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.

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 Analysis of the Oxidative Burst and Its Relevant Signaling Pathways in Leptosphaeria maculans—Brassica napus Pathosystem

2021 ◽  
Vol 22 (9) ◽  
pp. 4812
Author(s):  
Cunchun Yang ◽  
W. G. Dilantha Fernando
Keyword(s):  
Cell Death ◽  
Signaling Pathways ◽  
Oxidative Burst ◽  
Defense Mechanisms ◽  
Leptosphaeria Maculans ◽  
Gene Interaction ◽  
Early Response ◽  
Marker Genes ◽  
Ros Accumulation ◽  
Microbe Interactions

An oxidative burst is an early response of plants to various biotic/abiotic stresses. In plant-microbe interactions, the plant body can induce oxidative burst to activate various defense mechanisms to combat phytopathogens. A localized oxidative burst is also one of the typical behaviors during hypersensitive response (HR) caused by gene-for-gene interaction. In this study, the occurrence of oxidative burst and its signaling pathways was studied from different levels of disease severity (i.e., susceptible, intermediate, and resistant) in the B. napus–L. maculans pathosystem. Canola cotyledons with distinct levels of resistance exhibited differential regulation of the genes involved in reactive oxygen species (ROS) accumulation and responses. Histochemical assays were carried out to understand the patterns of H2O2 accumulation and cell death. Intermediate and resistant genotypes exhibited earlier accumulation of H2O2 and emergence of cell death around the inoculation origins. The observations also suggested that the cotyledons with stronger resistance were able to form a protective region of intensive oxidative bursts between the areas with and without hyphal intrusions to block further fungal advancement to the uninfected regions. The qPCR analysis suggested that different onset patterns of some marker genes in ROS accumulation/programmed cell death (PCD) such as RBOHD, MPK3 were associated with distinct levels of resistance from B. napus cultivars against L. maculans. The observations and datasets from this article indicated the distinct differences in ROS-related cellular behaviors and signaling between compatible and incompatible interactions.

scholarly journals The Root-Knot Nematode Calreticulin Mi-CRT Is a Key Effector in Plant Defense Suppression

2013 ◽  
Vol 26 (1) ◽  
pp. 97-105 ◽  
Author(s):  
M. Jaouannet ◽  
M. Magliano ◽  
M. J. Arguel ◽  
M. Gourgues ◽  
E. Evangelisti ◽  
...  
Keyword(s):  
Parasitic Infection ◽  
Marker Genes ◽  
Compatible Interaction ◽  
Host Defenses ◽  
Wild Type ◽  
Root Knot Nematode ◽  
Callose Deposition ◽  
Root Pathogen ◽  
Molecular Pattern ◽  
Pathogen Associated Molecular Pattern

Root-knot nematodes (RKN) are obligate biotrophic parasites that settle close to the vascular tissues in roots, where they induce the differentiation of specialized feeding cells and maintain a compatible interaction for 3 to 8 weeks. Transcriptome analyses of the plant response to parasitic infection have shown that plant defenses are strictly controlled during the interaction. This suggests that, similar to other pathogens, RKN secrete effectors that suppress host defenses. We show here that Mi-CRT, a calreticulin (CRT) secreted by the nematode into the apoplasm of infected tissues, plays an important role in infection success, because Mi-CRT knockdown by RNA interference affected the ability of the nematodes to infect plants. Stably transformed Arabidopsis thaliana plants producing the secreted form of Mi-CRT were more susceptible to nematode infection than wild-type plants. They were also more susceptible to infection with another root pathogen, the oomycete Phytophthora parasitica. Mi-CRT overexpression in A. thaliana suppressed the induction of defense marker genes and callose deposition after treatment with the pathogen-associated molecular pattern elf18. Our results show that Mi-CRT secreted in the apoplasm by the nematode has a role in the suppression of plant basal defenses during the interaction.

