Plant Biology Commons^™

Biosafety: Evaluation And Regulation Of Genetically Modified (Gm) Crops In The United States, Richard E. Goodman

Department of Food Science and Technology: Faculty Publications

This review of the safety assessment of genetically modified (GM) crops is focused primarily on the process and progress in the United States (US). It reviews the development of the safety evaluation process from the Asilomar conference in 1975 considering issues relevant to recombinant DNA technology, to discussions between the US government, academic and industrial scientists between 1984 and 1994 when the first GM crops were being field tested and evaluated commercial release for food and feed production. International guidelines were also reviewed for consistency with the US system. The overall process includes consideration of information relating to history of …

Msh1-Induced Non-Genetic Variation Provides A Source Of Phenotypic Diversity In Sorghum Bicolor, Roberto De La Rosa Santamaria, Mon-Ray Shao, Guomei Wang, David O. Nino-Liu, Hardik Kundariya, Yashitola Wamboldt, Ismail M. Dweikat, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

MutS Homolog 1 (MSH1) encodes a plant-specific protein that functions in mitochondria and chloroplasts. We showed previously that disruption or suppression of the MSH1 gene results in a process of developmental reprogramming that is heritable and non-genetic in subsequent generations. In Arabidopsis, this developmental reprogramming process is accompanied by striking changes in gene expression of organellar and stress response genes. This developmentally reprogrammed state, when used in crossing, results in a range of variation for plant growth potential. Here we investigate the implications of MSH1 modulation in a crop species. We found that MSH1-mediated phenotypic variation in Sorghum bicolor …

The Trehalose Pathway In Maize: Conservation And Gene Regulation In Response To The Diurnal Cycle And Extended Darkness, Clémence Henry, Samuel W. Bledsoe, Allison Siekman, Alec Kollman, Brian M. Waters, Regina Feil, Mark Stitt, L. Mark Lagrimini

Department of Agronomy and Horticulture: Faculty Publications

Energy resources in plants are managed in continuously changing environments, such as changes occurring during the day/night cycle. Shading is an environmental disruption that decreases photosynthesis, compromises energy status, and impacts on crop productivity. The trehalose pathway plays a central but not well-defined role in maintaining energy balance. Here, we characterized the maize trehalose pathway genes and deciphered the impacts of the diurnal cycle and disruption of the day/night cycle on trehalose pathway gene expression and sugar metabolism. The maize genome encodes 14 trehalose-6-phosphate synthase (TPS) genes, 11 trehalose-6-phosphate phosphatase (TPP) genes, and one trehalase gene. Transcript abundance of most …

Contrasting Metabolism In Perenniating Structures Of Upland And Lowland Switchgrass Plants Late In The Growing Season, Nathan Palmer, Aaron J. Saathoff, Christian M. Tobias, Paul Twigg, Yuannan Xia, Kenneth P. Vogel, Soundararajan Madhavan, Scott E. Sattler, Gautam Sarath

Department of Agronomy and Horticulture: Faculty Publications

Background: Switchgrass (Panicum virgatum L.) is being developed as a bioenergy crop for many temperate regions of the world. One way to increase biomass yields is to move southern adapted lowland cultivars to more northern latitudes. However, many southerly adapted switchgrass germplasm can suffer significant winter kill in northerly climes.

Materials and Methods: Here, we have applied next-generation sequencing in combination with biochemical analyses to query the metabolism of crowns and rhizomes obtained from two contrasting switchgrass cultivars. Crowns and rhizomes from field-grown lowland (cv Kanlow) and upland (cv Summer) switchgrass cultivars were collected from three randomly selected post-flowering …

Grazing Method Effects On Forage Production, Utilization, And Animal Performance On Nebraska Sandhills Meadow, Miles D. Redden

