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Gene Expression Programs During Shoot, Root, And Callus Development In Arabidopsis Tissue Culture, Ping Che, Sonia Lall, Dan Nettleton, Stephen H. Howell Jul 2019

Gene Expression Programs During Shoot, Root, And Callus Development In Arabidopsis Tissue Culture, Ping Che, Sonia Lall, Dan Nettleton, Stephen H. Howell

Dan Nettleton

Shoots can be regenerated from Arabidopsis (Arabidopsis thaliana) root explants in tissue culture through a two-step process requiring preincubation on an auxin-rich callus induction medium. Regenerating tissues can be directed along different developmental pathways leading to the formation of shoots, new roots, or callus by transferring to the appropriate organ induction medium. Using gene-profiling methods, we identified groups of genes that serve as molecular signatures of the different developmental processes, i.e. genes that were specifically up- or down-regulated on one developmental pathway, but not on others. One transcription factor gene that was up-regulated during early shoot development was …


Hierarchical Modeling And Differential Expression Analysis For Rna-Seq Experiments With Inbred And Hybrid Genotypes, Andrew Lithio, Dan Nettleton Jul 2019

Hierarchical Modeling And Differential Expression Analysis For Rna-Seq Experiments With Inbred And Hybrid Genotypes, Andrew Lithio, Dan Nettleton

Dan Nettleton

The performance of inbred and hybrid genotypes is of interest in plant breeding and genetics. High-throughput sequencing of RNA (RNA-seq) has proven to be a useful tool in the study of the molecular genetic responses of inbreds and hybrids to environmental stresses. Commonly used experimental designs and sequencing methods lead to complex data structures that require careful attention in data analysis. We demonstrate an analysis of RNA-seq data from a split-plot design involving drought stress applied to two inbred genotypes and two hybrids formed by crosses between the inbreds. Our generalized linear modeling strategy incorporates random effects for whole-plot experimental …


Nested Hierarchical Functional Data Modeling And Inference For The Analysis Of Functional Plant Phenotypes, Yuhang Xu, Yehua Li, Dan Nettleton Jul 2019

Nested Hierarchical Functional Data Modeling And Inference For The Analysis Of Functional Plant Phenotypes, Yuhang Xu, Yehua Li, Dan Nettleton

Dan Nettleton

In a plant science Root Image Study, the process of seedling roots bending in response to gravity is recorded using digital cameras, and the bending rates are modeled as functional plant phenotype data. The functional phenotypes are collected from seeds representing a large variety of genotypes and have a three-level nested hierarchical structure, with seeds nested in groups nested in genotypes. The seeds are imaged on different days of the lunar cycle, and an important scientific question is whether there are lunar effects on root bending. We allow the mean function of the bending rate to depend on the lunar …


Effects Of Cage Stocking Density On Feeding Behaviors Of Group-Housed Laying Hens, Rachel Nichole Cook, Hongwei Xin, Dan Nettleton Jul 2019

Effects Of Cage Stocking Density On Feeding Behaviors Of Group-Housed Laying Hens, Rachel Nichole Cook, Hongwei Xin, Dan Nettleton

Dan Nettleton

Quantitative measurement of animal welfare continues to be a challenging task for both the animal agriculture industry and the scientific community. Characterization of animal feeding behavior provides a comparative elucidation of the animal’s behavioral deviation from its norms and thus carries implications for its welfare. This study examines the effects of cage stocking density (348, 387, 426, and 465 cm2; or 54, 60, 66, and 72 in.2 cage floor space per hen) on feeding behavior of W-36 White Leghorn laying hens kept in groups of six hens. The study employed a specialized instrumentation system and computational algorithm. The results revealed …


Feeding Behaviors Of Laying Hens With Or Without Beak Trimming, Kelly E. Persyn, Hongwei Xin, Dan Nettleton, Atsuo Ikeguchi, Richard S. Gates Jul 2019

Feeding Behaviors Of Laying Hens With Or Without Beak Trimming, Kelly E. Persyn, Hongwei Xin, Dan Nettleton, Atsuo Ikeguchi, Richard S. Gates

