Identification and characterization of the fungus Dothiorella sarmentorum on necrotic shoots of declining ash in Slovakia

Abstract Formerly, before the current Hymenoscyphus fraxineus epidemic, symptomatic ash twigs were habitually colonized by fungi occurring occasionally in the early stages of ash diseases. Some of these fungi are endophytes or facultative parasites. The segments of diseased shoots of the studied trees were collected from a seed orchard situated in southwest Slovakia. The frequently isolated fungus Dothiorella sarmentorum was identified microscopically and characterized with the aid of morphological keys. The disease symptoms comprise wood cankers, bud necrosis, and shoot and branch dieback displayed through bleached, necrotic or discoloured canes in infected trees. Despite the Dothiorella species has not yet been recognized to have significant economic consequences, the cumulative effects of various stressful biotic and abiotic factors may induce disorder and decline of ash trees in Slovakia.

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Identification and Characterization of a Well-Defined Series of Coronatine Biosynthetic Mutants of Pseudomonas syringae pv. tomato DC3000

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2004.17.2.162 ◽

2004 ◽

Vol 17 (2) ◽

pp. 162-174 ◽

Cited By ~ 137

Author(s):

David M. Brooks ◽

Gustavo Hernández-Guzmán ◽

Andrew P. Kloek ◽

Francisco Alarcón-Chaidez ◽

Aswathy Sreedharan ◽

...

Keyword(s):

Pseudomonas Syringae ◽

High Performance ◽

Tomato Dc3000 ◽

Disease Symptoms ◽

Coronafacic Acid ◽

Tn5 Mutants ◽

Cor Genes ◽

Identification And Characterization

To identify Pseudomonas syringae pv. tomato genes involved in pathogenesis, we carried out a screen for Tn5 mutants of P. syringae pv. tomato DC3000 with reduced virulence on Arabidopsis thaliana. Several mutants defining both known and novel virulence loci were identified. Six mutants contained insertions in biosynthetic genes for the phytotoxin coronatine (COR). The P. syringae pv. tomato DC3000 COR genes are chromosomally encoded and are arranged in two separate clusters, which encode enzymes responsible for the synthesis of coronafacic acid (CFA) or coronamic acid (CMA), the two defined intermediates in COR biosynthesis. High-performance liquid chromatography fractionation and exogenous feeding studies confirmed that Tn5 insertions in the cfa and cma genes disrupt CFA and CMA biosynthesis, respectively. All six COR biosynthetic mutants were significantly impaired in their ability to multiply to high levels and to elicit disease symptoms on A. thaliana plants. To assess the relative contributions of CFA, CMA, and COR in virulence, we constructed and characterized cfa6 cmaA double mutant strains. These exhibited virulence phenotypes on A. thalliana identical to those observed for the cmaA or cfa6 single mutants, suggesting that reduced virulence of these mutants on A. thaliana is caused by the absence of the intact COR toxin. This is the first study to use biochemically and genetically defined COR mutants to address the role of COR in pathogenesis.

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Identification and Characterization of theErwinia amylovora rpoS Gene: RpoS Is Not Involved in Induction of Fireblight Disease Symptoms

Journal of Bacteriology ◽

10.1128/jb.180.24.6789-6792.1998 ◽

1998 ◽

Vol 180 (24) ◽

pp. 6789-6792 ◽

Cited By ~ 12

Author(s):

M. Anderson ◽

C. E. Pollitt ◽

I. S. Roberts ◽

J. A. Eastgate

Keyword(s):

Sigma Factor ◽

Erwinia Amylovora ◽

Environmental Stresses ◽

Alternative Sigma Factor ◽

Gene Encoding ◽

Disease Symptoms ◽

Highly Sensitive ◽

Identification And Characterization ◽

Sigma Factor Rpos

ABSTRACT The Erwinia amylovora rpoS gene, encoding the alternative sigma factor RpoS, has been cloned and characterized. Though highly sensitive to a number of environmental stresses, anE. amylovora rpoS mutant was not compromised in its ability to grow or cause disease symptoms within apple seedlings or in an overwintering model.

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Identification and Characterization of Bacterial Agents Causing Moderate Damage and Souring of the Fig Fruits

Journal of Plant Studies ◽

10.5539/jps.v10n1p40 ◽

2021 ◽

Vol 10 (1) ◽

pp. 40

Author(s):

Seyedeh Asiyeh Mousavi ◽

Nader Hasanzadeh

Keyword(s):

