Plant Sciences Commons^™

The Pho1;2a'-M1.1 Allele Of Phosphate1 Conditions Misregulation Of The Phosphorus Starvation Response In Maize (Zea Mays Ssp. Mays L.), Ana Laura Alonso-Nieves, M. Nancy Salazar-Vidal, J. Vladimir Torres-Rodríguez, Leonardo M. Pérez-Vázquez, Julio A. Massange-Sánchez, C. Stewart Gillmor, Ruairidh J. H. Sawers

Center for Plant Science Innovation: Faculty and Staff Publications

Plant PHO1 proteins play a central role in the translocation and sensing of inorganic phosphate. The maize (Zea mays ssp. mays) genome encodes two co-orthologs of the Arabidopsis PHO1 gene, designated ZmPho1;2a and ZmPho1;2b. Here, we report the characterization of the transposon footprint allele Zmpho1;2a'-m1.1, which we refer to hereafter as pho1;2a. The pho1;2a allele is a stable derivative formed by excision of an Activator transposable element from the ZmPho1;2a gene. The pho1;2a allele contains an 8-bp insertion at the point of transposon excision that disrupts the reading frame and is predicted to …

Association Mapping Across A Multitude Of Traits Collected In Diverse Environments In Maize, Ravi V. Mural, Guangchao Sun, Marcin Grzybowski, Michael C. Tross, Hongyu Jin, Christine Smith, Linsey Newton, Carson M. Andorf, Margaret R. Woodhouse, Addie M. Thompson, Brandi Sigmon, James C. Schnable

Center for Plant Science Innovation: Faculty and Staff Publications

Classical genetic studies have identified many cases of pleiotropy where mutations in individual genes alter many different phenotypes. Quantitative genetic studies of natural genetic variants frequently examine one or a few traits, limiting their potential to identify pleiotropic effects of natural genetic variants. Widely adopted community association panels have been employed by plant genetics communities to study the genetic basis of naturally occurring phenotypic variation in a wide range of traits. High-density genetic marker data—18M markers—from 2 partially overlapping maize association panels comprising 1,014 unique genotypes grown in field trials across at least 7 US states and scored for 162 …

Hyperspectral Reflectance-Based Phenotyping For Quantitative Genetics In Crops: Progress And Challenges, Marcin Grzybowski, Kuwan K. Wijewardane, Abbas Atefi, Yufeng Ge, James C. Schnable

Center for Plant Science Innovation: Faculty and Staff Publications

Many biochemical and physiological properties of plants that are of interest to breeders and geneticists have extremely low throughput and/or can only be measured destructively. This has limited the use of information on natural variation in nutrient and metabolite abundance, as well as photosynthetic capacity in quantitative genetic contexts where it is necessary to collect data from hundreds or thousands of plants. A number of recent studies have demonstrated the potential to estimate many of these traits from hyperspectral reflectance data, primarily in ecophysiological contexts. Here, we summarize recent advances in the use of hyperspectral reflectance data for plant phenotyping, …

Resistance To Aflatoxin Accumulation In Maize Mediated By Host-Induced Gene Silencing Of Aspergillus Flavus Alkaline Protease And O-Methyltransferase-A Genes, Olanike Omotola Omolehin

LSU Doctoral Dissertations

Aspergillus flavus is a soil-borne fungal pathogen that infects maize and produces aflatoxins. In the current study, portions of the alkaline protease (alk) and the O-methyl transferase (omtA) genes, which are key in A. flavus virulence and aflatoxin biosynthesis, respectively, were targeted for suppression through an RNAi (RNA interference) approach known as Host-Induced Gene Silencing (HIGS). Separate RNAi vectors were designed to carry regions of the alk and omtA gene fragments (Alk-RNAi and OmtA-RNAi) and introduced into B104 maize zygotic embryos. Eight and six transformation events were positive for the alk and omtA transgene, respectively. …

72-H Diurnal Rna-Seq Analysis Of Fully Expanded Third Leaves From Maize, Sorghum, And Foxtail Millet At 3-H Resolution, Xianjun Lai, Claire Bendix, Yan Zhang, James Schnable, Frank G. Harmon

