The kinetic mechanism of the unidirectional
H2-oxidizing hydrogenase from soybean nodule bacteroids has
been investigated with highly purified enzyme. Measurements
of the K, for H2 vary from 0.97 to 2.6 pM, and the K,,, for
methylene blue varies from 6 to 17 pM. With H2 and
methylene blue as substrates,...
Carbonyl sulfide (COS) has been investigated as a rapid-equilibrium inhibitor of CO oxidation
by the CO dehydrogenase purified from Rhodospirillum rubrum. The kinetic evidence suggests that the
inhibition by COS is largely competitive versus CO (Ki = 2.3 pM) and uncompetitive versus methylviologen
as electron acceptor (Ki = 15.8 pM)....
The virus-encoded proteins of tobacco etch virus (TEV), a plant potyvirus, arise by proteolytic processing of
a large polyprotein precursor. The TEV genome codes for two proteinases, a 49-kilodalton proteinase and
helper component proteinase (HC-Pro), which cleave the polyprotein at specific sites. The only known cleavage
event catalyzed by HC-Pro...
The RNA genome of tobacco etch virus (TEV), a plant potyvirus, functions as an mRNA for synthesis of a
346-kilodalton polyprotein that undergoes extensive proteolytic processing. The RNA lacks a normal 5' cap
structure at its terminus, which suggests that the mechanism of translational initiation differs from that of a...
The objectives of this study are to isolate and characterize pathogenic agrobacteria that cause crown gall in grapevines and test hot water dips as a method for eradicating the infectious bacteria . Crown gall is commonly found among Oregon vineyards and the causative agent, Agrobacterium vitis, is known to be...
A genetic complementation system was developed
in which tobacco etch virus (TEV) polymerase (NIb)-
expressing transgenic plants or protoplasts were inoculated
with NIb-defective TEV mutants. A β-glucuronidase (GUS)
reporter gene integrated into the genomes of parental and four
mutant viruses was used to assay RNA amplification. Two
mutants (termed VNN...
Tobacco etch virus (TEV) encodes three proteinases that catalyze processing of the genome-encoded polyprotein.
The P1 proteinase originates from the N terminus of the polyprotein and catalyzes proteolysis between
itself and the helper component proteinase (HC-Pro). Mutations resulting in substitution of a single amino
acid, small insertions, or deletions were...
The tobacco etch potyvirus (TEV) polyprotein is proteolytically processed by three viral proteinases (NIa,
HC-Pro, and P1). While the NIa and HC-Pro proteinases each provide multiple functions essential for viral
infectivity, the role of the P1 proteinase beyond its autoproteolytic activity is understood poorly. To determine
if P1 is necessary...
A mutational analysis was conducted to investigate the functions of the tobacco etch potyvirus VPgproteinase
(NIa) protein in vivo. The NIa N-terminal domain contains the VPg attachment site, whereas the
C-terminal domain contains a picornavirus 3C-like proteinase. Cleavage at an internal site separating the two
domains occurs in a subset...
Plum pox virus (PPV) is a member of the Potyvirus genus that, in nature, infects trees of the Prunus genus.
Although PPV infects systemically several species of the Nicotiana genus, such as N. clevelandii and N.
benthamiana, and replicates in the inoculated leaves of N. tabacum, it is unable to...
MicroRNAs (miRNAs) are an extensive class of noncoding genes that regulate gene expression through
posttranscriptional repression. Given the potential for large viral genomes to encode these transcripts, we
examined the human cytomegalovirus AD169 genome for miRNAs using a bioinformatics approach. We
identified 406 potential stem-loops, of which 110 were conserved...
Rice, maize, sorghum, wheat, barley and the other
major crop grasses from the family Poaceae
(Gramineae) are mankind’s most important source
of calories and contribute tens of billions of dollars
annually to the world economy (FAO 1999, http://www.fao.org; USDA 1997, http://www.usda.gov).
