Other Plant Sciences Commons^™

Genome-Wide Association Analysis Identifies Candidate Genes Associated With Iron Deficiency Chlorosis In Soybean, Sujan Mamidi, Shireen Chikara, R. Jay Goos, D. L. Hyten, Deepti Annam, Samira Mafi Moghaddam, Rian K. Lee, P. B. Cregan, Phillip E. Mcclean

Department of Agronomy and Horticulture: Faculty Publications

Iron deficiency chlorosis (IDC) is a significant yield-limiting problem in several major soybean [Glycine max (L.) Merr.] production regions in the United States. Soybean plants display a variety of symptoms that range from a slight yellowing of the leaf to interveinal chlorosis, to stunted growth that reduces yield. The objective of this analysis was to employ single nucleotide polymorphism (SNP)-based genome-wide association mapping to uncover genomic regions associated with IDC tolerance. Two populations [2005 (n = 143) and 2006 (n = 141)] were evaluated in replicated, multilocation IDC trials. After controlling for population structure and individual relatedness, and selecting …

The Role Of Transition Metal Homeostasis In Plant Seed Development, Elsbeth L. Walker, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Copyright © 2011 Elsevier Ltd. Used by permission.

Moving Magnesium In Plant Cells, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Magnesium (Mg) is among the most abundant mineral elements in plants, yet the knowledge of which genes control its accumulation in specific tissues and organelles lags behind that of many other mineral elements. Only in recent years has identification of important molecular players begun to take shape. In this issue of New Phytologist, Conn et al. (pp. 583–594) shed additional light on two Mg transporters that play important roles in accumulation of Mg in leaf cell vacuoles. Using subcellular-level ion measurements on leaves, gene expression measurements after single-cell sampling, a genetic approach, and clever use of calcium (Ca) and …

Registration Of Seven Winter Wheat Germplasm Lines Carrying The Wsm1 Gene For Wheat Streak Mosaic Virus Resistance, Jasdeep S. Mutti, P. Stephen Baenziger, Robert A. Graybosch, Roy French, Kulvinder S. Gill

Department of Agronomy and Horticulture: Faculty Publications

Seven winter wheat (Triticum aestivum L.) germplasm lines carrying the Wsm1 gene conferring resistance to Wheat streak mosaic virus (WSMV)—Alliance-Wsm1 (Reg. No. GP-858, PI 653710), Arrowsmith-Wsm1 (Reg. No. GP-859, PI 653711), Goodstreak-Wsm1 (Reg. No. GP-860, PI 653712), Harry-Wsm1 (Reg. No. GP-861, PI 653713), Millennium-Wsm1 (Reg. No. GP-862, PI 653714), Wahoo-Wsm1 (Reg. No. GP-863, PI 653715), and Wesley-Wsm1 (Reg. No. GP-864, PI 653716)—were codeveloped by Washington State University, Pullman, WA; the University of Nebraska, Lincoln, NE; and the USDA-ARS. These seven different winter wheat cultivars were selected to provide more sources of effective …

Increased Plant Uptake Of Nitrogen From 15N-Depleted Fertilizer Using Plant Growth-Promoting Rhizobacteria, A. O. Adesemoye, H. A. Torbert, J. W. Kloepper

Department of Plant Pathology: Faculty Publications

Harmful environmental effects resulting from fertilizer use have spurred research into integrated nutrient management strategies which can include the use of specific microorganisms to enhance nutrient use efficiency by plants. Some strains of plant growth-promoting rhizobacteria (PGPR) have been reported to enhance nutrient uptake by plants, but no studies with PGPR have used ¹⁵N isotope techniques to prove that the increased N in plant tissues came from the N applied as fertilizer. The current study was conducted to demonstrate that a model PGPR system can enhance plant uptake of fertilizer N applied to the soil using different rates of …

Unique Functionality Of 22 Nt Mirnas In Triggering Rdr6-Dependent Sirna Biogenesis From Target Transcripts In Arabidopsis, Josh T. Cuperus, Alberto Carbonell, Noah Fahlgren, Hernan Garcia-Ruiz, Russell T. Burke, Atsushi Takeda, Christopher M. Sullivan, Sunny D. Gilbert, Taiowa A. Montgomery, James C. Carrington

