Life Sciences Commons^™

Analysis Of Cereal Aphid Feeding Behavior And Transcriptional Responses Underlying Switchgrass-Aphid Interactions, Kyle G. Koch

Department of Entomology: Dissertations, Theses, and Student Research

Switchgrass, Panicum virgatum L., is a perennial warm-season grass that is a model species for the development of bioenergy crops. However, the sustainability of switchgrass as a bioenergy feedstock will require efforts directed at improved biomass yield under a variety of stress factors. The objectives of this research were to: (1) elucidate greenbug and yellow sugarcane aphid feeding behavior on resistant and susceptible switchgrasses using electronic penetration graphs (EPG), (2) define transcriptional changes before and during insect feeding through RNA-seq to identify candidate resistance genes in a hybrid switchgrass cultivar, and (3) utilize methods in RNA sequencing of insects to …

Effects Of Precipitation Changes On Aboveground Net Primary Production And Soil Respiration In A Switchgrass Field, Qi Deng, Sadiye Aras, Chih-Li Yu, Kudjo E. Dzantor, Philip A. Fay, Yiqi Luo, Weijun Shen, Dafeng Hui

Biology Faculty Research

Switchgrass (Panicum virgatum L.) is widely selected as a model feedstock for sustainable replacement of fossil fuels and climate change mitigation. However, how climate changes, such as altered precipitation (PPT), will influence switchgrass growth and soil carbon storage potential have not been well investigated. We conducted a two-year PPT manipulation experiment with five treatments: −50%, −33%, +0%, +33%, and +50% of ambient PPT, in an “Alamo” switchgrass field in Nashville, TN. Switchgrass aboveground net primary production (ANPP), leaf gas exchange, and soil respiration (SR) were determined each growing season. Data collected from this study was then used to test whether …

Adoption Of Switchgrass Cultivation For Biofuel Under Uncertainty: A Discrete-Time Modeling Approach, Pralhad Burli, Eric Forgoston, Pankaj Lal, Lora Billings, Bernabas Wolde

Lora Billings

Adoption Of Switchgrass Cultivation For Biofuel Under Uncertainty: A Discrete-Time Modeling Approach, Pralhad Burli, Eric Forgoston, Pankaj Lal, Lora Billings, Bernabas Wolde

Eric Forgoston

Adoption Of Switchgrass Cultivation For Biofuel Under Uncertainty: A Discrete-Time Modeling Approach, Pralhad Burli, Eric Forgoston, Pankaj Lal, Lora Billings, Bernabas Wolde

Pankaj Lal

Intraspecific Differences In Belowground Associations And Seedling Root Morphology For The Biofuel Crop, Panicum Virgatum., Erin Renee Kinnetz

Electronic Theses and Dissertations

The perennial C₄ grass Panicum virgatum (switchgrass) is a promising bioenergy feedstock. Switchgrass is symbiotic with arbuscular mycorrhizal fungi (AMF). I examined 12 varieties of switchgrass grouped into 2 ecotypes (upland, lowland) to see if they differed in AMF abundance and root colonization using the GLBRC Variety Trials experiment. There was higher root colonization of lowland ecotype. A greenhouse experiment evaluated the role of live soil organisms in seedling establishment of 11 varieties. Live soil increased seedling survival, growth and influenced root morphology. Ecotypes differed in root architecture. Lowland developed a higher specific root length (SRL), a trait associated …

Assessing The Potential To Decrease The Gulf Of Mexico Hypoxic Zone With Midwest Us Perennial Cellulosic Feedstock Production, Andy Vanloocke, Tracy E. Twine, Christopher J. Kucharik, Carl J. Bernacchi

