Performing Department
(N/A)
Non Technical Summary
A rapid increase in the use of wood as a renewable feedstock for energy and bioproducts is expected as new global climate change policies encourage a transition away from fossil fuels. Effective production of biomass feedstocks requires overcoming economic, environmental, and societal obstacles. Deploying tree crops that produce high yields (to improve profitability) with minimal inputs (for low environmental impacts) on non-crop land (avoiding competition with food and fiber production) will be critical. This project seeks to demonstrate that our promising new transgenic tree crop can be commercialized to achieve these goals. We use an innovative propriety technology (EliteTree TM) to genetically engineer superior tree crops that feature both accelerated stem growth and increased wood density. Deploying these trees in Short Rotation Coppice plantations has the potential to produce a consistent supply of woody biomass feedstock that will overcome existing economic, environmental, and social obstacles. If commercialized, otherwise unproductive secondary agriculture land can become the source of the woody feedstocks required to contribute to renewable energy and non-fossil product goals of the future while strengthening rural economies around the country and world. In-field validation of this technology is a required step toward commercial deployment. Building on the preliminary success in establishing EliteTreeTM poplars in our stool beds, we propose to measure the growth performance of the trees; analyze the properties of the EliteTree TM biomass; and establish 'real life' SRC production system. Successful completion of this project will reduce the technical risk and make the technology more attractive to potential investors/partners.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
The overall goal of this Phase I project is to reduce the technical risk of EliteTreeTM technology by demonstrating that the technology effectively delivers economically and environmentally sustainable means to produce biomass feedstock, offering competitive advantages over the current and anticipated solutions in the marketplace.
Project Methods
Phenological Observations. Spring and autumn phenology characterized by timing of bud break and bud set will be monitored in existing stool beds for two seasons (2023 and 2024). The observations will be made and recorded by the same personnel walking through the field twice a week (every Monday and Thursday) using a scale of 0 to 10 to describe the different phenological stages. The spring budbreak of the terminal buds will be scored on a scale from 0 to 3 (0 = dormant bud, 1 = bud swollen, 2 = bud open with visible green tip, 3 = complete bud flush), immediately followed by recording leaf unfolding (very small leaves with visible petiole, stage 4). Within a few weeks of leaf unfolding, the condition of the apical meristem of the terminal shoot will be scored on a scale from 5 to 7 (5 = current terminal of the main stem actively growing, 6 = terminal bud beginning to form on shoot apex, 7 = final bud set with terminal bud fully developed and covered by dark brown scales). Finally, we will visually score for autumn senescence as stages 8 to 10 using the Swedish autumn senescence score card (8 = ~25% of the leaves on the tree turned yellow, 9 = ~50% of the leaves on the tree turned yellow and 10 = 100% leaf drop). The tree-averaged green-cover period (GCP) will be calculated as the difference between the day of the year (DOY) recorded for stages 4 and 9, as described by Soolanayakanahally et al. (2012).Measuring Photosynthesis. A LI-COR 6400XT (LI-COR Biosciences, Lincoln, NE) will be used to measure photosynthetic rates on randomly selected plants (5 trees per construct and control) in the existing stool beds. Plants will be measured on the Leaf Plastocron Index (LPI) 10 leaf of each tree at two hours before solar noon on the 1st and 15th of the month during the growing season. It is expected that transgenic poplars expressing EliteTreeTM construct will have higher assimilation of carbohydrates in the stems than the non-transgenic control plants throughout the experiment. During the photosynthesis measuring, the chlorophyll fluorescence parameters of photosystem II efficiency will be taken on each plant using a MultispeQ device as part of the PhotosynQ platform (photosynq.org). We expect that plants with increased GA and sink-strength have higher photosynthesis.Growth Measurements. This experiment is to determine differences in growth rate and survival by measuring the height (from the ground to the apex of the tallest stem) and caliper (of the largest stem at 22cm above ground level) of the trees in the existing stool beds. Height is a useful measure for comparing the growth of trees from various transgenic lines and diameter is useful for calculating stem volume and ultimately biomass. Two sets of measurements will be made: the first at the beginning and