Department of Plant Pathology: Faculty Publications

RNA interference pathways may involve amplification of secondary siRNAs by RNA-dependent RNA polymerases. In plants, RDR6-dependent secondary siRNAs arise from transcripts targeted by some microRNA (miRNA). Here, Arabidopsis thaliana secondary siRNA from mRNA, and trans-acting siRNA, are shown to be triggered through initial targeting by 22 nt miRNA that associate with AGO1. In contrast to canonical 21 nt miRNA, 22 nt miRNA primarily arise from foldback precursors containing asymmetric bulges. Using artificial miRNA constructs, conversion of asymmetric foldbacks to symmetric foldbacks resulted in production of 21 nt forms of miR173, miR472 and miR828. Both 21 and 22 nt forms associated …

Heterokaryotic Nuclear Conditions And A Heterogeneous Nuclear Population Are Observed By Flow Cytometry In Phytophthora Infestans, Mursel Catal, Louis King, Pavani Tumbalam, Prissana Wiriyajitsomboon, William W. Kirk, Gerard C. Adams

Department of Plant Pathology: Faculty Publications

A simple and reliable method for preparation of whole nuclei of a common oomycete, Phytophthora infestans, is described for laser flow cytometry. The ease of preparation, the absence of detectable debris and aggregates, and the precision in determinations of DNA content per nucleus improve interpretation and understanding of the genetics of the organism. Phytophthora infestans is the pathogen that causes potato and tomato late blight. The genetic flexibility of P. infestans and other oomycete pathogens has complicated understanding of the mechanisms of variation contributing to shifts in race structure and virulence profiles on important agricultural crops. Significant phenotypic and …

Alteration In Lignin Biosynthesis Restricts Growth Of Fusarium Spp. In Brown Midrib Sorghum, Deanna L. Funnell-Harris, Jeffrey F. Pedersen, Scott E. Sattler

Department of Plant Pathology: Faculty Publications

To improve sorghum for bioenergy and forage uses, brown midrib (bmr)6 and -12 near-isogenic genotypes were developed in different sorghum backgrounds. The bmr6 and bmr12 grain had significantly reduced colonization by members of the Gibberella fujikuroi species complex compared with the wild type, as detected on two semiselective media. Fusarium spp. were identified using sequence analysis of a portion of the translation elongation factor (TEF) 1-α gene. The pathogens Fusarium thapsinum, F. proliferatum, and F. verticillioides, G. fujikuroi members, were commonly recovered. Other frequently isolated Fusarium spp. likely colonize sorghum asymptomatically. The χ2 analyses showed that the …

Following Tetraploidy In Maize, A Short Deletion Mechanism Removed Genes Preferentially From One Of The Two Homeologs, Margaret R. Woodhouse, James C. Schnable, Brent S. Pedersen, Eric Lyons, Damon Lisch, Shabarinath Subramaniam, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Previous work in Arabidopsis showed that after an ancient tetraploidy event, genes were preferentially removed from one of the two homeologs, a process known as fractionation. The mechanism of fractionation is unknown. We sought to determine whether such preferential, or biased, fractionation exists in maize and, if so, whether a specific mechanism could be implicated in this process. We studied the process of fractionation using two recently sequenced grass species: sorghum and maize. The maize lineage has experienced a tetraploidy since its divergence from sorghum approximately 12 million years ago, and fragments of many knocked-out genes retain enough sequence similarity …

Vittatidera Zeaphila (Nematoda: Heteroderidae), A New Genus And Species Of Cyst Nematode Parasitic On Corn (Zea Mays), Ernest C. Bernard, Zafar A. Handoo, Thomas O. Powers, Patricia A. Donald, Robert D. Heinz

Department of Plant Pathology: Faculty Publications

A new genus and species of cyst nematode, Vittatidera zeaphila, is described from Tennessee. The new genus is superficially similar to Cactodera but is distinguished from other cyst-forming taxa in having a persistent lateral field in females and cysts, persistent vulval lips covering a circumfenestrate vulva, and subventral gland nuclei of the female contained in a separate small lobe. Infective juveniles (J2) are distinguished from all previously described Cactodera spp. by the short stylet in the second-stage juvenile (14-17 mm); J2 of Cactodera spp. have stylets at least 18 mm long. The new species also is unusual in that …

Good Agricultural Practices For Food Safety Of Fresh Produce, Laurie Hodges

Department of Agronomy and Horticulture: Faculty Publications

What are the guiding principles of food safety for fresh produce?