Center for Plant Science Innovation: Faculty and Staff Publications

Objectives: The purpose of this data set is to capture the complete diurnal (i.e., daily) transcriptome of fully expanded third leaves from the C4 panacoid grasses sorghum (Sorghum bicolor), maize (Zea mays), and foxtail millet (Setaria italica) with RNA-seq transcriptome profiling. These data are the cornerstone of a larger project that examined the conservation and divergence of gene expression networks within these crop plants. This data set focuses on tem- poral changes in gene expression to identify the network architecture responsible for daily regulation of plant growth and metabolic activities. The power of this data set is fine temporal resolution …

Identification Of Loci Influencing Teosinte Crossing Barrier 1 (Tcb1) Efficacy In Maize By Quantitative Trait Loci (Qtl) Mapping And Genome-Wide Association Study (Gwas), Namrata Maharjan

Electronic Theses and Dissertations

Pollen cross-contamination has been a major problem for maize breeders. Various mechanical methods applied to avoid the contaminations are ineffective. The genetic factors related to maize fertilization can be used to develop an effective method to prevent pollen contamination. Pollen rejection ability controlled by Teosinte crossing barrier 1 (Tcb1) is such a genetic system. Silks possessing dominant Tcb1-s reject pollen possessing the recessive allele (tcb1). Successful fertilization occurs when Tcb1-s pollen falls upon tcb1 silks. The efficacy of dominant Tcb1-s was, however, reduced when repeatedly backcross with maize inbred lines, which suggests that there are modifiers to Tcb1-s. To find …

Leaf Angle Extractor: A High-Throughput Image Processing Framework For Leaf Angle Measurements In Maize And Sorghum, Sunil Kumar Kenchanmane Raju, Miles Adkins, Alex Enersen, Daniel Santana De Carvalho, Anthony J. Studer, Baskar Ganapathysubramanian, Patrick S. Schnable, James C. Schnable

Center for Plant Science Innovation: Faculty and Staff Publications

PREMISE: Maize yields have significantly increased over the past half-century owing to advances in breeding and agronomic practices. Plants have been grown in increasingly higher densities due to changes in plant architecture resulting in plants with more upright leaves, which allows more efficient light interception for photosynthesis. Natural variation for leaf angle has been identified in maize and sorghum using multiple mapping populations. However, conventional phenotyping techniques for leaf angle are low throughput and labor intensive, and therefore hinder a mechanistic understanding of how the leaf angle of individual leaves changes over time in response to the environment.

METHODS …

Extreme‐Phenotype Genome‐Wide Association Study (Xp‐Gwas): A Method For Identifying Trait‐Associated Variants By Sequencing Pools Of Individuals Selected From A Diversity Panel, Jinliang Yang, Haiying Jiang, Cheng-Ting Yeh, Jianming Yu, Jeffrey A. Jeddeloh, Dan Nettleton, Patrick S. Schnable

Dan Nettleton

Although approaches for performing genome‐wide association studies (GWAS) are well developed, conventional GWAS requires high‐density genotyping of large numbers of individuals from a diversity panel. Here we report a method for performing GWAS that does not require genotyping of large numbers of individuals. Instead XP‐GWAS (extreme‐phenotype GWAS) relies on genotyping pools of individuals from a diversity panel that have extreme phenotypes. This analysis measures allele frequencies in the extreme pools, enabling discovery of associations between genetic variants and traits of interest. This method was evaluated in maize (Zea mays) using the well‐characterized kernel row number trait, which was …

Mu Transposon Insertion Sites And Meiotic Recombination Events Co-Localize With Epigenetic Marks For Open Chromatin Across The Maize Genome, Sanzhen Liu, Cheng-Ting Yeh, Tieming Ji, Kai Ying, Haiyan Wu, Ho Man Tang, Yan Fu, Daniel S. Nettleton, Patrick S. Schnable