Continued improvement of Poaceae crops is necessary
in order...
RNA silencing is an evolutionarily conserved system that
functions as an antiviral mechanism in higher plants and
insects. To counteract RNA silencing, viruses express
silencing suppressors that interfere with both siRNA- and
microRNA-guided silencing pathways. We used comparative
in vitro and in vivo approaches to analyse the molecular
mechanism of...
Plant growth stages are identified as distinct morphological landmarks in a continuous developmental process. The terms
describing these developmental stages record the morphological appearance of the plant at a specific point in its life cycle. The
widely differing morphology of plant species consequently gave rise to heterogeneous vocabularies describing growth...
Formal description of plant phenotypes and standardized annotation of gene expression and protein localization data require
uniform terminology that accurately describes plant anatomy and morphology. This facilitates cross species comparative
studies and quantitative comparison of phenotypes and expression patterns. A major drawback is variable terminology that is
used to describe...
Background: Large molecular sequence databases are fundamental resources for modern
bioscientists. Whether for project-specific purposes or sharing data with colleagues, it is often
advantageous to maintain smaller sequence databases. However, this is usually not an easy task for
the average bench scientist.
Results: We present the Personal Sequence Database (PSD),...
Nitrobacter hamburgensis X14 is a facultative lithoautotroph that conserves energy from the
oxidation of nitrite (NO
2 ) and fixes carbon dioxide (CO2) as its sole source of carbon. The
availability of the N. hamburgensis X14 genome sequence initiated a re-examination of its
mixotrophic and organotrophic potential, as genes encoding...
Primula sect. Parryi comprises five species endemic to western North America: P. parryi, P. angustifolia, P. rusbyi, P. capillaris, and P. cusickiana with four varieties. This section, derived from a clade with representatives in Asia and Europe, exemplifies a phytogeographic pattern in which a widespread species is accompanied by multiple...
The placement of ‘Pseudomonas butanovora’ in the genus Thauera was proposed previously, based on 16S rRNA gene sequence analysis, upon further studies of taxonomical characteristics. In this study, physiological characteristics and DNA–DNA reassociation data are presented and the transfer of ‘P. butanovora’ to the genus Thauera is proposed. The original...
The advent of high-throughput sequencing (HTS) methods has enabled direct approaches to quantitatively profile small RNA
populations. However, these methods have been limited by several factors, including representational artifacts and lack of
established statistical methods of analysis. Furthermore, massive HTS data sets present new problems related to data processing
and...
Background: Short RNAs, and in particular microRNAs, are important regulators of gene
expression both within defined regulatory pathways and at the epigenetic scale. We investigated
the short RNA (sRNA) population (18-24 nt) of the transcriptome of green leaves from the
sequenced Populus trichocarpa using a concatenation strategy in combination with...
Flowering is the primary trait affected by ambient
temperature changes. Plant microRNAs
(miRNAs) are small non-coding RNAs playing an
important regulatory role in plant development. In
this study, to elucidate the mechanism of
flowering-time regulation by small RNAs, we
identified six ambient temperature-responsive
miRNAs (miR156, miR163, miR169, miR172, miR398
and...
Restriction of long-distance movement of several potyviruses in Arabidopsis (Arabidopsis thaliana) is controlled by at least three
dominant restricted TEV movement (RTM) genes, named RTM1, RTM2, and RTM3. RTM1 encodes a protein belonging to the
jacalin family, and RTM2 encodes a protein that has similarities to small heat shock proteins....
Hypogymnia imshaugii is one of the most common, conspicuous and morphologically variable epiphytic lichens of the Pacific coastal states and provinces. The species varies greatly in morphology and chemistry, suggesting multiple closely related species or one or more phenotypically plastic species. We sought to determine whether additional ecologically meaningful species...