• Once contaminated, removing or killing pathogens on produce is very difficult.

• Preventing microbial contamination at all steps, from production to distribution, is strongly favored over treatments to eliminate contamination that may have occurred.

• Document the implementation of prevention programs, and educate workers at all levels of the agricultural and packing environments on food safety.

Key Signatures of a Credible Food Safety Program

The following is a condensed checklist of practices and conditions that reduce the potential for fresh produce to be exposed to pathogenic microbes. Review …

Wheat Cultivar-Specific Disease Synergism And Alteration Of Virus Accumulation During Co-Infection With Wheat Streak Mosaic Virus And Triticum Mosaic Virus, Satyanarayana Tatineni, Robert A. Graybosch, Gary L. Hein, Stephen N. Wegulo, Roy French

Department of Plant Pathology: Faculty Publications

Triticum mosaic virus (TriMV), the type member of the newly proposed Poacevirus genus, and Wheat streak mosaic virus (WSMV), the type member of Tritimovirus genus of the family Potyviridae, infect wheat naturally in the Great Plains and are transmitted by wheat curl mites. In this study, we examined the ability of these viruses to infect selected cereal hosts, and found several differential hosts between TriMV and WSMV. Additionally, we examined the interaction between WSMV and TriMV in three wheat cultivars at two temperature regimens (19 and 20 to 26°C), and quantified the virus concentration in single and double infections …

First Report Of Two Curtoviruses In Spinach And Common Beet In Arizona, Claudia Nischwitz

All Current Publications

No abstract provided.

Arabidopsis Rna-Dependent Rna Polymerases And Dicer-Like Proteins In Antiviral Defense And Small Interfering Rna Biogenesis During Turnip Mosaic Virus Infection, Hernan Garcia-Ruiz, Atsushi Takeda, Elisabeth J. Chapman, Christopher M. Sullivan, Noah Fahlgren, Katherine J. Brempelis, James C. Carrington

Department of Plant Pathology: Faculty Publications

Plants respond to virus infections by activation of RNA-based silencing, which limits infection at both the single-cell and system levels. Viruses encode RNA silencing suppressor proteins that interfere with this response. Wild-type Arabidopsis thaliana is immune to silencing suppressor (HC-Pro)-deficient Turnip mosaic virus, but immunity was lost in the absence of DICER-LIKE proteins DCL4 and DCL2. Systematic analysis of susceptibility and small RNA formation in Arabidopsis mutants lacking combinations of RNA-dependent RNA polymerase (RDR) and DCL proteins revealed that the vast majority of virus derived small interfering RNAs (siRNAs) were dependent on DCL4 and RDR1, although full antiviral defense …

Meloidogyne Spp. Infecting Ornamental Plants In Florida, J. A. Brito, R. Kaur, R. Cetintas, J. D. Stanley, M. L. Mendes, Thomas O. Powers, D. W. Dickson

Department of Plant Pathology: Faculty Publications

A total of 206 root samples were collected from ornamental plants growing in ornamental nurseries and various landscapes in Florida. Isozyme phenotypes, especially esterase (EST) and malate dehydrogenase (MDH) were the main methods used to identify the root-knot nematode species. When needed, the morphology of female perineal patterns, morphometric characters and mitochondrial DNA were used to aid in the identification. Six Meloidogyne spp., M. arenaria , M. floridensis , M. graminis , M. incognita , M. javanica and M. mayaguensis were found infecting ornamental plants in Florida. As previously reported EST activity was of highest diagnostic value to identify Meloidogyne …

Importance Of Myxomycetes In Biological Research And Teaching, Harold W. Keller, Sydney E. Everhart