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Mob grazing using ultrahigh stocking densities is promoted as a tool to increase the health and productivity of grasslands by increasing nutrient cycling and soil organic matter. Mob grazing can be defined as a strategy in which area available to grazing animals is restricted to achieve stocking densities of 200,000 kg/ha or greater. Objectives were to determine herbage production, utilization, and cattle weight gains among ultrahigh stocking density grazing and more conventional grazing methods on a Sandhills subirrigated meadow. Treatments included two replications of each of the following: four-pasture rotational grazing with two occupations per pasture in an 80-day grazing …

Synthesis Of The Effect Of Fire On Lesser Prairie‐Chickens, Eric Thacker, Dirac L. Twidwell Jr

Department of Agronomy and Horticulture: Faculty Publications

In this synthesis, we reviewed the scientific literature pertaining to the effects of fire on lesser prairie‐chickens and their habitat. Overall, research is generally lacking that directly assesses relationships among fire, both as a regime and a discrete event, to its effect on lesser prairie‐chicken behavior and habitat value. Yet, research has quantified the effects of fire on vegetation throughout the distribution of the lesser prairie‐chicken, which has been linked to known metrics of habitat value and broad landscape‐level habitat requirements.

To summarize the literature, lesser prairie‐chickens require broad landscapes of fire‐dependent grass‐shrub vegetation. Changes in the eco‐evolutionary fire regime …

Stacking Of A Stearoyl-Acp Thioesterase With A Dual-Silenced Palmitoyl-Acp Thioesterase And Δ12 Fatty Acid Desaturase In Transgenic Soybean, Hyunwoo Park, George L. Graef, Yixiang Xu, Patrick Tenopir, Thomas E. Clemente

Department of Agronomy and Horticulture: Faculty Publications

Soybean (Glycine max (L.) Merr) is valued for both its protein and oil, whose seed is composed of 40% and 20% of each component, respectively. Given its high percentage of polyunsaturated fatty acids, linoleic acid and linolenic acid, soybean oil oxidative stability is relatively poor. Historically food processors have employed a partial hydrogenation process to soybean oil as a means to improve both the oxidative stability and functionality in end-use applications. However, the hydrogenation process leads to the formation of trans-fats, which are associated with negative cardiovascular health. As a means to circumvent the need for the hydrogenation process, genetic …

Qtl Architecture Of Reproductive Fitness Characters In Brassica Rapa, Jennifer M. Dechaine, Marcus T. Brock, Cynthia Weinig

All Faculty Scholarship for the College of the Sciences

Background

Reproductive output is critical to both agronomists seeking to increase seed yield and to evolutionary biologists interested in understanding natural selection. We examine the genetic architecture of diverse reproductive fitness traits in recombinant inbred lines (RILs) developed from a crop (seed oil) × wild-like (rapid cycling) genotype of Brassica rapa in field and greenhouse environments.

Results

Several fitness traits showed strong correlations and QTL-colocalization across environments (days to bolting, fruit length and seed color). Total fruit number was uncorrelated across environments and most QTL affecting this trait were correspondingly environment-specific. Most fitness components were positively correlated, consistent with life-history …

First Report Of Curvularia Inaequalis And Bipolaris Spicifera Causing Leaf Blight Of Buffalograss In Nebraska, B. S. Amaradasa, K. Amundsen

Department of Agronomy and Horticulture: Faculty Publications

During the summer of 2011, foliar blight was observed on buffalograss (Buchloë dactyloides (Nutt.) Engelm.) lawns in Lincoln and Waverly, Nebraska. Disease symptoms were common when buffalograss was growing above 30°C and in drought conditions. Disease symptoms began as dark brown oblong leaf spots, followed by leaf tip dieback and eventual blighting of entire tillers. Leaf infections would progress into patches of thinning turf. Diseased leaf pieces were rinsed in distilled water and placed on 1.5% water agar. Two mitosporic fungal species having conidial morphology of Curvularia and Bipolaris were isolated. Colonies of Curvularia isolates grown on ¼× PDA …

