Plant Pathology Commons^™

Currencies Of Mutualisms: Sources Of Alkaloid Genes In Vertically Transmitted Epichloae, Christopher L. Schardl, Carolyn A. Young, Juan Pan, Simona Florea, Johanna E. Takach, Daniel G. Panaccione, Mark L. Farman, Jennifer S. Webb, Jolanta Jaromczyk, Nikki D. Charlton, Padmaja Nagabhyru, Li Chen, Chong Shi, Adrian Leuchtmann

Plant Pathology Faculty Publications

The epichloae (Epichloë and Neotyphodium species), a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae). Most epichloae are vertically transmitted in seeds (endophytes), and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens), which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates. Several Epichloë species have been described which are sexual and capable of horizontal transmission, and most are vertically transmissible also. Asexual epichloae are mainly or exclusively vertically transmitted, and many are …

Initial Fine Mapping Of The Spinach Downy Mildew Resistance Locus Rpf1, Wei Yang

Graduate Theses and Dissertations

Spinach is an important vegetable crop grown in many parts of the world (Correll et al. 2011). It has become increasingly popular due to its nutritional value as it is very high in antioxidants (Prior, 2003). Spinach production, however, is affected by many biotic stresses. Downy mildew, caused by Peronospora farinosa f. sp. spinaciae (Pfs) , is perhaps the most important biotic constraint for spinach production worldwide (Correll et al, 1994). As of 2012, 14 races of Pfs have been reported (Correll et al., 2011). The rapid increase of new races is likely a direct result of substantial changes in …

Morphological And Molecular Taxonomic Identification And Phylogenetics Of Criconematoidea, Marco Cordero

Graduate Theses and Dissertations

The superfamily Criconematoidea has been studied since 1886. It is composed of two families: Criconematidae (subfam. Criconematinae, Hemicycliophorinae) and Tylenchulidae (subfam. Tylenchulinae, Paratylenchinae and Tylenchocriconematinae). Multiple species in genera have been identified and differences and similarities have been found. Species belonging to genera Mesocriconema and Criconemoides show very few differences making their identification difficult. Seventy two populations were studied. They were collected in Arkansas and/or received from the following states: California, Florida, Kansas, Missouri, North Carolina and Tennessee. Populations of the following species were identified: Mesocriconema curvatum, M. kirjanovae, M. onoense, M. ornatum, M. sphaerocephala, M. surinamense, M. vadense, M. …

Evaluation Of Wetland Plants For Susceptibility To Species Of Phytophthora Present In Runoff Water At Ornamental Plant Nurseries, Garrett Ridge

All Theses

Competition between agricultural producers and urban communities for high quality water is increasing; therefore, growers need to adopt water conservation and reuse practices to ensure an adequate supply of irrigation water. One concern with recycled irrigation water is the potential to recirculate propagules of oomycete pathogens. Constructed wetlands are a biologically-based treatment option for nutrient and chemical remediation that potentially also could filter pathogen propagules. The goal of this study was to assess the susceptibility of plants routinely used in constructed wetlands to infection by species of Phytophthora commonly found at ornamental plant nurseries. In laboratory and greenhouse experiments, an …

Uromyces Appendiculatus In Honduras: Pathogen Diversity And Host Resistance Screening, Maricelis Acevedo, James R. Steadman, Juan C. Rosas

Department of Plant Pathology: Faculty Publications

Bean rust, caused by the fungus Uromyces appendiculatus, is a major constraint for common bean production worldwide. Virulence of U. appendiculatus collected from wild and cultivated Phaseolus spp. was examined in 28 locations across Honduras. Host accessions representing wild and domesticated Phaseolus spp. collected at the same sampling locations were evaluated for resistance against U. appendiculatus. In total, 91 pathotypes were identified from 385 U. appendiculatus isolates according to their virulence on each of the 12 host differentials. No significant difference in pathogen total virulence, measured as the mean disease score, was found between locations. However, significant differences …

Puccinia Mariae-Wilsoniae And Claytonia Virginica: A Pathogen's Tale, Sarah A. Schlund

Undergraduate Honors Theses

Rusts are economically important fungal plant pathogens. For the majority of rust species, complete life history data, including host range, geographic distribution, plant response to the rust, identity of alternate hosts, and mode of sexual reproduction are incomplete. The purpose of this study was to examine the life history of Puccinia mariae-wilsoniae, a rust on Claytonia virginica (spring beauty), and to observe responses in leaf anatomy to its fungal pathogen. Spring beauty is an ephemeral woodland plant that lasts three to four weeks and P. mariae-wilsoniae infects C. virginica almost as soon as the plant emerges from dormancy in …

