scholarly journals Characterization of an antimicrobial and phytotoxic ribonuclease secreted by the fungal wheat pathogen Zymoseptoria tritici

2017 ◽  
Vol 217 (1) ◽  
pp. 320-331 ◽  
Author(s):  
Graeme J. Kettles ◽  
Carlos Bayon ◽  
Caroline A. Sparks ◽  
Gail Canning ◽  
Kostya Kanyuka ◽  
...  
Keyword(s):  
Zymoseptoria Tritici

scholarly journals Spatially-explicit modeling improves empirical characterization of dispersal: theory and a case study

2019 ◽  
Author(s):  
Petteri Karisto ◽  
Frédéric Suffert ◽  
Alexey Mikaberidze
Keyword(s):  
Empirical Studies ◽  
Dispersal Kernel ◽  
Spatially Explicit ◽  
Zymoseptoria Tritici ◽  
Rain Splash ◽  
Spatially Explicit Modeling ◽  
Dispersal Kernels ◽  
Source Geometry

AbstractDispersal is a key ecological process. An individual dispersal event has a source and a destination, both are well localized in space and can be seen as points. A probability to move from a source point to a destination point can be described by a dispersal kernel. However, when we measure dispersal, the source of dispersing individuals is usually an area, which distorts the shape of the dispersal gradient compared to the dispersal kernel. Here, we show theoretically how different source geometries affect the gradient shape depending on the type of the kernel. We present an approach for estimating dispersal kernels from measurements of dispersal gradients independently of the source geometry. Further, we use the approach to achieve the first field measurement of dispersal kernel of an important fungal pathogen of wheat, Zymoseptoria tritici. Rain-splash dispersed asexual spores of the pathogen spread on a scale of one meter. Our results demonstrate how analysis of dispersal data can be improved to achieve more rigorous measures of dispersal. Our findings enable a direct comparison between outcomes of different experiments, which will allow to acquire more knowledge from a large number of previous empirical studies of dispersal.

Characterization of Effector–Target Interactions in Necrotrophic Pathosystems Reveals Trends and Variation in Host Manipulation

2021 ◽  
Vol 59 (1) ◽  
Author(s):  
Timothy L. Friesen ◽  
Justin D. Faris
Keyword(s):  
Current Model ◽  
Annual Review ◽  
Publication Date ◽  
Zymoseptoria Tritici ◽  
Effective Response ◽  
Pyrenophora Tritici Repentis ◽  
Effector Triggered Immunity ◽  
Parastagonospora Nodorum ◽  
Made In

Great strides have been made in defining the details of the plant defense response involving biotrophic fungal and bacterial pathogens. The groundwork for the current model was laid by H.H. Flor and others who defined the gene-for-gene hypothesis, which is now known to involve effector-triggered immunity (ETI). PAMP-triggered immunity (PTI) is also a highly effective response to most pathogens because of the recognition of common pathogen molecules by pattern recognition receptors. In this article, we consider the three pathogens that make up the foliar disease complex of wheat, Zymoseptoria tritici, Pyrenophora tritici-repentis, and Parastagonospora nodorum, to review the means by which necrotrophic pathogens circumvent, or outright hijack, the ETI and PTI pathways to cause disease. Expected final online publication date for the Annual Review of Phytopathology, Volume 59 is August 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Characterization of Zymoseptoria tritici populations in Belarus by morphologic and cultural features

2021 ◽  
Vol 104 (4) ◽  
pp. 223-225
Author(s):  
N. A. Krupenko* ◽  
I. N. Odintsova
Keyword(s):  
Phenotypic Diversity ◽  
Southern Population ◽  
Zymoseptoria Tritici ◽  
Northern Population ◽  
Septoria Leaf Blotch ◽  
Leaf Blotch ◽  
The North ◽  
Shannon’S Index ◽  
Cultural Features

