bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetically tunable rf wave absorption in polycrystalline La0.67Ba0.33MnO3
Authors: Naik V. B. , Mahendiran R.
Published: April 2009

We investigated temperature and magnetic field dependent radio-frequency electromagnetic absorption in La0.67Ba0.33MnO3 by monitoring changes in resonance frequency (fr) and current (I) through a LC resonant circuit powered by an integrated chip oscillator. The ferromagnetic to paramagnetic transition at TC in zero magnetic field is accompanied by an abrupt increase in fr and I and they are tunable by small external magnetic field. We observed fractional changes as much as 46% in Δfr/fr and 23% in ΔI/I around TC under μ0H=0.1 T that can be exploited for low-magnetic field sensors and other applications.
Neoliberalism, Mike Moore, and the WTO
Authors: Lamer Wendy
Published: April 2009

Mike Moore is a working-class boy from rural New Zealand who subsequently became Director General of the World Trade Organization. This paper uses his experiences and understanding to analyse the embodied forms in which neoliberalism travelled from nation-state to global settings. It shows that neoliberal discourses and techniques do not always emerge in the sites we assume, travel in the forms we expect, or move in the directions we anticipate. By analysing Moore's understanding of relationships between the global economy and nation-states, the reforms he made to WTO processes following the ‘Battle of Seattle’, and the implications these reforms had for broader conceptions of global spaces and subjects, the paper contributes to a conceptual argument that neoliberalism can be usefully understood as an assemblage which comes together in much more disjunctive ways than is often recognised, and that it should be theorised and researched as such.
Cognitive Dimensions of Way-Finding: The Implications of Habitus, Safety, and Gender Dissonance among Gay and Lesbian Populations
Authors: Doan Petra , Higgins Harrison
Published: April 2009

This paper critiques the proposition that way-finding strategies can be differentiated by sex. We argue that way-finding is better understood as a function of gender differences where gender is understood as a lived social relation, a product of the interaction between an embodied habitus and a particular social field. The use of survey versus landmark way-finding strategies is linked to an individual's gendered experiences of urban life. The study examines way-finding strategies from a sample of 127 gay men and lesbians from the Tallahassee, Florida metropolitan region to explore urban habitation patterns. We find that different way-finding strategies (most commonly a survey or landmark approach) are influenced by the habitus and gendered experiences of fear and anxiety in urban areas. Both bivariate and multivariate analyses suggest that individuals who perceive that their own gender presentation violates gender norms (gender dissonance) experience higher levels of social sanctions (harassment, hostility, and discrimination). In multivariate analysis, the study finds that gender-dissonant men tend to navigate using the landmark way-finding approach usually associated with women, whereas gender-dissonant women navigate using the survey way-finding approach usually associated with men.
Explaining Changes in Walking and Bicycling Behavior: Challenges for Transportation Research
Authors: Krizek Kevin J , Handy Susan L , Forsyth Ann
Published: April 2009

As issues of traffic congestion, obesity, and environmental conservation receive increased attention globally and in the US, focus turns to the role that walking and cycling can play in mitigating such problems. This enthusiasm has created a need for evidence on the degree to which policies to increase walking and cycling travel have worked. This paper outlines the important challenges researchers face in their attempts to produce credible evidence on walking and cycling interventions. It closes by discussing matters to consider in such research endeavors, including the importance of clear conceptualization, sound research design, measurement innovations, and strategic sampling.
Genetic parameters for bodyweight, wool, and disease resistance and reproduction traits in Merino sheep. 4. Genetic relationships between and within wool traits
Authors: Huisman A. E. , Brown D. J.
Published: April 2009

The aim of this paper was to describe the genetic relationship among expressions at different ages of seven wool traits: greasy and clean fleece weights, fibre diameter, coefficient of variation of fibre diameter, staple length and strength, and mean fibre curvature. Genetic correlations among measurements at different ages for the same trait were moderate to high, and ranged from ~0.6 for both fleece weights to 0.9 and higher for mean fibre diameter and curvature. Generally, low to moderate genetic correlations (0.3–0.4) were estimated between fleece weights and fibre diameter, clean fleece weight and staple length, and fibre diameter and staple strength. Small positive genetic correlations (0.2) were estimated between greasy and clean fleece weight with fibre diameter coefficient of variation, and between fibre diameter and staple length. Mean fibre curvature had a negative genetic correlation (approximately –0.4) with most other wool traits, the exceptions were staple strength (~0.0) and coefficient of variation of fibre diameter (approximately –0.1). Fibre diameter, staple length and staple strength had negative genetic correlations with coefficient of variation of fibre diameter (–0.15, –0.10, and –0.61, respectively). The results indicate that for most wool traits only one measurement across ages is required to make accurate selection decisions. The relationships between traits are generally moderate to low suggesting that simultaneous genetic improvement is possible.
Nematode parasites and faecal soiling of sheep in lairage: evidence of widespread potential production losses for the sheep industry
Authors: Jacobson C. L. , Bell K. , Besier R. B.
Published: April 2009