Citrus Tristeza Virus-Host Interactions, W. O. Dawson, S. M. Garnsey, Satyanarayana Tatineni, S. Y. Folimonova, S. J. Harper, S. Gowda

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV) is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. There is little understanding of how the virus causes severe disease in some citrus and none in others. Movement and distribution of CTV differs considerably from that of well-studied viruses of herbaceous plants where movement occurs largely through adjacent cells. In contrast, CTV systemically infects plants mainly by …

Genetic Diversity Of Seed Dormancy And Molecular Evolution Of Weedy Red Rice, Te Ming Tseng

Graduate Theses and Dissertations

Rice is the grain with the third-highest global production. In the US, Arkansas is the largest rice producing state; however, an estimated 62% of the rice fields in the state are infested with red rice, and can cause up to 80% yield reduction in rice. Among its weedy traits, seed dormancy plays an important role in its persistence, and helps red rice escape weed management techniques thereby increasing the red rice soil seedbank. Red rice also has the potential to hybridize among themselves and with cultivated rice, thus resulting in diverse phenotypes and genotypes. In this study we measured variation …

Neofusicoccum Luteum As A Pathogen On Tejocote (Crataegus Mexicana), Anthony O. Adesemoye, Joey S. Mayorquin, Akif Eskalen

Department of Plant Pathology: Faculty Publications

Tejocote (Crataegus mexicana), a small pome crab-apple-like fruit, is becoming economically important in California with increasing production, so consideration of diseases that hinder the yield is important. Diseased trees of tejocote were observed in four orchards of Riverside and San Diego Counties of California. Ten symptomatic/asymptomatic samples were studied from each of the orchards. Five most frequently isolated fungi were identified on the basis of morphological characters and sequence data of the internal transcribed spacer ITS1-5.8SITS2 and partial β-tubulin gene. Three isolates were identified as Neofusicoccum luteum and two as Phomopsis sp. Pathogenicity tests were conducted by inoculating …

Three-Dimensional Structure Of Victorivirus Hvv190s Suggests Coat Proteins In Most Totiviruses Share A Conserved Core, Sarah E. Dunn, Hua Li, Giovanni Cardone, Max L. Nibert, Said A. Ghabrial, Timothy S. Baker

Plant Pathology Faculty Publications

Double-stranded (ds)RNA fungal viruses are currently assigned to six different families. Those from the family Totiviridae are characterized by nonsegmented genomes and single-layer capsids, 300-450 Å in diameter. Helminthosporium victoriae virus 190S (HvV190S), prototype of recently recognized genus Victorivirus, infects the filamentous fungus Helminthosporium victoriae (telomorph: Cochliobolus victoriae), which is the causal agent of Victoria blight of oats. The HvV190S genome is 5179 bp long and encompasses two large, slightly overlapping open reading frames that encode the coat protein (CP, 772 aa) and the RNA-dependent RNA polymerase (RdRp, 835 aa). To our present knowledge, victoriviruses uniquely express their RdRps via …

Brassica Variety Trials 2012, Rebecca Brown

University of Rhode Island Vegetable Production Research Reports

Variety trials of broccoli, cauliflower and Brussels sprouts conducted in Kingston, RI, USA.

Pseudomonas Hopu1 Modulates Plant Immune Receptor Levels By Blocking The Interaction Of Their Mrnas With Grp7, Valerie Nicaise, Anna Joe, Byeong-Ryool Jeong, Christin Korneli, Freddy Boutrot, Isa Westedt, Dorothee Staiger, James R. Alfano, Cyril Zipfel

Center for Plant Science Innovation: Faculty Publications

Pathogens target important components of host immunity to cause disease. The Pseudomonas syringae type III-secreted effector HopU1 is a mono-ADP-ribosyltransferase required for full virulence on Arabidopsis thaliana. HopU1 targets several RNA-binding proteins including GRP7, whose role in immunity is still unclear. Here, we show that GRP7 associates with translational components, as well as with the pattern recognition receptors FLS2 and EFR. Moreover, GRP7 binds specifically FLS2 and EFR transcripts in vivo through its RNA recognition motif. HopU1 does not affect the protein–protein associations between GRP7, FLS2 and translational components. Instead, HopU1 blocks the interaction between GRP7 and FLS2 and …