Quantitative Trait Locus Analysis Of Unsaturated Fatty Acids In A Recombinant Inbred Population Of Soybean, Xianzhi Wang, Guo-Liang Jiang, Marci Green, Roy A. Scott, D. L. Hyten, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Soybean [Glycine max (L.) Merr.] is an important oilseed crop which produces about 30 %of the world’s edible vegetable oil. The quality of soybean oil is determined by its fatty acid composition. Soybean oil high in oleic and low in linolenic fatty acids is desirable for human consumption and other uses. The objectives of this study were to identify quantitative trait loci (QTLs) for unsaturated fatty acids and to evaluate the genetic effects of single QTL and QTL combinations in soybean. A population of recombinant inbred lines derived from the cross of SD02-4-59 X A02-381100 was evaluated for fatty …

Transcriptomic And Physiological Characterization Of The Fefe Mutant Of Melon (Cucumis Melo) Reveals New Aspects Of Iron-Copper Crosstalk, Brian M. Waters, Samuel A. Mcinturf, Keenan Amundsen

Department of Agronomy and Horticulture: Faculty Publications

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. In previous work, Fe deficiency interacted with Cu-regulated genes and stimulated Cu accumulation. The C940-fe (fefe) Fe-uptake mutant of melon (Cucumis melo) was characterized, and the fefe mutant was used to test whether Cu deficiency could stimulate Fe uptake. Wild-type and fefe mutant transcriptomes were determined by RNA-seq under Fe and Cu deficiency. FeFe-regulated genes included core Fe uptake, metal homeostasis, and transcription factor genes. Numerous genes were regulated by both Fe and Cu. The fefe mutant was rescued by high Fe or by …

Boron Nutrition Of Burley And Dark Tobacco, Laura Ann Frakes Mitchell

Theses and Dissertations--Plant and Soil Sciences

The incidences of suspected Boron (B) deficiency have increased recently in Kentucky tobacco fields, potentially due to recent changes in management practices. The symptoms observed in the field include; hollow stalk, stunted growth, deformed or no bud formation, small slits on the lower leaf midrib and uncontrollable breaking of the midrib approximately two inches from the stalk. B is a micronutrient tobacco needs in minute amounts, however excessive additions of B could cause toxicity. The objectives of this work were to 1) establish critical points for B sufficiency, 2) describe and define B deficiency and toxicity symptoms and 3) develop …

Identification Of A Sphingolipid Α-Glucuronosyltransferase That Is Essential For Pollen Function In Arabidopsis, Emilie A. Rennie, Berit Ebert, Godfrey P. Miles, Rebecca E. Cahoon, Katy M. Christiansen, Solomon Stonebloom, Hoda Khatab, David Twell, Christopher J. Petzold, Paul D. Adams, Paul Dupree, Joshua L. Heazlewood, Edgar B. Cahoon, Henrik Vibe Scheller

Department of Agronomy and Horticulture: Faculty Publications

Glycosyl inositol phosphorylceramide (GIPC) sphingolipids are a major class of lipids in fungi, protozoans, and plants. GIPCs are abundant in the plasma membrane in plants, comprising around a quarter of the total lipids in these membranes. Plant GIPCs contain unique glycan decorations that include a conserved glucuronic acid (GlcA) residue and various additional sugars; however, no proteins responsible for glycosylating GIPCs have been identified to date. Here, we show that the Arabidopsis thaliana protein INOSITOL PHOSPHORYLCERAMIDE GLUCURONOSYLTRANSFERASE1 (IPUT1) transfers GlcA from UDP-GlcA to GIPCs. To demonstrate IPUT1 activity, we introduced the IPUT1 gene together with genes for a UDP-glucose dehydrogenase …

Mapping The Low Palmitate Fap1 Mutation And Validation Of Its Effects In Soybean Oil And Agronomic Traits In Three Soybean Populations, Andrea J. Cardinal, Rebecca Whetten, Sanbao Wang, Jérôme Auclair, D. L. Hyten, P. B. Cregan, Eleni Bachlava, Jason Gillman, Martha Ramirez, Ralph Dewey, Greg Upchurch, Lilian Miranda, Joesph W. Burton