Department of Plant Pathology: Faculty Publications

Myxomycetes, the true slime molds, are highlighted in research and teaching that emphasizes various stages of the life cycle as experimental models. Past and current phylogenetic classifications of Myxomycetes on the tree of life are presented. Life cycle stages are illustrated, described, and discussed. Simple laboratory demonstrations and experiments are described that include spore germination, spore release, and moist chamber cultures utilizing organic matter from various microhabitats. Novel compounds isolated from fruiting bodies and plasmodia of 22 myxomycete species are tabulated, some of which exhibit biological activity that function as antibiotics, antimicrobials, and are cytotoxic to cancer cells. Aeroallergens include …

Shiga Toxin Is Transported Into The Nucleoli Of Intestinal Epithelial Cells Via A Carrier-Dependent Process, Boris Baibakov, Rakhilya Murtazina, Christian Elowsky, Francis M. Giardiello, Olga Kovbasnjuk

Department of Plant Pathology: Faculty Publications

Shiga toxin (Stx) produced by the invasive Shigella dysenteriae serotype 1 (S. dysenteriae1) causes gastrointestinal and kidney complications. It has been assumed that Stx is released intracellularly after enterocyte invasion by S. dysenteriae1. However, there is little information about Stx distribution inside S. dysenteriae1-infected enterocytes. Here, we use intestinal epithelial T84 cells to characterize the trafficking of Stx delivered into the cytosol, in ways that mimic aspects of S. dysenteriae1 infection. We find that cytoplasmic Stx is transported into nucleoli. Stx nucleolar movement is carrier- and energy-dependent. Stx binding to the nucleoli of normal human …

Summer Heat And An Epidemic Of Cytospora Canker Of Alnus, James J. Worrall, Gerard C. Adams, Sarah C. Tharp

Department of Plant Pathology: Faculty Publications

An epidemic of cytospora canker [Valsa melanodiscus, anamorph Cytospora umbrina] is associated with dieback and mortality of Alnus incana ssp. tenuifolia in the Southern Rocky Mountains and had begun by the late 1980s. Isolations showed that inoculum was often abundant on bark and bud surfaces even in winter, especially near diseased stems. The pathogen was occasionally isolated from internal tissues of dormant buds and asymptomatic wood and phloem. In infected stems, the pathogen was detected up to 5 cm beyond visible canker margins. The data suggest that the pathogen can cause latent infections, but the infection court …

An Integrative Approach To Genomic Introgression Mapping, Andrew J. Severin, Gregory A. Peiffer, Wayne W. Xu, D. L. Hyten, Bruna Bucciarelli, Jamie A. O'Rourke, Yung-Tsi Bolon, David Grant, Andrew Farmer, Gregory D. May, Carroll P. Vance, Randy C. Shoemaker, Robert M. Stupar

Department of Agronomy and Horticulture: Faculty Publications

Near-isogenic lines (NILs) are valuable genetic resources for many crop species, including soybean (Glycine max). The development of new molecular platforms promises to accelerate the mapping of genetic introgressions in these materials. Here, we compare some existing and emerging methodologies for genetic introgression mapping: single-feature polymorphism analysis, Illumina GoldenGate single nucleotide polymorphism (SNP) genotyping, and de novo SNP discovery via RNA-Seq analysis of next-generation sequence data. We used these methods to map the introgressed regions in an iron-inefficient soybean NIL and found that the three mapping approaches are complementary when utilized in combination. The comparative RNA-Seq approach offers …

Soydb: A Knowledge Database Of Soybean Transcription Factors, Zheng Wang, Marc Libault, Trupti Joshi, Babu Valliyodan, Henry T. Nguyen, Dong Xu, Gary Stacey, Jianlin Cheng

Department of Agronomy and Horticulture: Faculty Publications

Background: Transcription factors play the crucial rule of regulating gene expression and influence almost all biological processes. Systematically identifying and annotating transcription factors can greatly aid further understanding their functions and mechanisms. In this article, we present SoyDB, a user friendly database containing comprehensive knowledge of soybean transcription factors.