Small Interfering Rna–Mediated Translation Repression Alters Ribosome Sensitivity To Inhibition By Cycloheximide In Chlamydomonas Reinhardtii, Xinrong Ma, Eun-Jeong Kim, Insun Kook, Fangrui Ma, Adam Voshall, Etsuko N. Moriyama, Heriberto D. Cerutti

Center for Plant Science Innovation: Faculty Publications

Small RNAs (sRNAs; approximately 20 to 30 nucleotides in length) play important roles in gene regulation as well as in defense responses against transposons and viruses in eukaryotes. Their biogenesis and modes of action have attracted great attention in recent years. However, many aspects of sRNA function, such as the mechanism(s) of translation repression at postinitiation steps, remain poorly characterized. In the unicellular green alga Chlamydomonas reinhardtii, sRNAs derived from genomeintegrated inverted repeat transgenes, perfectly complementary to the 39 untranslated region of a target transcript, can inhibit protein synthesis without or with only minimal mRNA destabilization. Here, we report …

Proceedings Of The 40th Annual Meeting, Southern Soybean Disease Workers (March 13-14, 2013, Pensacola Beach, Florida), Clayton A. Hollier, Tom Allen, Edward J. Sikora, Myra Purvis, Danise Beadle, Stephen R. Koenning

Southern Soybean Disease Workers: Conference Proceedings

Contents

Southern United States Soybean Disease Loss Estimates for 2012. Compiled by SR Koenning

Update on Detection and Management of QoI Fungicide Resistant Cercospora sojina, the Causal Agent of Frogeye Leaf Spot in Soybean. C Bradley, G Zhang, V Chapara, R Ming, F Zeng, H Young Kelly, and M Newman

Identification of Soybean Genotypes to Cercopsora sojina by Field Screening and Molecular Markers. A Mengistu and R Mian

Soybean Vein Necrosis Virus. D Hershman

Single Applications of Triazole Fungicides at R1 for Management of Cercospora Leaf Blight and Rust in Soybean. RW Schneider, CL Robertson, BM Ward, and EC …

Plant-Symbiotic Fungi As Chemical Engineers: Multi-Genome Analysis Of The Clavicipitaceae Reveals Dynamics Of Alkaloid Loci, Christopher L. Schardl, Carolyn A. Young, Uljana Hesse, Stefan G. Amyotte, Kalina Andreeva, Patrick J. Calie, Damien J. Fleetwood, David C. Haws, Neil Moore, Birgitt Oeser, Daniel G. Panaccione, Kathryn K. Schweri, Christine R. Voisey, Mark L. Farman, Jerzy W. Jaromczyk, Bruce A. Roe, Donal M. O'Sullivan, Barry Scott, Paul Tudzynski, Zhiqiang An, Elissaveta G. Arnaoudova, Charles T. Bullock, Nikki D. Charlton, Li Chen, Murray Cox, Randy D. Dinkins, Simona Florea, Anthony E. Glenn, Anna Gordon, Ulrich Güldener, Daniel R. Harris, Walter Hollin, Jolanta Jaromczyk, Richard D. Johnson, Anar K. Khan, Eckhard Leistner, Adrian Leuchtmann, Chunjie Li, Jinge Liu, Jinze Liu, Miao Liu, Wade Mace, Caroline Machado, Padmaja Nagabhyru, Juan Pan, Jan Schmid, Koya Sugawara, Ulrike Steiner, Johanna E. Takach, Eiji Tanaka, Jennifer S. Webb, Ella V. Wilson, Jennifer L. Wiseman, Ruriko Yoshida, Zheng Zeng

Plant Pathology Faculty Publications

The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some-including the infamous ergot alkaloids-have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne), and still others vary in pathogenic …

Mites In The Promoters Of Effector Genes Allow Prediction Of Novel Virulence Genes In Fusarium Oxysporum, Sarah M. Schmidt, Petra M. Houterman, Ines Schreiver, Lisong Ma, Stefan G. Amyotte, Biju Chellappan, Sjef Boeren, Frank L. W. Takken, Martijn Rep

Plant Pathology Faculty Publications

BACKGROUND: The plant-pathogenic fungus Fusarium oxysporum f.sp.lycopersici (Fol) has accessory, lineage-specific (LS) chromosomes that can be transferred horizontally between strains. A single LS chromosome in the Fol4287 reference strain harbors all known Fol effector genes. Transfer of this pathogenicity chromosome confers virulence to a previously non-pathogenic recipient strain. We hypothesize that expression and evolution of effector genes is influenced by their genomic context.