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.

scholarly journals Advances and complications of regenerative medicine in diabetes therapy

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9746
Author(s):  
Olga Brovkina ◽  
Erdem Dashinimaev
Keyword(s):  
Stem Cells ◽  
Regenerative Medicine ◽  
Beta Cells ◽  
Rapid Development ◽  
Embryonic Stem ◽  
Direct Conversion ◽  
Marker Genes ◽  
Diabetes Therapy ◽  
Advantages And Disadvantages ◽  
Regeneration Medicine

The rapid development of technologies in regenerative medicine indicates clearly that their common application is not a matter of if, but of when. However, the regeneration of beta-cells for diabetes patients remains a complex challenge due to the plurality of related problems. Indeed, the generation of beta-cells masses expressing marker genes is only a first step, with maintaining permanent insulin secretion, their protection from the immune system and avoiding pathological modifications in the genome being the necessary next developments. The prospects of regenerative medicine in diabetes therapy were promoted by the emergence of promising results with embryonic stem cells (ESCs). Their pluripotency and proliferation in an undifferentiated state during culture have ensured the success of ESCs in regenerative medicine. The discovery of induced pluripotent stem cells (iPSCs) derived from the patients’ own mesenchymal cells has provided further hope for diabetes treatment. Nonetheless, the use of stem cells has significant limitations related to the pluripotent stage, such as the risk of development of teratomas. Thus, the direct conversion of mature cells into beta-cells could address this issue. Recent studies have shown the possibility of such transdifferentiation and have set trends for regeneration medicine, directed at minimizing genome modifications and invasive procedures. In this review, we will discuss the published results of beta-cell regeneration and the advantages and disadvantages illustrated by these experiments.

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 The Use of Defined Microbial Communities To Model Host-Microbe Interactions in the Human Gut

2019 ◽  
Vol 83 (2) ◽  
Author(s):  
Janneke Elzinga ◽  
John van der Oost ◽  
Willem M. de Vos ◽  
Hauke Smidt
Keyword(s):  
Gut Microbiota ◽  
Microbial Communities ◽  
Well Being ◽  
Human Gut ◽  
Human Host ◽  
Advantages And Disadvantages ◽  
Human Gut Microbiota ◽  
Microbe Interactions ◽  
Host Microbe Interactions

SUMMARYThe human intestinal ecosystem is characterized by a complex interplay between different microorganisms and the host. The high variation within the human population further complicates the quest toward an adequate understanding of this complex system that is so relevant to human health and well-being. To study host-microbe interactions, defined synthetic bacterial communities have been introduced in gnotobiotic animals or in sophisticatedin vitrocell models. This review reinforces that our limited understanding has often hampered the appropriate design of defined communities that represent the human gut microbiota. On top of this, some communities have been applied toin vivomodels that differ appreciably from the human host. In this review, the advantages and disadvantages of using defined microbial communities are outlined, and suggestions for future improvement of host-microbe interaction models are provided. With respect to the host, technological advances, such as the development of a gut-on-a-chip system and intestinal organoids, may contribute to more-accuratein vitromodels of the human host. With respect to the microbiota, due to the increasing availability of representative cultured isolates and their genomic sequences, our understanding and controllability of the human gut “core microbiota” are likely to increase. Taken together, these advancements could further unravel the molecular mechanisms underlying the human gut microbiota superorganism. Such a gain of insight would provide a solid basis for the improvement of pre-, pro-, and synbiotics as well as the development of new therapeutic microbes.

Fungi associated with root and hypocotyl diseases of seedling lupins in Western Australia

1989 ◽  
Vol 40 (4) ◽  
pp. 781 ◽  
Author(s):  
MW Sweetingham
Keyword(s):  
Field Experiment ◽  
Western Australia ◽  
Root Rot ◽  
Fusarium Spp ◽  
Pythium Irregulare ◽  
Root Pathogen ◽  
Isolation Frequency ◽  
South West ◽  
Pot Experiments ◽  
Pathogenicity Tests

Pleiochaeta setosa, Pythium irregulare, Fusarium spp. and Rhizoctonia spp. were frequently isolated from root lesions on lupin seedlings growing at 18 locations in the temperate south-west of Western Australia. P. setosa was isolated from all 13 sites where lupins had previously been grown (average isolation frequency 90%) but from none of the 5 sites with no lupin history. P. setosa was pathogenic in pot experiments using colonized millet or conidia as inoculum. Certain isolates of P. irregulare and Rhizoctonia spp. were pathogenic, but all Fusarium isolates appeared very weak or non-pathogenic. In a fungicide drench field experiment Rovral� reduced the isolation of P, setosa from roots by 97% and reduced root rot by 42%, providing complementary evidence for the importance of P. setosa as a root pathogen in Western Australia.Rhizoctonia solani was isolated from characteristic reddish-brown hypocotyl lesions and reproduced these symptoms in pathogenicity tests.