Pathogenic Bacteria ◽

Fruit Rot ◽

Phenotypic Traits ◽

Rrna Gene ◽

Pseudomonas Fragi ◽

Disease Symptoms ◽

Bacillus Paralicheniformis ◽

Fig Trees ◽

Identification And Characterization

In order to determine the factors of decay and sourness of fig fruits, in the summer of 2016-17, 60 leaf, fruit and stem samples from different regions of Tehran, Varamin (Qal'e No), Mazandaran (Amol, Noor and Sari), Lorestan from Iran and a branch of fig fruit sample from Italy were collected. We obtained 30 isolates from the sample. The pathogenicity of 30 isolates were confirmed by artificially inoculation using fig fruits. They were also characterized based on key phenotypic traits. All 30 isolates showed hypersensitivity reaction to tobacco, pelargonium and did not show pathogenicity to potato tubers. 16S rRNA gene of the 10 representative isolates were sequenced. Ten isolates were identified as Stenotrophomonas maltophilia, Pseudomonas aeruginosa, Pseudomonas fulva, Brevibacterium linens, Pseudomonas fragi, Bacillus licheniformis, Bacillus paralicheniformis and Bacillus cereus based on the determined sequences. None of the isolates caused fruit rot but typical disease symptoms were observed on fig leaves and fruits. This is the first report of the presence of pathogenic bacteria on fig trees in Iran.

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Genome-wide identification, phylogeny, and expression analysis of the SBP-box gene family in Euphorbiaceae

BMC Genomics ◽

10.1186/s12864-019-6319-4 ◽

2019 ◽

Vol 20 (S9) ◽

Cited By ~ 3

Author(s):

Jing Li ◽

Xiaoyang Gao ◽

Shiye Sang ◽

Changning Liu

Keyword(s):

Growth Form ◽

Expression Profiles ◽

Abiotic Factors ◽

Physicochemical Characteristics ◽

Genome Wide ◽

Ancient Times ◽

Response Expression ◽

Identification And Characterization ◽

Intensity Expression

Abstract Background Euphorbiaceae is one of the largest families of flowering plants. Due to its exceptional growth form diversity and near-cosmopolitan distribution, it has attracted much interest since ancient times. SBP-box (SBP) genes encode plant-specific transcription factors that play critical roles in numerous biological processes, especially flower development. We performed genome-wide identification and characterization of SBP genes from four economically important Euphorbiaceae species. Results In total, 77 SBP genes were identified in four Euphorbiaceae genomes. The SBP proteins were divided into three length ranges and 10 groups. Group-6 was absent in Arabidopsis thaliana but conserved in Euphorbiaceae. Segmental duplication played the most important role in the expansion processes of Euphorbiaceae SBP genes, and all the duplicated genes were subjected to purify selection. In addition, about two-thirds of the Euphorbiaceae SBP genes are potential targets of miR156, and some miR-regulated SBP genes exhibited high intensity expression and differential expression in different tissues. The expression profiles related to different stress treatments demonstrated broad involvement of Euphorbiaceae SBP genes in response to various abiotic factors and hormonal treatments. Conclusions In this study, 77 SBP genes were identified in four Euphorbiaceae species, and their phylogenetic relationships, protein physicochemical characteristics, duplication, tissue and stress response expression, and potential roles in Euphorbiaceae development were studied. This study lays a foundation for further studies of Euphorbiaceae SBP genes, providing valuable information for future functional exploration of Euphorbiaceae SBP genes.

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Advances in the Detection of Emerging Tree Diseases by Measurements of VOCs and HSPs Gene Expression, Application to Ash Dieback Caused by Hymenoscyphus fraxineus

Pathogens ◽

10.3390/pathogens10111359 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1359

Author(s):

Piotr Borowik ◽

Tomasz Oszako ◽

Tadeusz Malewski ◽

Zuzanna Zwierzyńska ◽

Leszek Adamowicz ◽

...

Keyword(s):

Electronic Nose ◽

Root Rot ◽

Natural Infection ◽

Root Systems ◽

Ash Dieback ◽

Disease Symptoms ◽

Tree Diseases ◽

Hymenoscyphus Fraxineus ◽

Ash Trees ◽

Armillaria Gallica

Ash shoot dieback has now spread throughout Europe. It is caused by an interaction between fungi that attack shoots (Hymenoscyphus fraxineus) and roots (Armillaria spp., in our case Armillaria gallica). While detection of the pathogen is relatively easy when disease symptoms are present, it is virtually impossible when the infestation is latent. Such situations occur in nurseries when seedlings become infected (the spores are carried by the wind several dozen miles). The diseases are masked by pesticides, fertilisers, and adequate irrigation to protect the plants. Root rot that develops in the soil is also difficult to detect. Currently, there is a lack of equipment that can detect root rot pathogens without digging up root systems, which risks damaging trees. For this reason, the use of an electronic nose to detect pathogens in infected tissue of ash trees grown in pots and inoculated with the above fungi was attempted. Disease symptoms were detected in all ash trees exposed to natural infection (via spores) in the forest. The electronic nose was able to detect the pathogens (compared to the control). Detection of the pathogens in seedlings will enable foresters to remove diseased trees and prevent the path from nursery to forest plantations by such selection.

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