scholarly journals In-depth evaluation of root infection systems with the vascular fungus Verticillium longisporum as soil-borne model pathogen

2020 ◽  
Author(s):  
Christian Fröschel
Keyword(s):  
Host Responses ◽  
Root Infection ◽  
Root Pathogen ◽  
Verticillium Longisporum ◽  
Indole Glucosinolates ◽  
Advantages And Disadvantages ◽  
Pathogenicity Tests ◽  
Microbe Interactions ◽  
Indole Glucosinolate ◽  
Defence Strategies

ABSTRACTPREMISEWhile leaves are far more accessible for analysing plant defences, roots are hidden in the soil leading to difficulties in studying soil-borne interactions. Literature describes inoculation strategies to infect model plants with model root pathogens, but it remains demanding to obtain a methodological overview. To address this challenge, this study uses the model root pathogen Verticillium longisporum on Arabidopsis thaliana and provides recommendations based on evident examples for the selection and management of suitable infection systems to investigate root-microbe interactions.METHODS AND RESULTSA novel root infection system is introduced, while two existing ones are precisely described and optimized. Advantages and disadvantages of each are assessed, step-by-step protocols are presented and accompanied by pathogenicity tests, transcriptional analyses of indole-glucosinolate markers and independent confirmations using reporter constructs. The results validate the importance of indole-glucosinolates as secondary metabolites limiting V. longisporum propagation in hosts.DISCUSSIONWe provide detailed guidelines for studying host responses and defence strategies against V. longisporum. Furthermore, other soil-borne microorganisms or other model plants, such as economically important oilseed rape, can be used in the infection systems described. Hence, these proven manuals help to find a root infection system for your specific research questions to decipher root-microbe interactions.

scholarly journals In-depth evaluation of root infection systems using the vascular fungus Verticillium longisporum as soil-borne model pathogen

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Christian Fröschel
Keyword(s):  
Marker Genes ◽  
Root Infection ◽  
Root Pathogen ◽  
Verticillium Longisporum ◽  
Indole Glucosinolates ◽  
Advantages And Disadvantages ◽  
Root Pathogens ◽  
Pathogenicity Tests ◽  
Microbe Interactions ◽  
Defence Strategies

Abstract Background While leaves are far more accessible for analysing plant defences, roots are hidden in the soil, leading to difficulties in studying soil-borne interactions. Inoculation strategies for infecting model plants with model root pathogens are described in the literature, but it remains demanding to obtain a methodological overview. To address this challenge, this study uses the model root pathogen Verticillium longisporum on Arabidopsis thaliana host plants and provides recommendations for selecting appropriate infection systems to investigate how plants cope with root pathogens. Results A novel root infection system is introduced, while two existing ones are precisely described and optimized. Step-by-step protocols are presented and accompanied by pathogenicity tests, transcriptional analyses of indole-glucosinolate marker genes and independent confirmations using reporter constructs. Advantages and disadvantages of each infection system are assessed. Overall, the results validate the importance of indole-glucosinolates as secondary metabolites that limit the Verticillium propagation in its host plant. Conclusion Detailed assistances on studying host defence strategies and responses against V. longisporum is provided. Furthermore, other soil-borne microorganisms (e.g., V. dahliae) or model plants, such as economically important oilseed rape and tomato, can be introduced in the infection systems described. Hence, these proven manuals can support finding a root infection system for your specific research questions to further decipher root-microbe interactions.

Animal models of human pneumonia

2008 ◽  
Vol 294 (3) ◽  
pp. L387-L398 ◽  
Author(s):  
Joseph P. Mizgerd ◽  
Shawn J. Skerrett
Keyword(s):  
Public Health ◽  
Animal Models ◽  
Lung Infection ◽  
Host Responses ◽  
Murine Models ◽  
Biological Mechanisms ◽  
Advantages And Disadvantages ◽  
Microbe Interactions ◽  
Translational Studies ◽  
Similarities And Differences

Pneumonia is a medical and public health priority, and advances against this disease will require improved knowledge of biological mechanisms. Human pneumonia is modeled with experimental infections of animals, most frequently mice. Mouse models are leading to important discoveries relevant to pneumonia, but their limitations must be carefully considered. Several approaches to establishing pneumonia in mice have been developed, and each has specific strengths and weaknesses. Similarly, procedures for characterizing microbial and host responses to infection have unique advantages and disadvantages. Mice are not small humans, and the applicability of results from murine models to human disease depends on understanding the similarities and differences between species. Additional considerations such as mouse strain, microbe strain, and prior mouse-microbe interactions also influence the design and interpretation of experiments. Results from studies of pneumonia in animals, combined with complementary basic and translational studies, are elucidating mechanisms responsible for susceptibility to and pathophysiology of lung infection.

