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Articles 1 - 30 of 4097

Full-Text Articles in Physical Sciences and Mathematics

Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabián G. Fernández, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan Sep 2019

Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabián G. Fernández, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan

Agronomy Publications

Nitrogen (N) fertilizer recommendation tools could be improved for estimating corn (Zea mays L.) N needs by incorporating site-specific soil and weather information. However, an evaluation of analytical methods is needed to determine the success of incorporating this information. The objectives of this research were to evaluate statistical and machine learning (ML) algorithms for utilizing soil and weather information for improving corn N recommendation tools. Eight algorithms [stepwise, ridge regression, least absolute shrinkage and selection operator (Lasso), elastic net regression, principal component regression (PCR), partial least squares regression (PLSR), decision tree, and random forest] were evaluated using a dataset containing ...


Relative Salt Tolerance Of Seven Japanese Spirea Cultivars, Yuxiang Wang, Liqin Li, Youping Sun, Xin Dai Aug 2019

Relative Salt Tolerance Of Seven Japanese Spirea Cultivars, Yuxiang Wang, Liqin Li, Youping Sun, Xin Dai

Youping Sun

Spirea (Spiraea sp.) plants are commonly used in landscapes in Utah and the intermountain western United States. The relative salt tolerance of seven japanese spirea (Spiraea japonica) cultivars (Galen, Minspi, NCSX1, NCSX2, SMNSJMFP, Tracy, and Yan) were evaluated in a greenhouse. Plants were irrigated with a nutrient solution with an electrical conductivity (EC) of 1.2 dSmL1 (control) or saline solutions with an EC of 3.0 or 6.0 dSmL1 once per week for 8 weeks. At 8 weeks after the initiation of treatment, all japanese spirea cultivars irrigated with saline solution with an EC of 3.0 dSmL1 ...


Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabián G. Fernández, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan Aug 2019

Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabián G. Fernández, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan

John E. Sawyer

Nitrogen (N) fertilizer recommendation tools could be improved for estimating corn (Zea mays L.) N needs by incorporating site-specific soil and weather information. However, an evaluation of analytical methods is needed to determine the success of incorporating this information. The objectives of this research were to evaluate statistical and machine learning (ML) algorithms for utilizing soil and weather information for improving corn N recommendation tools. Eight algorithms [stepwise, ridge regression, least absolute shrinkage and selection operator (Lasso), elastic net regression, principal component regression (PCR), partial least squares regression (PLSR), decision tree, and random forest] were evaluated using a dataset containing ...


Adjusting For Spatial Effects In Genomic Prediction, Xiaojun Mao, Somak Dutta, Raymond K. W. Wong, Dan Nettleton Aug 2019

Adjusting For Spatial Effects In Genomic Prediction, Xiaojun Mao, Somak Dutta, Raymond K. W. Wong, Dan Nettleton

Dan Nettleton

This paper investigates the problem of adjusting for spatial effects in genomic prediction. Despite being seldomly considered in genome-wide association studies (GWAS), spatial effects often affect phenotypic measurements of plants. We consider a Gaussian random field (GRF) model with an additive covariance structure that incorporates genotype effects, spatial effects and subpopulation effects. An empirical study shows the existence of spatial effects and heterogeneity across different subpopulation families while simulations illustrate the improvement in selecting genotypically superior plants by adjusting for spatial effects in genomic prediction.


Qqs Orphan Gene And Its Interactor Nf‐Yc4 Reduce Susceptibility To Pathogens And Pests, Mingsheng Qi, Wenguang Zheng, Xuefeng Zhao, Jessica D. Hohenstein, Yuba Kandel, Seth O’Conner, Yifan Wang, Chuanlong Du, Dan Nettleton, Gustavo C. Macintosh, Gregory L. Tylka, Eve Syrkin Wurtele, Steven A. Whitham, Ling Li Aug 2019

Qqs Orphan Gene And Its Interactor Nf‐Yc4 Reduce Susceptibility To Pathogens And Pests, Mingsheng Qi, Wenguang Zheng, Xuefeng Zhao, Jessica D. Hohenstein, Yuba Kandel, Seth O’Conner, Yifan Wang, Chuanlong Du, Dan Nettleton, Gustavo C. Macintosh, Gregory L. Tylka, Eve Syrkin Wurtele, Steven A. Whitham, Ling Li

Ling Li

Enhancing the nutritional quality and disease resistance of crops without sacrificing productivity is a key issue for developing varieties that are valuable to farmers and for simultaneously improving food security and sustainability. Expression of the Arabidopsis thaliana species‐specific AtQQS (Qua‐Quine Starch) orphan gene or its interactor, NF‐YC4 (Nuclear Factor Y, subunit C4), has been shown to increase levels of leaf/seed protein without affecting the growth and yield of agronomic species. Here, we demonstrate that overexpression of AtQQS and NF‐YC4 in Arabidopsis and soybean enhances resistance/reduces susceptibility to viruses, bacteria, fungi, aphids, and soybean cyst ...