Diarrhoea (scouring) and subsequent faecal soiling of fleece are important economic and welfare issues for the sheep industry. Nematode worm infections are commonly implicated as a cause of scouring. This study aimed to investigate the extent of strongyle parasite infections, and identify any association with faecal worm egg count (WEC) and scouring in sheep from winter rainfall environments in Western Australia consigned to an abattoir. Faeces were collected from sheep with evidence of scouring and normal sheep (firm faecal pellets and no evidence of fresh diarrhoea on breech). A total of 4430 sheep from 113 lines of lambs (<12 months old), 10 lines of yearlings (12–24 months old) and 235 lines of adult sheep (>24 months old) were sampled between September and January. Mean WEC in lamb lines was 1525 eggs per gram (epg) of faeces with mean WEC >1000 epg in 42% of lines and >2000 in 22% of lines. Mean WEC in adult lines was 486 epg, with 13% lines having mean WEC >1000 epg. There was a trend (P = 0.099) to higher WEC in scouring lambs (2289 epg) compared with normal lambs (1523 epg). The scouring adult sheep had lower WEC (417 epg) compared with normal adults (482 epg, P = 0.021). The findings suggest that large strongyle infections were common in lambs consigned for slaughter. The low WEC in scouring adult sheep was consistent with the suggestion that a hypersensitivity to ingested nematode larvae, rather than large worm burdens, may be responsible for scouring in mature sheep.
The Na+/H+ exchanger NHE1 is required for directional migration stimulated via PDGFR-α in the primary cilium
Authors: Schneider Linda , Stock Christian-Martin , Dieterich Peter , Jensen Bo Hammer , Pedersen Lotte Bang , Satir Peter , Schwab Albrecht , Christensen Søren Tvorup , Pedersen Stine Falsig
Published: April 2009

We previously demonstrated that the primary cilium coordinates platelet-derived growth factor (PDGF) receptor (PDGFR) α–mediated migration in growth-arrested fibroblasts. In this study, we investigate the functional relationship between ciliary PDGFR-α and the Na+/H+ exchanger NHE1 in directional cell migration. NHE1 messenger RNA and protein levels are up-regulated in NIH3T3 cells and mouse embryonic fibroblasts (MEFs) during growth arrest, which is concomitant with cilium formation. NHE1 up-regulation is unaffected in Tg737orpk MEFs, which have no or very short primary cilia. In growth-arrested NIH3T3 cells, NHE1 is activated by the specific PDGFR-α ligand PDGF-AA. In wound-healing assays on growth-arrested NIH3T3 cells and wild-type MEFs, NHE1 inhibition by 5′-(N-ethyl-N-isopropyl) amiloride potently reduces PDGF-AA–mediated directional migration. These effects are strongly attenuated in interphase NIH3T3 cells, which are devoid of primary cilia, and in Tg737orpk MEFs. PDGF-AA failed to stimulate migration in NHE1-null fibroblasts. In conclusion, stimulation of directional migration in response to ciliary PDGFR-α signals is specifically dependent on NHE1 activity, indicating that NHE1 activation is a critical event in the physiological response to PDGFR-α stimulation.
Rhabdomere biogenesis in Drosophila photoreceptors is acutely sensitive to phosphatidic acid levels
Authors: Raghu Padinjat , Coessens Elise , Manifava Maria , Georgiev Plamen , Pettitt Trevor , Wood Eleanor , Garcia-Murillas Isaac , Okkenhaug Hanneke , Trivedi Deepti , Zhang Qifeng , Razzaq Azam , Zaid Ola , Wakelam Michael , O'Kane Cahir J , Ktistakis Nicholas
Published: April 2009

Phosphatidic acid (PA) is postulated to have both structural and signaling functions during membrane dynamics in animal cells. In this study, we show that before a critical time period during rhabdomere biogenesis in Drosophila melanogaster photoreceptors, elevated levels of PA disrupt membrane transport to the apical domain. Lipidomic analysis shows that this effect is associated with an increase in the abundance of a single, relatively minor molecular species of PA. These transport defects are dependent on the activation state of Arf1. Transport defects via PA generated by phospholipase D require the activity of type I phosphatidylinositol (PI) 4 phosphate 5 kinase, are phenocopied by knockdown of PI 4 kinase, and are associated with normal endoplasmic reticulum to Golgi transport. We propose that PA levels are critical for apical membrane transport events required for rhabdomere biogenesis.
Integrin-linked kinase is required for radial sorting of axons and Schwann cell remyelination in the peripheral nervous system
Authors: Pereira Jorge A. , Benninger Yves , Baumann Reto , Gonçalves Ana Filipa , Özçelik Murat , Thurnherr Tina , Tricaud Nicolas , Meijer Dies , Fässler Reinhard , Suter Ueli , Relvas João B.
Published: April 2009

During development, Schwann cells (SCs) interpret different extracellular cues to regulate their migration, proliferation, and the remarkable morphological changes associated with the sorting, ensheathment, and myelination of axons. Although interactions between extracellular matrix proteins and integrins are critical to some of these processes, the downstream signaling pathways they control are still poorly understood. Integrin-linked kinase (ILK) is a focal adhesion protein that associates with multiple binding partners to link integrins to the actin cytoskeleton and is thought to participate in integrin and growth factor–mediated signaling. Using SC-specific gene ablation, we report essential functions for ILK in radial sorting of axon bundles and in remyelination in the peripheral nervous system. Our in vivo and in vitro experiments show that ILK negatively regulates Rho/Rho kinase signaling to promote SC process extension and to initiate radial sorting. ILK also facilitates axon remyelination, likely by promoting the activation of downstream molecules such as AKT/protein kinase B.
Large-scale chromatin structure of inducible genes: transcription on a condensed, linear template
Authors: Hu Yan , Kireev Igor , Plutz Matt , Ashourian Nazanin , Belmont Andrew S.
Published: April 2009