Department of Agronomy and Horticulture: Faculty Publications

Soybean oil with reduced palmitic acid content is desirable to reduce the health risks associated with consumption of this fatty acid. The objectives of this study were: to identify the genomic location of the reduced palmitate fap1 mutation, determine its molecular basis, estimate the amount of phenotypic variation in fatty acid composition explained by this locus, determine if there are epistatic interactions between the fap1 and fap_nc loci and, determine if the fap1 mutation has pleiotropic effects on seed yield, oil and protein content in three soybean populations. This study detected two major QTL for 16:0 content located in …

Evaluation Of Soilless Media Sensors For Managing Winter-Time Greenhouse Strawberry Production Using A Capmat System, George E. Meyer, Ellen T. Paparozzi, Stacy A. Adams, Diego Scacalossi Voltan

Department of Agronomy and Horticulture: Faculty Publications

It is important for a greenhouse strawberry grower to know that their capillary mat (CapMat™) fertigation system is working correctly and that plants are receiving the correct amounts of water and fertilizer. Pots with soilless mix are not expected to hold more than 70% water on a volumetric basis. Pots with less than 40% water content continuously are not supplied enough water and nutrients to the plants. Typically, pots located near the manifold distribution system get a little more water than those at the other locations, but water use will really vary according to the factors listed above as well …

Quantitative Trait Loci (Qtl) That Underlie Scn Resistance In Soybean [Glycine Max (L.) Merr.] Pi438489b By ‘Hamilton’ Recombinant Inbred Line (Ril) Population, Kassem My Abdelmajid, Laura Ramos, D. L. Hyten, Jason Bond, Abdelhafid Bendahmane, Prakash R. Arelli, Victor N. Njiti, Silvia Cianzio, Stella K. Kantartzi, Khalid Meksem

Department of Agronomy and Horticulture: Faculty Publications

Soybean cyst nematode caused by Heterodera glycines Ichinohe is the most devastating pest in soybean [Glycine max (L.) Merr.]. Resistance to SCN is complex, polygenic, race and cultivar specific, and it is controlled by several quantitative trait loci (QTL). Our objective was to identify and map QTL for SCN resistance to races 3 (HG Type 0) and 5 (HG Type 2.5.7) using a high density SNP-based genetic linkage map based on the PI438489B by ‘Hamilton’ (PIxH, n=50) recombinant inbred line population. The PI438489B by Hamilton map contained 648 SNPs distributed on 31 LGs with coverage of 1,524.7 cM and …

Eqtl Networks Reveal Complex Genetic Architecture In The Immature Soybean Seed, Yung-Tsi Bolon, D. Hyten, James H. Orf, Carroll P. Vance, Gary J. Muehlbauer

Department of Agronomy and Horticulture: Faculty Publications

The complex network of regulatory factors and interactions involved in transcriptional regulation within the seed is not well understood. To evaluate gene expression regulation in the immature seed, we utilized a genetical genomics approach on a soybean [Glycine max (L.) Merr.] recombinant inbred line (RIL) population and produced a genome-wide expression quantitative trait loci (eQTL) dataset. The validity of the dataset was confirmed by mapping the eQTL hotspot for flavonoid biosynthesis-related genes to a region containing repeats of chalcone synthase (CHS) genes known to correspond to the soybean inhibitor locus that regulates seed color. We then identified eQTL for …

Glyphosate-Resistant Giant Ragweed (Ambrosia Trifida) Control In Glufosinate-Resistant Soybean, Simranpreet Kaur, Lowell D. Sandell, John L. Lindquist, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

Glyphosate-resistant giant ragweed is one of the most competitive weeds of agronomic crops in the United States. Early emergence and rapid growth rate makes giant ragweed a competitive weed early in the season and reduces crop yields. Therefore, early spring control of giant ragweed using a preplant herbicide is critical. Glufosinate is an alternative POST herbicide for weed control in glufosinate-resistant soybean. Field experiments were conducted at David City, NE, in 2012 and 2013 to evaluate the efficacy of preplant herbicides followed by glufosinate applied alone or in tank mixes for control of glyphosate-resistant giant ragweed in glufosinate-resistant soybean. Preplant …