the second at the end of the 2023 growing season. Existing stems will be harvested during the winter of 2023-24 and cuttings prepared for the establishment of the Phase II yield trial. Re-sprouting of the coppiced plants will occur in the spring of 2024 and the number of sprouts on each "stool" will be tallied in early summer of that year. It is important to determine how vigorously candidate SRC transgenic lines will re-sprout after cutting and ultimately how they partition biomass into these sprouts (i.e., will they produce a few large stems or many small stems). This has a bearing on harvesting efficiency. Missing stems will be noted at each measurement interval in order to calculate survival.Biomass Production Calculation. In this study, the term ''woody biomass'' is defined as the total aboveground portion of stems and branches expressed on a unit area basis. At the end of 2023 growing season, trees in the existing stool bed will be cut and the aboveground portion (branches and stem) of each will be weighed fresh using a tripod scale. It is important to note that the Phase I stool bed planting was not designed as a yield trial but rather as a means for producing numerous hardwood cuttings in subsequent field trials. Consequently, any areal estimate of biomass production derived from these trees will be highly speculative. This is why the Phase II yield trial planting will be so critical in moving this technology forward toward commercialization. Given the limitations of the Phase I planting, the average total fresh weight per tree will be calculated based on field weight measurements of stems and branches, and used to compare the various genotypes in the trial. Determining dry weights and areal biomass yield will not be attempted using Phase I data but will be done in Phase II.Cell Wall Analysis. Cell wall carbohydrate and lignin analysis will be carried out at the Research Technology Support Core Facility (RTSF) at MSU. In brief, stem internode segments between leaf plastochron index 10 and 15 of the Stool bed trees at the end of the 2023 growing season will be collected. Wood samples with or without bark will be prepared and submitted to the RTSF for analysis.Lignin Isolation/ Characterization for Downstream Applications / Products. Lignin will be isolated following the Klason method, and the acid-insoluble lignin samples will be analyzed to evaluate their suitability as reactive intermediates for bioproducts developments. The following properties of the lignins will be measured: (1) ash content according to TAPPI T 212 om-93 using a muffle furnace at 575°C for 4 hrs; (2) elemental analysis, using PerkinElmer 2400 Series II CHNS/O elemental analyzer; (3) mineral content (Na, Ca, K, Fe, Al, and Mg) following American Association of Analytical Chemists (AOAC) procedure 985.01, using inductively coupled plasma-optic emission spectroscopy (ICP-OES); (4) glass transition temperatures (Tg), using differential scanning calorimeter (DSC-Q100), (5) Hydroxyl content, using phosphorus nuclear magnetic resonance spectroscopy (31P NMR); (6) Average molecular weight, number, and polydispersity index of acetylated lignin using gel permeation chromatography (GPC). The characterization data will help us to assess the suitability of isolated lignins for phenolic resin, if it has high guaiacyl content, for polyurethane applications if it contains high aliphatic hydroxyl content, and for epoxy resin if it has high phenolic hydroxyl content and low molecular weights.Establishment of a SRC Field Test. Mid-western SRC poplar plantations are established using 10"-long dormant hardwood cuttings that are produced in stool beds. We propose using a yield trial planting design similar to one previously developed and used by PI Miller (https://www.canr.msu.edu/uploads/396/36452/2016c.pdf). Recognizing the limited number of cuttings that can be made from these small trees, it will be necessary to forego the use of replications in this trial and rely on a single measurement plot to represent each genotype.A site covered by our APHIS permit will be prepared in the fall of 2023 by removing existing vegetation with a combination of chemical and mechanical methods. As many as thirty superior EliteTreeTM lines will be selected based on measurements made in Phase I and 10" hardwood cuttings of these will be prepared during the winter of 2023-24. The planting design calls for 48 cuttings to complete one measurement plot. Cuttings will be inserted in well cultivated ground in the Spring of 2024 in rectangular plots composed of 6 columns (spaced 91 cm apart) and 8 rows (spaced 61 cm apart). This will result in a planting density of 18,000 stems per acre. The outer 2 columns and rows of each plot will provide a border for the 8 measurement trees on the interior. This will isolate the measurement trees from any unequal competition from surrounding plots and provide reliable observations of how the various genotypes might perform under commercial plantation conditions.