Dan Nettleton

This study quantifies feeding behavior of W-36 White Leghorn laying hens (77 to 80 weeks old) as influenced by the management practice of beak trimming. The feeding behavior was characterized using a newly developed measurement system and computational algorithm. Non-trimmed (NT) and beak-trimmed (BT) hens showed similar daily feed intake and meal size. However, the BT hens tended to spend longer time feeding (3.3 vs. 2.0 h/d, P < 0.01), which coincided with their slower ingestion rate of 0.43 g/min-kg0.75 vs. 0.79 g/min-kg0.75 for the NT counterparts (P < 0.05). The BT hens had shorter time intervals between meals (101 s vs. 151 s, P < 0.01). Selective feeding, as demonstrated by larger feed particles apparent in the leftover feed, was noted for the BT hens. The leftover feed had a lower crude protein/adjusted crude protein content for the BT birds than that for the NT birds (16.7% vs. 18.7%, P < 0.05). In addition, the leftover feed of the BT birds had lower contents in phosphorus, magnesium, potassium, zinc, and manganese (P < 0.05), although no significant differences were detected in calcium, sodium, or metabolic energy content. Baseline feeding behavior data of this nature may help quantify and ensure the welfare of animals through exercising proper engineering design and/or management considerations.


Root Type-Specific Reprogramming Of Maize Pericycle Transcriptomes By Local High Nitrate Results In Disparate Lateral Root Branching Patterns, Peng Yu, Jutta A. Baldauf, Andrew Lithio, Caroline Marcon, Dan Nettleton, Chunjian Li, Frank Hochholdinger Jul 2019

Root Type-Specific Reprogramming Of Maize Pericycle Transcriptomes By Local High Nitrate Results In Disparate Lateral Root Branching Patterns, Peng Yu, Jutta A. Baldauf, Andrew Lithio, Caroline Marcon, Dan Nettleton, Chunjian Li, Frank Hochholdinger

Dan Nettleton

The adaptability of root system architecture to unevenly distributed mineral nutrients in soil is a key determinant of plant performance. The molecular mechanisms underlying nitrate dependent plasticity of lateral root branching across the different root types of maize are only poorly understood. In this study, detailed morphological and anatomical analyses together with cell type-specific transcriptome profiling experiments combining laser capture microdissection with RNA-seq were performed to unravel the molecular signatures of lateral root formation in primary, seminal, crown, and brace roots of maize (Zea mays) upon local high nitrate stimulation. The four maize root types displayed divergent branching …


Using Random Forests To Estimate Win Probability Before Each Play Of An Nfl Game, Dennis Lock, Dan Nettleton Jul 2019

Using Random Forests To Estimate Win Probability Before Each Play Of An Nfl Game, Dennis Lock, Dan Nettleton

Dan Nettleton

Before any play of a National Football League (NFL) game, the probability that a given team will win depends on many situational variables (such as time remaining, yards to go for a first down, field position and current score) as well as the relative quality of the two teams as quantified by the Las Vegas point spread. We use a random forest method to combine pre-play variables to estimate Win Probability (WP) before any play of an NFL game. When a subset of NFL play-by-play data for the 12 seasons from 2001 to 2012 is used as a training dataset, …


Stability Of Single-Parent Gene Expression Complementation In Maize Hybrids Upon Water Deficit Stress, Caroline Marcon, Anja Paschold, Waqas Ahmed Malik, Andrew Lithio, Jutta A. Baldauf, Lena Altrogge, Nina Opitz, Christa Lanz, Heiko Schoof, Dan Nettleton, Hans-Peter Piepho, Frank Hochholdinger Jul 2019

Stability Of Single-Parent Gene Expression Complementation In Maize Hybrids Upon Water Deficit Stress, Caroline Marcon, Anja Paschold, Waqas Ahmed Malik, Andrew Lithio, Jutta A. Baldauf, Lena Altrogge, Nina Opitz, Christa Lanz, Heiko Schoof, Dan Nettleton, Hans-Peter Piepho, Frank Hochholdinger

Dan Nettleton

Heterosis is the superior performance of F1 hybrids compared with their homozygous, genetically distinct parents. In this study, we monitored the transcriptomic divergence of the maize (Zea mays) inbred lines B73 and Mo17 and their reciprocal F1 hybrid progeny in primary roots under control and water deficit conditions simulated by polyethylene glycol treatment. Single-parent expression (SPE) of genes is an extreme instance of gene expression complementation, in which genes are active in only one of two parents but are expressed in both reciprocal hybrids. In this study, 1,997 genes only expressed in B73 and 2,024 genes …