scholarly journals A Cell Atlas of Microbe-Responsive Processes in the Zebrafish Intestine

2020 ◽  
Author(s):  
Reegan J. Willms ◽  
Jennifer C. Hocking ◽  
Edan Foley
Keyword(s):  
Transcriptional Activity ◽  
Cell Types ◽  
Cellular Heterogeneity ◽  
Host Responses ◽  
Cellular Specificity ◽  
Direct Growth ◽  
A Cell ◽  
Microbe Interactions ◽  
Regulatory Effects ◽  
Host Microbe Interactions

ABSTRACTGut microbial products direct growth, differentiation and development in the animal host. Disruptions to host-microbe interactions have profound health consequences, that include onset of chronic inflammatory illnesses. However, we lack system-wide understanding of cell-specific responses to the microbiome. We profiled transcriptional activity in individual cells from the intestine, and associated tissue, of zebrafish larvae that we raised in the presence, or absence, of a microbiome. We uncovered extensive cellular heterogeneity in the conventional zebrafish intestinal epithelium, including previously undescribed cell types with known mammalian homologs. By comparing conventional to germ-free profiles, we mapped microbial impacts on transcriptional activity in each cell population. We revealed intricate degrees of cellular specificity in host responses to the microbiome, that included regulatory effects on patterning, metabolic and immune activity. For example, we showed that removal of microbes hindered transduction of vascular endothelial growth factor-dependent signals in the developing vasculature, resulting in impaired intestinal vascularization. Our work provides a high-resolution atlas of intestinal cellular composition in the developing fish gut and details the effects of the microbiome on each cell type.

Interaction between Glomus fasciculatum and Sclerotium rolfsii in peanut

1983 ◽  
Vol 61 (9) ◽  
pp. 2349-2351 ◽  
Author(s):  
K. R. Krishna ◽  
D. J. Bagyaraj
Keyword(s):  
Mycorrhizal Fungus ◽  
Sclerotium Rolfsii ◽  
Glomus Fasciculatum ◽  
Root Infection ◽  
Culture Experiment ◽  
Root Pathogen ◽  
Simultaneous Addition ◽  
Severity Of Disease ◽  
P Content ◽  
Pot Culture

The interaction between the mycorrhizal fungus Glomus fasciculatum and the root pathogen Sclerotium rolfsii was studied in a pot culture experiment. The mycorrhizal fungus reduced the number of sclerotia produced by the pathogen and the pathogen reduced the percentage root infection and chlamydospore production by the mycorrhizal fungus. Root and shoot dry weights of the host and their P content was highest in plants inoculated with mycorrhiza only and lowest in plants inoculated with the pathogen only. Simultaneous addition of mycorrhizal inoculum and the pathogen reduced the severity of disease.

GLUCOSINOLATE CONTENT OF DEVELOPING RAPESEED (Brassica napus L. ’Midas’) SEEDLINGS

1988 ◽  
Vol 68 (2) ◽  
pp. 367-380 ◽  
Author(s):  
D. I. McGREGOR
Keyword(s):  
Brassica Napus ◽  
Seedling Development ◽  
Glucosinolate Content ◽  
Brassica Napus L ◽  
Indole Glucosinolates ◽  
Indole Glucosinolate ◽  
The Individual ◽  
Different Parts

The content of aliphatic, aromatic and indole glucosinolates were measured in the roots, hypocotyl, cotyledons and leaves of the high glucosinolate Brassica napus cultivar Midas over the first 10–14 d after seeding. For seedlings grown in light from emergence, glucosinolate content declined slightly then increased. Increase in the indole glucosinolate content of the shoot (hypocotyl and cotyledons) was caused by an increase in 3-indolylmethyl glucosinolate. When seedlings were confined to darkness for either 6 or 10 d after seeding, 3-indolylmethyl glucosinolate did not increase. The content of 4-hydroxy-3-indolylmethyl the dominant glucosinolate in the seed, declined in both light and dark grown seedlings. The individual glucosinolates in different parts of the seedling appeared to vary independently and to be related to development of specific organs or tissues. The complexity and relative rapidity with which amounts of the individual glucosinolates changed suggests the existence of an intricate metabolic control.Key words: Rapeseed, Brassica napus L., Cruciferae, glucosinolate, seedling development

scholarly journals Comparative evaluation of the genomes of common bacterial members of the Drosophila intestinal community

2016 ◽  
Author(s):  
Kristina Petkau ◽  
David Fast ◽  
Aashna Duggal ◽  
Edan Foley
Keyword(s):  
Immune Responses ◽  
Intestinal Bacteria ◽  
Lactobacillus Brevis ◽  
Host Responses ◽  
Gene Products ◽  
Starting Point ◽  
Microbe Interactions ◽  
Microbial Products ◽  
Host Microbe Interactions ◽  
Alternative Sources

