190 research outputs found
Is PhoR–PhoP partner fidelity strict? PhoR is required for the activation of the pho regulon in Streptomyces coelicolor
Alternative oxidase gene family in Hypericum perforatum L.: characterization and expression at the post-germinative phase
info:eu-repo/semantics/publishedVersio
Investigation of phase transformations and corrosion resistance in Co/CoCo2O4 nanowires and their potential use as a basis for lithium-ion batteries
The paper is devoted to the study of the effect of thermal annealing on the change in the structural properties and phase composition of metal Co nanostructures, as well as the prospects of their use as anode materials for lithium-ion batteries. During the study, a four-stage phase transition in the structure of nanowires consisting of successive transformations of the structure (Со-FCC/Co-HCP) → (Со-FCС) → (Со-FCC/СоСо2О4) → (СоСо2О4), accompanied by uniform oxidation of the structure of nanowires with an increase in temperature above 400 °C. In this case, an increase in temperature to 700 °C leads to a partial destruction of the oxide layer and surface degradation of nanostructures. During life tests, it was found that the lifetime for oxide nanostructures exceeds 500 charge/discharge cycles, for the initial nanostructures and annealed at a temperature of 300 °С, the lifetimes are 297 and 411 cycles, respectively. The prospects of using Co/CoCo2O4 nanowires as the basis for lithium-ion batteries is shown. © 2019, The Author(s)
Purification and Characterization of a Novel Hypersensitive Response-Inducing Elicitor from Magnaporthe oryzae that Triggers Defense Response in Rice
<div><h3>Background</h3><p><em>Magnaporthe oryzae</em>, the rice blast fungus, might secrete certain proteins related to plant-fungal pathogen interactions.</p> <h3>Methodology/Principal Findings</h3><p>In this study, we report the purification, characterization, and gene cloning of a novel hypersensitive response-inducing protein elicitor (MoHrip1) secreted by <em>M. oryzae</em>. The protein fraction was purified and identified by de novo sequencing, and the sequence matched the genomic sequence of a putative protein from <em>M. oryzae</em> strain 70-15 (GenBank accession No. XP_366602.1). The elicitor-encoding gene <em>mohrip1</em> was isolated; it consisted of a 429 bp cDNA, which encodes a polypeptide of 142 amino acids with a molecular weight of 14.322 kDa and a pI of 4.53. The deduced protein, MoHrip1, was expressed in <em>E. coli</em>. And the expression protein collected from bacterium also forms necrotic lesions in tobacco. MoHrip1 could induce the early events of the defense response, including hydrogen peroxide production, callose deposition, and alkalization of the extracellular medium, in tobacco. Moreover, MoHrip1-treated rice seedlings possessed significantly enhanced systemic resistance to <em>M. oryzae</em> compared to the control seedlings. The real-time PCR results indicated that the expression of some pathogenesis-related genes and genes involved in signal transduction could also be induced by MoHrip1.</p> <h3>Conclusion/Significance</h3><p>The results demonstrate that MoHrip1 triggers defense responses in rice and could be used for controlling rice blast disease.</p> </div
The Ustilago maydis Effector Pep1 Suppresses Plant Immunity by Inhibition of Host Peroxidase Activity
The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1) as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H2O2 strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction
Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.)
[EN] Nerium
oleander
is an
ornamental
species
of high
aesthetic
value,
grown
in arid
and
semi-
arid
regions
because
of its
drought
tolerance,
which
is also
considered
as
relatively
resistant
to salt;
yet
the
biochemical
and
molecular
mechanisms
underlying
oleander¿s
stress
toler-
ance
remain
largely
unknown.
To
investigate
these
mechanisms,
one-year-old
oleander
seedlings
were
exposed
to 15
and
30
days
of treatment
with
increasing
salt
concentratio
ns,
up
to 800
mM
NaCl,
and
to complete
withholding
of irrigation;
growth
parameters
and
bio-
chemical
markers
characteristic
of conserved
stress-response
pathways
were
then
deter-
mined
in stressed
and
control
plants.
Strong
water
deficit
and
salt
stress
both
caused
inhibition
of growth,
degradation
of photosynthetic
pigments,
a slight
(but
statistically
signifi-
cant)
increase
in the
leaf
levels
of specific
osmolytes,
and
induction
of oxidative
stress¿as
indicated
by
the
accumulation
of malondialdehyde
(MDA),
a reliable
oxidative
stress
marker
¿accompanied
by
increases
in the
levels
of total
phenolic
compounds
and
antioxidant
fla-
vonoids
and
in the
specific
activities
of ascorbate
peroxidase
(APX)
and
glutathione
reduc-
tase
(GR).
High
salinity,
in addition,
induced
accumulation
of Na
+
and
Cl
-
in roots
and
leaves
and
the
activation
of superoxide
dismutase
(SOD)
and
catalase
(CAT)
activities.
Apart
from
anatomical
adaptations
that
protect
oleander
from
leaf
dehydration
at moderate
levels
of
stress,
our
results
indicate
that
tolerance
of this
species
to salinity
and
water
deficit
is based
on
the
constitutive
accumulation
in leaves
of high
concentratio
ns
of soluble
carbohydrates
and,
to a lesser
extent,
of glycine
betaine,
and
in the
activation
of the
aforementioned
antiox-
idant
systems.
