Progress 06/01/23 to 05/31/24
Outputs
Target Audience:Target audiences for our project include academic researchers, germplasm developers, land managers of pine forests, stakeholders in the silvicultural industry, and the general public concerned with forest health for intrinsic, aesthetic, and recreational reasons. This year, we reached many of these audiences by presenting at multiple scientific conferences in Florida and San Francisco, which were attended by academic researchers. Additionally, PD Hammond and co-PD Mantova attended and presented findings from the current reporting period at the Forest Biology Research Cooperative (FBRC, co-directed by Co-PD's Peter and Martin), which was attended by a consortium of corporate partners who collectively breed, deploy, and manage millions of hectares of southern pine plantations in the USA. Changes/Problems:For Task 1.1, we originally proposed to sample the 315 genotypes present in the ADEPT2 common garden. During our initial mortality surveys, we detected complete mortality in several of the genotypes as well as individuals highly affected by rust fungi that preclude the use of these genotypes in our project. Finally, we identified that 192 provenances remained replicated with a tree in each of the six blocks of the experiment, from which we could sample. During the first weeks of the first field season, we identified that our throughput might be limited to 51 provenances per field season. With two planned field seasons, we held a meeting with all project Co-PDs and decided to maximize the genetic variation in our collected traits by sampling more provenances (100 in total over Y1 and Y2) instead of sampling more replicates of fewer provenances. We thus carried out an analysis to identify the 100 provenances which best represented the geographic and climatic diversity of the natural range of loblolly pine. In spite of this unexpected change to our sampling design, both the number of available genotypes, the trait variability among them, and the variability in their geographic and climatic origin is still large, encompassing the entire species native range, and will not prevent us from achieving our goal of phenotyping the diversity of growth and survival traits across the distribution of the species. Indeed, as reported in the accomplishments above, the first year's sampling revealed exciting variation in key climate-resilient growth and survival traits of loblolly pine, which we will double our sampling depth of in the second year. Because of the sampling changes described for Task 1.1, the number of genotypes available for hyperspectral measurements is also smaller than originally proposed in Task 1.3. However, the current number of point-source spectral measurements sampled is already several times larger than the recommended number of samples (~200) to develop robust models that can predict plant traits. The fact that these measurements already cover over 25% of the existing genotypic diversity available within ADEPT2 ensures that models trained with these data cover a wide range of the genetic variability existing within the distribution of the species. We will also complement our existing efforts with additional pv-curve and hyperspectral measurements in the 5 cloned provenances during the PlantArray drought experiments planned for Task 2.1. We expect to begin developing hyperspectral models a year earlier (originally planned for Y3, now beginning in Y2) given the broad variation in traits already observed in the first 51 genotypes. During year 1, we collected 654 hyperspectral reflectance measurements across 51 different genotypes that were paired with point measurements of plant water potential and water content. During year two, we will leverage this dataset to build models for hyperspectral trait prediction. For Task 1.3 We had originally proposed to use provenances from Virginia, Georgia, Alabama, Texas, and Florida. However, our partner company was unable to supply the provenances from Virginia and Georgia by the time the project got funded. We decided to replace these two provenances by two other pure lines from Arkansas and South Carolina that were currently in stock, after a project-wide meeting to determine the most useful provenances, and based on our further phenotyping after project initiation. The South Carolina provenance will serve as a replacement for Georgia as it is also at the Atlantic edge of the species distribution. The Arkansas provenance comes from the west side of the Mississippi, which acts as a natural barrier for gene flow between populations located at each side of the river in this species. As such, the Arkansas provenance -alongside the Texas provenance- will provide a second source of genetic diversity from the west side of the Mississippi and ensure a more balanced coverage of the existing trait variability across the species distribution. What opportunities for training and professional development has the project provided?Undergraduate training and development: During this project, three undergraduate scholars were trained: Emily Perry and Eric Torres. Each student was paid as an undergraduate research assistant, and received direct mentorship from the project postdoctoral researcher (co-PD Mantova) and from project director Hammond. This resulted in two poster presentations (see outputs) led by undergraduate researchers, and a total of four presentations in which undergraduate students were co-authors. The first manuscript resulting from this project also includes them. Graduate student training and development: This project supports one graduate student full-time, co-advised by co-PD Cochard, co-PD Torres-Ruiz, and co-PD Hammond. In the first year, the student had the opportunity to participate in the development