Description: The soybean genome was recently sequenced by the Department of Energy-Joint Genome Institute (DOE-JGI) and is publicly available. Mining of this sequence identified 5,671 soybean genes as putative transcription factors. These genes were comprehensively annotated as an aid to the soybean research community. We developed SoyDB - a knowledge database …

The Pathogenicity Determinant Of Citrus Tristeza Virus Causing The Seedling Yellows Syndrome Maps At The 3′-Terminal Region Of The Viral Genome, Maria R. Albiach-Marti, Cecile J. Robertson, Siddarame Gowda, Satyanarayana Tatineni, Belen Belliure, Stephen M. Garnsey, Svetlana Y. Folimonova, Pedro Moreno, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV) (genus Closterovirus, family Closteroviridae) causes some of the more important viral diseases of citrus worldwide. The ability to map disease-inducing determinants of CTV is needed to develop better diagnostic and disease control procedures. A distinctive phenotype of some isolates of CTV is the ability to induce seedling yellows (SY) in sour orange, lemon and grapefruit seedlings. In Florida, the decline isolate of CTV, T36, induces SY, whereas a widely distributed mild isolate, T30, does not. To delimit the viral sequences associated with the SY syndrome, we created a number of T36/T30 hybrids by substituting T30 …

Heterologous Minor Coat Proteins Of Citrus Tristeza Virus Strains Affect Encapsidation, But The Coexpression Of Hsp70h And P61 Restores Encapsidation To Wild-Type Levels, Satyanarayana Tatineni, Siddarame Gowda, William O. Dawson

Department of Plant Pathology: Faculty Publications

The long flexuous bipolar virions of Citrus tristeza virus (CTV), a Closterovirus, are encapsidated with two capsid proteins at opposite ends: the minor coat protein (CPm) encapsidates the 5′ 630 nts of the genomic RNA and the major coat protein encapsidates the remainder of the genome. In this study, we found encapsidation of CTV CPm in the absence of other assembly-related proteins is highly specific in contrast to most plant viruses that allow virion assembly by a range of heterologous coat proteins. Heterologous CPms with 95–96% amino acid identity from related strains in CTV-CPm, a replicon with CPm as …

Soil And Root Populations Of Fluorescent Pseudomonas Spp. Associated With Seedlings And Field-Grown Plants Are Affected By Sorghum Genotype, Deanna L. Funnell-Harris, Jeffrey F. Pedersen, Scott E. Sattler

Department of Plant Pathology: Faculty Publications

Sorghum [Sorghum bicolor (L.) Moench] is valued for bioenergy, feed and food. Potential of sorghum genotypes to support differing populations of root- and soil-associated fluorescent Pseudomonas spp. or Fusarium spp., in two soils, was assessed. Culturable pseudomonads were enumerated from roots and soil of sorghum (Redlan and RTx433) and wheat (Lewjain) seedlings repeatedly grown in cycled soils in the growth chamber. Pseudomonads and Fusarium spp. were assessed from roots and soil of field-grown sorghum along with biological control traits hydrogen cyanide (HCN) and 2,4-diacetylphlorogluconol (phl) production. After four 4-week cycles, soil associated with Redlan seedlings had greater numbers …

Brown Midrib Mutations And Their Importance To The Utilization Of Maize, Sorghum, And Pearl Millet Lignocellulosic Tissues, Scott E. Sattler, Deanna L. Funnell-Harris, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

Brown midrib mutants have been isolated in maize (Zea mays), sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum) arising by either spontaneous or chemical mutagenesis. The characteristic brown coloration of the leaf mid veins is associated with reduced lignin content and altered lignin composition, traits useful to improve forage digestibility for livestock. Brown midrib phenotype is correlated with two homologous loci in maize (bm1 and bm3) and sorghum (bmr6 and bmr12), which encode cinnamyl alcohol dehydrogenase (CAD) and a caffeic O-methyl transferase (COMT). These enzymes are involved in the last …

Upper Canopy Collection And Identification Of Grapevines (Vitis) From Selected Forests In The Southeastern United States, Sydney E. Everhart

Department of Plant Pathology: Faculty Publications

Woody grapevines (Vitis spp.) are common in the deciduous forests of the southeastern United States. Their growth habit makes leaf collection challenging and polymorphic leaves make identification of species difficult. Mature grapevines can grow up to 48 cm in diameter at breast height and reach the upper canopy of trees more than 35 m in height. Leaf morphology is the most readily available character used for species identification. However, most mature grapevines do not produce leaves below the upper canopy and if they do, these leaves are morphologically indistinguishable from other species. In order to sample leaves from …