Plants possess two myosin classes, VIII and XI. The myosins XI are implicated in organelle transport, filamentous actin
organization, and cell and plant growth. Due to the large size of myosin gene families, knowledge of these molecular motors
remains patchy. Using deep transcriptome sequencing and bioinformatics, we systematically investigated myosin...
Although Oregon white oak (Quercus garryana) woodlands are a characteristic landscape component in southwestern Oregon, little is known about their current or historical stand structures. Meanwhile, fuel reduction thinning treatments that change stand structures in non-coniferous communities are ongoing and widespread on public lands in this region; some of these...
A new Phytophthora species was detected (i) in the USA, infecting foliage of Kalmia latifolia, (ii) in substrate underneath Pieris, and (iii) in Germany in soil samples underneath Aesculus hippocastanum showing disease symptoms. The new species Phytophthora obscura sp. nov. is formally named based on phylogenetic analysis, host range, Kochs...
Biofortification of staple crops like potato via breeding is an attractive strategy to reduce human micronutrient deficiencies. A prerequisite is metabolic phenotyping of genetically diverse material which can potentially be used as parents in breeding programs. Thus, the natural genetic diversity of thiamin and folate contents was investigated in indigenous...
SEE ARTICLE FOR ABSTRACT IN SPANISH. English Abstract: In order to study the quantitative relationship between tuber yield of two potato (Solanum tuberosum L.) cultivars (‘Alpha’, susceptible, and ‘Zafiro’, moderately resistant to late blight), and severity of the pathogen in Toluca, México, managed by weekly foliar sprays of 0.575 kg...
Deep sequencing analysis of an asymptomatic grapevine revealed a virome containing five RNA viruses and a viroid. Of these, Grapevine leafroll-associated virus 7 (GLRaV-7), an unassigned closterovirus, was by far the most prominently represented sequence in the analysis. Graft-inoculation of the infection to another grape variety confirmed the lack of...
The fluorescence signal emitted from phytoplankton exposed to natural sunlight has been considered a potentially useful tool to examine phytoplankton physiology from in situ radiometers and satellites, but variability in the fluorescence signal is confounded by non-photochemical quenching (NPQ). This pathway dissipates excitation energy as heat rather than fluorescence. It...
Des séquences entières ou partielles de génomes deviennent de plus en plus accessibles. En ce qui concerne plusieurs systèmes plante-agent
pathogène, nous abordons l’ère du recéquençage du génome. Les premiers génomes de Phytophthora, P. ramorum et P. sojae, ont été
disponibles à partir de 2004, suivis de près par celui...
Fusarium crown rot (FCR), caused by and , reduces wheat ( L.) yields in the Pacific Northwest (PNW) of the US by as much as 35%. Resistance to FCR has not yet been discovered in currently grown PNW wheat cultivars. Several significant quantitative trait loci (QTL) for FCR resistance have...
Trade in live plants has been recognized worldwide as an important invasion pathway for non-native plant pests. Such pests can have severe economic and ecological consequences. Nearly 70% of damaging forest insects and pathogens established in the US between 1860 and 2006 most likely entered on imported live plants. The...
Antibiotics are essential for control of bacterial diseases of plants, especially fire blight of pear and apple and bacterial spot of peach. Streptomycin is used in several countries; the use of oxytetracycline, oxolinic acid and gentamicin is limited to only a few countries. Springtime antibiotic sprays suppress pathogen growth on...
In June 2009, wilted hop bines were observed in a yard in Marion County, OR. The wilt was associated with a stem rot that occurred ∽1 m from the ground near the point where bines are tied together for horticultural purposes. Samples of affected stems were submitted to the Oregon...
Many plant disease epidemic models, and the disease management decision aids developed from them, are created based on temperature or other weather conditions measured in or above the crop canopy at intervals of 15 or 30 min. Disease management decision aids, however, commonly are implemented based on hourly weather measurements...