Small Rna Discovery In The Interaction Between Barley And The Powdery Mildew Pathogen, Matt Hunt, Sagnik Banerjee, Priyanka Surana, Meiling Liu, Greg Fuerst, Sandra Mathioni, Blake C. Meyers, Dan Nettleton, Roger P. Wise Jul 2019

Small Rna Discovery In The Interaction Between Barley And The Powdery Mildew Pathogen, Matt Hunt, Sagnik Banerjee, Priyanka Surana, Meiling Liu, Greg Fuerst, Sandra Mathioni, Blake C. Meyers, Dan Nettleton, Roger P. Wise

Dan Nettleton

Background: Plants encounter pathogenic and non-pathogenic microorganisms on a nearly constant basis. Small RNAs such as siRNAs and miRNAs/milRNAs influence pathogen virulence and host defense responses. We exploited the biotrophic interaction between the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh), and its diploid host plant, barley (Hordeum vulgare) to explore fungal and plant sRNAs expressed during Bgh infection of barley leaf epidermal cells.

Results: RNA was isolated from four fast-neutron immune-signaling mutants and their progenitor over a time course representing key stages of Bgh infection, including appressorium formation, penetration of epidermal cells, and development of haustorial feeding ...


Consecutive Extreme Flooding And Heat Wave In Japan: Are They Becoming A Norm?, Shih-Yu Simon Wang, Hyungjun Kim, Dim Coumou, Jin-Ho Yoon, Lin Zhao, Robert R. Gillies Jul 2019

Consecutive Extreme Flooding And Heat Wave In Japan: Are They Becoming A Norm?, Shih-Yu Simon Wang, Hyungjun Kim, Dim Coumou, Jin-Ho Yoon, Lin Zhao, Robert R. Gillies

Plants, Soils, and Climate Faculty Publications

In July 2018, Japan experienced two contrasting, yet consecutive, extreme events: a devastating flood in early July followed by unprecedented heat waves a week later. Death tolls from these two extreme events combined exceeded 300, accompanying tremendous economic losses (BBC: July 24, 2018; AP: July 30, 2018). Meteorological analysis on these 2018 events quickly emerged (JMA-TCC, 2018; Kotsuki et al., 2019; Tsuguti et al., 2019), highlighting several compound factors: a strengthened subtropical anticyclone, a deepened synoptic trough, and Typhoon Prapiroon that collectively enhanced the Baiu rainband (the Japanese summer monsoon), fostering heavy precipitation. The comprehensive study of these events, conducted ...


Adjusting For Spatial Effects In Genomic Prediction, Xiaojun Mao, Somak Dutta, Raymond K. W. Wong, Dan Nettleton Jul 2019

Adjusting For Spatial Effects In Genomic Prediction, Xiaojun Mao, Somak Dutta, Raymond K. W. Wong, Dan Nettleton

Statistics Publications

This paper investigates the problem of adjusting for spatial effects in genomic prediction. Despite being seldomly considered in genome-wide association studies (GWAS), spatial effects often affect phenotypic measurements of plants. We consider a Gaussian random field (GRF) model with an additive covariance structure that incorporates genotype effects, spatial effects and subpopulation effects. An empirical study shows the existence of spatial effects and heterogeneity across different subpopulation families while simulations illustrate the improvement in selecting genotypically superior plants by adjusting for spatial effects in genomic prediction.