Septoria leaf blotch caused by Zymoseptoria tritici is one of the most harmful diseases in Belarus. Isolates of the pathogen were obtained from northern, central and southern populations: in 2018–2019, whichvaried significantly among in the structure of colonies. The rate of fungal isolates forming yeast-like colonies decreased from 55.0 % in the North of Belarus to 6.7 % in the South, whereas incidence of filamentous isolates increased from 31.3 % to 80.0 %, respectively. In the northern population, phenotypic diversity was high, while in the southern population it was the lowest (Shannon’s index was 1.53 and 1.14, respectively).

scholarly journals A dispensable paralog of succinate dehydrogenase subunit C mediates standing resistance towards a subclass of SDHI fungicides inZymoseptoria tritici

2019 ◽  
Author(s):  
Diana Steinhauer ◽  
Marie Salat ◽  
Regula Frey ◽  
Andreas Mosbach ◽  
Torsten Luksch ◽  
...  
Keyword(s):  
Succinate Dehydrogenase ◽  
Rational Design ◽  
Population Genomics ◽  
Computational Modelling ◽  
Differential Sensitivity ◽  
Strong Impact ◽  
Zymoseptoria Tritici ◽  
C Subunit ◽  
Succinate Dehydrogenase Inhibitor

AbstractSuccinate dehydrogenase inhibitor (SDHI) fungicides are widely used for the control of a broad range of fungal diseases. This has been the most rapidly expanding fungicide group in terms of new molecules discovered and introduced for agricultural use over the past fifteen years. A particular pattern of differential sensitivity (resistance) to a subclass of chemically-related SDHIs (SHA-SDHIs) was observed in naïveZymoseptoria triticipopulations. Class specific SHA-SDHI resistance was confirmed at the enzyme level but did not correlate with the genotypes of the succinate dehydrogenase (SDH) encoding genes. Mapping and characterization of the genetic factor responsible for standing SHA-SDHI resistance in natural field isolates identified a gene (alt-SDHC) encoding a paralog of the C subunit of succinate dehydrogenase. This paralog was not present within our sensitive reference isolates and found at variable frequencies withinZ. triticipopulations. Using reverse genetics, we showed that alt-SDHC associates with the three other SDH subunits leading to a fully functional enzyme and that a unique Qp-site residue within the alt-SDHC protein confers SHA-SDHI resistance. Enzymatic assays, computational modelling and docking simulations for the two types of SQR enzymes (alt-SDHC, SDHC) enabled us to describe protein-inhibitor interactions at an atomistic level and to propose rational explanations for differential potency and resistance across SHA-SDHIs. EuropeanZ. triticipopulations displayed a presence (20-30%) / absence polymorphism ofalt-SDHC, as well as differences inalt-SDHCexpression levels and splicing efficiency. These polymorphisms have a strong impact on SHA-SDHI resistance phenotypes. Characterization of thealt-SDHCpromoter in EuropeanZ. triticipopulations suggest that transposon insertions are associated with the strongest resistance phenotypes. These results establish that a dispensable paralogous gene determines SHA-SDHIs fungicide resistance in natural populations ofZ. tritici. This study paves the way to an increased awareness of the role of fungicidal target paralogs in resistance to fungicides and demonstrates the paramount importance of population genomics in fungicide discovery.Author SummaryZymoseptoria triticiis the causal agent of Septoria tritici leaf blotch (STB) of wheat, the most devastating disease for cereal production in Europe. Multiple succinate dehydrogenase inhibitor (SDHI) fungicides have been developed and introduced for the control of STB. We report the discovery and detailed characterization of a paralog of the C subunit of the SDH enzyme conferring standing resistance towards a particular chemical subclass of the SDHIs. The resistance gene is characterized by its presence/absence, expression and splicing polymorphisms which in turn affect resistance levels. The identified mechanism influenced the chemical optimization phase which led to the discovery of pydiflumetofen, exemplifying the importance of population genomics for discovery and rational design of the most adapted solutions.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 144-145
Author(s):  
B. H. Kear ◽  
J. M. Oblak
Keyword(s):  
Stable Phase ◽  
Nickel Base Superalloy ◽  
Alloy 718 ◽  
Commercial Alloy ◽  
Precipitate Morphology ◽  
Continuous Precipitation ◽  
Nickel Base ◽  
Base Superalloy ◽  
Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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