Dan Nettleton

The Mu transposon system of maize is highly active, with each of the ∼50–100 copies transposing on average once each generation. The approximately one dozen distinct Mutransposons contain highly similar ∼215 bp terminal inverted repeats (TIRs) and generate 9-bp target site duplications (TSDs) upon insertion. Using a novel genome walking strategy that uses these conserved TIRs as primer binding sites, Mu insertion sites were amplified from Mu stocks and sequenced via 454 technology. 94% of ∼965,000 reads carried Mu TIRs, demonstrating the specificity of this strategy. Among these TIRs, 21 novel Mu TIRs were discovered, revealing additional complexity of …

Validation Of Candidate Loci For Maize Regrowability And Selection Of Near Isogenic Lines For The Loci, Tajbir Raihan

Electronic Theses and Dissertations

Developing perennial grain crops is an effective way for sustainable agriculture and it can be a tool for the betterment of the overall ecosystem. To understand how perenniality works in perennial species, we made a cross between Zea diploperennis and maize (Z. mays) inbred line B73. F1 hybrids produced from this cross were selfed to get the F2 population and later the F2 population underwent Genotyping-By- Sequencing (GBS) analysis. Based on the candidate loci identified on chromosome 2 and chromosome 7 from GBS, SNP-specific markers were developed from the candidate locus interval and used to genotype the F2 …

Conventional And Hyperspectral Time-Series Imaging Of Maize Lines Widely Used In Field Trials, Zhikai Liang, Piyush Pandey, Vincent Stoerger, Yuhang Xu, Yumou Qiu, Yufeng Ge, James C. Schnable

Center for Plant Science Innovation: Faculty and Staff Publications

Background: Maize (Zea mays ssp. mays) is 1 of 3 crops, along with rice and wheat, responsible for more than one-half of all calories consumed around the world. Increasing the yield and stress tolerance of these crops is essential to meet the growing need for food. The cost and speed of plant phenotyping are currently the largest constraints on plant breeding efforts. Datasets linking new types of high-throughput phenotyping data collected from plants to the performance of the same genotypes under agronomic conditions across a wide range of environments are essential for developing new statistical approaches and computer …

Quantitative And Molecular Analysis Of Habituation At The Maize R1 Locus, Robert C. Lindsay

Theses and Dissertations

Epigenetics is the study of heritable changes in phenotypes that are not the result of changes in DNA sequence. Examples of epigenetic affecters include methylation changes, chromatin modifications, transcription factors, and RNA-based changes. The molecular mechanisms behind epigenetic changes are not fully understood. Canalization is the buffering of gene expression against environmental changes over time, while habituation is semi-stable expression change over time due to selection. This work characterized the molecular changes associated with the kernel color changes of the R-sc:86-17pale allele at the maize red color1 (r1) locus to determine if the changes are epigenetic in nature. …

Identification Of Qtl Modifying The Activity Of The Tcb1-S Locus And Characterization And Sequencing Of Two Plutonium-Beryllium Induced Reduced Gametophyte Transmission Mutants In Maize, Merritt Bryer Burch

Electronic Theses and Dissertations

This thesis is split into two independent projects both involving the male gametophyte generation of maize. The first project looks at how pollen interacts with the female gametophyte to reduce its transmission in cross-incompatible reactions controlled by the unilateral cross-incompatibility system, teosinte crossing barrier 1. The second project explores two plutonium-beryllium induced male gametophyte mutants and attempts to uncover their genetic basis.

Identification of QTL Modifying the Activity of the Tcb1-s Locus
Teosinte crossing barrier 1 (Tcb1) is a unilateral cross-incompatibility system present in maize that provides a pre-zygotic pistil barrier to plants carrying Tcb1-s (strong allele) from pollen …

Biochemical And Proteomic Profiling Of Maize Endosperm Texture And Protein Quality, Kyla J. Morton