Genomic Neighborhoods For Arabidopsisretrotransposons: A Role For Targeted Integration In The Distribution Of The Metaviridae, Brooke D. Peterson-Burch, Dan Nettleton, Daniel F. Voytas Jul 2019

Genomic Neighborhoods For Arabidopsisretrotransposons: A Role For Targeted Integration In The Distribution Of The Metaviridae, Brooke D. Peterson-Burch, Dan Nettleton, Daniel F. Voytas

Dan Nettleton

Background: Retrotransposons are an abundant component of eukaryotic genomes. The high quality of the Arabidopsis thaliana genome sequence makes it possible to comprehensively characterize retroelement populations and explore factors that contribute to their genomic distribution.

Results: We identified the full complement of A. thaliana long terminal repeat (LTR) retroelements using RetroMap, a software tool that iteratively searches genome sequences for reverse transcriptases and then defines retroelement insertions. Relative ages of full-length elements were estimated by assessing sequence divergence between LTRs: the Pseudoviridae were significantly younger than the Metaviridae. All retroelement insertions were mapped onto the genome sequence and their distribution …


Gene Expression Profiling In Salmonella Choleraesuis-Infected Porcine Lung Using A Long Oligonucleotide Microarray, Shu-Hong Zhao, Daniel Kuhar, Joan K. Lunney, Harry Dawson, Catherine Guidry, Jolita J. Uthe, Shawn M. D. Bearson, Justin Recknor, Dan Nettleton, Christopher K. Tuggle Jul 2019

Gene Expression Profiling In Salmonella Choleraesuis-Infected Porcine Lung Using A Long Oligonucleotide Microarray, Shu-Hong Zhao, Daniel Kuhar, Joan K. Lunney, Harry Dawson, Catherine Guidry, Jolita J. Uthe, Shawn M. D. Bearson, Justin Recknor, Dan Nettleton, Christopher K. Tuggle

Dan Nettleton

Understanding the transcriptional response to pathogenic bacterial infection within food animals is of fundamental and applied interest. To determine the transcriptional response to Salmonella enterica serovar Choleraesuis (SC) infection, a 13,297-oligonucleotide swine array was used to analyze RNA from control, 24-h postinoculation (hpi), and 48-hpi porcine lung tissue from pigs infected with SC. In total, 57 genes showed differential expression (p < 0.001; false discovery rate = 12%). Quantitative real-time PCR (qRT-PCR) of 61 genes was used to confirm the microarray results and to identify pathways responding to infection. Of the 33 genes identified by microarray analysis as differentially expressed, 23 were confirmed by qRT-PCR results. A novel finding was that two transglutaminase family genes (TGM1 and TGM3) showed dramatic increases in expression postinoculation; combined with several other apoptotic genes, they indicated the induction of apoptotic pathways during SC infection. A predominant T helper 1-type immune response occurred during infection, with interferon …


Laser Microdissection Of Narrow Sheath Mutant Maize Uncovers Novel Gene Expression In The Shoot Apical Meristem, Xiaolan Zhang, Shahinez Madi, Lisa Borsuk, Dan Nettleton, Robert J. Elshire, Brent Buckner, Diane Janick-Buckner, Jon Beck, Marja Timmermans, Patrick S. Schnable, Michael J. Scanlon Jul 2019

Laser Microdissection Of Narrow Sheath Mutant Maize Uncovers Novel Gene Expression In The Shoot Apical Meristem, Xiaolan Zhang, Shahinez Madi, Lisa Borsuk, Dan Nettleton, Robert J. Elshire, Brent Buckner, Diane Janick-Buckner, Jon Beck, Marja Timmermans, Patrick S. Schnable, Michael J. Scanlon

Dan Nettleton

Microarrays enable comparative analyses of gene expression on a genomic scale, however these experiments frequently identify an abundance of differentially expressed genes such that it may be difficult to identify discrete functional networks that are hidden within large microarray datasets. Microarray analyses in which mutant organisms are compared to nonmutant siblings can be especially problematic when the gene of interest is expressed in relatively few cells. Here, we describe the use of laser microdissection microarray to perform transcriptional profiling of the maize shoot apical meristem (SAM), a ~100-μm pillar of organogenic cells that is required for leaf initiation. Microarray analyses …


Scanning Microarrays At Multiple Intensities Enhances Discovery Of Differentially Expressed Genes, David S. Skibbe, Xiujuan Wang, Xuefeng Zhao, Lisa A. Borsuk, Dan Nettleton, Patrick S. Schnable Jul 2019

Scanning Microarrays At Multiple Intensities Enhances Discovery Of Differentially Expressed Genes, David S. Skibbe, Xiujuan Wang, Xuefeng Zhao, Lisa A. Borsuk, Dan Nettleton, Patrick S. Schnable

Dan Nettleton

Motivation: Scanning parameters are often overlooked when optimizing microarray experiments. A scanning approach that extends the dynamic data range by acquiring multiple scans of different intensities has been developed.