Shattercane X Als-Tolerant Sorghum F1 Hybrid And Shattercane Interference In Als-Tolerant Sorghum, Rodrigo Werle, Jared J. Schmidt, John Laborde, Angela Tran, Cody F. Creech, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

ALS-tolerant grain sorghum cultivars are expected to be available for farmers within the next few years. Knowing that: (i) crosses between sorghum and shattercane are likely to occur resulting in crop-to-weed gene flow; (ii) ALS-susceptible shattercane X ALS-tolerant grain sorghum F1 hybrids (hybrids) were ultimately resistant to ALS-herbicides under field conditions; and (iii) hybrid fitness is equal to, or greater than, the wild parent, we conducted a greenhouse study to compare the competitive effect of shattercane and hybrid on sorghum, and whether or not herbicide application would influence the competitive ability of the hybrid …

Corn (Zea Mays) Emergence And Early Growth As Influenced By Tansymustard (Descurainia Pinnata) Residue, Rodrigo Werle, Leonardo L. Perez, Lowell D. Sandell, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Farmers have observed reduced early growth of corn in the presence of tansymustard [Descurainia pinnata (Walt.) Britt.], a winter annual weed of the Brassicaceae family. A greenhouse study was conducted to evaluate the effect of tansymustard on corn (Zea mays L.) emergence and early growth. Treatments included corn growing in pots with only tansymustard root residue, with only tansymustard shoot residue, and with whole tansymustard plant residue (roots plus shoots); tansymustard plants treated with glyphosate 2 days after planting (DAP) corn seeds; and a control (no tansymustard residue). Corn emergence was recorded and biomass measured after 4 weeks of …

Phytophthora Root Rot Resistance In Soybean E00003, Zhongnan Zhang, Jianjun Hao, Jiazheng Yuan, Qijian Song, D. L. Hyten, P. B. Cregan, Guorong Zhang, Cuihua Gu, Ming Li, Dechun Wang

Department of Agronomy and Horticulture: Faculty Publications

Phytophthora root rot (PRR) is a devastating disease in soybean [Glycine max (L.) Merr.] production. Michigan elite soybean E00003 is resistant to Phytophthora sojae and has been used as a resistance source in breeding. Genetic control of PRR resistance in this source is unknown. To facilitate marker-assisted selection (MAS), the PRR resistance loci in E00003 and their map locations need to be determined. In this study, a genetic mapping approach was used to identify major PRR -resistant loci in E00003. The mapping population consists of 240 F₄–derived lines developed by crossing E00003 with the P. sojae susceptible …

Identification And Validation Of Quantitative Trait Loci For Seed Yield, Oil And Protein Contents In Two Recombinant Inbred Line Populations Of Soybean, Xianzhi Wang, Guo‑Liang Jiang, Marci Green, Roy A. Scott, Qijian Song, D. L. Hyten, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Soybean seeds contain high levels of oil and protein, and are the important sources of vegetable oil and plant protein for human consumption and livestock feed. Increased seed yield, oil and protein contents are the main objectives of soybean breeding. The objectives of this study were to identify and validate quantitative trait loci (QTLs) associated with seed yield, oil and protein contents in two recombinant inbred line populations, and to evaluate the consistency of QTLs across different environments, studies and genetic backgrounds. Both the mapping population (SD02- 4-59 × A02-381100) and validation population (SD02- 911 × SD00-1501) were phenotyped for …

Detection And Confirmation Of Quantitative Trait Loci For Soybean Seed Isoflavones, Christopher J. Smallwood, Catherine N. Nyinyi, Dean A. Kopsell, Carl E. Sams, Dennis R. West, Pengyin Chen, Stella K. Kantartzi, P. B. Cregan, D. L. Hyten, Vincent R. Pantalone

