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

Overviews

Trees are foundation species on earth, forming a major part of the global biomass and provides habitat, important ecosystem services (e.g. carbon sequestration and soil stability) and conservation of biodiversity in both natural and man-made landscapes. However, climate change alters the distribution of tree pathogens and can impact tree immunity, collectively increasing the likelihood of new disease outbreaks.

One predicted element of climate change is increased atmospheric CO₂ concentration ([CO₂]) (reaching 550 μmol mol⁻¹ in 2050). Elevated [CO₂] (e[CO₂]) levels affect tree growth, susceptibility and tolerance to diseases. It increases the rate of photosynthetic carbon fixation by leaves, which will lead to a large variety of secondary effects on plant physiology, such as faster growth, with more above- and below-ground biomass. eCO₂ also leads to changes in the chemical composition of plant tissues such as decreasing leaf nitrogen concentrations.

Plant ecosystems rely heavily on their microbial communities to optimise health. It is well known that microbial species composition and abundance are closely related to plant growth, function and physiology of host plants. Plant-associated microbes are critical for plant’ tolerance to diverse stresses including pathogens by boosting plant defence responses, which could benefit plant resilience. However, the relationship between the diversity of microbial community and the changes of tree response to e[CO₂] is largely unexplored. With the Birmingham Institute of Forest Research (BIFoR) Free Air Carbon Dioxide (FACE) facility and our collective expertise we are in the unique position to investigate e[CO₂] effects on the diversity of microbial communities (bacteria/fungi/bacteriophage) on different tree species, 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 a resultant negative impact in 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) (Figure1). This approach is essential for making accurate predictions regarding future tree health and disease management. 

Training and Skills:

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.

The student will receive specialist training for this multidisciplinary project, encompassing fieldwork, microbiology, genomics, metabolomics, data management and statistical analysis and interpretation of large and complex data sets.

The student will be supported to develop these skills within the School of Biosciences and BIFoR (Birmingham) and at the University of Warwick (metabolomics), allowing the student to excel in all of these aspects of data acquisition, analysis and dissemination and to build important networks.

The supervisory team is multi-disciplinary and highly experienced, based in excellent, well-equipped institutions, and will provide comprehensive support for the student across all aspects of the project. 

If you wish to apply to the project, applications should include:

• A CENTA application form, downloadable from: CENTA application
• A CV with the names of at least two referees (preferably three and who can comment on your academic abilities)
• The application should please completed via: https://sits.bham.ac.uk/lpages/LES068.htm. Please select Apply Now in the PhD Bioscience (CENTA) section. Please quote CENTA23_B2 when completing the application form.

For further information on how to apply please visit https://centa.ac.uk/apply/how-to-apply/.