Background: Little is known about the potential of Brachypodium distachyon as a model for low temperature stress
responses in Pooideae. The ice recrystallization inhibition protein (IRIP) genes, fructosyltransferase (FST) genes, and
many C-repeat binding factor (CBF) genes are Pooideae specific and important in low temperature responses. Here
we used comparative...
Premise of study: Sequence analyses for Pinaceae have suggested that extant genera diverged in the late Mesozoic. While the fossil record indicates that Pinaceae was highly diverse during the Cretaceous, there are few records of living genera. This description of an anatomically preserved seed cone extends the fossil record for...
The Arabidopsis Information Portal (AIP), a resource expected to provide access to all community data and combine outputs into
a single user-friendly interface, has emerged from community discussions over the last 23 months. These discussions began
during two closely linked workshops in early 2010 that established the International Arabidopsis Informatics...
The improvement of the agricultural and wine-making qualities of the grapevine (Vitis vinifera) is hampered by adherence to traditional varieties, the recalcitrance of this plant to genetic modifications, and public resistance to genetically modified organism (GMO) technologies. To address these challenges, we developed an RNA virus-based vector for the introduction...
Background: Through next-generation sequencing, the amount of sequence data potentially available for phylogenetic analyses has increased exponentially in recent years. Simultaneously, the risk of incorporating ‘noisy’ data with misleading phylogenetic signal has also increased, and may disproportionately influence the topology of weakly supported nodes and lineages featuring rapid radiations and/or...
Premise of the study: Bio-ontologies are essential tools for accessing and analyzing the rapidly growing pool of plant genomic and phenomic data. Ontologies provide structured vocabularies to support consistent aggregation of data and a semantic framework for automated analyses and reasoning. They are a key component of the semantic web....
Phytophthora borealis and Phytophthora riparia, identified in recent Phytophthora surveys of forest streams in Oregon, California and Alaska, are described as new species in Phytophthora ITS Glade 6. They are similar in growth form and morphology to P. gonapodyides and are predominately sterile. They present unique DNA sequences, however, and...
Faced with landscapes degraded by fire suppression, logging, and grazing, land managers in the interior western US are attempting to restore habitat structure and function. In southwest Oregon, landscape-scale fuels treatments are being implemented with goals including recreating historic vegetation structure, despite poor understanding of the nature of the landscape...
In RNA-directed silencing pathways, ternary complexes result from small RNA-guided ARGONAUTE (AGO) associating with target transcripts. Target transcripts are often silenced through direct cleavage (slicing), destabilization through slicer-independent turnover mechanisms, and translational repression. Here, wild-type and active-site defective forms of several Arabidopsis thaliana AGO proteins involved in posttranscriptional silencing were...
Downy mildew (caused by Pseudoperonospora humuli) and powdery mildew (caused by Podosphaera macularis) are important diseases of hop in the Pacific Northwest United States, and cultural practices may affect the severity of both diseases. The association of spring pruning quality and timing with severity of downy mildew and powdery mildew...
Fifty-nine stems of Tetrastichia bupatides, numerous frond segments, and roots from Oxroad Bay, Scotland, have recently been analyzed. They reveal that many characters originally used to describe this species exhibit a wider range of variation than previously suspected. These data suggest that ribs of the protostele are most commonly four...
The particulate optical backscattering coefficient (bbₚ) is a
fundamental optical property that allows monitoring of marine suspended
particles both in situ and from space. Backscattering measurements in the
open ocean are still scarce, however, especially in oligotrophic regions.
Consequently, uncertainties remain in bbₚ parameterizations as well as
in satellite estimates...
Sphaerellopsis filum is a mycoparasite of Puccinia graminis subsp. graminicola, a rust fungus that causes widespread crop damage on perennial ryegrass grown for seed. In observations taken over the winter months, S. filum was found naturally colonizing 2% of P. graminis subsp. graminicola uredinia on first-year plantings and 25% of...