Transcript-Based Cloning Of Rrp46, A Regulator Of Rrna Processing And R Gene–Independent Cell Death In Barley–Powdery Mildew Interactions, Liu Xi, Matthew J. Moscou, Yan Meng, Weihui Xu, Rico A. Caldo, Miranda Shaver, Dan Nettleton, Roger P. Wise Jul 2019

Transcript-Based Cloning Of Rrp46, A Regulator Of Rrna Processing And R Gene–Independent Cell Death In Barley–Powdery Mildew Interactions, Liu Xi, Matthew J. Moscou, Yan Meng, Weihui Xu, Rico A. Caldo, Miranda Shaver, Dan Nettleton, Roger P. Wise

Dan Nettleton

Programmed cell death (PCD) plays a pivotal role in plant development and defense. To investigate the interaction between PCD and R gene–mediated defense, we used the 22K Barley1 GeneChip to compare and contrast time-course expression profiles of Blumeria graminis f. sp hordei (Bgh) challenged barley (Hordeum vulgare) cultivar C.I. 16151 (harboring the Mla6 powdery mildew resistance allele) and its fast neutron–derived Bgh-induced tip cell death1 mutant, bcd1. Mixed linear model analysis identified genes associated with the cell death phenotype as opposed to Rgene–mediated resistance. One-hundred fifty genes were found at the threshold P value < 0.0001 and a false discovery rate bcd1mutant. Gene Ontology and rice (Oryza ...


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 ...


Toward Mass Spectrometry Imaging In The Metabolomics Scale: Increasing Metabolic Coverage Through Multiple On-Tissue Chemical Modifications, Maria Emilia Dueñas, Evan A. Larson, Young Jin Lee Jul 2019

Toward Mass Spectrometry Imaging In The Metabolomics Scale: Increasing Metabolic Coverage Through Multiple On-Tissue Chemical Modifications, Maria Emilia Dueñas, Evan A. Larson, Young Jin Lee

Young-Jin Lee

Exploring the metabolic differences directly on tissues is essential for the comprehensive understanding of how multicellular organisms function. Mass spectrometry imaging (MSI) is an attractive technique toward this goal; however, MSI in metabolomics scale has been hindered by multiple limitations. This is most notable for single cell level high-spatial resolution imaging because of the limited number of molecules in small sampling size and the low ionization yields of many metabolites. Several on-tissue chemical derivatization approaches have been reported to increase MSI signals of targeted compounds, especially in matrix-assisted laser desorption/ionization (MALDI)- MSI. Herein, we adopt a combination of chemical ...


Toward Mass Spectrometry Imaging In The Metabolomics Scale: Increasing Metabolic Coverage Through Multiple On-Tissue Chemical Modifications, Maria Emilia Dueñas, Evan A. Larson, Young Jin Lee Jul 2019

Toward Mass Spectrometry Imaging In The Metabolomics Scale: Increasing Metabolic Coverage Through Multiple On-Tissue Chemical Modifications, Maria Emilia Dueñas, Evan A. Larson, Young Jin Lee

Chemistry Publications

Exploring the metabolic differences directly on tissues is essential for the comprehensive understanding of how multicellular organisms function. Mass spectrometry imaging (MSI) is an attractive technique toward this goal; however, MSI in metabolomics scale has been hindered by multiple limitations. This is most notable for single cell level high-spatial resolution imaging because of the limited number of molecules in small sampling size and the low ionization yields of many metabolites. Several on-tissue chemical derivatization approaches have been reported to increase MSI signals of targeted compounds, especially in matrix-assisted laser desorption/ionization (MALDI)- MSI. Herein, we adopt a combination of chemical ...


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 patterns of ...


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 only expressed ...


Barleybase—An Expression Profiling Database For Plant Genomics, Lishuang Shen, Jian Gong, Rico A. Caldo, Dan Nettleton, Dianne Cook, Roger P. Wise, Julie A. Dickerson Jul 2019

Barleybase—An Expression Profiling Database For Plant Genomics, Lishuang Shen, Jian Gong, Rico A. Caldo, Dan Nettleton, Dianne Cook, Roger P. Wise, Julie A. Dickerson

Dan Nettleton

BarleyBase (BB) ( www.barleybase.org ) is an online database for plant microarrays with integrated tools for data visualization and statistical analysis. BB houses raw and normalized expression data from the two publicly available Affymetrix genome arrays, Barley1 and Arabidopsis ATH1 with plans to include the new Affymetrix 61K wheat, maize, soybean and rice arrays, as they become available. BB contains a broad set of query and display options at all data levels, ranging from experiments to individual hybridizations to probe sets down to individual probes. Users can perform cross-experiment queries on probe sets based on observed expression profiles and/or ...