RESULTS: To gain a better understanding of the genomic context of the effector genes, we manually curated the annotated genes on the pathogenicity chromosome and identified and classified transposable elements. Both retro- and DNA transposons are present …

The Voltage-Sensing Domain Of A Phosphatase Gates The Pore Of A Potassium Channel, Cristina Arrigoni, Indra Schroeder, Giulia Romani, James L. Van Etten, Gerhard Thiel, Anna Moroni

James Van Etten Publications

The modular architecture of voltage-gated K⁺ (Kv) channels suggests that they resulted from the fusion of a voltage-sensing domain (VSD) to a pore module. Here, we show that the VSD of Ciona intestinalis phosphatase (Ci-VSP) fused to the viral channel Kcv creates Kv_Synth1, a functional voltage-gated, outwardly rectifying K⁺ channel. Kv_Synth1 displays the summed features of its individual components: pore properties of Kcv (selectivity and filter gating) and voltage dependence of Ci-VSP (V1/2 = +56 mV; z of approx. 1), including the depolarizationinduced mode shift. The degree of outward rectification of the channel is critically …

Strong Genetic Differentiation Between North American And European Populations Of Phytophthora Alni Subsp. Uniformis, Jaime Aguayo, Gerard C. Adams, Fabien Halkett, Mursel Catal, Claude Husson, Zoltán Á. Nagy, Everett M. Hansen, Benoît Marçais, Pascal Frey

Department of Plant Pathology: Faculty Publications

Alder decline caused by Phytophthora alni has been one of the most important diseases of natural ecosystems in Europe during the last 20 years. The emergence of P. alni subsp. alni—the pathogen responsible for the epidemic—is linked to an interspecific hybridization event between two parental species: P. alni subsp. multiformis and P. alni subsp. uniformis. One of the parental species, P. alni subsp. uniformis, has been isolated in several European countries and, recently, in North America. The objective of this work was to assess the level of genetic diversity, the population genetic structure, and the putative reproduction …

Isolation And Characterization Of The Grain Mold Fungi Cochliobolus And Alternaria Spp. From Sorghum Using Semiselective Media And Dna Sequence Analyses, Deanna L. Funnell-Harris, Louis K. Prom, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

Mold diseases, caused by fungal complexes including Alternaria, Cochliobolus, and Fusarium species, limit sorghum grain production. Media were tested by plating Fusarium thapsinum, Alternaria sp., and Curvularia lunata, individually and competitively. Dichloran chloramphenicol rose bengal (DRBC) and modified V8 juice (ModV8) agars, found to be useful, were compared with commonly used agar media, dichloran chloramphenicol peptone (DCPA) and pentachloronitrobenzene (PCNB). Radial growth, starting with mycelia or single-conidia and hyphal tips, demonstrated an effect of media. For isolation of grain fungi, DRBC and ModV8 were similar or superior to DCPA and PCNB. When seedlings were inoculated with conidia of C. lunata, …

Occurrence And Distribution Of Triticum Mosaic Virus In The Central Great Plains, E. Byamukama, D. L. Seifers, G. L. Hein, E. De Wolf, N. A. Tisserat, M. A. C. Langham, L. E. Osborne, A. Timmerman, S. N. Wegulo

Department of Plant Pathology: Faculty Publications

Wheat curl mite (WCM)-transmitted viruses—namely, Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), and the High Plains virus (HPV)—are three of the wheat-infecting viruses in the central Great Plains of the United States. TriMV is newly discovered and its prevalence and incidence are largely unknown. Field surveys were carried out in Colorado, Kansas, Nebraska, and South Dakota in spring and fall 2010 and 2011 to determine TriMV prevalence and incidence and the frequency of TriMV co-infection with WSMV or HPV in winter wheat. WSMV was the most prevalent and was detected in 83% of 185 season–counties (= s-counties), 73% …

A Virus-Encoded Potassium Ion Channel Is A Structural Protein In The Chlorovirus Paramecium Bursaria Chlorella Virus 1 Virion, Giulia Romani, Adrianna Piotrowski, Stefan Hillmer, James Gurnon, James L. Van Etten, Anna Moroni, Gerhard Thiel, Brigitte Hertel