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

The research described herein, focuses on the biochemical and proteomic analysis of the maize endosperm and what influences kernel texture. Quality Protein Maize (QPM) is a hard endosperm version of the high-lysine opaque2 (o2) mutant but the genes involved in modifying the soft o2 endosperm are unknown. Pyrophosphate (PPi)-dependent fructose 6-phosphate 1-phosphotransferase (PFP) catalyzes the ATP-independent conversion of fructose 6-phosphate to fructose 1, 6-bisphosphate in glycolysis. We found a large increase in transcript and protein levels of the alpha regulatory subunit of PFP (PFPα) in QPM endosperm. In vitro enzyme assays show a significant increase in forward PFP …

Carbohydrate Metabolism And The Trehalose Biosynthetic Pathway In Maize Kernels Grown In Vitro Under Sucrose Starvation Stress, Samuel W. Bledsoe

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

Drought is an increasing issue that many farmers encounter especially in hot arid climates with little rainfall. High temperatures and inadequate rainfall at certain stages in crop development can have disastrous consequences to yield. In maize, drought occurring near or during the flowering stage often causes significant kernel abortion that greatly impacts potential yield. The trehalose biosynthetic pathway has recently been found to be important in plant metabolism in response to stress in higher order plants. Trehalose is currently known throughout the plant and animal kingdoms as an osmoprotectant, high energy fuel source, structural component, and involved in pathogen response. …

Functional Genomics Of Maize Endosperm Maturation And Protein Quality, Lingling Yuan

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

Maize is one of the most important cereal crops and widely cultivated throughout the world. The study on maize kernel development including protein quality improvement is essential for removing dietary protein deficiency because of the lack of essential amino acids, especially lysine and tryptophan, in maize kernel. Quality Protein Maize (QPM) is a hard kernel variant of the high-lysine mutant, opaque-2. We created opaque QPM variants to identify opaque-2 modifier genes and to investigate deletion mutagenesis combined with Illumina sequencing as a maize functional genomics tool. A K0326Y-QPM deletion mutant, line 107, was null for the 27- and 50-kD …

Molecular And Biochemical Mechanisms Of Pathogenesis In The Maize Foliar Pathogen Cercospora Zeae-Maydis, Winfred-Peck Dorleku

Graduate Theses and Dissertations

GLS is a serious foliar disease of maize, a major staple crop grown commercially in the USA for both human and animal feed production, and increasingly, for ethanol production. The disease is caused by two Cercospora species, C. zeae-maydis and C. zeina, both of which infect maize in the USA and in other parts of the world, with yield losses potentially greater than 50%, depending on local conditions. In culture, C. zeae-maydis produces a phytotoxic, host non-specific perylenequinone, cercosporin, and abscisic acid (ABA), for which there is no known pathological or physiological function in the fungus. Experimental evidence indicates …

Xenia Effects On Quality Of Maize Female Inbred In Production Of Hybrid Seeds, Leandro Castañeda

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

In Maize (Zea maize L.), cost of hybrid seed production is directly related to the yield and quality of seed obtained per hectare of female parent. It is also important to consider the effects that a male parent can exert on the development of hybrid seed in the female parent. This effect is known as xenia. The objectives of this study were to evaluate xenia effects on 1) yield as 80K units, 2) germination of the hybrid seed and 3) susceptibility of the hybrid seed to mechanical damage. One female inbred and four male inbred lines were selected from a …

Molecular-Marker-Facilitated Investigations Of Quantitative-Trait Loci In Maize. I. Numbers, Genomic Distribution And Types Of Gene Action, Jonathan F. Wendel, M. D. Edwards, Charles W. Stuber

Jonathan F. Wendel

Individual genetic factors which underlie variation in quantitative traits of maize were investigated in each of two F 2 populations by examining the mean trait expressions of genotypic classes at each of 17-20 segregating marker loci. It was demonstrated that the trait expression of marker locus classes could be interpreted in terms of genetic behavior at linked quantitative trait loci (QTLs). For each of 82 traits evaluated, QTLs were detected and located to genomic sites. The numbers of detected factors varied according to trait, with the average trait significantly influenced by almost two-thirds of the marked genomic sites. Most of …

Additional Mapping Of Isozyme Loci: Localization Of Acp4, Dia2, Adkl, Tpi3, And Sadl, Jonathan F. Wendel, Major M. Goodman, Charles W. Stuber

Jonathan F. Wendel

We recently listed the isozyme loci being studied by starch gel electrophoresis in our laboratory and summarized the available mapping data in a series of reports (Wendel et al., MGCNL 59:87-90). Subsequent work has resulted in further clarification of the chromosomal locations of markers on chromosomes 1 (Acp4, Dia2), 6 (Adkl), 8 (Tpi3), and 10 (Sadl). Previously unreported information on these loci and their chromosomal locations follows.

