了对病原体和其他压力（如干旱）的保护，以换取生活在富含碳的栖息地。这种相互依赖的植物及其相关微生物被称为植物微生物组。在气候变化、害虫、病原体和入侵物种增加、粮食和纤维需求增加、化肥和农药用量减少的情况下，了解植物微生物群现在被认为是实现可持续森林和农业生态系统的关键。然而，我们对与不同植物物种相关的各种微生物及其功能的了解仍处于起步阶段，因为直到最近，由于我们缺乏研究它们的技术，许多这些微生物无法被识别。分子生物学的最新进展意味着微生物不必在实验室中培养就可以进行研究，同时新的“组学”技术使我们能够将微生物与功能联系起来，我们将揭开植物微生物组的复杂性。本研究将使用各种新颖的分子和“组学”技术，结合稳定同位素标记和探测方法来了解植物与其微生物组之间的关系，以及这种关系如何影响生态系统功能，以期优化这些伙伴关系的可持续性。植物和微生物之间最普遍的联盟之一，也是植物为了生存而不得不形成的联盟，就是菌根（真菌根）联盟。自然界中有两种主要的菌根关联，一种是在大多数温带树种上发现的外生菌根（ECM），另一种是在作物和草本植物中发现的丛枝菌根（AM）。然而，作为BC的关键树种之一，西部红杉的不同寻常之处在于它与真菌形成AM而不是ECM的关系。我们对在雪松上形成AM的真菌的多样性知之甚少，尽管没有这些真菌雪松无法生存。越来越多的证据表明植物通过根释放碳，根分泌物，形成微生物群。为了加强这些伙伴关系，我们需要表征植物微生物组中完整的微生物多样性，我们还需要更好地了解植物及其菌根伴生菌和其他密切相关微生物之间的碳流、生化信号和分子相互作用。未来，对健康植物微生物组功能的理解可能会带来新的方法，例如操纵微生物组，以改善食物和纤维的生产，并保护植物免受生物和非生物胁迫。

There is growing recognition that plants, like animals, including humans, are not self-sufficient organisms, but are inhabited by a multitude of assorted microorganisms, including fungi, bacteria and archaea. Many of these microorganisms provide valuable benefits for the host, such as cycling of nutrients like nitrogen and phosphorus and providing protection against pathogens and other stresses, such as drought, in return for living in a carbon-rich habitat. This mutual dependency of plants and their associated microorganisms in known as the plant microbiome. Understanding the plant microbiome, is now recognized as being key to achieving sustainable forest and agro-ecosystems in the face of climate change, increasing pests, pathogens and invasive species coupled with increased demand for food and fibre with decreasing fertilizer and pesticide application. However, our understanding of the variety of microorganisms associated with different plant species, and their functions, is still in its infancy because until recently many of these microorganisms could not be identified because we lacked techniques to study them. With recent advances in molecular biology that mean microorganisms do not have to be grown in the lab in order to be studied, along with new “omics” technologies which enable us to link microorganisms to functions we are set to unravel the complexity of plant microbiomes. This research will use a variety of novel molecular and “omics” techniques, coupled with stable isotope labelling and probing approaches to understand the relationships between plants and their microbiome and in turn how this affects ecosystem function, with a view to optimizing these partnerships for sustainability. One of the most universal unions between plants and microbes, and one that plants are largely obliged to form for survival, is the mycorrhizal (fungus-root) alliance. There are two main mycorrhizal associations in nature, ectomycorrhizae (ECM) found on most temperate tree species and arbuscular mycorrhizae (AM), found in crops and herbaceous plants. However, one of the key tree species in BC, western redcedar is unusual in that it forms a relationship with fungi forming AM, not ECM. We know very little about the diversity of fungi forming AM on cedar, though without these fungi cedar cannot survive. There is increasing evidence that carbon released by plants through their roots, root exudates, shape microbiomes. In order to augment these partnerships we need to characterize the complete microbial diversity in plant microbiomes and we also need better understanding of the flows of carbon, biochemical signals and molecular interactions between plants, their mycorrhizal associates and other closely-associated microorganisms. In future, understanding of the functions of a healthy plant microbiome could lead to novel approaches e.g. manipulation of the microbiome, to improve food and fibre production and protect plants from biotic and abiotic stress.