Nonsyntenic Genes Drive Highly Dynamic Complementation Of Gene Expression In Maize Hybrids, Anja Paschold, Nick B. Larson, Caroline Marcon, James C. Schnable, Cheng-Ting Yeh, Christa Lanz, Dan Nettleton, Hans-Peter Piepho, Patrick S. Schnable, Frank Hochholdinger Jul 2019

Nonsyntenic Genes Drive Highly Dynamic Complementation Of Gene Expression In Maize Hybrids, Anja Paschold, Nick B. Larson, Caroline Marcon, James C. Schnable, Cheng-Ting Yeh, Christa Lanz, Dan Nettleton, Hans-Peter Piepho, Patrick S. Schnable, Frank Hochholdinger

Dan Nettleton

Maize (Zea mays) displays an exceptional level of structural genomic diversity, which is likely unique among higher eukaryotes. In this study, we surveyed how the genetic divergence of two maize inbred lines affects the transcriptomic landscape in four different primary root tissues of their F1-hybrid progeny. An extreme instance of complementation was frequently observed: genes that were expressed in only one parent but in both reciprocal hybrids. This single-parent expression (SPE) pattern was detected for 2341 genes with up to 1287 SPE patterns per tissue. As a consequence, the number of active genes in hybrids exceeded that of their parents ...


Interaction-Dependent Gene Expression In Mla-Specified Response To Barley Powdery Mildew, Rico A. Caldo, Dan Nettleton, Roger P. Wise Jul 2019

Interaction-Dependent Gene Expression In Mla-Specified Response To Barley Powdery Mildew, Rico A. Caldo, Dan Nettleton, Roger P. Wise

Dan Nettleton

Plant recognition of pathogen-derived molecules influences attack and counterattack strategies that affect the outcome of host–microbe interactions. To ascertain the global framework of host gene expression during biotrophic pathogen invasion, we analyzed in parallel the mRNA abundance of 22,792 host genes throughout 36 (genotype × pathogen × time) interactions between barley (Hordeum vulgare) and Blumeria graminis f. sp hordei (Bgh), the causal agent of powdery mildew disease. A split-split-plot design was used to investigate near-isogenic barley lines with introgressed Mla6, Mla13, and Mla1 coiled-coil, nucleotide binding site, Leu-rich repeat resistance alleles challenged with Bgh isolates 5874 (AvrMla6 and AvrMla1) and ...


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 ...


Microdissection Of Shoot Meristem Functional Domains, Lionel Brooks Iii, Josh Strable, Xiaolan Zhang, Kazuhiro Ohtsu, Ruilian Zhou, Ananda Sarkar, Sarah Hargreaves, Robert J. Elshire, Douglas Eudy, Teresa Pawlowska, Doreen Ware, Diane Janick-Buckner, Brent Buckner, Marja C. P. Timmermans, Patrick S. Schnable, Dan Nettleton, Michael J. Scanlon Jul 2019

Microdissection Of Shoot Meristem Functional Domains, Lionel Brooks Iii, Josh Strable, Xiaolan Zhang, Kazuhiro Ohtsu, Ruilian Zhou, Ananda Sarkar, Sarah Hargreaves, Robert J. Elshire, Douglas Eudy, Teresa Pawlowska, Doreen Ware, Diane Janick-Buckner, Brent Buckner, Marja C. P. Timmermans, Patrick S. Schnable, Dan Nettleton, Michael J. Scanlon

Dan Nettleton

The shoot apical meristem (SAM) maintains a pool of indeterminate cells within the SAM proper, while lateral organs are initiated from the SAM periphery. Laser microdissection–microarray technology was used to compare transcriptional profiles within these SAM domains to identify novel maize genes that function during leaf development. Nine hundred and sixty-two differentially expressed maize genes were detected; control genes known to be upregulated in the initiating leaf (P0/P1) or in the SAM proper verified the precision of the microdissections. Genes involved in cell division/growth, cell wall biosynthesis, chromatin remodeling, RNA binding, and translation are especially upregulated in ...


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 ...


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 ...


Beyond The Black Box: Promoting Mathematical Collaborations For Elucidating Interactions In Soil Ecology, Alison E. Bennett, Lori Biederman, Matthew Warren, Et Al. Jul 2019

Beyond The Black Box: Promoting Mathematical Collaborations For Elucidating Interactions In Soil Ecology, Alison E. Bennett, Lori Biederman, Matthew Warren, Et Al.