Results: Data from each of three scan intensities (low, medium, high) were analyzed separately using multiple scan and linear regression approaches to identify and compare the sets of genes that exhibit statistically significant differential expression. In the multiple scan approach only one-third of the differentially expressed genes were shared among the three intensities, and each scan intensity identified unique sets of differentially expressed genes. The set of differentially expressed genes from …


The B73 Maize Genome: Complexity, Diversity, And Dynamics, Patrick S. Schnable, Doreen Ware, Kai Ying, Cheng-Ting Yeh, Scott J. Emrich, Yi Jia, Ananth Kalyanaraman, An-Ping Hsia, Yan Fu, Sanzhen Liu, Alan M. Myers, Dan Nettleton, Srinivas Aluru Jul 2019

The B73 Maize Genome: Complexity, Diversity, And Dynamics, Patrick S. Schnable, Doreen Ware, Kai Ying, Cheng-Ting Yeh, Scott J. Emrich, Yi Jia, Ananth Kalyanaraman, An-Ping Hsia, Yan Fu, Sanzhen Liu, Alan M. Myers, Dan Nettleton, Srinivas Aluru

Dan Nettleton

We report an improved draft nucleotide sequence of the 2.3-gigabase genome of maize, an important crop plant and model for biological research. Over 32,000 genes were predicted, of which 99.8% were placed on reference chromosomes. Nearly 85% of the genome is composed of hundreds of families of transposable elements, dispersed nonuniformly across the genome. These were responsible for the capture and amplification of numerous gene fragments and affect the composition, sizes, and positions of centromeres. We also report on the correlation of methylation-poor regions with Mu transposon insertions and recombination, and copy number variants with insertions and/or deletions, as well …


Microarray Gene Expression Profiles Of Fasting Induced Changes In Liver And Adipose Tissues Of Pigs Expressing The Melanocortin-4 Receptor D298n Variant, Sender Lkhagvadorj, Long Qu, Weiguo Cai, Oliver P. Coutoure, C. Richard Barb, Gary J. Hausman, Dan Nettleton, Lloyd L. Anderson, Jack C. M. Dekkers, Christopher K. Tuggle Jul 2019

Microarray Gene Expression Profiles Of Fasting Induced Changes In Liver And Adipose Tissues Of Pigs Expressing The Melanocortin-4 Receptor D298n Variant, Sender Lkhagvadorj, Long Qu, Weiguo Cai, Oliver P. Coutoure, C. Richard Barb, Gary J. Hausman, Dan Nettleton, Lloyd L. Anderson, Jack C. M. Dekkers, Christopher K. Tuggle

Dan Nettleton

Transcriptional profiling coupled with blood metabolite analyses were used to identify porcine genes and pathways that respond to a fasting treatment or to a D298N missense mutation in the melanocortin-4 receptor (MC4R) gene. Gilts (12 homozygous for D298 and 12 homozygous for N298) were either fed ad libitum or fasted for 3 days. Fasting decreased body weight, backfat, and serum urea concentration and increased serum nonesterified fatty acid. In response to fasting, 7,029 genes in fat and 1,831 genes in liver were differentially expressed (DE). MC4R genotype did not significantly affect gene expression, body weight, backfat depth, or any measured …


Analysis Of Porcine Transcriptional Response To Salmonella Enterica Serovar Choleraesuis Suggests Novel Targets Of Nfkappab Are Activated In The Mesenteric Lymph Node, Yanfang Wang, Olivre P. Couture, Long Qu, Jolita J. Uthe, Shawn M. D. Bearson, Daniel Kuhar, Joan K. Lunney, Dan Nettleton, Jack C. M. Dekkers, Christopher K. Tuggle Jul 2019