The structure of interphase chromosomes, and in particular the changes in large-scale chromatin structure accompanying transcriptional activation, remain poorly characterized. Here we use light microscopy and in vivo immunogold labeling to directly visualize the interphase chromosome conformation of 1–2 Mbp chromatin domains formed by multi-copy BAC transgenes containing 130–220 kb of genomic DNA surrounding the DHFR, Hsp70, or MT gene loci. We demonstrate near-endogenous transcription levels in the context of large-scale chromatin fibers compacted nonuniformly well above the 30-nm chromatin fiber. An approximately 1.5–3-fold extension of these large-scale chromatin fibers accompanies transcriptional induction and active genes remain mobile. Heat shock–induced Hsp70 transgenes associate with the exterior of nuclear speckles, with Hsp70 transcripts accumulating within the speckle. Live-cell imaging reveals distinct dynamic events, with Hsp70 transgenes associating with adjacent speckles, nucleating new speckles, or moving to preexisting speckles. Our results call for reexamination of classical models of interphase chromosome organization.
Exportin 4 mediates a novel nuclear import pathway for Sox family transcription factors
Authors: Gontan Cristina , Güttler Thomas , Engelen Erik , Demmers Jeroen , Fornerod Maarten , Grosveld Frank G. , Tibboel Dick , Görlich Dirk , Poot Raymond A. , Rottier Robbert J.
Published: April 2009

SRY and other Sox-type transcription factors are important developmental regulators with various implications in human disease. In this study, we identified Exp4 (exportin 4) as an interaction partner of Sox2 in mouse embryonic stem cells and neural progenitors. We show that, besides its established function in nuclear export, Exp4 acts as a bona fide nuclear import receptor for Sox2 and SRY. Thus, Exp4 is an example of a nuclear transport receptor carrying distinct cargoes into different directions. In contrast to a published study, we observed that the import activity of Imp-α (importin-a) isoforms toward Sox2 is negligible. Instead, we found that Imp9 and the Imp-β/7 heterodimer mediate nuclear import of Sox2 in parallel to Exp4. Import signals for the three pathways overlap and include conserved residues in the Sox2 high-mobility group (HMG) box domain that are also critical for DNA binding. This suggests that nuclear import of Sox proteins is facilitated by several parallel import pathways.
Molecular signatures of cell migration in C. elegans Q neuroblasts
Authors: Ou Guangshuo , Vale Ronald D.
Published: April 2009

Metazoan cell movement has been studied extensively in vitro, but cell migration in living animals is much less well understood. In this report, we have studied the Caenorhabditis elegans Q neuroblast lineage during larval development, developing live animal imaging methods for following neuroblast migration with single cell resolution. We find that each of the Q descendants migrates at different speeds and for distinct distances. By quantitative green fluorescent protein imaging, we find that Q descendants that migrate faster and longer than their sisters up-regulate protein levels of MIG-2, a Rho family guanosine triphosphatase, and/or down-regulate INA-1, an integrin α subunit, during migration. We also show that Q neuroblasts bearing mutations in either MIG-2 or INA-1 migrate at reduced speeds. The migration defect of the mig-2 mutants, but not ina-1, appears to result from a lack of persistent polarization in the direction of cell migration. Thus, MIG-2 and INA-1 function distinctly to control Q neuroblast migration in living C. elegans.
Primary Metabolism and Plant Defense—Fuel for the Fire
Authors: Bolton Melvin D.
Published: April 2009

Plants have the ability to recognize and respond to a multitude of microorganisms. Recognition of pathogens results in a massive reprogramming of the plant cell to activate and deploy defense responses to halt pathogen growth. Such responses are associated with increased demands for energy, reducing equivalents, and carbon skeletons that are provided by primary metabolic pathways. Although pathogen recognition and downstream resistance responses have been the focus of major study, an intriguing and comparatively understudied phenomenon is how plants are able to recruit energy for the defense response. To that end, this review will summarize current research on energy-producing primary metabolism pathways and their role in fueling the resistance response.
Impaired Colonization and Infection of Tomato Roots by the Δfrp1 Mutant of Fusarium oxysporum Correlates with Reduced CWDE Gene Expression
Authors: Jonkers Wilfried , Rodrigues Christopher D. Andrade , Rep Martijn
Published: April 2009

The vascular wilt pathogen Fusarium oxysporum f. sp. lycopersici efficiently invades roots and colonizes vascular tissues of its host tomato. For these processes, the F-box protein Frp1 is required. The Fusarium oxysporum Δfrp1 mutant was characterized in detail to uncover the cause of its colonization defect. Using growth assays, we could attribute poor root colonization to reduced assimilation of organic acids, amino acids (except proline), or polysaccharides, singly or in combination. External root colonization by the Δfrp1 mutant is restored by the addition of 0.1% glucose or proline but infection still does not occur. This is due to the inability of the Δfrp1 mutant to penetrate the roots, as demonstrated by the lack of expression of SIX1 in the Δfrp1 strain, which is a gene exclusively expressed inside roots, and loss of cell wall–degrading enzyme (CWDE) gene expression. Many of the metabolic defects of the Δfrp1 strain can be attributed to reduced expression of the ICL1 (isocitrate lyase) gene. Strikingly, an Δicl1 mutant is still fully pathogenic and capable of external root colonization. We conclude that the inability of the Δfrp1 strain to colonize and invade roots is not primarily due to metabolic defects but can be attributed to reduced expression of several CWDE genes.
Characterization of the Mesorhizobium loti MAFF303099 Type-Three Protein Secretion System
Authors: Sánchez Cintia , Iannino Florencia , Deakin William J. , Ugalde Rodolfo A. , Lepek Viviana C.
Published: April 2009