This study describes a specimen that extends the oldest fossil evidence of Pinus L. to the Early Cretaceous Wealden Formation of Yorkshire, UK (131-129 million years ago), and prompts a critical reevaluation of criteria that are employed to identify crown group genera of Pinaceae from anatomically preserved seed cones. The...
Two techniques widely recommended for managing Port-Orford-cedar root disease (caused by the introduced pathogen Phytophthora lateralis) are vehicle washing and roadside sanitation. However, their effectiveness has never been tested using a sample-based approach. Vehicle washing effectiveness was evaluated using Port-Orford-cedar seedling baits and a double-washing method. Washing with water can...
The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) shares biological activities with 4-formylaminooxyvinylglycine, a related molecule produced by Pseudomonas fluorescens WH6. We found that culture filtrates of a P.aeruginosa strain overproducing AMB weakly interfered with seed germination of the grassy weed Poa annua and strongly inhibited growth of Erwinia amylovora, the...
Background: Mangroves are ecologically important and highly threatened forest communities. Observational and genetic evidence has confirmed the long distance dispersal capacity of water-dispersed mangrove seeds, but less is known about the relative importance of pollen vs. seed gene flow in connecting populations. We analyzed 980 Avicennia germinans for 11 microsatellite...
Through a phylogenetic study Using LECCYCIA nucleotide sequences and a survey of historical Botanical literature, we propose clarifications in the nomenclature of Lupinus oreganus and Lupinus biddlei. The former taxon has been incorrectly classified as Lupinus sulphurcus ssp. kincaidii and recently as L. oreganus var. kincaidii. The latter has recently...
The genetic basis of the biosynthesis of the germination-arrest factor (GAF) produced by Pseudomonas fluorescens WH6, and previously identified as 4-formylaminooxyvinylglycine, has been investigated here. In addition to inhibiting the germination of a wide range of grassy weeds, GAF exhibits a selective antimicrobial activity against the bacterial plant pathogen Erwinia...
Parmelina quercina is a well-studied foliose macro-lichen found on rocks and trees in the Northern Hemisphere. Recent studies support multiple species within P. quercina based on material from Europe, North America and western Asia. The identities of Parmelina quercina s.lat. reported from eastern Asia and Alaska remain unknown. We compared...
Reconciling rates of organic carbon export from the euphotic zone with the consumption of organic material in the dark ocean remains one of the major quantitative uncertainties of the ocean carbon cycle. Euphotic zone net community production (NCP) provides one broad constraint on export flux and potential carbon drawdown. However,...
The cultivated strawberry is one of the youngest domesticated plants, developed in France in the 1700s from chance hybridization between two western hemisphere octoploid species. However, little is known about the evolution of the species that gave rise to this important fruit crop. Phylogenetic analysis of chloroplast genome sequences of...
• Premise of the study: Colonists of even the most inhospitable environments, lichens are present in all terrestrial ecosystems.
Because of their ecological versatility and ubiquity, they have been considered excellent candidates for early colonizers of terrestrial
environments. Despite such predictions, good preservation potential, and the extant diversity of lichenized...
The soil bacterium Pseudomonas protegens Pf-5 (previously called P. fluorescens Pf-5) produces two siderophores, enantio-pyochelin and a compound in the large and diverse pyoverdine family. Using high-resolution mass spectroscopy, we determined the structure of the pyoverdine produced by Pf-5. In addition to producing its own siderophores, Pf-5 also utilizes ferric...
The Plant Ontology (PO;http://www.plantontology.org/" is a publicly available, collaborative effort to develop and maintain a controlled, structured vocabulary ('ontology') of terms to describe plant anatomy, morphology and the stages of plant development. The goals of the PO are to link (annotate) gene expression and phenotype data to plant structures and...
Field surveys in 2006 confirmed that the
exotic rust fungus Phragmidium violaceum was widespread
on Rubus armeniacus and Rubus laciniatus in
the Pacific Northwest of the USA. The origin and
dispersal pattern of this obligate biotrophic pathogen in
the USA were investigated by comparing the genetic
diversity and structure of...