and data collection of vulnerability to cavitation curves, a key trait for parameterizing the mechanistic model used in aim 2. During the first year of the project, this PhD student also had the opportunity to develop and submit a Fulbright proposal to support their travel to PD Hammond's laboratory at the University of Florida. Their application was successful, and Elizabeth (PhD student) will arrive at the Hammond lab in October of 2024, to continue working on climate-resilient growth and survival of loblolly pine, as a part of our PINE-PHYS project. Her Fulbright project will allow her also to sample trees outside of the common garden, and across sites of interest in the natural range of the species--complementing the outputs of this PINE-PHYS project. Postdoctoral training and development: Additionally, Dr. Mantova had opportunities for professional development: she was able to attend the 2023 fall meeting of the American Geophysical Union, where she presented findings from the first year of this project as an oral presentation. Additionally, she was able to organize as co-chair a Gordon Research Seminar on Multi-Scale Vascular Plant Biology, providing her with leadership opportunities in the field of plant vascular biology. Finally, throughout the first year of the project virtually, and from mid-April to mid-May of 2024 while visiting in-person in France, Dr. Mantova had the opportunity to learn and develop skills in mechanistic modeling of plant hydraulics using the SurEau model, with Co-PD Cochard from INRAe. PD/Co-PD training and development: During the first year, project PD Hammond was in communication with co-PD Cochard and co-PD Mantova regarding the use of the mechanistic plant hydraulics model, SurEau, which he learned to operate and use. This skill will be useful in completing the stated objectives in aim 2 of the project, and more broadly in his research program. How have the results been disseminated to communities of interest?Presentations of the work from this project during the first year have been primarily at research conferences and with stakeholder audiences. Scientific conference presentations: One presentation was given by Co-PD Mantova in December 2023 at the American Geophysical Union annual meeting (AGU23) in San Francisco, California. The AGU meeting is the largest gathering of Earth and space scientists, reuniting, each year, more than 25,000 scientists coming from around the world. It also convenes educators, policymakers, journalists and communicators to better understand our planet and environment. Additionally, PD Hammond organized and chaired a special session at the 2023 Ecological Society of America meeting in Portland, Oregon, titled "How hot is too hot for land plants?" that was attended by over 100 people, from diverse backgrounds--including foresters, land managers, and tribal leaders, to discuss the impact of climate extremes on plants and trees, and the importance of deploying and developing climate-resilient materials. Stakeholder presentations: During 2023, presentations at the Forest Biology Research Cooperative meeting were given by Co-PD Mantova, as shown in the outputs of this report. The Forest Biology Research Cooperative is a cooperative group composed of academics and industry stakeholders interested in southeastern pine forests, especially in the silviculture and production of loblolly pine, the focal species of our PINE-PHYS project. This annual meeting was also attended by project director Hammond, who engaged directly with stakeholders at the meeting to understand their interests in climate-resilient growth and survival traits of loblolly pine, and their present plans for deployment and development of further improvements (as proposed in our project). What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period (6/01/2024-05/31/2025) we plan to conduct the following work to accomplish progress on each of the tasks of our project. survival traits needed to accomplish task 1.2, 1.3, and 2.2. Task 1.1: We will continue phenotyping of provenances of loblolly pine under task 1.1 at the Millhopper common garden site (ADEPT2). This is expected to double our provenances for which we have collected the full suite of climate-resilient growth, exceeding the 100 needed to begin preliminary analyses of task 1.2. In order to accelerate the phenotyping of the physiological traits, particularly the production of PV-curves, to reach the initial target number of provenances, we are developing new methods that will allow us high throughput phenotyping. The development of the new method will be the topic of a technical publication that we aim to submit during the next reporting period. Data supporting this method was collected alongside the classic pressure-volume curve method for our year 1 provenances, providing a large dataset of comparison by which we can train and test a model for PV-trait prediction with high-throughput measurement systems in development. Additionally, given the wide variation in key traits observed in the first year, a Fullbright scholar (PhD student Elizabeth Ilinca--supported by this project in Clermont-Ferrand, France) will visit the Hammond lab at UF from October 2024 through May 2025 to conduct additional field sampling of climate-resilient growth and survival traits in loblolly pine. During their Fulbright project, they will visit provenances of loblolly pine from the year 1 dataset that represent extreme and average trait values, and travel to these locations to sample trees growing in natural populations under local provenance-specific climate conditions, to investigate the plasticity of these key traits in comparison with the common garden trait values already collected in Gainesville. Additionally, they will sample some replicated