Department of Agronomy and Horticulture: Faculty Publications

Interest in soybean [Glycine max (L.) Merr.] isoflavones has increased in recent years owing to numerous reported health benefits. Consequently, quantitative trait loci (QTL) detection for marker-assisted breeding for isoflavones is being examined for genetic gains. This study sought to detect QTL for soybean isoflavones in a population of 274 recombinant inbred lines derived from a cross between ‘Essex’ and ‘Williams 82’ that were subdivided and tested by maturity (early, mid, and late). The field tests were conducted in three environments in 2009 (Knoxville, TN; Harrisburg, IL; and Stuttgart, AR). The population was genotyped with 480 polymorphic single nucleotide …

A Reference Genome For Common Bean And Genome-Wide Analysis Of Dual Domestications, Jeremy Schmutz, Phillip E. Mcclean, Sujan Mamidi, G. Albert Wu, Steven B. Cannon, Jane Grimwood, Jerry Jenkins, Shengqiang Shu, Qijian Song, Carolina Chavarro, Mirayda Torres-Torres, Valerie Geffroy, Samira Mafi Moghaddam, Dongying Gao, Brian Abernathy, Kerrie Barry, Matthew Blair, Mark A. Brick, Mansi Chovatia, Paul Gepts, David M. Goodstein, Michael Gonzales, Uffe Hellsten, D. L. Hyten, Gaofeng Jia, James D. Kelly, Dave Kudrna, Rian Lee, Manon M.S. Richard, Phillip N. Miklas, Juan M. Osorno, Josiane Rodrigues, Vincent Thareau, Carlos A. Urrea Florez, Mei Wang, Yeisoo Yu, Ming Zhang, Rod A. Wing, P. B. Cregan, Daniel S. Rokhsar, Scott A. Jackson

Department of Agronomy and Horticulture: Faculty Publications

Common bean (Phaseolus vulgaris L.) is the most important grain legume for human consumption and has a role in sustainable agriculture owing to its ability to fix atmospheric nitrogen. We assembled 473 Mb of the 587-Mb genome and genetically anchored 98% of this sequence in 11 chromosome-scale pseudomolecules. We compared the genome for the common bean against the soybean genome to find changes in soybean resulting from polyploidy. Using resequencing of 60 wild individuals and 100 landraces from the genetically differentiated Mesoamerican and Andean gene pools, we confirmed 2 independent domestications from genetic pools that diverged before human colonization. …

Identification Of New Qtls For Seed Mineral, Cysteine, And Methionine Concentrations In Soybean [Glycine Max (L.) Merr.], Raghuprakash Kastoori Ramamurthy, Joseph Jedlicka, George L. Graef, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Increased concentrations of important nutrients in edible parts of plants could result in biofortified foods. Soybean [Glycine max (L.) Merr.] is a major legume crop and an important source of certain nutrients, including protein and minerals, in human and animal diets. Understanding the underlying genetic basis of seed composition is crucial to improving seed nutrient composition. In this study we used three soybean recombinant inbred line mapping populations derived from the crosses Williams 82 × DSR-173, Williams 82 × NKS19-90 and Williams 82 × Vinton 81, and constructed a joint linkage map from these populations. Forty quantitative trait loci (QTLs) …

The Interaction Of Climate Change, Land Cover, And Political Representation In The Usa, Brady W. Allred, Dirac L. Twidwell, Samuel D. Fuhlendorf

Department of Agronomy and Horticulture: Faculty Publications

The difficulties in tackling climate change are inherently complex and primarily centered on political and social values. This is evident in the United States where political divisions and polarizations are fundamental barriers to advancing national policies, which in turn hinder international agreements, mitigation, and adaptation. Within the United States, the vast majority of agricultural and natural resource lands are projected to incur significant climate departures and are represented by the Republican Party. The resources and economic sectors that will be directly affected by climate change are represented by national leadership that is unlikely to accept policies to prevent or adapt …

Development Of Scar Markers And Up-Pcr Cross-Hybridization Method For Specific Detection Of Four Major Subgroups Of Rhizoctonia From Infected Turfgrasses, Bimal S. Amaradasa, Dilip Lakshman, Brandon J. Horvath, Keenan Amundsen