Ecology, Evolution and Organismal Biology Publications

Understanding soil systems is critical because they form the structural and nutritional foundation for plants and thus every terrestrial habitat and agricultural system. In this paper, we encourage increased use of mathematical models to drive forward understanding of interactions in soil ecological systems. We discuss several distinctive features of soil ecosystems and empirical studies of them. We explore some perceptions that have previously deterred more extensive use of models in soil ecology and some advances that have already been made using models to elucidate soil ecological interactions. We provide examples where mathematical models have been used to test the plausibility ...


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 ...


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 ...


Non-Syntenic Genes Drive Rtcs-Dependent Regulation Of The Embryo Transcriptome During Formation Of Seminal Root Primordia In Maize (Zea Mays L.), Huanhuan Tai, Nina Opitz, Andrew Lithio, Xin Lu, Dan Nettleton, Frank Hochholdinger Jun 2019

Non-Syntenic Genes Drive Rtcs-Dependent Regulation Of The Embryo Transcriptome During Formation Of Seminal Root Primordia In Maize (Zea Mays L.), Huanhuan Tai, Nina Opitz, Andrew Lithio, Xin Lu, Dan Nettleton, Frank Hochholdinger

Dan Nettleton

Seminal roots of maize are pivotal for early seedling establishment. The maize mutant rootless concerning crown and seminal roots (rtcs) is defective in seminal root initiation during embryogenesis. In this study, the transcriptomes of wild-type and rtcs embryos were analyzed by RNA-Seq based on histological results at three stages of seminal root primordia formation. Hierarchical clustering highlighted that samples of each genotype grouped together along development. Determination of their gene activity status revealed hundreds of genes specifically transcribed in wild-type or rtcs embryos, while K-mean clustering revealed changes in gene expression dynamics between wild-type and rtcs during embryo development. Pairwise ...


Complexity And Specificity Of The Maize (Zea Mays L.) Root Hair Transcriptome, Stefan Hey, Jutta Baldauf, Nina Opitz, Andrew Lithio, Asher Pasha, Nicholas Provart, Dan Nettleton, Frank Hochholdinger Jun 2019

Complexity And Specificity Of The Maize (Zea Mays L.) Root Hair Transcriptome, Stefan Hey, Jutta Baldauf, Nina Opitz, Andrew Lithio, Asher Pasha, Nicholas Provart, Dan Nettleton, Frank Hochholdinger

Dan Nettleton

Root hairs are tubular extensions of epidermis cells. Transcriptome profiling demonstrated that the single cell-type root hair transcriptome was less complex than the transcriptome of multiple cell-type primary roots without root hairs. In total, 831 genes were exclusively and 5585 genes were preferentially expressed in root hairs [false discovery rate (FDR) ≤1%]. Among those, the most significantly enriched Gene Ontology (GO) functional terms were related to energy metabolism, highlighting the high energy demand for the development and function of root hairs. Subsequently, the maize homologs for 138 Arabidopsis genes known to be involved in root hair development were identified and ...


Empirical Comparisons Of Different Statistical Models To Identify And Validate Kernel Row Number-Associated Variants From Structured Multi-Parent Mapping Populations Of Maize, Jinliang Yang, Cheng-Ting “Eddy” Yeh, Raghuprakash Kastoori Ramamurthy, Xinshuai Qi, Rohan L. Fernando, Jack C. M. Dekkers, Dorian J. Garrick, Dan Nettleton, Patrick S. Schnable Jun 2019

Empirical Comparisons Of Different Statistical Models To Identify And Validate Kernel Row Number-Associated Variants From Structured Multi-Parent Mapping Populations Of Maize, Jinliang Yang, Cheng-Ting “Eddy” Yeh, Raghuprakash Kastoori Ramamurthy, Xinshuai Qi, Rohan L. Fernando, Jack C. M. Dekkers, Dorian J. Garrick, Dan Nettleton, Patrick S. Schnable

Dan Nettleton

Advances in next generation sequencing technologies and statistical approaches enable genome-wide dissection of phenotypic traits via genome-wide association studies (GWAS). Although multiple statistical approaches for conducting GWAS are available, the power and cross-validation rates of many approaches have been mostly tested using simulated data. Empirical comparisons of single variant (SV) and multi-variant (MV) GWAS approaches have not been conducted to test if a single approach or a combination of SV and MV is effective, through identification and cross-validation of trait-associated loci. In this study, kernel row number (KRN) data were collected from a set of 6,230 entries derived from ...