Tannins are a diverse group of plant-produced, polyphenolic compounds with metal-chelating and antimicrobial properties that are prevalent in many soils. Using transcriptomics, we determined that tannic acid, a form of hydrolysable tannin, broadly affects the expression of genes involved in iron and zinc homeostases, sulfur metabolism, biofilm formation, motility, and...
A perithecial ascomycete, Spataporthe taylori gen. et sp. nov., represented by >70 sporocarps is preserved by
cellular permineralization in marine carbonate concretions dated at the Valanginian-Hauterivian boundary (Early
Cretaceous) from Vancouver Island, British Columbia, Canada. The spheroid perithecia with lumina 330–470 µm
wide and 220–320 µm high are densely distributed...
A framework for understanding the synthesis and catalysis of metabolites and other biochemicals by proteins is crucial for unraveling the physiology of cells. To create such a framework for Zea mays L. subsp. mays (maize), we developed MaizeCyc, a metabolic network of enzyme catalysts, proteins, carbohydrates, lipids, amino acids, secondary...
A fossil seed cone with characters that have been hypothesized as transitional to the origin of crown group gnetophytes has been discovered in Lower Cretaceous deposits on Vancouver Island, British Columbia, Canada. This cone, described as Protoephedrites eamesii gen. et sp. nov., provides the first anatomically preserved fossil evidence for...
A cylindrical permineralized conifer seed cone has been identified from the Officer Member of the Trowbridge Formation, near Izee, in east-central Oregon. The cone is preserved in a Middle Jurassic (Callovian) marine calcium carbonate concretion, associated with araucarian seed cones, conifer twigs and wood, cycad seeds, fern rachides, and lycopodialean...
We investigated habitat attributes related to the occupancy of the globally rare and endangered
epiphytic lichen, Erioderma pedicellatum, in a newly discovered (2009) population center in Denali National
Park and Preserve (DNPP), Alaska. We measured forest, tree and epiphytic lichen community
characteristics on eighty-five systematically selected plots in four study...
Premise of the Study: Hybrid zones provide "natural laboratories" for understanding the processes of selection, reinforcement, and speciation. We sought to gain insight into the degree of introgression and the extent of ecological-phenotypic intermediacy in the natural hybrid strawberry, Fragaria x ananassa subsp. cuneifolia.
Methods: We used whole-plastome sequencing to...
Disease predictive systems are intended to be management aids. With a few exceptions, these systems typically do not have direct sustained use by growers. Rather, their impact is mostly pedagogic and indirect, improving recommendations from farm advisers and shaping management concepts. The degree to which a system is consulted depends...
Premise of research. The lianoid habit is found in 125 extant plant families and is most diverse and abundant in structurally complex forests, such as tropical forests. A stem with lianoid anatomy is described from Cretaceous sediments of Hornby Island, British Columbia.
Methodology. The stem segment, 2.5 cm in diameter...
Pythium species are common soilborne oomycetes that occur in forest nursery soils throughout the United States. Numerous species have been described from nursery soils. However, with the exception of P. aphanidermatum, P irregulare, P. sylvaticum, and P ultimum, little is known about the potential for other Pythium species found in...
Premise of research. A third genus of anatomically preserved conifer seed cones has been recognized from
a Late Jurassic deposit in northeastern Scotland. This cone is described as Bancroftiastrobus digitata Rothwell,
Mapes, Stockey et Hilton.
Methodology. The cone was sectioned with the classic coal ball peel technique and studied and...
Satellite measurements allow global assessments of phytoplankton concentrations and, from observed temporal changes in biomass, direct access to net biomass accumulation rates (r). For the subarctic Atlantic basin, analysis of annual cycles in r reveals that initiation of the annual blooming phase does not occur in spring after stratification surpasses...
