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Engineering phenolics metabolism in the grasses using transcription factors

Description: The economical competitiveness of agriculture-derived biofuels can be significantly enhanced by increasing biomass/acre yields and by furnishing the desired carbon balance for facilitating liquid fuel production (e.g., ethanol) or for high-energy solid waste availability to be used as biopower (e.g., for electricity production). Biomass production and carbon balance are tightly linked to the biosynthesis of phenolic compounds, which are found in crops and in agricultural residues either as lignins, as part of the cell wall, or as soluble phenolics which play a variety of functions in the biology of plants. The grasses, in particular maize, provide the single major source of agricultural biomass, offering significant opportunities for increasing renewable fuel production. Our laboratory has pioneered the use of transcription factors for manipulating plant metabolic pathways, an approach that will be applied here towards altering the composition of phenolic compounds in maize. Previously, we identified a small group of ten maize R2R3-MYB transcription factors with all the characteristics of regulators of different aspects of phenolic biosynthesis. Here, we propose to investigate the participation of these R2R3-MYB factors in the regulation of soluble and insoluble maize phenolics, using a combination of over-expression and down-regulation of these transcription factors in transgenic maize cultured cells and in maize plants. Maize cells and plants altered in the activity of these regulatory proteins will be analyzed for phenolic composition by targeted metabolic profiling. Specifically, we will I) Investigate the effect of gain- and loss-of-function of a select group of R2R3-MYB transcription factors on the phenolic composition of maize plants and II) Identify the biosynthetic genes regulated by each of the selected R2R3-MYB factors. While a likely outcome of these studies are transgenic maize plants with altered phenolic composition, this research will significantly contribute to understanding how different branches of the phenolic biosynthetic grid are regulated. Given ...
Date: July 26, 2013
Creator: Grotewold, Erich
Partner: UNT Libraries Government Documents Department

Molecular Genetic Analysis of Maize Starch Branching Isoforms: Modulation of Starch Branching Enzyme Isoform Activities in Maize to Produce Starch with Novel Branching Architecture and Properties

Description: Modulation of Starch Branching enzyme Isoform Activities in Maize to Produce Starch with Novel Branching Architecture and Properties.
Date: July 21, 2009
Creator: Guiltinan, Mark J. & Thompson, Donald
Partner: UNT Libraries Government Documents Department

The plant mitochondrial mat-r gene/nad1 gene complex

Description: We have completed sequencing segments of the maize mitochondrial (mt) DNA that contains all five of the exons (A-E) of the gene (nad1) for subunit I of the respiratory chain NADH dehydrogenase. Analysis of these sequences indicates that exons B and C are joined by a continuous group II intron, but the remaining exons are associated with partial group II introns and are encoded at widely separated locations in the maize mtDNA molecule. We have shown that mature transcripts of the maize nad1 gene contain 23 edited nucleotides, and that transcripts of maize and soybean mat-r genes contain 15 and 14 edits, respectively. The majority of edits in nad1 transcripts result in amino acid replacements that increase similarity between the maize NAD1 protein and NAD1 proteins of other plant species and of animal species. We found that the intron between exons b and c is not edited. From data obtained using PCR and sequencing we have shown that transcripts containing all possible exon combinations exist in maize mitochondria.
Date: December 31, 1996
Creator: Wolstenhome, D.R.
Partner: UNT Libraries Government Documents Department

Molecular genetics of the R complex of maize. Final technical report DE-FG02-86ER13627

Description: A molecular genetic characterization of the maize R-r complex of maize was completed during the period of support. The complex was shown to consist of two main regions: the P region, containing the r-p gene which controlled pigmentation of plant parts, and the S subcomplex, containing two rl-s genes in head-to-head orientation and a nonfunctional component termed rl-q. By examining the DNA sequences at the junction of the rl genes, the complex was shown to be derived by a series of abortive transposition events. The transposable element involved in the gene duplication and rearrangements was characterized and called doppia. Meiotic instability of the R-r complex was also characterized. Loss of P or S function was associated with several structural changes including intrachromosomal recombination and excision of a novel transposable element that appears to show instability only during meiosis.
Date: October 1, 2000
Creator: Dellaporta, Stephen
Partner: UNT Libraries Government Documents Department