Drosophila melanogaster is an excellent model to explore the molecular exchanges that occur between an animal intestine and their microbial passengers. For example, groundbreaking studies in flies uncovered a sophisticated web of host responses to intestinal bacteria. The outcomes of these responses define critical events in the host, such as the establishment of immune responses, access to nutrients, and the rate of larval development. Despite our steady march towards illuminating the host machinery that responds to bacterial presence in the gut, we know remarkably little about the microbial products that influence bacterial association with a fly host. To address this deficiency, we sequenced and characterized the genomes of three common Drosophila-associated microbes: Lactobacillus plantarum, Lactobacillus brevis and Acetobacter pasteurianus. In each case, we compared the genomes of Drosophila-associated strains to the genomes of strains isolated from alternative sources. This approach allowed us to identify molecular functions common to Drosophila-associated microbes, and, in the case of A. pasteurianus, to identify genes that are essential for association with the host. Of note, many of the gene products unique to fly-associated strains have established roles in the stabilization of host-microbe interactions. We believe that these data provide a valuable starting point for a more thorough examination of the microbial perspective on host-microbe relationships.

scholarly journals Multiple indole glucosinolates and myrosinases defend Arabidopsis against Tetranychus urticae herbivory

2021 ◽  
Author(s):  
Emilie Widemann ◽  
Kristie Bruinsma ◽  
Brendan Walshe-Roussel ◽  
Repon Kumer Saha ◽  
David Letwin ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Tetranychus Urticae ◽  
Metabolic Pathways ◽  
Spider Mite ◽  
Generalist Herbivore ◽  
Defense Compounds ◽  
Indole Glucosinolates ◽  
Indole Glucosinolate ◽  
Two Spotted Spider Mite

ABSTRACTArabidopsis defenses against herbivores are regulated by the jasmonate hormonal signaling pathway, which leads to the production of a plethora of defense compounds, including tryptophan-derived metabolites produced through CYP79B2/CYP79B3. Jasmonate signaling and CYP79B2/CYP79B3 limit Arabidopsis infestation by the generalist herbivore two-spotted spider mite, Tetranychus urticae. However, the phytochemicals responsible for Arabidopsis protection against T. urticae are unknown. Here, using Arabidopsis mutants that disrupt metabolic pathways downstream of CYP79B2/CYP79B3, and synthetic indole glucosinolates, we identified phytochemicals involved in the defense against T. urticae. We show that Trp-derived metabolites depending on CYP71A12 and CYP71A13 are not affecting mite herbivory. Instead, the supplementation of cyp79b2 cyp79b3 mutant leaves with the 3-indolylmethyl glucosinolate and its derived metabolites demonstrated that the indole glucosinolate pathway is sufficient to assure CYP79B2/CYP79B3-mediated defenses against T. urticae. We demonstrate that three indole glucosinolates can limit T. urticae herbivory, but that they have to be processed by the myrosinases to hinder T. urticae oviposition. Finally, the supplementation of the mutant myc2 myc3 myc4 with indole glucosinolates indicated that the transcription factors MYC2/MYC3/MYC4 induce additional indole glucosinolate-independent defenses that control T. urticae herbivory. Together, these results reveal the complexity of Arabidopsis defenses against T. urticae that rely on multiple indole glucosinolates, specific myrosinases, and additional MYC2/MYC3/MYC4-dependent defenses.One sentence summaryThree indole glucosinolates and the myrosinases TGG1/TGG2 help protect Arabidopsis thaliana against the herbivory of the two-spotted spider mite Tetranychus urticae.

Artificial inoculation with Armillaria ostoyae in established conifers stressed by defoliation, planting, and thinning in Newfoundland

2000 ◽  
Vol 30 (11) ◽  
pp. 1758-1765 ◽  
Author(s):  
M D Piercey-Normore ◽  
J A Bérubé
Keyword(s):  
Black Spruce ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Root Infection ◽  
Armillaria Ostoyae ◽  
Significant Difference ◽  
Balsam Woolly Adelgid ◽  
Pathogenicity Tests ◽  
Mill Stand ◽  
Hemlock Looper