Department of Agronomy and Horticulture: Faculty Publications

A rapid identification assay for Waitea circinata (anamorph: Rhizoctonia spp.) varieties zeae and circinata causing patch diseases on turfgrasses was developed based on the universally primed PCR (UPPCR) products cross-blot hybridization. Tester isolates belonging to the two varieties of W. circinata were amplified with a single UP primer L21, which generated multiple DNA fragments for each variety. Probes were prepared with UP-PCR products of each tester isolate by labeling with digoxigenin. Fieldcollected W. circinata isolates and representative isolates of different R. solani anastomosis groups (AG) and AG subgroups were amplified with L21, immobilized on nylon membrane and cross hybridized with …

Porocercospora Seminalis Gen. Et Comb. Nov., The Causal Organism Of Buffalograss False Smut, Bimal S. Amaradasa, Hugo Madrid, Johannes Z. Groenewald, Pedro W. Crous, Keenan L. Amundsen

Department of Agronomy and Horticulture: Faculty Publications

False smut caused by Cercospora seminalis is an important disease of buffalograss (Buchloe dactyloides) affecting seed production. The pathogen prevents normal caryopsis development and causes considerable yield loss and reduced seed germination. The current taxonomic placement of the false-smut causal pathogen in the genus Cercospora is incorrect based on its morphological characteristics and DNA phylogeny. In the present study the phylogenetic position of C. seminalis is clarified based on DNA sequence analysis of three loci namely the internal transcribed spacer (ITS) region, partial nuclear ribosomal large subunit (LSU) and partial sequences of the RNA polymerase II second largest …

Drought Effects On Composition And Yield For Corn Stover, Mixed Grasses, And Miscanthus As Bioenergy Feedstocks, Rachel Emerson, Amber Hoover, Allison Ray, Jeffrey Lacey, Marnie Cortez, Courtney Payne, Douglas L. Karlen, Stuart Birrell, David Laird, Robert Kallenbach, Josh Egenolf, Matthew Sousek, Thomas Voigt

Department of Agronomy and Horticulture: Faculty Publications

Drought conditions in 2012 were some of the most severe in recent history. The purpose of this study is to examine the impact of drought on quality, quantity, and theoretical ethanol yield (TEY) of three bioenergy feedstocks, corn stover, mixed grasses from Conservation Reserve Program lands, and Miscanthus × giganteus. To assess drought effects on these feedstocks, samples from 2010 (minimal to no drought) and 2012 (severe drought) were compared from multiple locations in the US. In all feedstocks, drought significantly increased extractives and reduced structural sugars and lignin; subsequently, TEYs were reduced 10–15%. Biomass yields were significantly reduced …

Arabidopsis Lipins, Pdat1 Acyltransferase, And Sdp1 Triacylglycerol Lipase Synergistically Direct Fatty Acids Toward Β-Oxidation, Thereby Maintaining Membrane Lipid Homeostasis, Jilian Fan, Chengshi Yan, Rebecca Roston, John Shanklin, Changcheng Xu

Department of Agronomy and Horticulture: Faculty Publications

Triacylglycerol (TAG) metabolism is a key aspect of intracellular lipid homeostasis in yeast and mammals, but its role in vegetative tissues of plants remains poorly defined. We previously reported that PHOSPHOLIPID:DIACYLGLYCEROL ACYLTRANSFERASE1 (PDAT1) is crucial for diverting fatty acids (FAs) from membrane lipid synthesis to TAG and thereby protecting against FA-induced cell death in leaves. Here, we show that overexpression of PDAT1 enhances the turnover of FAs in leaf lipids. Using the trigalactosyldiacylglycerol1-1 (tgd1-1) mutant, which displays substantially enhanced PDAT1- mediated TAG synthesis, we demonstrate that disruption of SUGAR-DEPENDENT1 (SDP1) TAG lipase or PEROXISOMAL TRANSPORTER1 (PXA1) severely decreases …