Type III secretion systems (T3SS) have been found in several species of rhizobia. Proteins (termed effectors) secreted by this system are involved in host-range determination and influence nodulation efficiency. Mesorhizobium loti MAFF303099 possesses a functional T3SS in its symbiotic island whose expression is induced by flavonoids. As in other rhizobia, conserved cis-elements (tts box) were found in the promoter regions of genes or operons encoding T3SS components. Using a bioinformatics approach, we searched for other tts-box-controlled genes, and confirmed this transcriptional regulation for some of them using lacZ fusions to the predicted promoter regions. Translational fusions to a reporter peptide were created to demonstrate T3SS-mediated secretion of two new MAFF303099 effectors. Finally, we showed that mutation of the M. loti MAFF303099 T3SS affects its competitiveness on Lotus glaber and investigated, at the molecular level, responses of the model legume L. japonicus to the T3SS.
Different Regulation and Roles of Lactonases AiiB and AttM in Agrobacterium tumefaciens C58
Authors: Haudecoeur Elise , Tannières Mélanie , Cirou Amélie , Raffoux Aurélie , Dessaux Yves , Faure Denis
Published: April 2009

The phytopathogen Agrobacterium tumefaciens C58 expresses two lactonases, AttM and AiiB. We showed that expression of the aiiB gene was controlled by agrocinopines A and B and required the agrocinopine-ABC transporter Acc, but was not affected by the level of quorum-sensing (QS) signal 3-oxo-octanoylhomoserine lactone (OC8-HSL). In the presence of agrocinopines, a constructed aiiB mutant accumulated OC8-HSL at a level 10-fold higher than that of the wild-type strain, and showed an exacerbated expression of a key QS-regulated function, conjugation of Ti plasmid (in vitro and in planta), as well as an increase of the number of emerging tumors on the host plant. The expression and acyl-HSL-degrading activity of AttM were evident in the presence of wounded tissues; however, in unwounded plant tumors, the QS-regulated functions were weakly affected in an attM mutant. By contrast, we observed that attM conferred a selective advantage in the course of colonization of plant tumors. Finally, polymerase chain reaction survey of genes attM and aiiB showed that they were not strictly conserved in the genus Agrobacterium. This work proved that the lactonases AttM and AiiB are regulated by different plant signals and are implicated in different functions in the course of the A. tumefaciens C58–host interaction.
A Gall-Inducing Caterpillar Species Increases Essential Fatty Acid Content of Its Host Plant Without Concomitant Increases in Phytohormone Levels
Authors: Tooker John F. , De Moraes Consuelo M.
Published: April 2009

Gall-inducing insects are accomplished plant parasites that can profoundly influence host-plant physiology. We recently reported that the caterpillar Gnorimoschema gallaesolidaginis failed to significantly alter emissions of host-plant volatiles that often recruit natural enemies of insect herbivores, and demonstrated that a caterpillar species feeding on linolenate-deficient plant tissues avoids inducing some of the indirect defenses of its host plant. Here, we investigate whether absence of volatile responses to the galler G. gallaesolidaginis could similarly be explained by a lack of linolenate in galls. We screened interior and exterior tissue of galls and control stems of Solidago altissima for free linolenate, linoleate, 12-oxo-phytodienoate, jasmonate, and salicylate. We found, unexpectedly, that G. gallaesolidaginis strongly increased amounts of linolenic and linoleic acids inside galls without associated increases in two downstream products, 12-oxo-phytodienoic or jasmonic acid. In contrast, the generalist caterpillar Heliothis virescens induced elevated levels of linolenic, linoleic, 12-oxo-phytodienoic, and jasmonic acids in S. altissima. Moreover, these two fatty acids and 12-oxo-phytodienoate were significantly and positively associated with jasmonic acid, suggesting that increased levels of these precursors can lead directly to greater amounts of jasmonic acid. Taken together, these findings suggest that gall insects may be able to nutritionally enhance their food source without inducing concomitant increases in phytohormones and associated defense responses.
Characterization of Two Unusual Features of Resistance to Soilborne cereal mosaic virus in Hexaploid Wheat: Leakiness and Gradual Elimination of Viral Coat Protein from Infected Root Tissues
Authors: Lyons Rebecca , Yilmaz Nazli D. Kutluk , Powers Stephen , Hammond-Kosack Kim E. , Kanyuka Kostya
Published: April 2009