Tpi4 Is Located Near The Centromere On The Long Arm Of Chromosome 3, Jonathan F. Wendel, J. B. Beckett

Jonathan F. Wendel

Tpi4, one of the three genes encoding cytosolic triose phosphate isomerase isozymes, was earlier shown to be on 3L between Pgd2 (phosphogluconate dehydrogenase) and the centromere (Wendel et al., MNL 59:88). In an effort to better localize Tpi4, a series of crosses was made between Tpi4 testers and stocks carrying three B-A translocations believed to be near the centromere on 3L.

Localization Of Two New Isozyme Loci, Hexl And Tpi4, To Chromosome 3, Jonathan F. Wendel, Charles W. Stuber, Major M. Goodman

Jonathan F. Wendel

Recent work with starch gel electrophoresis of coleoptile extracts has indicated that Hexl, the structural locus for the most anodal set of hexokinase isozymes, and Tpi4, which encodes the slowest migrating set of triose phosphate isomerase bands, are located on chromosome 3.

Mapping Data For 34 Isozyme Loci Currently Being Studied, Jonathan F. Wendel, Charles W. Stuber, Major M. Goodman

Jonathan F. Wendel

With the recent localization of several new loci, a composite listing of these loci and chromosomal locations has been compiled and is shown in Table 1. Although locations of some of the loci are tentative, many are very precisely located from studies involving 1600 to more than 1900 F2 plants.

Linkage Relationships Between A New Locus, Hex2, And Previously Assigned Loci On Chromosome 6, Jonathan F. Wendel, Charles W. Stuber, Major M. Goodman

Jonathan F. Wendel

Starch gel electrophoresis of maize coleoptile extracts in our laboratory has shown two zones of staining for isozymes of hexokinase. Genetic analyses 9 indicate that the slower migrating set of bands is encoded by the structural gene Hex2 and that the enzyme is monomeric. Recent linkage analyses and work with B-A translocation stocks (generously supplied by Jack Beckett) have allowed for the placement ofHex2 on the long arm of chromosome 6. Its location relative to other markers on 6L was determined from the analysis of two very large F2 populations generated for other reasons.

The Effects Of Irradiating Dormant Maize Seeds With Xrays And Thermal Neutrons, Rosalind Morris, E. F. Frolik

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

In 1951 a research program was started at the University of Nebraska to compare the developmental effects of thermal neutrons and X rays on different crop seeds. Three crops, barley, tomato and maize, were chosen for additional information involving induced chromosomal aberrations and seedling mutations. The maize investigations are presented in this bulletin, along with a comparison among the three crops with respect to irradiation effects.

Progress From Recurrent Selection Procedures For The Improvement Of Corn Populations, John H. Lonnquist

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The possibilities of developing synthetic varieties suitable for the fringe areas of the corn belt, where cost of hybrid seed is high relative to the value of the expected crop, and in areas where hybrid corn might not be a feasible approach for other reasons, made it seem a worthwhile objective for study. Effort has been made in recent years to increase the productivity of hybrid combinations through selection of new superior lines using standard breeding procedures. The limited progress realized has resulted in an increased interest in the possible use of alternate methods for the development of superior germplasm …

The Inheritance Of A Recurring Somatic Variation In Variegated Ears Of Maize, R. A. Emerson

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The inheritance of variegation has special interest and importance in genetics. In this paper I shall present data from maize and attempt to show how they can be interpreted in strictly Mendelian terms.