Armillaria ostoyae (Romagnesi) Herink causes root disease in conifers of the northern hemisphere. Pathogenicity tests of established conifer trees with A. ostoyae, has never been done in the boreal forest. Seven forest plots were selected in Newfoundland; a black spruce (Picea mariana (Mill.) BSP) plantation, a naturally regenerated black spruce stand, a balsam fir (Abies balsamea (L.) Mill.) stand with hemlock looper (Lambdina fiscellaria (Guen.)) defoliation, two balsam woolly adelgid (Adelges piceae (Ratz.)) infested balsam fir stands (thinned and unthinned sites), a balsam fir sawfly (Neodiprion abietis Harris) defoliated balsam fir stand, and an artificially defoliated black spruce stand. Roots of fir and spruce trees were inoculated with two isolates of A. ostoyae and re-examined after 2 years. The purpose of this study was to compare differences in root infection within plots for different types of host stress to examine the response of trees to controlled inoculations of A. ostoyae. There was a statistically significant difference in number of infected roots between the two isolates used as inoculum. There was significantly more root response with severity of infection within all sites except both adelgid plots. A marginally significant relationship between tree health and root infection was present in the balsam fir sawfly plot. There was a significantly larger number of infected roots associated with rhizomorphs in the naturally regenerated black spruce stand and the artificially defoliated balsam fir stand. These results suggest that stress prediposes the host tree to root infection by A. ostoyae.

scholarly journals A model symbiosis reveals a role for sheathed-flagellum rotation in the release of immunogenic lipopolysaccharide

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Caitlin A Brennan ◽  
Jason R Hunt ◽  
Natacha Kremer ◽  
Benjamin C Krasity ◽  
Michael A Apicella ◽  
...  
Keyword(s):  
Immune Responses ◽  
Unknown Function ◽  
Vibrio Fischeri ◽  
Host Responses ◽  
Tissue Tropism ◽  
Human Pathogens ◽  
Bacterial Flagella ◽  
Host Immune Responses ◽  
Microbe Interactions ◽  
Host Microbe Interactions

Bacterial flagella mediate host–microbe interactions through tissue tropism during colonization, as well as by activating immune responses. The flagellar shaft of some bacteria, including several human pathogens, is encased in a membranous sheath of unknown function. While it has been hypothesized that the sheath may allow these bacteria to evade host responses to the immunogenic flagellin subunit, this unusual structural feature has remained an enigma. Here we demonstrate that the rotation of the sheathed flagellum in both the mutualist Vibrio fischeri and the pathogen Vibrio cholerae promotes release of a potent bacteria-derived immunogen, lipopolysaccharide, found in the flagellar sheath. We further present a new role for the flagellar sheath in triggering, rather than circumventing, host immune responses in the model squid-vibrio symbiosis. Such an observation not only has implications for the study of bacterial pathogens with sheathed flagella, but also raises important biophysical questions of sheathed-flagellum function.

GLUCOSINOLATE PROFILES IN THE SEED, ROOT AND LEAF TISSUE OF CABBAGE, MUSTARD, RAPESEED, RADISH AND SWEDE

1984 ◽  
Vol 64 (1) ◽  
pp. 77-93 ◽  
Author(s):  
J. P. SANG ◽  
I. R. MINCHINTON ◽  
P. K. JOHNSTONE ◽  
R. J. W. TRUSCOTT
Keyword(s):  
Raphanus Sativus ◽  
High Performance ◽  
Leaf Tissue ◽  
Distribution Patterns ◽  
Gas Chromatography Mass Spectrometry ◽  
Plant Tissues ◽  
Indole Glucosinolates ◽  
Indole Glucosinolate ◽  
Low Levels ◽  
Cruciferous Plants

Due to the limitations of previous methods for glucosinolate analysis, only fragmentary information has been available on glucosinolate profiles in plant tissues. Using a newly developed high performance liquid chromatography (HPLC) procedure for the separation of desulphoglucosinolates formed by enzymic desulphation of endogenous glucosinolates, the glucosinolate contents in the seed, root and leaf of five cruciferous plants (cabbage, mustard, radish, rapeseed and swede) have been investigated. Identities of peaks in the HPLC chromatograms were confirmed by gas chromatography/mass spectrometry. Major differences between the seed, leaf and root profiles in the same plant were obtained for all five species investigated. Particular attention was directed to the indole glucosinolates, including the recently discovered compounds, 4-hydroxy-3-indolylmethyl glucosinolate and 4-methoxy-3-indolymethyl glucosinolate, for which analytical methods have been previously lacking. These indole glucosinolates were found to have defined distribution patterns: 4-methoxyl-3-indolymethyl glucosinolate and 1-methoxy-3-indolylmethyl glucosinolate were absent in seed material whereas 4-hydroxy-3-indolylmethyl glucosinolate was found in highest concentrations in this tissue. 3-Indolylmethyl glucosinolate was found in low levels in seed but was the dominant indole glucosinolate in the leaf. The possible implications of these findings are discussed. Keywords: Indole glucosinolates, Brassica napus, B. juncea, B. oleracea, B. napobrassica, Raphanus sativus, Cruciferae

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