Spatiotemporal infection patterns of Soilborne cereal mosaic virus (SBCMV) were compared between resistant and susceptible wheat cultivars to elucidate disease resistance mechanisms. Resistance to SBCMV was manifested by a gradual disappearance of the viral coat protein (CP) from the roots following an initial short period of steady accumulation. Interestingly, viral RNA persisted in the roots of resistant cultivars even after the CP had disappeared. Traces of viral RNA were also detected in the uninoculated leaves of the resistant cv. Cadenza. These findings suggest that the resistance mechanism to SBCMV in wheat involves the efficient disassembly of virus particles and either an inhibition of further synthesis of viral CP or its proteolytic degradation. SBCMV accumulated in the leaves of a small proportion of individual plants of Cadenza and other recognized resistant cultivars, highlighting the leaky nature of the resistance, but the roots of these plants were often devoid of viral CP. Increasing or decreasing the concentration of the inocula had no effect on the incidence rate of such “resistance breakdown”; however, a positive correlation was found between the incidence rate of resistance breakdown and the percentage of systemically infected individuals of recognized susceptible cultivars in each separate experiment.
Sinorhizobium fredii HH103 cgs Mutants Are Unable to Nodulate Determinate- and Indeterminate Nodule–Forming Legumes and Overproduce an Altered EPS
Authors: Crespo-Rivas Juan C. , Margaret Isabel , Hidalgo Ángeles , Buendía-Clavería Ana M. , Ollero Francisco J. , López-Baena Francisco J. , del Socorro Murdoch Piedad , Rodríguez-Carvajal Miguel A. , Soria-Díaz M. Eugenia , Reguera María , Lloret Javier , Sumpton David P. , Mosely Jackie A. , Thomas-Oates Jane E. , van Brussel Anton A. N. , Gil-Serrano Antonio , Vinardell Jose M. , Ruiz-Sainz Jose E.
Published: April 2009

Sinorhizobium fredii HH103 produces cyclic β glucans (CG) composed of 18 to 24 glucose residues without or with 1-phosphoglycerol as the only substituent. The S. fredii HH103-Rifr cgs gene (formerly known as ndvB) was sequenced and mutated with the lacZ-gentamicin resistance cassette. Mutant SVQ562 did not produce CG, was immobile, and grew more slowly in the hypoosmotic GYM medium, but its survival in distilled water was equal to that of HH103-Rifr. Lipopolysaccharides and K-antigen polysaccharides produced by SVQ562 were not apparently altered. SVQ562 overproduced exopolysaccharides (EPS) and its exoA gene was transcribed at higher levels than in HH103-Rifr. In GYM medium, the EPS produced by SVQ562 was of higher molecular weight and carried higher levels of substituents than that produced by HH103-Rifr. The expression of the SVQ562 cgs∷lacZ fusion was influenced by the pH and the osmolarity of the growth medium. The S. fredii cgs mutants SVQ561 (carrying cgs∷Ω) and SVQ562 only formed pseudonodules on Glycine max (determinate nodules) and on Glycyrrhiza uralensis (indeterminate nodules). Although nodulation factors were detected in SVQ561 cultures, none of the cgs mutants induced any macroscopic response in Vigna unguiculata roots. Thus, the nodulation process induced by S. fredii cgs mutants is aborted at earlier stages in V. unguiculata than in Glycine max.
Mapping and Cloning of Late Blight Resistance Genes from Solanum venturii Using an Interspecific Candidate Gene Approach
Authors: Pel Mathieu A. , Foster Simon J. , Park Tae-Ho , Rietman Hendrik , van Arkel Gert , Jones Jonathan D. G. , Van Eck Herman J. , Jacobsen Evert , Visser Richard G. F. , Van der Vossen Edwin A. G.
Published: April 2009

Late blight, caused by the oomycete Phytophthora infestans, is one of the most devastating diseases of potato. Resistance (R) genes from the wild species Solanum demissum have been used by breeders to generate late-blight-resistant cultivars but resistance was soon overcome by the pathogen. A more recent screening of a large number of wild species has led to the identification of novel sources of resistance, many of which are currently being characterized further. Here, we report on the cloning of dominant Rpi genes from S. venturii. Rpi-vnt1.1 and Rpi-vnt1.3 were mapped to chromosome 9 using nucleotide binding site (NBS) profiling. Subsequently, a Tm-22-based allele mining strategy was used to clone both genes. Rpi-vnt1.1 and Rpi-vnt1.3 belong to the coiled-coil NBS leucine-rich repeat (LRR) class of plant R genes and encode predicted peptides of 891 and 905 amino acids (aa), respectively, which share 75% amino acid identity with the Tomato mosaic virus resistance protein Tm-22 from tomato. Compared with Rpi-vnt1.1, Rpi-vnt1.3 harbors a 14-aa insertion in the N-terminal region of the protein and two different amino acids in the LRR domain. Despite these differences, Rpi-vnt1.1 and Rpi-vnt1.3 genes have the same resistance spectrum.
Soil Solarization as a Component of an Integrated Program for Control of Raspberry Root Rot
Authors: Pinkerton J. N. , Bristow P. R. , Windom G. E. , Walters T. W.
Published: April 2009

Field and growth chamber studies were conducted during 2000 to 2005 to determine the efficacy of soil solarization for the control of Phytophthora root rot of raspberry (PRR). The exposure time that was lethal to Phytophthora rubi cultures on V8 juice agar plates was evaluated at intervals up to 240 h and at a range of temperatures from 20 to 35°C. Colonies incubated at 20 and 25°C nearly covered the plates in 240 h, while radial growth slowed at 27°C and ceased at temperatures ≥29°C. The exposure times required to kill P. rubi were estimated to be 222 h at 29°C, 168 h at 31°C, 108 h at 33°C, and 52 h at 35°C. Previous exposure to shorter durations at temperature ≥29°C slowed growth of colonies when they later were incubated at 20°C. Field trials were established in 2000 and 2003 at three locations in Washington State to evaluate soil solarization for the management of PRR. Cumulative hours with soil temperatures >29°C at 30 cm soil depth in solarized plots exceeded 200 h in each trial. In the 2000 trial, combinations of solarization, bed shape, and amendments of gypsum were evaluated. Over the 3 years after planting PRR-susceptible raspberry ‘Malahat’ and ‘Willamette’, primocane growth and survival were greater (P < 0.05) in raised bed plots that were solarized than in solarized and nonsolarized flat bed plots or hilled bed plots with gypsum. In 2003, trials were initiated to evaluate solarization in combination with applications of mefenoxam and fosetyl-Al. In 2004, solarization increased (P < 0.05) primocane growth of ‘Malahat’ and ‘Qualicum’ raspberries at both locations compared to application of fungicides alone and nontreated control plots. At both locations in 2005, density and growth of ‘Qualicum’ primocanes were greatest in solarized plots, while canes in solarized and fungicide only plots of ‘Malahat’ were similar. Incidence of diseased canes was lowest in plots that received fungicides. Primocane survival and fruit yields were very low at both locations in the third season because of favorable conditions for PRR and plant stress in late spring. These results indicate that soil solarization can be an effective component of integrated management of PRR in the Pacific Northwest, especially when combined with raised beds and gypsum amendments.
Propagule Production by Phytophthora ramorum on Lilac (Syringa vulgaris) Leaf Tissue Left on the Surface of Potting Mix in Nursery Pots
Authors: Shishkoff Nina
Published: April 2009