Analysis Of Porcine Transcriptional Response To Salmonella Enterica Serovar Choleraesuis Suggests Novel Targets Of Nfkappab Are Activated In The Mesenteric Lymph Node, Yanfang Wang, Olivre P. Couture, Long Qu, Jolita J. Uthe, Shawn M. D. Bearson, Daniel Kuhar, Joan K. Lunney, Dan Nettleton, Jack C. M. Dekkers, Christopher K. Tuggle

Dan Nettleton

Background: Specific knowledge of the molecular pathways controlling host-pathogen interactions can increase our understanding of immune response biology as well as provide targets for drug development and genetic improvement of disease resistance. Toward this end, we have characterized the porcine transcriptional response to Salmonella enterica serovar Choleraesuis (S. Choleraesuis), a Salmonella serovar that predominately colonizes swine, yet can cause serious infections in human patients. Affymetrix technology was used to screen for differentially expressed genes in pig mesenteric lymph nodes (MLN) responding to infection with S. Choleraesuis at acute (8 hours (h), 24 h and 48 h post-inoculation (pi)) and chronic …


Loss Of Rna–Dependent Rna Polymerase 2 (Rdr2) Function Causes Widespread And Unexpected Changes In The Expression Of Transposons, Genes, And 24-Nt Small Rnas, Yi Jia, Damon R. Lisch, Kazuhiro Ohtsu, Michael J. Scanlon, Dan Nettleton, Patrick S. Schnable Jul 2019

Loss Of Rna–Dependent Rna Polymerase 2 (Rdr2) Function Causes Widespread And Unexpected Changes In The Expression Of Transposons, Genes, And 24-Nt Small Rnas, Yi Jia, Damon R. Lisch, Kazuhiro Ohtsu, Michael J. Scanlon, Dan Nettleton, Patrick S. Schnable

Dan Nettleton

Transposable elements (TEs) comprise a substantial portion of many eukaryotic genomes and are typically transcriptionally silenced. RNA–dependent RNA polymerase 2 (RDR2) is a component of the RNA–directed DNA methylation (RdDM) silencing pathway. In maize, loss of mediator of paramutation1 (mop1) encoded RDR2 function results in reactivation of transcriptionally silenced Mu transposons and a substantial reduction in the accumulation of 24 nt short-interfering RNAs (siRNAs) that recruit RNA silencing components. An RNA–seq experiment conducted on shoot apical meristems (SAMs) revealed that, as expected based on a model in which RDR2 generates 24 nt siRNAs that suppress expression, most differentially …


Comparative Gene Expression Profiles Between Heterotic And Non-Heterotic Hybrids Of Tetraploid Medicago Sativa, Xuehui Li, Yanling Wei, Dan Nettleton, E. Charles Brummer Jul 2019

Comparative Gene Expression Profiles Between Heterotic And Non-Heterotic Hybrids Of Tetraploid Medicago Sativa, Xuehui Li, Yanling Wei, Dan Nettleton, E. Charles Brummer

Dan Nettleton

Background: Heterosis, the superior performance of hybrids relative to parents, has clear agricultural value, but its genetic control is unknown. Our objective was to test the hypotheses that hybrids expressing heterosis for biomass yield would show more gene expression levels that were different from midparental values and outside the range of parental values than hybrids that do not exhibit heterosis.

Results: We tested these hypotheses in three Medicago sativa (alfalfa) genotypes and their three hybrids, two of which expressed heterosis for biomass yield and a third that did not, using Affymetrix M. truncatula GeneChip arrays. Alfalfa hybridized to approximately 47% …


Use Of Legume Green Manures As Nitrogen Sources For Corn Production, Matt Liebman, Rhonda L. Graef, Daniel Nettleton, Cynthia A. Cambardella Jul 2019

Use Of Legume Green Manures As Nitrogen Sources For Corn Production, Matt Liebman, Rhonda L. Graef, Daniel Nettleton, Cynthia A. Cambardella

Dan Nettleton

Recent volatility in supplies and prices of natural gas and synthetic nitrogen (N) fertilizer suggests a need to develop and refine alternative strategies for supplying N to corn. In this study, conducted in north-eastern Iowa, we examined the use of red clover and alfalfa green manures as means of supplying N to a succeeding corn crop. Red clover intercropped with oat produced significantly more biomass and contained more N than alfalfa intercropped with oat. Tilling green manures in the fall or delaying tillage until the following spring did not have a consistent effect on green manure N content. Without N …