Conjugative plasmids are known to facilitate the acquisition and dispersal of genes contributing to the fitness of Pseudomonas spp. Here, we report the characterization of pA506, the 57-kb conjugative plasmid of Pseudomonas fluorescens A506, a plant epiphyte used in the United States for the biological control of fire blight disease...
Spatial variation of available food resources can be difficult to accurately quantify for wide ranging organisms
at landscape scales. Lichens with usnic acid, a yellowish pigment, constitute a large portion of caribou winter
diet across much of their range. We take a new approach of modeling lichen abundances by capitalizing...
Using spatial autocorrelation analysis, we
examined the within-population genetic structure of
Rhizopogon vinicolor and R. vesiculosus, two hypogeous
ectomycorrhizal (EM) species that are sympatric
sister taxa known to differ in their clonal structure.
We collected 121 sporocarps and 482 tuberculate EM
of both species from a 20 ha forest stand...
Photosynthetic production of organic matter by microscopic oceanic phytoplankton fuels ocean ecosystems
and contributes roughly half of the Earth's net primary production. For 13 years, the Sea-viewing Wide
Field-of-view Sensor (SeaWiFS) mission provided the first consistent, synoptic observations of global ocean
ecosystems. Changes in the surface chlorophyll concentration, the primary...
Transcriptome analysis of Pseudomonas fluorescensSBW25 showed that 702 genes were differentially regulated in a gacS::Tn5 mutant, with 300 and 402 genes up- and downregulated respectively. Similar to the Gac regulon of other Pseudomonas species, genes involved in motility, biofilm formation, siderophore biosynthesis and oxidative stress were differentially regulated in the...
To characterize the mechanism through which myosin XI-K attaches to its principal endomembrane cargo, a yeast two-hybrid library of Arabidopsis thaliana cDNAs was screened using the myosin cargo binding domain as bait. This screen identified two previously uncharacterized transmembrane proteins (hereinafter myosin binding proteins or MyoB1/2) that share a myosin...
Raman scattering can be a significant contributor to the emergent radiance spectrum from the surface ocean. Here, we present an analytical approach to directly estimate the Raman contribution to remote sensing reflectance, and evaluate its effects on optical properties estimated from two common semi analytical inversion models. For application of...
Global ocean phytoplankton biomass (C-phyto) and total particulate organic carbon (POC) stocks have largely been characterized from space using passive ocean color measurements. A space-based light detection and ranging (lidar) system can provide valuable complementary observations for C-phyto and POC assessments, with benefits including day-night sampling, observations through absorbing aerosols...
Heterodera avenae is widely distributed in areas where most cereal crops are produced in Algeria. However, the virulence of the Algerian populations of this nematode on individual cereal species and cultivars has not been well documented. The virulence of H. avenae populations from Tiaret and from Oued Smar were tested...
Viruses and/or virus-like selfish elements are associated with all cellular life forms and are the most abundant biological entities on Earth, with the number of virus particles in many environments exceeding the number of cells by one to two orders of magnitude. The genetic diversity of viruses is commensurately enormous...
Submarine volcanic eruptions can result in both real and apparent changes in marine algal communities, e.g., increases in phytoplankton biomass and/or growth rates that can cover thousands of square kilometers. Satellite ocean color monitoring detects these changes as increases in chlorophyll and particulate backscattering. Detailed, high resolution analysis is needed...
Convergent evolution is common throughout the tree of life, but the molecular mechanisms causing similar phenotypes to appear repeatedly are obscure. Yeasts have arisen in multiple fungal clades, but the genetic causes and consequences of their evolutionary origins are unknown. Here we show that the potential to develop yeast forms...
Phytophthora infestans, the cause of the devastating late blight disease of potato and tomato, exhibits a clonal reproductive lifestyle in North America. Phenotypes such as fungicide sensitivity and host preference are conserved among individuals within clonal lineages, while substantial phenotypic differences can exist between lineages. Whole P. infestans genomes were...