James Van Etten Publications

Most chloroviruses encode small K+ channels, which are functional in electrophysiological assays. The experimental finding that initial steps in viral infection exhibit the same sensitivity to channel inhibitors as the viral K+ channels has led to the hypothesis that the channels are structural proteins located in the internal membrane of the virus particles. This hypothesis was questioned recently because proteomic studies failed to detect the channel protein in virions of the prototype chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1). Here, we used a mAb raised against the functional K+ channel from chlorovirus MA-1D to search for the viral K+ channel …

Product Comparison Of Foliar Fungicide Efficacy On Diseases Of Field Corn In Nebraska, 2013, C. M. Schleicher, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide efficacy trial was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory near Clay Center, NE. Corn hybrid NK ‘N68B’, rating of “fair” (7 out of 9) for gray leaf spot (GLS), not rated for common rust (CR), and “excellent” (2 out of 9) for southern rust (SR), was planted on 15 May in 30-in. rows at a target population of 31,763 plants/A. The trial area was disked with corn as the previous year’s crop. Eight treatments and a non-treated control were replicated six times in a randomized complete block design. Each plot was four rows …

Beech Bark Disease Distribution And Resistance In Michigan And Fungal Endophyte Ecology Of Resistant And Susceptible Beech (Fagus Grandifolia Ehrh.), Rachel E. Griesmer-Zakhar

Dissertations, Master's Theses and Master's Reports - Open

Beech bark disease (BBD), a non-native association of the fungal pathogen Neonectria faginata and the beech scale insect Cryptococcus fagisuga, has dramatically affected American beech within North American forests. To monitor the spread and effects of BBD in Michigan, a network of forest health monitoring plots was established in 2001 following the disease discovery in Ludington State Park (Mason County). Forest health canopy condition and basic forestry measurements including basal area were reassessed on beech trees in these plots in 2011 and 2012. The influence of bark-inhabiting fungal endophytes on BBD resistance was investigated by collecting cambium tissue from …

Complementarity To An Mirna Seed Region Is Sufficient To Induce Moderate Repression Of A Target Transcript In The Unicellular Green Alga Chlamydomonas Reinhardtii, Tomohito Yamasaki, Adam Voshall, Eun-Jeong Kim, Etsuko N. Moriyama, Heriberto Cerutti, Takeshi Ohama

Center for Plant Science Innovation: Faculty Publications

MicroRNAs (miRNAs) are 20–24 nt noncoding RNAs that play important regulatory roles in a broad range of eukaryotes by pairing with mRNAs to direct post-transcriptional repression. The mechanistic details of miRNA-mediated post-transcriptional regulation have been well documented in multicellular model organisms. However, this process remains poorly studied in algae such as Chlamydomonas reinhardtii, and specific features of miRNA biogenesis, target mRNA recognition and subsequent silencing are not well understood. In this study, we report on the characterization of a Chlamydomonas miRNA, cre-miR1174.2, , which is processed from a near-perfect hairpin RNA. Using Gaussia luciferase (gluc) reporter genes, …

Camelina Seed Transcriptome: A Tool For Meal And Oil Improvement And Translational Research, Huu T. Nguyen, Jillian E. Silva, Ram Podicheti, Jason Macrander, Wenyu Yang, Tara J. Nazarenus, Jeong-Won Nam, Jan G. Jaworski, Chaofu Lu, Brian E. Scheffler, Keithanne Mockaitis, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Camelina (Camelina sativa), a Brassicaceae oilseed, has received recent interest as a biofuel crop and production platform for industrial oils. Limiting wider production of camelina for these uses is the need to improve the quality and content of the seed protein-rich meal and oil, which is enriched in oxidatively unstable polyunsaturated fatty acids that are deleterious for biodiesel. To identify candidate genes for meal and oil quality improvement, a transcriptome reference was built from 2047 Sanger ESTs and more than 2 million 454-derived sequence reads, representing genes expressed in developing camelina seeds. The transcriptome of approximately 60K transcripts …

Comparative Analyses Of Two Geraniaceae Transcriptomes Using Next-Generation Sequencing, Jinxin Zhang, Tracey A. Ruhlman, Jeffrey P. Mower, Robert K. Jansen

Center for Plant Science Innovation: Faculty Publications

Background: Organelle genomes of Geraniaceae exhibit several unusual evolutionary phenomena compared to other angiosperm families including accelerated nucleotide substitution rates, widespread gene loss, reduced RNA editing, and extensive genomic rearrangements. Since most organelle-encoded proteins function in multi-subunit complexes that also contain nuclear-encoded proteins, it is likely that the atypical organellar phenomena affect the evolution of nuclear genes encoding organellar proteins. To begin to unravel the complex co-evolutionary interplay between organellar and nuclear genomes in this family, we sequenced nuclear transcriptomes of two species, Geranium maderense and Pelargonium x hortorum.