Lilac leaf tissue infected with Phytophthora ramorum was placed on top of potting mix in pots and exposed to different watering regimes or different temperatures to determine if it could serve as a source of inoculum. If pieces of infected leaf were placed in pots containing healthy lilac plants kept under constantly moist conditions or under twice-a-day trickle irrigation for 1 month, inoculum production from infected tissue declined for the first 4 days but declined significantly less steeply under constantly moist conditions. At the end of the experiment, 28% of plants exposed to moist conditions developed root infections, whereas only 6% exposed to trickle irrigation did. If infected leaf pieces were placed on the surface of potting mix in pots containing lilacs and watered for 5 min one, two, or three times a day, inoculum production in the first 4 days declined but declined significantly more slowly in pots watered three times a day. If 0 to 16 leaf pieces were placed on the surface of potting mix in pots containing healthy lilacs under constantly moist conditions, leaf number significantly influenced the incidence of root infection. The effect of temperature was more difficult to quantify. At 10 or 15°C, propagules included zoospores whereas, at 20 or 25°C, they were predominantly sporangia. These results confirm the importance of detached leaves as inoculum producers under greenhouse conditions.
Suppression of Verticillium Wilt of Eggplant by Earthworms
Authors: Elmer Wade H. , Ferrandino Francis J.
Published: April 2009

The role of earthworms in plant disease has received little attention. To address whether earthworms would affect the severity of Verticillium wilt of eggplant (Solanum melongena) in the field, we grew eggplants in experimental field plots that were naturally infested with Verticillium dahliae in 2005, 2006, and 2007. Three earthworm treatments were compared: (i) no treatment (untreated control), (ii) earthworm populations reduced via chemical eradicants (carbaryl or hot mustard) (reduced treatment), and (iii) earthworm populations increased by addition of adult Canadian nightcrawlers (Lumbricus terrestris, 11 earthworms per m2) (augmented treatment). Compared to the untreated control, the estimates of the area under the disease progress curve (AUDPC) were reduced while estimates of the canopy growth curve (CGC) and the final plant weights were increased in plots augmented with earthworms in all 3 years. In 2 out of 3 years, eggplant yield (weight and number of fruit) was increased in plots augmented with earthworms. When a carbaryl drench was used to reduce earthworm numbers, the treatment resulted in plants with more disease than in the untreated controls in 2005. However, in 2005 and 2006, carbaryl-treated plants had larger CGC values and higher yield than in the untreated controls and were not significantly different from the augmented plots. When a hot mustard extraction procedure was used to reduce earthworm densities in 2007, plant growth, yield, and disease variables did not differ from the untreated control. Although the effects of reducing earthworms were variable and difficult to explain, our findings suggest that augmenting earthworm populations can suppress Verticillium wilt of eggplant, and strategies that increase earthworm numbers may contribute to disease suppression.
Resistance to QoI Fungicides in Ascochyta rabiei from Chickpea in the Northern Great Plains
Authors: Wise K. A. , Bradley C. A. , Pasche J. S. , Gudmestad N. C.
Published: April 2009

Ascochyta blight, caused by Ascochyta rabiei (teleomorph: Didymella rabiei), is an important fungal disease of chickpea (Cicer arietinum). A monitoring program was established in 2005 to determine the sensitivity of A. rabiei isolates to the QoI (strobilurin) fungicides azoxystrobin and pyraclostrobin. A total of 403 isolates of A. rabiei from the Northern Great Plains and the Pacific Northwest were tested. Ninety-eight isolates collected between 2005 and 2007 were tested using an in vitro spore germination assay to determine the effective fungicide concentration at which 50% of conidial germination was inhibited (EC50) for each isolate–fungicide combination. A discriminatory dose of 1 μg/ml azoxystrobin was established and used to test 305 isolates from 2006 and 2007 for in vitro QoI fungicide sensitivity. Sixty-five percent of isolates collected from North Dakota in 2005, 2006, and 2007 and from Montana in 2007 were found to exhibit a mean 100-fold decrease in sensitivity to both azoxystrobin and pyraclostrobin when compared to sensitive isolates, and were considered to be resistant to azoxystrobin and pyraclostrobin. Under greenhouse conditions, QoI-resistant isolates of A. rabiei caused significantly higher amounts of disease than sensitive isolates on azoxystrobin- or pyraclostrobin-amended plants. These results suggest that disease control may be inadequate at locations where resistant isolates are present.
Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2007
Authors: Kolmer J. A. , Long D. L. , Hughes M. E.
Published: April 2009