Distinct Peripheral Blood Rna Responses To Salmonella In Pigs Differing In Salmonella Shedding Levels: Intersection Of Ifng, Tlr And Mirna Pathways, Ting-Hua Huang, Jolita J. Uthe, Shawn M. D. Bearson, Cumhur Yusuf Demirkale, Dan Nettleton, Susan Knetter, Curtis Christian, Amanda E. Ramer-Tait, Michael J. Wannemeuhler, Christopher K. Tuggle Jul 2019

Distinct Peripheral Blood Rna Responses To Salmonella In Pigs Differing In Salmonella Shedding Levels: Intersection Of Ifng, Tlr And Mirna Pathways, Ting-Hua Huang, Jolita J. Uthe, Shawn M. D. Bearson, Cumhur Yusuf Demirkale, Dan Nettleton, Susan Knetter, Curtis Christian, Amanda E. Ramer-Tait, Michael J. Wannemeuhler, Christopher K. Tuggle

Dan Nettleton

Transcriptomic analysis of the response to bacterial pathogens has been reported for several species, yet few studies have investigated the transcriptional differences in whole blood in subjects that differ in their disease response phenotypes. Salmonella species infect many vertebrate species, and pigs colonized with Salmonella enterica serovar Typhimurium (ST) are usually asymptomatic, making detection of these Salmonella-carrier pigs difficult. The variable fecal shedding of Salmonella is an important cause of foodborne illness and zoonotic disease. To investigate gene pathways and biomarkers associated with the variance in Salmonellashedding following experimental inoculation, we initiated the first analysis of the whole …


Gene Mapping Via Bulked Segregant Rna-Seq (Bsr-Seq), Sanzhen Liu, Cheng-Ting Yeh, Ho Man Tang, Dan Nettleton, Patrick S. Schnable Jul 2019

Gene Mapping Via Bulked Segregant Rna-Seq (Bsr-Seq), Sanzhen Liu, Cheng-Ting Yeh, Ho Man Tang, Dan Nettleton, Patrick S. Schnable

Dan Nettleton

Bulked segregant analysis (BSA) is an efficient method to rapidly and efficiently map genes responsible for mutant phenotypes. BSA requires access to quantitative genetic markers that are polymorphic in the mapping population. We have developed a modification of BSA (BSR-Seq) that makes use of RNA-Seq reads to efficiently map genes even in populations for which no polymorphic markers have been previously identified. Because of the digital nature of next-generation sequencing (NGS) data, it is possible to conduct de novo SNP discovery and quantitatively genotype BSA samples by analyzing the same RNA-Seq data using an empirical Bayesian approach. In addition, analysis …


Unique Genome-Wide Transcriptome Profiles Of Chicken Macrophages Exposed To Salmonella-Derived Endotoxin, Ceren Ciraci, Christopher K. Tuggle, Michael J. Wannemeuhler, Dan Nettleton, Susan J. Lamont Jul 2019

Unique Genome-Wide Transcriptome Profiles Of Chicken Macrophages Exposed To Salmonella-Derived Endotoxin, Ceren Ciraci, Christopher K. Tuggle, Michael J. Wannemeuhler, Dan Nettleton, Susan J. Lamont

Dan Nettleton

Background: Macrophages play essential roles in both innate and adaptive immune responses. Bacteria require endotoxin, a complex lipopolysaccharide, for outer membrane permeability and the host interprets endotoxin as a signal to initiate an innate immune response. The focus of this study is kinetic and global transcriptional analysis of the chicken macrophage response to in vitro stimulation with endotoxin from Salmonella typhimurium-798.

Results: The 38535-probeset Affymetrix GeneChip Chicken Genome array was used to profile transcriptional response to endotoxin 1, 2, 4, and 8 hours post stimulation (hps). Using a maximum FDR (False Discovery Rate) of 0.05 to declare genes as differentially …


Complementation Contributes To Transcriptome Complexity In Maize (Zea Mays L.) Hybrids Relative To Their Inbred Parents, Anja Paschold, Yi Jia, Caroline Marcon, Steve Lund, Nick B. Larson, Cheng-Ting Yeh, Stephan Ossowski, Christa Lanz, Dan Nettleton, Patrick S. Schnable, Frank Hochholdinger Jul 2019