Final Report-DE FG02 92ER20061

Description: A dosage analysis of gene expression was conducted using aneuploids of maize. The findings of this project led to the concept that regulatory genes in higher eukaryotes has mostly dosage dependent and are the underlying basis of quantitative traits and aneuploid syndromes.
Date: April 22, 2004
Creator: Birchler, James A.
Partner: UNT Libraries Government Documents Department

Assessment of Options for the Collection, Handling, and Transport of Corn Stover

Description: In this report, we discuss the logistics and estimate the delivered costs for collecting, handling, and hauling corn stover to an ethanol conversion facility. We compare costs for two conventional baling systems (large round bales and large rectangular bales), a silage-harvest system, and an unprocessed-pickup system. Our results generally indicate that stover can be collected, stored, and hauled for about $43.60 to $48.80/dry ton ($48.10-$53.80/dry Mg) using conventional baling equipment for conversion facilities ranging in size from 500 to 2000 dry tons/day (450-1810 dry Mg/day). These estimates are inclusive of all costs including farmer payments for the stover. Our results also suggest that costs might be significantly reduced with an unprocessed stover pickup system provided more efficient equipment is developed.
Date: November 18, 2002
Creator: Perlack, R.D.
Partner: UNT Libraries Government Documents Department

Defining the maize transcriptome de novo using deep RNA-Seq

Description: De novo assembly of the transcriptome is crucial for functional genomics studies in bioenergy research, since many of the organisms lack high quality reference genomes. In a previous study we successfully de novo assembled simple eukaryote transcriptomes exclusively from short Illumina RNA-Seq reads [1]. However, extensive alternative splicing, present in most of the higher eukaryotes, poses a significant challenge for current short read assembly processes. Furthermore, the size of next-generation datasets, often large for plant genomes, presents an informatics challenge. To tackle these challenges we present a combined experimental and informatics strategy for de novo assembly in higher eukaryotes. Using maize as a test case, preliminary results suggest our approach can resolve transcript variants and improve gene annotations.
Date: June 1, 2011
Creator: Martin, Jeffrey; Gross, Stephen; Choi, Cindy; Zhang, Tao; Lindquist, Erika; Wei, Chia-Lin et al.
Partner: UNT Libraries Government Documents Department

Diurnal oscillation of SBE expression in sorghum endosperm

Description: Spatial and temporal expression patterns of the sorghum SBEI, SBEIIA and SBEIIB genes, encoding, respectively, starch branching enzyme (SBE) I, IIA and IIB, in the developing endosperm of sorghum (Sorghum bicolor) were studied. Full-length genomic and cDNA clones for sorghum was cloned and the SBEIIA cDNA was used together with gene-specific probes for sorghum SBEIIB and SBEI. In contrast to sorghum SBEIIB, which was expressed primarily in endosperm and embryo, SBEIIA was expressed also in vegetative tissues. All three genes shared a similar temporal expression profile during endosperm development, with a maximum activity at 15-24 days after pollination. This is different from barley and maize where SBEI gene activity showed a significantly later onset compared to that of SBEIIA and SBEIIB. Expression of the three SBE genes in the sorghum endosperm exhibited a diurnal rhythm during a 24-h cycle.
Date: January 15, 2009
Creator: Sun, Chuanxin; Mutisya, J.; Rosenquist, S.; Baguma, Y. & Jansson, C.
Partner: UNT Libraries Government Documents Department

The roles played by mitochondrial DNA and nuclear genes in reversion to fertility in S-Type male-sterile maize. Progress report, April 1, 1985--March 31, 1989