Moreover,
regarding
specifically
salt
stress,
mechanisms
efficiently
blocking
transport
of toxic
ions
from
the
roots
to the
aerial
parts
of the
plant
appear
to contribute
to a
large
extent
to tolerance
in
Nerium
oleanderThis work was financed by internal funds of the Polytechnic University of Valencia to Monica Boscaiu and Oscar Vicente. Dinesh Kumar’s stay in Valencia was financed by a NAMASTE fellowship from the European Union, and Mohamad Al Hassan was a recipient of an Erasmus Mundus pre-doctoral scholarship financed by the European Commission (Welcome Consortium).Kumar, D.; Al Hassan, M.; Naranjo Olivero, MA.; Agrawal, V.; Boscaiu, M.; Vicente, O. (2017). Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.). PLoS ONE. 12(9). doi:10.1371/journal.pone.0185017Se018501712
An eQTL Analysis of Partial Resistance to Puccinia hordei in Barley
Background - Genetic resistance to barley leaf rust caused by Puccinia hordei involves both R genes and quantitative trait loci. The R genes provide higher but less durable resistance than the quantitative trait loci. Consequently, exploring quantitative or partial resistance has become a favorable alternative for controlling disease. Four quantitative trait loci for partial resistance to leaf rust have been identified in the doubled haploid Steptoe (St)/Morex (Mx) mapping population. Further investigations are required to study the molecular mechanisms underpinning partial resistance and ultimately identify the causal genes.Methodology/Principal Findings - We explored partial resistance to barley leaf rust using a genetical genomics approach. We recorded RNA transcript abundance corresponding to each probe on a 15K Agilent custom barley microarray in seedlings from St and Mx and 144 doubled haploid lines of the St/Mx population. A total of 1154 and 1037 genes were, respectively, identified as being P. hordei-responsive among the St and Mx and differentially expressed between P. hordei-infected St and Mx. Normalized ratios from 72 distant-pair hybridisations were used to map the genetic determinants of variation in transcript abundance by expression quantitative trait locus (eQTL) mapping generating 15685 eQTL from 9557 genes. Correlation analysis identified 128 genes that were correlated with resistance, of which 89 had eQTL co-locating with the phenotypic quantitative trait loci (pQTL). Transcript abundance in the parents and conservation of synteny with rice allowed us to prioritise six genes as candidates for Rphq11, the pQTL of largest effect, and highlight one, a phospholipid hydroperoxide glutathione peroxidase (HvPHGPx) for detailed analysis.Conclusions/Significance - The eQTL approach yielded information that led to the identification of strong candidate genes underlying pQTL for resistance to leaf rust in barley and on the general pathogen response pathway. The dataset will facilitate a systems appraisal of this host-pathogen interaction and, potentially, for other traits measured in this populatio
Pepper pectin methylesterase inhibitor protein CaPMEI1 is required for antifungal activity, basal disease resistance and abiotic stress tolerance
Pectin is one of the main components of the plant cell wall that functions as the primary barrier against pathogens. Among the extracellular pectinolytic enzymes, pectin methylesterase (PME) demethylesterifies pectin, which is secreted into the cell wall in a highly methylesterified form. Here, we isolated and functionally characterized the pepper (Capsicum annuum L.) gene CaPMEI1, which encodes a pectin methylesterase inhibitor protein (PMEI), in pepper leaves infected by Xanthomonascampestris pv. vesicatoria (Xcv). CaPMEI1 transcripts are localized in the xylem of vascular bundles in leaf tissues, and pathogens and abiotic stresses can induce differential expression of this gene. Purified recombinant CaPMEI1 protein not only inhibits PME, but also exhibits antifungal activity against some plant pathogenic fungi. Virus-induced gene silencing of CaPMEI1 in pepper confers enhanced susceptibility to Xcv, accompanied by suppressed expression of some defense-related genes. Transgenic ArabidopsisCaPMEI1-overexpression lines exhibit enhanced resistance to Pseudomonas syringae pv. tomato, mannitol and methyl viologen, but not to the biotrophic pathogen Hyaloperonospora parasitica. Together, these results suggest that CaPMEI1, an antifungal protein, may be involved in basal disease resistance, as well as in drought and oxidative stress tolerance in plants
Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease
Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
ATR-FTIR spectroscopy non-destructively detects damage-induced sour rot infection in whole tomato fruit
Main conclusion
ATR-FTIR spectroscopy with subsequent multivariate analysis non-destructively identifies plant–pathogen interactions during disease progression, both directly and indirectly, through alterations in the spectral fingerprint.
Plant–environment interactions are essential to understanding crop biology, optimizing crop use, and minimizing loss to ensure food security. Damage-induced pathogen infection of delicate fruit crops such as tomato (Solanum lycopersicum) are therefore important processes related to crop biology and modern horticulture. Fruit epidermis as a first barrier at the plant–environment interface, is specifically involved in environmental interactions and often shows substantial structural and functional changes in response to unfavourable conditions. Methods available to investigate such systems in their native form, however, are limited by often required and destructive sample preparation, or scarce amounts of molecular level information. To explore biochemical changes and evaluate diagnostic potential for damage-induced pathogen infection of cherry tomato (cv. Piccolo) both directly and indirectly, mid-infrared (MIR) spectroscopy was applied in combination with exploratory multivariate analysis. ATR-FTIR fingerprint spectra (1800–900 cm−1) of healthy, damaged or sour rot-infected tomato fruit were acquired and distinguished using principal component analysis and linear discriminant analysis (PCA–LDA). Main biochemical constituents of healthy tomato fruit epidermis are characterized while multivariate analysis discriminated subtle biochemical changes distinguishing healthy tomato from damaged, early or late sour rot-infected tomato indirectly based solely on changes in the fruit epidermis. Sour rot causing agent Geotrichum candidum was detected directly in vivo and characterized based on spectral features distinct from tomato fruit. Diagnostic potential for indirect pathogen detection based on tomato fruit skin was evaluated using the linear discriminant classifier (PCA–LDC). Exploratory and diagnostic analysis of ATR-FTIR spectra offers biological insights and detection potential for intact plant–pathogen systems as they are found in horticultural industries
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