In 2007, leaf rust of wheat was severe throughout the Great Plains region of North America. Yield losses in wheat due to leaf rust were estimated to be 14% in Kansas. Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio River Valley, southeast, California, and Washington State in order to determine the virulence of the wheat leaf rust population in 2007. Single uredinial isolates (868 in total) were derived from the collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3a, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17a, Lr30, LrB, Lr10, Lr14a, Lr18, Lr21, and Lr28, and on winter wheat lines with genes Lr41 and Lr42. Fifty-two virulence phenotypes were found. Virulence phenotypes TDBJG, MFPSC, and TDBJH were among the four most common phenotypes and were all virulent to resistance gene Lr24. These phenotypes were found throughout the Great Plains region. Phenotype MLDSD, with virulence to Lr9, Lr17, and Lr41, was also widely distributed in the Great Plains. In the soft red winter wheat region of the southeastern states, phenotypes TCRKG, with virulence to genes Lr11, Lr26, and Lr18, and MFGJH, with virulence to Lr24, Lr26, and Lr11, were among the common phenotypes. Virulence phenotypes with virulence to Lr16 were most frequent in the spring wheat region of the northern Great Plains. Virulence phenotypes with virulence to Lr11, Lr18, and Lr26 were most common in the soft red winter areas of the southeastern states and Ohio Valley. Virulence to Lr21 was not found in any of the tested isolates.
Tomatillo (Physalis ixocarpa) as a Natural New Host for Tomato yellow leaf curl virus in Sinaloa, Mexico
Authors: Gámez-Jiménez C. , Romero-Romero J. L. , Santos-Cervantes M. E. , Leyva-López N. E. , Méndez-Lozano J.
Published: April 2009

Tomatillo, also known as husk or green tomato, is cultivated in 29 of 32 states in Mexico, with the main production areas located in the states of Sinaloa, Michoacán, Puebla, Sonora, Guanajuato, Jalisco, and Hidalgo. The national production of tomatillo in 2006 was 805,721 tons with a value of $259 million. Tomato yellow leaf curl virus (TYLCV) is one of the most damaging begomoviruses affecting tomato worldwide. TYLCV was first identified in Mexico in 1999 in Yucatán (1) and most recently identified as infecting tomato in Sinaloa (3). During December of 2006, symptoms including chlorotic margins, yellowing, and interveinal yellowing were observed in tomatillo fields. Symptomatic plants were associated with the presence of whiteflies in many fields, suggesting a begomovirus etiology. Total DNA was extracted from leaves of 77 symptomatic tomatillo plants from Guasave and Ahome counties and amplified by PCR using a degenerate primer pair (2). These primers can differentiate between monopartite and bipartite begomoviruses on the basis of the size of the amplification products, approximately 750 and 650 bp, respectively. A PCR product of 742 bp was obtained from 48 of 97 samples. The PCR product of two representative samples from each county were cloned into pGEM-T Easy Vector (Promega, Madison, WI) and sequenced. The sequences of the four amplicons were identical (GenBank Accession No. EU224314) and were compared with sequences of others begomoviruses in the NCBI/GenBank database using the Clustal V alignment method (MegAlign, DNASTAR software, London). The highest sequence identity of 100% was with a TYLCV isolate from Sinaloa (GenBank Accession No. DQ377367), 99.8% with a TYLCV isolate from Tosa (GenBank Accession No. AB192965), 98.4% with a TYLCV isolate from China (GenBank Accession No. AM282874), 95.8% with a TYLCV isolate from Yucatán (GenBank Accession No. AF168709), and 94.6% with TYLCV-Is (GenBank Accession No. X15656). The genome of tomatillo TYLCV isolate was amplified using PCR and overlapping primer pair (TYLCV NcoI Forward GGCCCATGGCCGCGCAGCGG and Reverse CGGCCATGGAGACCCATAAG). Sequence of a 2,781-bp fragment was obtained (GenBank Accession No. FJ609655) and sequence analysis corroborated that the tomatillo TYLCV has 99.3% identity with two TYLCV isolates from Sinaloa (GenBank Accession Nos. EF5234478 and FJ012358). To our knowledge, this is the first report of tomatillo as a natural host of TYLCV in Mexico. These results suggest that TYLCV has begun to establish itself in others crops since it was first reported to be infecting tomato in Sinaloa, Mexico.

References: (1) J. T. Ascencio-Ibañez et al. Plant Dis. 83:1178, 1999. (2) J. T. Ascencio-Ibañez et al. Plant Dis. 86:692, 2002. (3) C. Gámez-Jímenez et al. (Abstr.) Phytopathology 96(suppl.):S38. 2006.
Tomato spotted wilt virus Found in Five Species of the genus Tragopogon in a Florida Greenhouse
Authors: Baker C. A. , Jones L. , Leahy R. M. , Soltis D. E.
Published: April 2009