clones in the Gainesville common garden, to explore trait variation within a genotype among clones. Task 1.2: We will begin undertaking the genetic analyses once we have collected the first 100 provenances, which encompass the range-wide geographic and climatic diversity of loblolly pine as a species. While this is detailed in the proposal, and our plans remain unchanged, briefly the plan is as follows. We will conduct genetic association analysis to identify SNPs in candidate genes that are significantly associated with individual traits. Importantly, this will reveal if some traits have opposite correlations. Next, we will test for heritability of the observed climate-resilient growth and survival traits. Both of these steps will help to identify which traits might be most viable as targets for future improvement of the species, and also will narrow down the total number of traits necessary to measure to capture a minimum set for improving climate resilience in the species. Additionally, we will begin to explore climate associated analyses between the genetics, through colleagues of Co-PD Peter at ORNL and already developed analysis pipelines. Note, these analyses were previously planned for Y3 of the project, but after a recent project meeting reviewing progress to date, we believe we can begin this work in Y2, ahead of schedule. Task 1.3: During the next reporting period, we will develop spectral models to predict climate-resilient growth and survival traits from spectral reflectance. Earlier this year, PD Hammond's lab published a proof of concept for "Spectral Ecophysiology" (doi:10.1111/nph.19669), demonstrating for the first time that spectral models can accurately predict physiological functional traits important to climate-resilient growth and survival, such as the turgor loss point. During the first year of this project, we collected hyperspectral reflectance data on the first 51 provenances alongside collection of the suite of physiological traits we consider key for predicting climate-resilient growth and survival. In year two, we expect that we will identify which traits are more or less promising for hyperspectral prediction, which can greatly accelerate phenotyping of functional traits through imaging approaches. In addition to developing models with already-collected data, we will collect hyperspectral data on seedling trees in our physiological phenotyping platform (Plant Array) in task 2.1 (see below), for further model development and to understand how if, and if so, how, relationships between physiological traits and spectral reflectance change across ontogeny. Note, these analyses were planned to initiate in Y3, but with such a large amount of data collected already in year 1, we expect that our initial hyperspectral trait prediction models will be developed by the end of year 2, and that we can refine and build upon these in subsequent years of the project.. Task 2.1: We have received 150 clones of each genotype and they are currently growing at our greenhouse in Gainesville, Florida. We will transplant them into pots once they start developing adult needles where they will continue to grow until they are large enough to be transferred to our high throughput physiological phenotyping platform (the UF Plant Array) by no later than June 2025.We plan to initiate the seedling experiment in summer 2025, as originally planned in our project proposal. The approach will remain as described in the proposal under task 2.1. Task 2.2: In year two, we plan to conduct genotype by provenance simulations of the > 100 provenances we expect to have phenotyped by the end of the second field season. We will conduct a trait sensitivity analysis to narrow down the suite of traits necessary to continue phenotyping in future work aimed at genetic improvement of climate resilience in the species, providing needed optimization to screening and breeding programs. Note, we have already begun the mechanistic modeling of task 2.2 (see this year's "what was accomplished", above) and postdoctoral researcher Dr. Mantova (co-PD) has dedicated significant time to learning how to use and apply the model across scales from individual plants to the entire Southeastern US. While this task was initially intended to begin during Year 2, the large amount of phenotypic data (and trait variation observed) encouraged us to begin work on this task early. We will continue to develop these modeling approaches, and the development of ideotypes for improvement and identification of fit between extant genotypes and particular locations in geographic and climatic space, for improved deployment. Planned publications: The first publication from this project is being led by Co-PD Mantova (postdoctoral researcher), and will be submitted during the next reporting period. A second publication, on the acceleration of phenotyping for physiological traits (specifically, turgor loss point) will aim to be submitted by the end of year two of this project. Planned meetings: During year two of the project, PD Hammond will organize quarterly project meetings to discuss progress, roadblocks, and products of the project.PD Hammond, co-PD Mantova, co-PD Cochard, and co-PD Torres will aim to meet in person during the XIM6 conference in Seville, Spain to discuss project progress and next steps. Planned conferences: PD Hammond and Co-PD Mantova plans to attend the AGU24 meeting in December 2024 and present the results of the second year of sampling. Co-PD Mantova and PD Hammond plan to attend the Xylem International Meeting 6 (XIM6) conference that will take place in Sevilla, Spain in March 2025. PD Hammond plans to attend the FBRC meeting in 2024 to present a project update to industry stakeholders growing loblolly pine throughout the Southeastern USA.