Results: Normalized cDNA libraries of G. maderense and …

Arabidopsis 56–Amino Acid Serine Palmitoyltransferase- Interacting Proteins Stimulate Sphingolipid Synthesis, Are Essential, And Affect Mycotoxin Sensitivity, Athen N. Kimberlin, Saurav Majumder, Gongshe Han, Ming Chen, Rebecca E. Cahoon, Julie M. Stone, Teresa M. Dunn, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Maintenance of sphingolipid homeostasis is critical for cell growth and programmed cell death (PCD). Serine palmitoyltransferase (SPT), composed of LCB₁ and LCB₂ subunits, catalyzes the primary regulatory point for sphingolipid synthesis. Small subunits of SPT (ssSPT) that strongly stimulate SPT activity have been identified in mammals, but the role of ssSPT in eukaryotic cells is unclear. Candidate Arabidopsis thaliana ssSPTs, ssSPTa and ssSPTb, were identified and characterized. Expression of these 56–amino acid polypeptides in a Saccharomyces cerevisiae SPT null mutant stimulated SPT activity from the Arabidopsis LCB₁/LCB₂ heterodimer by >100-fold through physical interaction with LCB …

Pseudomonas Syringae Pv. Syringae Uses Proteasome Inhibitor Syringolin A To Colonize From Wound Infection Sites, Johana C. Misas-Villamil, Izabella Kolodziejek, Emerson Crabill, Farnusch Kaschani, Sherry Niessen, Takayuki Shindo, Markus Kaiser, James R. Alfano, Renier A. L. Van De Hoorn

Center for Plant Science Innovation: Faculty Publications

Infection of plants by bacterial leaf pathogens at wound sites is common in nature. Plants defend wound sites to prevent pathogen invasion, but several pathogens can overcome spatial restriction and enter leaf tissues. The molecular mechanisms used by pathogens to suppress containment at wound infection sites are poorly understood. Here, we studied Pseudomonas syringae strains causing brown spot on bean and blossom blight on pear. These strains exist as epiphytes that can cause disease upon wounding caused by hail, sand storms and frost. We demonstrate that these strains overcome spatial restriction at wound sites by producing syringolin A (SylA), a …

Functional Modeling Identifies Paralogous Solanesyl-Diphosphate Synthases That Assemble The Side Chain Of Plastoquinone-9 In Plastids, Anna Block, Rikard Fristedt, Sara Rogers, Jyothi Kumar, Brian Barnes, Joshua Barnes, Christian Elowsky, Yashitola Wamboldt, Sally Ann Mackenzie, Kevin Redding, Sabeeha S. Merchant, Gilles J. Basset

Center for Plant Science Innovation: Faculty Publications

Background: Plastid isoforms of solanesyl-diphosphate synthase catalyze the elongation of the prenyl side chain of plastoquinone-9.

Results: Corresponding mutants display lower levels of plastoquinone-9 and plastochromanol-8 and display intact levels of vitamin E.

Conclusion: Plastochromanol-8 originates from a subfraction of non-photoactive plastoquinol-9 and is not essential for seed longevity.

Significance: Viable plastoquinone-9 mutants are invaluable tools for understanding plastid metabolism.

Mutational Analyses Of A Fork Head Associated Domain Protein, Dawdle, In Arabidopsis Thaliana, Lakshmi Ayiloor Narayanan, Dipaloke Mukherjee, Shuxin Zhang, Bin Yu, David Chevalier

Center for Plant Science Innovation: Faculty Publications

DAWDLE (DDL) gene encodes a protein that contains an N-terminal arginine-rich domain and a C-terminal Fork Head Associated (FHA) domain in Arabidopsis thaliana. DDL protein is believed to function in microRNA biogenesis by mediating the recruitment of pri-microRNA to DICER-LIKE 1 and also stabilizing the microRNA. The aim of this study was to conduct a structure-function analysis to identify the regions in DDL that are of functional significance. Targeted Induced Local Lesions in Genome screen was performed in the Columbia erecta-105 background of Arabidopsis resulting in the identification of eight point mutations spanning DDL. The mutants were characterized by …