Understanding the impact of climate change and elevated CO2 on tree microbial diversity

许多树木，如橡树，对英国的经济，环境和文化至关重要。它们支持许多物种，提供了一个栖息地，鼓励我们的自然环境中丰富的林地生物多样性。然而，它们受到气候变化的威胁。这导致树木病原体的丰度和分布发生变化，从而增加了新疾病爆发的可能性。急性橡树衰退（AOD）是由多种因素引起的，包括几种细菌物种，它们成为致病性橡树微生物组的关键成员。环境变化可能会增加树木对病原体的敏感性，从而增加AOD的流行。气候变化的一个核心组成部分是二氧化碳浓度的上升，这会影响树木的生长和疾病的易感性。例如，大气CO2（e[CO2]）水平的升高会导致叶片组成的变化，并通过放大的光合固碳水平增加生物量。微生物组组成与宿主植物的生理学之间存在明确的联系。微生物组通常扩展生物体的功能能力，重要的是增加对压力和疾病的耐受性。然而，[CO2]树生理学对树木微生物群落结构的影响还没有得到研究。利用伯明翰森林研究所（BIFoR）的自由空气二氧化碳（FACE）设施，我们可以研究二氧化碳对不同树种（包括橡树和樱桃）上微生物群落多样性（包括细菌，真菌和噬菌体）的影响，以及这些微生物如何与树木病原体相互作用。我们假设，随着树木在e[CO2]下生长得更大，可能会有更高的微生物丰度，但叶片化学成分的变化将改变微生物的多样性，可能会对微生物组抑制病原体建立的能力产生整体负面影响。我们将研究个体和微生物聚生体如何与关键病原体相互作用，例如，革兰氏阴性肠杆菌科的多微生物聚生体（例如Brenneria sp.，Gibbsiella sp.，Rahnella sp.）急性橡树衰退（Acute Oak Decline，AOD）这种方法对于准确预测未来树木健康和疾病至关重要。

Many trees, such as oak, are crucial to the British economy, environment, and culture. They support many species, providing a habitat that encourages rich woodland biodiversity across our natural environment. However, they are threatened by climate change. This causes alterations in the abundance and distribution of tree pathogens consequently increasing the likelihood of new disease breakouts. Acute Oak Decline (AOD) is caused by a multitude of factors including several bacterial species that become key members of the pathogenic oak microbiome. It is possible environmental change could increase trees' susceptibility to pathogens increasing AOD prevalence. A core component of climate change is a rise in carbon dioxide concentration, which affects tree growth and disease susceptibility. For instance, elevated levels of atmospheric CO2 (e[CO2]) cause changes in leaf composition and increase biomass through magnified levels of photosynthetic carbon fixation. There are well-established links between microbiome composition and the physiology of the host plant. Microbiomes typically extend an organism's functional capabilities, importantly increasing tolerance to stress and disease. However, the effect e[CO2] tree physiology has on tree microbiome community structure is somewhat unexplored. Utilising the Birmingham Institute of Forest Research (BIFoR) Free Air Carbon Dioxide (FACE) facility we can investigate e[CO2] effects on microbial community diversity (including bacteria, fungi, and bacteriophage) on different tree species (including Oak and Cherry), and how these microbes interact with tree pathogens. We hypothesise that as trees grow larger under e[CO2] there may be higher microbial abundance, but that leaf chemistry compositional changes will alter the diversity of the microbes, potentially with an overall negative impact in the microbiomes' ability to suppress pathogen establishment. We will examine how individuals and microbial consortia interact with key pathogens, for example, a polymicrobial consortium of Gram-negative Enterobacteriaceae (e.g. Brenneria sp., Gibbsiella sp., Rahnella sp.) that cause Acute Oak Decline (AOD). This approach is essential for making accurate predictions regarding future tree health and disease.