Impacts
What was accomplished under these goals?
Task 1.1: As proposed for year 1, we have measured a suite of important physiological growth and survival traits likely to determine the capacity of loblolly pine plantations and forests to survive and thrive under future climates. These measurements have been taken in a common garden of replicated, SNP-genotyped clones (ADEPT2) that cover the entire geographic, climatic, and genetic range of P. taeda. P. taeda covers 10-22°C of mean annual temperature and 850-1500 mm of mean annual precipitation across the south-eastern united states being present from Texas up to Oklahoma and from Florida up to West Virginia. For growth, these included carbon assimilation, stomatal conductance, and water use efficiency at both optimal and elevated temperatures. For survival, we measured xylem vulnerability, leaf residual conductance to water, and cell thermal tolerance. Additionally, we measured anatomical traits that drive growth and survival such as pressure-volume traits (e.g., turgor loss point, capacitance), diameter growth, and huber values in this highly-important timber species. During our first year, we have measured these traits across 51 genotypes of the 192 meeting our sampling criteria in the garden. Thus far, we have observed wide genetic variability in most anatomical, growth, and survival traits within the species. For most traits, variability among genotypes spans ca. +/-2.5 standard deviations from the mean trait value of the species. The only exceptions were the maximum intrinsic water use efficiency (iWUEmax) observed between 20°C and 40°C and the temperature at which iWUEmax occurs (iWUEopt). Both traits showed ca. +/-1 to +/-2 standard deviations from the mean trait value of the species. Based on these findings, extant populations might already harvest combinations of traits well adapted to increased compound heat and drought stress. Additionally, variability in both growth and survival is an essential requirement towards breeding new climate-resilient P.taeda lines. Thus, these findings provide hope for the future of this species both in natural and agricultural settings that will face the challenges of climate change. Task 1.2: As our first year has led to sampling of the first 51 provenances, we are not yet able to conduct quantitative genetic analyses; we expect that with the year two data set (> 100 provenances) we will begin this in the late stages of year 2 of the project. With this data we will calculate clonal repeatability for each trait and pairwise genetic correlations between traits of interest. Genetic analysis for heritability will identify traits suitable for future GWAS analyses. Task 1.3: As proposed in Task 1.3, we have collected plant hyperspectral reflectance data while sampling the genetically diverse common garden of loblolly pine for survival traits. To date, we have collected 654 point-source spectra paired with water potential and water content measurements made during the construction of pv-curves for 51 different genotypes. From this dataset, We will be able to extract 13 different water relations traits for each genotype and relate them to variation in spectral reflectance across genotypes. Coding pipelines for the construction, training, and testing of models of plant water content and water potential are already in place and ready to be deployed to predict these traits on new data. These spectra can also be associated with the 18 anatomical, growth, and survival traits obtained in Task 1.1 for the same 51 genotypes. Task 2.1: Although task 2.1 is scheduled for year 2, making preparations towards this task during the first year was paramount to its success. Towards that goal, we initiated our collaboration with our industry partner ArborGen and started the clone preparation process for 5 pure genotypes originally from Arkansas, South Carolina, Texas, Florida, and Alabama. Thus, covering the edges and middle range of the geographic distribution of P.taeda. 