Complementation Contributes To Transcriptome Complexity In Maize (Zea Mays L.) Hybrids Relative To Their Inbred Parents, Anja Paschold, Yi Jia, Caroline Marcon, Steve Lund, Nick B. Larson, Cheng-Ting Yeh, Stephan Ossowski, Christa Lanz, Dan Nettleton, Patrick S. Schnable, Frank Hochholdinger

Dan Nettleton

Typically, F1-hybrids are more vigorous than their homozygous, genetically distinct parents, a phenomenon known as heterosis. In the present study, the transcriptomes of the reciprocal maize (Zea mays L.) hybrids B73×Mo17 and Mo17×B73 and their parental inbred lines B73 and Mo17 were surveyed in primary roots, early in the developmental manifestation of heterotic root traits. The application of statistical methods and a suitable experimental design established that 34,233 (i.e., 86%) of all high-confidence maize genes were expressed in at least one genotype. Nearly 70% of all expressed genes were differentially expressed between the two parents and 42%–55% …


The Maize Brown Midrib2 (Bm2) Gene Encodes A Methylenetetrahydrofolate Reductase That Contributes To Lignin Accumulation, Ho Man Tang, Sanzhen Liu, Sarah Hill-Skinner, Wei Wu, Danielle Reed, Cheng-Ting Yeh, Dan Nettleton, Patrick S. Schnable Jun 2019

The Maize Brown Midrib2 (Bm2) Gene Encodes A Methylenetetrahydrofolate Reductase That Contributes To Lignin Accumulation, Ho Man Tang, Sanzhen Liu, Sarah Hill-Skinner, Wei Wu, Danielle Reed, Cheng-Ting Yeh, Dan Nettleton, Patrick S. Schnable

Dan Nettleton

The midribs of maize brown midrib (bm) mutants exhibit a reddish‐brown color associated with reductions in lignin concentration and alterations in lignin composition. Here, we report the mapping, cloning, and functional and biochemical analyses of the bm2 gene. The bm2 gene was mapped to a small region of chromosome 1 that contains a putative methylenetetrahydrofolate reductase (MTHFR) gene, which is down‐regulated in bm2 mutant plants. Analyses of multiple Mu‐induced bm2‐Mu mutant alleles confirmed that this constitutively expressed gene is bm2. Yeast complementation experiments and a previously published biochemical characterization show that the bm2 gene encodes a …


Reverse Engineering And Analysis Of Large Genome-Scale Gene Networks, Maneesha Aluru, Jaroslaw Zola, Dan Nettleton, Srinivas Aluru Jun 2019

Reverse Engineering And Analysis Of Large Genome-Scale Gene Networks, Maneesha Aluru, Jaroslaw Zola, Dan Nettleton, Srinivas Aluru

Dan Nettleton

Reverse engineering the whole-genome networks of complex multicellular organisms continues to remain a challenge. While simpler models easily scale to large number of genes and gene expression datasets, more accurate models are compute intensive limiting their scale of applicability. To enable fast and accurate reconstruction of large networks, we developed Tool for Inferring Network of Genes (TINGe), a parallel mutual information (MI)-based program. The novel features of our approach include: (i) B-spline-based formulation for linear-time computation of MI, (ii) a novel algorithm for direct permutation testing and (iii) development of parallel algorithms to reduce run-time and facilitate construction of large …


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 Jun 2019

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 …


Estimation And Testing Of Gene Expression Heterosis, Tieming Ji, Peng Liu, Dan Nettleton Jun 2019

Estimation And Testing Of Gene Expression Heterosis, Tieming Ji, Peng Liu, Dan Nettleton

Dan Nettleton

Heterosis, also known as the hybrid vigor, occurs when the mean phenotype of hybrid offspring is superior to that of its two inbred parents. The heterosis phenomenon is extensively utilized in agriculture though the molecular basis is still unknown. In an effort to understand phenotypic heterosis at the molecular level, researchers have begun to compare expression levels of thousands of genes between parental inbred lines and their hybrid offspring to search for evidence of gene expression heterosis. Standard statistical approaches for separately analyzing expression data for each gene can produce biased and highly variable estimates and unreliable tests of heterosis. …


Extensive Tissue-Specific Transcriptomic Plasticity In Maize Primary Roots Upon Water Deficit, Nina Opitz, Caroline Marcon, Anja Paschold, Waqas Ahmed Malik, Andrew Lithio, Ronny Brandt, Hans-Peter Piepho, Dan Nettleton, Frank Hochholdinger Jun 2019

