Performing Department
(N/A)
Non Technical Summary
Climate change is expected to increase the frequency of agricultural and ecological drought in Western North America during the 21st century. Tree plantations in the Pacific Northwest will undoubtedly be challenged by severe drought events, making it a priority to determine how best to foster climate-change resilient crops. Foliar Endophytic Fungi (FEF) are the collection of non-pathogenic fungal microbes that colonize the interior of plant leaf tissue. Although this plant-fungal symbiosis is ubiquitous for all land plants, it is understudied. Past research has demonstrated FEF to facilitate plant drought-tolerance, yet the mechanisms through which these symbionts regulate stress-tolerance and the degree to which this phenomenon can be generalized across plant species is still unclear. Examining how FEF communities support their host plants, and likewise the plant physiological trade-offs associated with supporting these symbionts, will provide insight into the context in which plants may rely on FEF microbiota for survival.The goal of this project is to determine the extent to which foliar endophytic fungi confer drought stress-tolerance for two tree species native to the Pacific Northwest, Douglas-fir (Pseudotsuga menziesii) and the black cottonwood (Populus trichocarpa). In addition to their role as focal tree species for the timber or feedstock industries,P. menziesii and P. trichocarpa study systems are unique in that the trees used for agriculture closely resemble those trees found in wild populations. Here we will investigate how microbial symbionts facilitate the survival of P. menziesiiand P. trichocarpain naturally stressful ecosystems to inform a potential role of microbes in supporting resilient agroecosystems during periods of environmental stress, such as drought.
Animal Health Component
0%
Research Effort Categories
Basic
90%
Applied
10%
Developmental
(N/A)
Goals / Objectives
Project Goal 1: Examine the extent to which foliar endophytic fungi confer drought stress tolerance for two tree species native to the Pacific Northwest, Douglas-fir (Pseudotsuga menziesii) and the black cottonwood (Populus trichocarpa).1. Design experiments that synthesizeguidance from stakeholders and mentors.2. Conduct two large greenhouse experiments, one with P. trichocarpa and the other with P. menziesii.This includes taking plant physiological data prior to and during a drought event, and collecting foliar tissue to sequence the fungal communities associated with each host seedling.4. Execute lab tasks associated withDNA sequencing of foliar fungal communities from these experiments.5. Process sequencing results through a computational pipeline.6. Work through data analysis and write up the manuscripts associated with these studies.Project Goal 2: Engage relevant communities, stakeholders, and undergraduate students with this project throughout its duration, to maximize the impact of this study and itsfindings.1. Meet regularly with my primary mentor, stakeholders, and collaborating mentors throughout the two years.2.Mentor at least two undergraduate studentsinterested in microbes and sustainable agriculture.3. Present the findings to relevant local communities, including my lab group, the HJ Andrews Experimental Forest community at monthly meetings and stakeholders from the timber industry.4. Present the findings at national conferences, including at the Mycological Society of America - Annual Meeting, Ecological Society of America - Annual Meeting, and the Long Term Ecological Research - All Scientists Meeting.
Project Methods
MethodsExperimental DesignThis project will be executedthrough two separate, yet methodologically similar reciprocal inoculation greenhouse experiments using (1)P. menziesiiseedlings or (2)P. trichocarpa cuttings. In both cases, plants of genotypes found along an environmental gradient will beexposed to foliar microbial communities collected at either the site considered most abiotically stressful or the site considered least abiotically stressful. Plants will then be subjected to a drought event, and I will assess the relative fitness of each seedling in combination with foliar fungal community composition.(1)P. menziesii:The first experiment will consist ofP. menziesiiseedlings, collected as seeds at sites along an elevation gradient in the Western Oregon Cascades. These sites were chosen because they vary in elevation and average annual relative humidity, with thehighest elevation site considered the most abiotically stressful site. Seedlings from all of the six sites will be subjected to one of three microbial treatments: + high elevation foliar microbes, + low elevation foliar microbes, no inoculum (control). Litter collected from the sitescharacterized by the highest and lowest elevation, will be used as the microbial inoculum. Foliar microbes will be applied by treating needles with a liquid microbial slurry, a method we recently applied to this system.(2)P. trichocarpa:The second experiment will use cuttings fromP. trichocarpagenotypes sourced from along an east-west moisture gradient present in the Pacific Northwest. These sites were chosen because they vary in average annual precipitation and theirClimate Moisture Index (CMI), a derived climate variable used as an indicator for potential site drought severity. The driest site will be considered the most abiotically stressful site. Cuttings from all six sites will be subjected to one of three microbialtreatments: + wet foliar microbes, + dry foliar microbes, no inoculum (control). Litter collected from sites characterized by the greatest and the least moisture respectively, will be used as the microbial inoculums. Consistent with theP. menziesiiexperiment, foliar microbes will be applied through a liquid slurry.Drought Event & Data Collection Plants will either be subjected to a well-watered or a water-stress treatment, in a drought event. I will collect foliage for FEF community analysis before, during, and after the drought event. This design is adapted from a similar study examining how the rice rhizosphere microbiome is affected by drought.Using LI-COR technology, I will concurrently take foliar stomatalconductance and Fv/Fm, both assessments of photosynthetic potential. Following the drought event, plants will be assessed for pre-dawn and midday water potential,which together will allow me to assess how plant water status has been affected by the drought. DNA metabarcoding analysis will be done using the ITS amplification region and through a pipeline that has been previously successful with both systems.I will also sequence the 16s region to capture the bacterial communities associated with each sample, enabling me to also observe patterns between bacteria and plant drought tolerance. At the end of the experiment, all plants will be assessed for relative growth rates, root/shoot ratios and total biomass. In total this data will allow me to compare how seedling source location, microbe source location, drought stress, and the interaction between the three conditions affect how seedlings relate with their microbes, and how the microbiota in turn influences seedling resilience to drought.Efforts:I will present my research locally at the HJ Andrews Experimental Forest Monthly meetings.I will present my research at the monthly Agricultural Microbiome meetings, a working group here at Oregon State University.I will visit tree planting sites with silviculturists working in theWillamette National Forest interested in incorporating microbes into tree plantings and reforestation.I will engage undergraduate students with this project to cultivate and further their interest in working in agricultural sciences.Evaluation Plan:I will adhere to a timeline with discrete milestonesto execute these projects over the two-year period. The milestones for both experiments include: (1) setting up the greenhouse experiment, (2) executing the drought event, (3) collecting physiological data during and after the drought event, (4) DNA sequencing of fungal community composition, (5) analyzing the data, (6) publishing associated manuscripts.I will also use professional development opportunities as milestones. This includes (1) presenting at conferences annually and (2) mentoring at least one REU student annually associated with the project.