Regulation Of Septum Formation By The Bud3–Rho4 Gtpase Module In Aspergillus Nidulans, Haoyu Si, Daniela Justa-Schuch, Stephan Seiler, Steven D. Harris

Department of Plant Pathology: Faculty Publications

The ability of fungi to generate polarized cells with a variety of shapes likely reflects precise temporal and spatial control over the formation of polarity axes. The bud site selection system of Saccharomyces cerevisiae represents the best-understood example of such a morphogenetic regulatory system. However, the extent to which this system is conserved in the highly polarized filamentous fungi remains unknown. Here, we describe the functional characterization and localization of the Aspergillus nidulans homolog of the axial bud site marker Bud3. Our results show that AnBud3 is not required for polarized hyphal growth per se, but is involved in septum …

An In Vitro Method For The Analysis Of Infection-Related Morphogenesis In Fusarium Graminearum, William R. Rittenour, Steven D. Harris

Department of Plant Pathology: Faculty Publications

Fusarium graminearum is a significant pathogen of many cereal crops. With its genetic tractability, ease of culture, genome sequence availability and economic significance, F. graminearum has become the subject of intensive molecular research. Although molecular tools have been developed to enhance research into virulence determinants of F. graminearum, simple assays for infection-related development are lacking. As such, the objective of this study was to develop an in vitro protocol for the analysis of infection-related morphogenesis in F. graminearum. We demonstrate that two morphologically distinct hyphal structures are produced by F. graminearum during the invasion of detached wheat glumes: subcuticular hyphae …

Structural And Functional Divergence Of A 1-Mb Duplicated Region In The Soybean (Glycine Max) Genome And Comparison To An Orthologous Region From Phaseolus Vulgaris, Jer-Young Lin, Robert M. Stupar, Christian Hans, D. L. Hyten, Scott A. Jackson

Department of Agronomy and Horticulture: Faculty Publications

Soybean (Glycine max) has undergone at least two rounds of polyploidization, resulting in a paleopolyploid genome that is a mosaic of homoeologous regions. To determine the structural and functional impact of these duplications, we sequenced two ~1-Mb homoeologous regions of soybean, Gm8 and Gm15, derived from the most recent ~13 million year duplication event and the orthologous region from common bean (Phaseolus vulgaris), Pv5. We observed inversions leading to major structural variation and a bias between the two chromosome segments as Gm15 experienced more gene movement (gene retention rate of 81% in Gm15 versus 91% in …

Deep And Comparative Transcriptome Analysis Of Rice Plants Infested By The Beet Armyworm (Spodoptera Exigua) And Water Weevil (Lissorhoptrus Oryzophilus), R. C. Venu, M. Sheshu Madhav, M. V. Sreerekha, Kan Nobuta, Yuan Zhang, Peter Carswell, Michael J. Boehm, B. C. Meyers, Kenneth L. Korth, Guo-Liang Wang

Department of Plant Pathology: Faculty Publications

The beet armyworm (Spodoptera exigua) and the rice water weevil (Lissorhoptrus oryzophilus) are two important insect pests in rice production. To identify insect-responsive genes in rice, we performed a deep transcriptome analysis of Nipponbare rice leaves infested with both beet armyworm and water weevil using massively parallel signature sequencing (MPSS). Many antisense, alternative, and novel transcripts were commonly and specifically induced and suppressed in the infested tissue. Key genes involved in the defense metabolic pathways such as salicylic acid and jasmonic acid biosynthesis pathways were up-regulated in the infested leaves. To validate theMPSS results, we analyzed …

Selecting Strawberry Cultivars For Winter Greenhouse Production, Ellen T. Paparozzi, Stacy A. Adams, George E. Meyer, M. Elizabeth Conley, Vicki L. Schlegel, Erin E. Blankenship, Paul E. Read

Department of Agronomy and Horticulture: Faculty Publications

Costs of transportation and food safety concerns have spawned an increase in public support of locally grown vegetables and fruit. With this in mind, a two-phase investigation was planned with the goal of combining low start up costs for sustainable greenhouse production with selection of strawberry cultivars that would provide the greatest number and largest size of berries. Additionally, berries from each cultivar will be analyzed for their beneficial nutraceutical properties to determine if there is a difference among cultivars.