Extensive Tissue-Specific Transcriptomic Plasticity In Maize Primary Roots Upon Water Deficit, Nina Opitz, Caroline Marcon, Anja Paschold, Waqas Ahmed Malik, Andrew Lithio, Ronny Brandt, Hans-Peter Piepho, Dan Nettleton, Frank Hochholdinger

Dan Nettleton

Water deficit is the most important environmental constraint severely limiting global crop growth and productivity. This study investigated early transcriptome changes in maize (Zea mays L.) primary root tissues in response to moderate water deficit conditions by RNA-Sequencing. Differential gene expression analyses revealed a high degree of plasticity of the water deficit response. The activity status of genes (active/inactive) was determined by a Bayesian hierarchical model. In total, 70% of expressed genes were constitutively active in all tissues. In contrast, <3% (50 genes) of water deficit-responsive genes (1915) were consistently regulated in all tissues, while >75% (1501 genes) were specifically regulated in a single root tissue. Water deficit-responsive genes were most numerous in the …


Transcriptomic And Anatomical Complexity Of Primary, Seminal, And Crown Roots Highlight Root Type-Specific Functional Diversity In Maize (Zea Mays L.), Huanhuan Tai, Xin Lu, Nin Opitz, Caroline Marcon, Anja Paschold, Andrew Lithio, Dan Nettleton, Frank Hochholdinger Jun 2019

Transcriptomic And Anatomical Complexity Of Primary, Seminal, And Crown Roots Highlight Root Type-Specific Functional Diversity In Maize (Zea Mays L.), Huanhuan Tai, Xin Lu, Nin Opitz, Caroline Marcon, Anja Paschold, Andrew Lithio, Dan Nettleton, Frank Hochholdinger

Dan Nettleton

Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across …


Computational Integration Of Structural And Functional Genomics Data Across Species To Develop Information On The Porcine Inflammatory Gene Regulatory Pathway, C. K. Tuggle, Y. F. Wang, O. P. Couture, L. Qu, J. J. Uthe, D. Kuhar, J. K. Lunney, D. Nettleton, J. C. Dekkers, S. M. D. Bearson Jun 2019

Computational Integration Of Structural And Functional Genomics Data Across Species To Develop Information On The Porcine Inflammatory Gene Regulatory Pathway, C. K. Tuggle, Y. F. Wang, O. P. Couture, L. Qu, J. J. Uthe, D. Kuhar, J. K. Lunney, D. Nettleton, J. C. Dekkers, S. M. D. Bearson

Dan Nettleton

We are investigating the porcine gut immune response to infection through gene expression profiling. Porcine Affymetrix GeneChip data was obtained from RNA prepared from mesenteric lymph node of swine infected with either Salmonella enterica serovar Typhimurium (ST) or S. Choleraesuis (SC) for 0, 8, 24, 48 or 504 hours post-inoculation (hpi). In total, 2,365 genes with statistical evidence for differential expression (DE; p < 0.01, q < 0.26, fold-change> 2) between at least two time-points were identified. Comparative Gene Ontology analyses revealed that a high proportion of annotated DE genes in both infections are involved in immune and defence responses. Hierarchical clustering of expression patterns and …


Stress Response To Co2 Deprivation By Arabidopsis Thaliana In Plant Cultures, Souvik Banerjee, Oskar Siemianowski, Meiling Liu, Kara R. Lind, Xinchun Tian, Dan Nettleton, Ludovico Cademartiri Jun 2019

Stress Response To Co2 Deprivation By Arabidopsis Thaliana In Plant Cultures, Souvik Banerjee, Oskar Siemianowski, Meiling Liu, Kara R. Lind, Xinchun Tian, Dan Nettleton, Ludovico Cademartiri

Dan Nettleton

After being the standard plant propagation protocol for decades, cultures of Arabidopsis thaliana sealed with Parafilm remain common today out of practicality, habit, or necessity (as in co-cultures with microorganisms). Regardless of concerns over the aeration of these cultures, no investigation has explored the CO2 transport inside these cultures and its effect on the plants. Thereby, it was impossible to assess whether Parafilm-seals used today or in thousands of older papers in the literature constitute a treatment, and whether this treatment could potentially affect the study of other treatments.For the first time we report the CO2concentrations in Parafilm-sealed cultures of …