Description: This is a progress report/renewal request for work of the roles played by mitochondrial DNA and nuclear genes in reversion to fertility in s-type male sterile maize. Information is included for the following major catagories of research on this project: molecular basis for nuclear reversion; molecular characterization of cytoplasmic revertants; nuclear control over cytoplasmic reversion and over replication of S1 and S2; developmental studies; transposition of nuclear restorer elements.
Date: March 1995
Creator: Laughnan, J. R.
Partner: UNT Libraries Government Documents Department

Organ-specific gene expression in maize: The P-wr allele. Final report, August 15, 1993--August 14, 1996

Description: The ultimate aim of our work is to understand how a regulatory gene produces a specific pattern of gene expression during plant development. Our model is the P-wr gene of maize, which produces a distinctive pattern of pigmentation of maize floral organs. We are investigating this system using a combination of classical genetic and molecular approaches. Mechanisms of organ-specific gene expression are a subject of intense research interest, as it is the operation of these mechanisms during eukaryotic development which determine the characteristics of each organism Allele-specific expression has been characterized in only a few other plant genes. In maize, organ-specific pigmentation regulated by the R, B, and Pl genes is achieved by differential transcription of functionally conserved protein coding sequences. Our studies point to a strikingly different mechanism of organ-specific gene expression, involving post-transcriptional regulation of the regulatory P gene. The novel pigmentation pattern of the P-wr allele is associated with differences in the encoded protein. Furthermore, the P-wr gene itself is present as a unique tandemly amplified structure, which may affect its transcriptional regulation.
Date: June 1, 1997
Creator: Peterson, T.A.
Partner: UNT Libraries Government Documents Department

Ethanol production from dry-mill corn starch in a fluidized-bed bioreactor

Description: The development of a high-rate process for the production of fuel ethanol from dry-mill corn starch using fluidized-bed bioreactor (FBR) technology is discussed. Experiments were conducted in a laboratory scale FBR using immobilized biocatalysts. Two ethanol production process designs were considered in this study. In the first design, simultaneous saccharification and fermentation was performed at 35 C using {kappa}-carageenan beads (1.5 mm to 1.5 mm in diameter) of co-immobilized glucoamylase and Zymomonas mobilis. For dextrin feed concentration of 100 g/L, the single-pass conversion ranged from 54% to 89%. Ethanol concentrations of 23 to 36 g/L were obtained at volumetric productivities of 9 to 15 g/L-h. No accumulation of glucose was observed, indicating that saccharification was the rate-limiting step. In the second design, saccharification and fermentation were carried out sequentially. In the first stage, solutions of 150 to 160 g/L dextrins were pumped through an immobilized glucoamylase packed column maintained at 55 C. Greater than 95% conversion was obtained at a residence time of 1 h, giving a product of 165 to 170 g glucose/L. In the second stage, these glucose solutions were fed to the FBR containing Z. mobilis immobilized in {kappa}-carageenan beads. At a residence time of 2 h, 94% conversion and ethanol concentration of 70 g/L was achieved, giving an overall productivity of 23 g/L-h.
Date: August 1, 1998
Creator: Krishnan, M. S.; Nghiem, N. P. & Davison, B. H.
Partner: UNT Libraries Government Documents Department

The iojap gene in maize

Description: The classical maize mutant iojap (Iodent japonica) has variegated green and white leaves. Green sectors have cells with normal chloroplasts whereas white sectors have cells where plastids fail to differentiate. These mutant plastids, when transmitted through the female gametophyte, do not recover in the presence of wild type Iojap. We cloned the Ij locus, and we have investigated the mechanism of epigenetic inheritance and phenotypic expression. More recently, a modifier of this type of variegation, ''Inhibitor of striate'', has also been cloned. Both the iojap and inhibitor of striate proteins have homologs in bacteria and are members of ancient conserved families found in multiple species. These tools can be used to address fundamental questions of inheritance and variegation associated with this classical conundrum of maize genetics. Since the work of Rhoades there has been considerable speculation concerning the nature of the Iojap gene product, the origin of leaf variegation and the mechanism behind the material inheritance of defective plastids. This has made Iojap a textbook paradigm for cytoplasmic inheritance and nuclear-organellar interaction for almost 50 years. Cloning of the Iojap gene in maize, and homologs in other plants and bacteria, provides a new means to address the origin of heteroplastidity, variegation and cytoplasmic inheritance in higher plants.
Date: December 1, 2001
Creator: Martienssen, Robert
Partner: UNT Libraries Government Documents Department