An obviously unhealthy plant identified as Tragopogon mirus Ownbey (remarkable goatsbeard) was sent for diagnosis to the Division of Plant Industry (DPI), Gainesville, FL in May of 2008. T. mirus is a recently formed allotetraploid that has T. dubius Scop. and T. porrifolius L. (goatsbeard or salsify) as parents. The parents (family Asteraceae) are diploid and originate from Eurasia. They were introduced to the northwest United States in the early 1900s. The allotetraploid T. mirus, which does not occur in Eurasia, was discovered in 1949 and named in 1950. It has been found in the northwest states of Washington and Idaho. It has also been found in Arizona (4). The plant sent to the DPI was grown in a greenhouse for research purposes at the Botany Department of the University of Florida (Alachua County). Symptoms exhibited on the leaves included mottling, chlorotic and necrotic spots, and mild distortion. Epidermal leaf strips from a mottled leaf were stained with the Orange-Green protein stain and Azure A nucleic acid stain (1). With a light microscope, granular inclusions typical for Tomato spotted wilt virus (TSWV) (1) were seen in leaf strips from both stains. The remainder of the leaf was ground in buffer and tested serologically for TSWV by TSWV-specific ImmunoStrips (Agdia, Elkhart, IN). The ImmunoStrip was positive for the presence of TSWV. This test was confirmed by double-antibody sandwich-ELISA using antiserum and conjugate for TSWV (Agdia). Further serological testing of other Tragopogon species with similar symptoms growing in the same greenhouse revealed that T. miscellus (another recently formed allotetraploid found in the northwestern United States; parents T. dubius and T. pratensis), T. dubius, T. porrifolius, and T. pratensis were also infected with TSWV. Total RNA was extracted from symptomatic leaves of T. mirus, T. dubius, T. porrifolius, and T. miscellus. Reverse transcription-PCR was performed with universal tospovirus primers BR60 and BR65 that amplify part of the nucleocapsid protein gene (2). Target amplicons of 454 bp were produced for all four samples. The PCR product from T. porrifolius was cloned and sequenced. The resulting sequence (GenBank Accession No. FJ655913) shows high homology, 98%, to several isolates of the Tomato spotted wilt virus deposited in the GenBank (Accession Nos. AY870391, AY744477, and AF020659). T. porrifolius has been reported to be naturally infected with TSWV in Italy (3); however, to our knowledge, this is the first report of this virus in the allotetraploids T. mirus and T. miscellus and in the diploids T. dubius and T. pratensis. This report adds five new Asteraceae weeds to the list of possible reservoirs of TSWV in the United States.

References: (1) J. R. Edwardson and R. G. Christie. Univ. Fla. Inst. Food Agric. Sci. Bull. 894. 1996. (2) M. Eiras et al. Fitopatol. Bras. 26:170, 2001. (3) G. Parrella et al. J. Plant Pathol. 85:227. 2003. (4) D. E. Soltis et al. Biol. J. Linn. Soc. 82:2004.
First Report of Fusarium solani Fruit Rot of Pumpkin (Cucurbita pepo) in Trinidad
Authors: Rampersad S. N.
Published: April 2009

Trinidad is a major exporter of pumpkins (Cucurbita pepo L.) to other Caribbean countries, Canada, and the United States. Producers and exporters have reported 50 to 80% yield losses because of soft rot and overnight collapse of fruit at the pre- and postharvest stages. Severe fruit rot occurred in fields in Victoria County in South Trinidad between April and May 2006 (mid-to-late dry season) with an increase in the severity and number of affected fruit in the rainy season (July to December). Symptoms began as water-soaked lesions on the fruit of any age at the point of contact with the soil. The disease progressed to a soft rot with leakage and whole fruit collapse. A dark brown, soft decay also developed at the base of the main vines. Fusarium solani was isolated on selective fusarium agar and potato dextrose agar (PDA) (1) after 7 to 10 days of incubation at 25°C. The pathogen was identified by morphological characteristics and pathogenicity tests. Colonies were fast growing with white aerial mycelia and a cream color on the reverse side; hyphae were septate and hyaline, conidiophores were unbranched, and microconidia were abundant, thin walled, hyaline, fusiform to ovoid, generally one to two celled, and 8 to 10 × 2 to 4 μm. Macroconidia were hyaline, two to three celled, moderately curved, thick walled, and 25 to 30 × 4 to 6 μm. Pathogenicity tests for 10 isolates were conducted on 2-week-old pumpkin seedlings (cv. Jamaican squash; seven plants per isolate) and mature pumpkin fruit (2). Briefly, seedlings were inoculated by dipping their roots in a spore suspension (1 × 104 spores per ml) for 20 min. The plants were repotted in sterile potting soil. For negative controls, plant roots were dipped in sterile water. After the rind of fruit was swabbed with 70% ethanol followed by three rinses with sterile distilled water, 0.4-cm-diameter agar plugs of the isolates were inserted into wounds made with a sterile 1-cm-diameter borer. Sterile PDA plugs served as negative controls. Fruit were placed in sealed, clear, plastic bags. Inoculated plants and fruit were placed on greenhouse benches (30 to 32°C day and 25 to 27°C night temperatures) and monitored over a 30-day period. Tests were repeated once. Inoculated fruit developed a brown, spongy lesion that expanded from the initial wound site over a period of approximately 17 days after inoculation. White mycelia grew diffusely over the lesion. Inoculated plants developed yellow and finally necrotic leaves and lesions developed on stems at the soil line approximately 21 days after inoculation. No symptoms developed on the control plants. The fungus was reisolated from symptomatic tissue, fulfilling Koch's postulates. To my knowledge, this is the first report of Fusarium fruit rot of pumpkin in Trinidad.

References: (1) J. Leslie and B. Summerell. Page 1 in: The Fusarium Laboratory Manual. Blackwell Publishing, Oxford, 2006. (2) W. H. Elmer. Plant Dis. 80:131, 1996.