150 clones of each genotype are already growing at our greenhouse in mini soil plugs. We expect them to be ready for planting the initially proposed seedling experiment in our high throughput phenotyping system (PlantArray) by June 2025. The PlantArray has been tested through multiple experiments and coding pipelines have been developed to automate data collection and enable real time assessment. Task 2.2: As proposed in task 2.2, we will mechanistically model growth, mortality risk, and time-to-death for loblolly pine based on quantified seedling and sapling traits measured during the PlantArray experiments described in Task 2.1. In preparation for that task, we have used the trait data collected in adult trees from 51 different genotypes planted in our common garden to further develop and train SurEau both at individual and landscape scales. This exercise not only allowed us to early-prepare and overcome any major roadblocks that we might have faced later with the modeling, but also unveiled the vulnerability and resilience to future climates of extant loblolly pine genotypes during the adult stage of their development across the landscape. We found that, across the 51 genotypes sampled, there is wide variation in time to cessation of growth (modeled as turgor loss) and time to death under drought and heat stress. At a daily maximum temperature of 30°C, the worst performing extant genotype would cease to grow after 21 days of drought and die 7 days after that. At 40°C, this same genotype would stop growing and die 6 and 9 days earlier, respectively. On the other hand, the best performing extant genotype would cease to grow after 167 days of drought and die after 42 days after that. At 40°C, this same genotype would stop growing and die 43 and 55 days earlier, respectively. These results suggest that the intraspecific variability in traits detected in Aim 1 Task 1.1 likely translates into variability in growth and survival across the current genetic and geographic landscape of loblolly pine and will determine the performance of this important species under future climates. Importantly, the best performing genotype in terms of time to cessation of growth and time to death is small in size and has characteristics that make it far from the ideal tree for timber. Thus, tradeoffs between maximizing yield and resilience to stress likely exist in this species. We performed a preliminary attempt at building a climate-resilient "ideotype" with optimal trait combinations for adult trees that maximize performance and achieved a modeled increase of 168% and 191% in time to death relative to the best performing extant genotype at 30°C and 40°C,respectively. While this preliminary ideotype is not yet constrained by the genetic associations that will be unveiled at the end of Task 1.2, its time to cessation of growth, its trunk diameter, and its trunk length were greater than the average across all modeled genotypes. Thus, suggesting that it might be possible to breed new varieties of loblolly pine with greater resilience to future hotter and drier climates with minimal impacts on yield potential.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2023
Citation:
Perry E. E., Mantova M., Castillo-Argaez R., Torres E., Heintzelman C., Clark D., Cochard H., Martin T., Peter G., Sapes G., Torres-Ruiz J., Hammond W. M.. Parched Pines: Investigating the Climatic-Resilience of Loblolly Pine. Poster Presentation.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2023
Citation:
Perry E. E., Mantova M., Castillo-Argaez R., Torres E., Heintzelman C., Clark D., Cochard H., Martin T., Peter G., Sapes G., Torres-Ruiz J., Hammond W. M.. "How Much Can Pine Trees Sweat?" Poster Presentation.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Mantova M., Castillo-Argaez R., Perry E. E., Torres E., Heintzelman C. J., Clark D., Cochard H., Martin T., Peter G., Sapes G., Torres-Ruiz J. M., Hammond W. M.. A Loblolly Pine for Tomorrow: When Genetics, Physiology and Modeling Collide for More Resilient Forests. AGU 2023 Fall Meeting. Oral presentation.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2024
Citation:
Mantova M., Castillo-Argaez R., Perry E. E., Torres E., Clark D., Cinquini A., Heintzelman C. J., Cochard H., Martin T., Peter G., Sapes G., Torres-Ruiz J. M., Hammond W. M.. Pine contains multitude: Intraspecific variation across genotypes in time to growth limitation and mortality risk. Poster presentation. Gordon Research Conference on Multi-Scale Vascular Plant Biology.
- Type:
Other
Status:
Other
Year Published:
2023
Citation:
Mantova M. A loblolly pine for tomorrow. Forest Biology Research Cooperative Annual Meeting. Oral Extension Presentation.
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