Biofuels News, Vol. 3, No. 1 (Spring/Summer 2000)

Description: This is the Newsletter for DOE Biofuels Program. Articles are presented on collection and use of corn stover for bioethanol production, the state workshop program on ethanol, and a subcontract to Genencor for improvement of cellulase enzyme production.
Date: August 15, 2000
Creator: Brown, H.
Partner: UNT Libraries Government Documents Department

Husker-shredders in corn-borer control.

Description: Describes the operation of the husker-shredder and makes suggestions as to its operations and care with special reference to corn-borer control.
Date: March 1931
Creator: Reed, I. F. (Irvin Fay), 1903- & Humphries, W. R. (Walter Raymond), b. 1886.
Partner: UNT Libraries Government Documents Department

Evaluation of Thermocompression Heat Pump Performance for American Maize, Decatur, AL [Advanced Industrial Heat Pump Applications and Evaluations]

Description: This work was carried out in two phases: Phase 1, identification of opportunities for heat pumps in industrial applications and Phase 2, evaluation of heat pumps in industrial applications. In Phase 1, pinch analysis was applied to several industrial sites to identify the best opportunities for heat pumping and other forms of heat integration. In Phase 2, more detailed analyses were undertaken, including the evaluation of a heat pump installed as a recommendation of Phase 1.
Date: June 1, 1993
Creator: Eastwood, A.
Partner: UNT Libraries Government Documents Department

Development of the Integrated Biomass Supply Analysis and Logistics Model (IBSAL)

Description: The Integrated Biomass Supply & Logistics (IBSAL) model is a dynamic (time dependent) model of operations that involve collection, harvest, storage, preprocessing, and transportation of feedstock for use at a biorefinery. The model uses mathematical equations to represent individual unit operations. These unit operations can be assembled by the user to represent the working rate of equipment and queues to represent storage at facilities. The model calculates itemized costs, energy input, and carbon emissions. It estimates resource requirements and operational characteristics of the entire supply infrastructure. Weather plays an important role in biomass management and thus in IBSAL, dictating the moisture content of biomass and whether or not it can be harvested on a given day. The model calculates net biomass yield based on a soil conservation allowance (for crop residue) and dry matter losses during harvest and storage. This publication outlines the development of the model and provides examples of corn stover harvest and logistics.
Date: June 1, 2008
Creator: Sokhansanj, Shahabaddine; Webb, Erin & Turhollow Jr, Anthony F
Partner: UNT Libraries Government Documents Department

Biomechanics of Wheat/Barley Straw and Corn Stover

Description: The lack of understanding of the mechanical characteristics of cellulosic feedstocks is a limiting factor in economically collecting and processing crop residues, primarily wheat and barley stems and corn stover. Several testing methods, including compression, tension, and bend have been investigated to increase our understanding of the biomechanical behavior of cellulosic feedstocks. Biomechanical data from these tests can provide required input to numerical models and help advance harvesting, handling, and processing techniques. In addition, integrating the models with the complete data set from this study can identify potential tools for manipulating the biomechanical properties of plant varieties in such a manner as to optimize their physical characteristics to produce higher value biomass and more energy efficient harvesting practices.
Date: March 1, 2005
Creator: Wright, Christopher T.; Pryfogle, Peter A.; Stevens, Nathan A.; Steffler, Eric D.; Hess, J. Richard & Ulrich, Thomas H.
Partner: UNT Libraries Government Documents Department