Andy VanLoocke

The goal of this research was to determine the changes in streamflow, dissolved inorganic nitrogen (DIN) leaching and export to the Gulf of Mexico associated with a range of large-scale dedicated perennial cellulosic bioenergy production scenarios within in the Mississippi–Atchafalaya River Basin (MARB). To achieve this goal, we used Agro-IBIS, a vegetation model capable of simulating the biogeochemistry of row crops, miscanthus and switchgrass, coupled with THMB, a hydrology model capable of simulating streamflow and DIN export. Simulations were conducted at varying fertilizer application rates (0–200 kg N ha -1) and fractional replacement (5–25%) of current row crops with miscanthus …

Candidate Perennial Bioenergy Grasses Have A Higher Albedo Than Annual Row Crops, Jesse N. Miller, Andy Vanloocke, Nuria Gomez-Casanovas, Carl J. Bernacchi

Andy VanLoocke

The production of perennial cellulosic feedstocks for bioenergy presents the potential to diversify regional economies and the national energy supply, while also serving as climate ‘regulators’ due to a number of biogeochemical and biogeophysical differences relative to row crops. Numerous observational and model-based approaches have investigated biogeochemical trade-offs, such as increased carbon sequestration and increased water use, associated with growing cellulosic feedstocks. A less understood aspect is the biogeophysical changes associated with the difference in albedo (a), which could alter the local energy balance and cause local to regional cooling several times larger than that associated with offsetting carbon. Here, …

Transcriptional Analysis Of Defense Mechanisms In Upland Tetraploid Switchgrass To Greenbugs, Teresa Donze-Reiner, Nathan A. Palmer, Erin D. Scully, Travis J. Prochaska, Kyle G. Koch, Tiffany Heng-Moss, Jeffery D. Bradshaw, Paul Twigg, Keenan Amundsen, Scott E. Sattler, Gautam Sarath

Department of Entomology: Faculty Publications

Background: Aphid infestation of switchgrass (Panicum virgatum) has the potential to reduce yields and biomass quality. Although switchgrass-greenbug (Schizaphis graminum; GB) interactions have been studied at the whole plant level, little information is available on plant defense responses at the molecular level.

Results: The global transcriptomic response of switchgrass cv Summer to GB was monitored by RNA-Seq in infested and control (uninfested) plants harvested at 5, 10, and 15 days after infestation (DAI). Differentially expressed genes (DEGs) in infested plants were analyzed relative to control uninfested plants at each time point. DEGs in GB-infested plants induced …

Seasonal Switchgrass Ecotype Contributions To Soil Organic Carbon, Deep Soil Microbial Community Composition And Rhizodeposit Uptake During An Extreme Drought, Catherine E. Stewart, Damaris Roosendaal, Karolien Denef, Elizabeth Pruessner, Louise H. Comas, Gautam Sarath, Virginia L. Jin, Marty R. Schmer, Madhavan Soundararajan

Department of Biochemistry: Faculty Publications

The importance of rhizodeposit C and associated microbial communities in deep soil C stabilization is relatively unknown. Phenotypic variability in plant root biomass could impact C cycling through belowground plant allocation, rooting architecture, and microbial community abundance and composition. We used a pulse-chase ¹³C labeling experiment with compound-specific stable-isotope probing to investigate the importance of rhizodeposit C to deep soil microbial biomass under two switchgrass ecotypes (Panicum virgatum L., Kanlow and Summer) with contrasting root morphology. We quantified root phenology, soil microbial biomass (phospholipid fatty acids, PLFA), and microbial rhizodeposit uptake (¹³C-PLFAs) to 150 cm over …

Native Species For Biomass Production And Roadside Habitat In South Dakota, Jacob Foley

Electronic Theses and Dissertations

Native grasses and forbs are being considered for planting along South Dakota roadsides to create a favorable habitat for wildlife while also allowing landowners a source of forage and biomass production. South Dakota is host to 54,900 hectares (145,000 acres) of right-of-way that are managed by the South Dakota Department of Transportation. Approximately 80% of the roadsides are used by landowners for hay production. Species diversity and potential biomass yield were determined for the current roadside vegetation along four transects (SD Highways 14, 34 and 50) and SD I- 29 between White, SD and Elk Point, SD. Smooth bromegrass (Bromus …