Identifying Genes Related to Stomatal Anatomy: An Approach to Predict Drought Tolerance in Sagebrush, a Keystone Species of Northwestern America

Drought, heat waves and fire have become more prevalent in northwestern North America threatening the sustainability of sagebrush (Artemisia tridentate) populations. This project aims to understand and predict pathways related to drought tolerance across sagebrush populations by identifying genes related to stomatal anatomy. Stomata control gas exchange, regulate transpiration, and enable photosynthesis becoming essential to estimate water use efficiency (WUE) in face of climate change. While the sagebrush genome has been recently published, it is not fully annotated, and genes related to stomatal anatomy have not been identified. The annotated genome of the model Arabidopsis thaliana is mined to identify genes underpinning stomatal anatomy and recover those in sagebrush. An automated literature review pipeline was designed and implemented to identify genes related to our target phenotype in Arabidopsis thaliana. The pipeline is seeded with a list of key genes and mines for additional genes, for which their function has been confirmed by publications deposited in the NCBI database. Those latter publications are checked to evaluate whether they connect to new genes involved in this phenotype. This resource is currently used to identify genes controlling stomatal anatomy in sagebrush and perform comparative analyses across populations to predict differences in WUE

Predicting Sustainability of Sagebrush Populations in a Changing Climate: Insights from a Greenhouse Experiment

The western U.S. has been experiencing the highest levels of drought and heat not seen in more than a century as a direct result of human influence. Big sagebrush- Artemisia tridentata- plays a pivotal role in the functioning of our local ecosystem as a keystone species and its dramatic decline at the population level is alarming. This project aims at predicting the adaptive capacity of sagebrush populations to cope with climate change by focusing on studying water use efficiency by way of stomata density and size. We hypothesize that plants pre-adapted to drought will display high density and low stomatal size to minimize transpiration while maximizing growth. Seeds from four sagebrush populations in Idaho, Nevada, and Utah representing contrasting climatic conditions (along an evapotranspiration gradient) were collected and grown in a common garden. Stomata size and density were determined by removing the leaf epidermis and analyzing microscope images. Theoretical fitness was assessed with comparative statistics to determine water use efficiency against potential evapotranspiration (PET). We found the Utah population had significantly higher density and lower stomatal size compared to other populations, which translates to the theoretical traits desired for sustainability in higher PET environments. Across all our populations, we saw a variety of traits at the individual level, suggesting that some proportion of each population are pre-adapted. Other researchers in ecology and evolution can utilize our work to more clearly assess sagebrush fitness. Future restoration efforts can use our findings to select for better adapted seedlings and conserve our natural ecosystem

When Math Meets Biology: Characterizing Stomatal Clusters

Drought has been increasing in intensity and frequency alongside soaring temperatures in the western United States. Sagebrush is a keystone species in this region threatened by anthropogenic climate change. This project investigated the adaptive capacity of sagebrush populations to cope with climate change by focusing on studying water use efficiency by way of stomatal clustering. This study developed a new means of characterizing clusters with low resolution data. We hypothesized that there would be significant differences in the clustering characteristics of the sagebrush in each of the sample locations due to differences in the climates of the sample locations. Seedlings representing populations from Utah, Idaho, and Nevada were grown in a common garden. Leaf epidermis was removed and imaged with a microscope for analysis. An R script was developed to calculate probabilities of clustering events. Comparative statistics were performed on the outputs of this script as a means to compare clustering characteristics of sample populations. This script is one of the first tools developed to characterize clusters using low resolution data. We found that the sampled sagebrush displayed stomatal clustering and that the characteristics of the clustering did not significantly differ between the sample populations. However, this clustering was weak; the stomata were over-dispersed indicating that our sample populations were nearing peak water use efficiency in this regard. Future research should focus on other characteristics, such as stomatal size and density, to quantify water use efficiency as sagebrush show little capacity for adaptation in terms of stomatal clustering. Our developed tool can be utilized by other researchers also working on quantifying stomatal clustering to extend research further into other drought adapted plants

Seen, but Not Heard?: Evaluating the Visibility of Plants in the Conservation Translocation Literature

Human activities are affecting the sustainability of functional ecosystems worldwide, with an estimated 100-1000x increase in recent extinction rates due to anthropogenic factors. Conservation translocations —or the movement of organisms to enhance recovery efforts— are an important tool to combat anthropogenic impacts such as climate change, habitat loss, fragmentation, and barriers to dispersal that can lead to reduced adaptive capacity and extinction. While exemplars in conservation translocation science have largely included vertebrates, fewer models exist for plants, despite their ecological importance as sources of food and habitat. In order to develop best management practices for improved plant translocation success, we evaluate the visibility of plants in the conservation translocation literature using the newly developed R-package LitRevieweR. Preliminary results indicate that plants constitute a mere 17% of IUCN conservation translocation case studies, but comprise 40% of peer-reviewed literature found through Scopus. Literature mining peer-reviewed studies and current IUCN Conservation Translocation Guidelines has revealed language specific to plant conservation translocations, including the words important to plant translocation success (e.g., soil microbial communities, and climate change). We recommend the development of IUCN conservation translocation guidelines specific to plants using this informed approach to increase plant conservation and restoration success worldwide

Hot Takes: A Comprehensive Review of Genes That Help Plants Survive Drought

Increasing temperatures and aridity negatively affect plant communities, including the recruitment of keystone ecological species like big sagebrush (Artemisia tridentata). While research on the genomic basis of plant resilience towards drought has been conducted in crops and model plants, fewer studies have evaluated natural plant communities. We provide a resource for identifying genes underpinning drought across a broad range of plants using a literature mining approach with the newly developed package LitRevieweR. Our results confirm that most peer-reviewed studies on drought resistance in plants are conducted on model and crop species that already have genomic resources available. This approach also identified over 4K genes associated with drought. Top-reported genes (e.g., AER, PER, and GWD) show associations with dozens of biological processes including proteogenesis, photosynthesis, stress response, and immune response. Our research will be used to construct networks for genome to phenome research, with applicability to assessing adaptive capacity of natural plant communities towards drought, pointedly big sagebrush. We anticipate this research informing future restoration efforts for sagebrush and other plant species by ensuring individuals have the adaptive capacity to endure future drought conditions