scholarly journals Host Specificity and Sensitivity of Established and Novel Sewage-Associated Marker Genes in Human and Nonhuman Fecal Samples

2019 ◽  
Vol 85 (14) ◽  
Author(s):  
Warish Ahmed ◽  
Pradip Gyawali ◽  
Shuchen Feng ◽  
Sandra L. McLellan
Keyword(s):  
Host Specificity ◽  
Fecal Contamination ◽  
The United States ◽  
Human Polyomavirus ◽  
Marker Genes ◽  
Human Feces ◽  
Fecal Samples ◽  
Advantages And Disadvantages ◽  
Specificity And Sensitivity ◽  
Sewage Contamination

ABSTRACT Microbial source tracking (MST) methods measure fecal contamination levels and identify possible sources using quantitative PCR (qPCR) that targets host-associated fecal microorganisms. To date, most established MST assays for human sources, especially bacterial markers, have shown some nonhuman host cross-reactions. Recently developed assays, such as the crAssphage CPQ_056, Lachnospiraceae Lachno3, and Bacteroides BacV6-21, have more limited information on host sensitivity and host specificity for human or sewage sources, particularly in countries other than the United States. In this study, we rigorously evaluated six sewage-associated MST assays (i.e., Bacteroides HF183, human adenovirus [HAdV], human polyomavirus [HPyV], crAssphage CPQ_056, Lachno3, and BacV6-21) to show advantages and disadvantages of their applications for MST. A total of 29 human and 3 sewage samples and 360 nonhuman fecal samples across 14 hosts collected from a subtropical region of Australia were tested for marker host specificity, host sensitivity, and concentrations. All sewage samples were positive for all six marker genes tested in this study. Bacterial markers were more prevalent than viral markers in human feces. Testing against animal hosts showed human feces (or sewage)-associated marker gene specificity was HAdV (1.00) > HPyV (0.99) > crAssphage CPQ_056 (0.98) > HF183 (0.96) > Lachno3 (0.95) > BacV6-21 (0.90), with marker concentrations in some animal fecal samples being 3 to 5 orders of magnitude lower than those in sewage. When considering host specificity, sensitivity, and concentrations in source samples, the HF183, Lachno3, and crAssphage CPQ_056 tests were the most suitable assays in this study for sewage contamination tracking in subtropical waters of Australia. IMPORTANCE Large financial investments are required to remediate fecal contamination sources in waterways, and accurate results from field studies are crucial to build confidence in MST approaches. Host specificity and sensitivity are two main performance characteristics for consideration when choosing MST assays. Ongoing efforts for marker assay validation will improve interpretation of results and could shed light on patterns of occurrence in nontarget hosts that might explain the underlying drivers of cross-reaction of certain markers. For field applications, caution should be taken to choose appropriate MST marker genes and assays based on available host specificity and sensitivity data and background knowledge of the contaminating sources in the study area. Since many waterborne pathogens are viruses, employing both viral and bacterial markers in investigations could provide insight into contamination dynamics and ecological behavior in the environment. Therefore, combined usage of marker assays is recommended for more accurate and informative sewage contamination detection and fecal source resolution.

scholarly journals The Three Lineages of the Diploid Hybrid Verticillium longisporum Differ in Virulence and Pathogenicity

2015 ◽  
Vol 105 (5) ◽  
pp. 662-673 ◽  
Author(s):  
Fluturë Novakazi ◽  
Patrik Inderbitzin ◽  
German Sandoya ◽  
Ryan J. Hayes ◽  
Andreas von Tiedemann ◽  
...  
Keyword(s):  
Host Range ◽  
Oilseed Rape ◽  
Parental Species ◽  
Diploid Hybrid ◽  
Potential Host ◽  
Verticillium Longisporum ◽  
Hybridization Event ◽  
The World ◽  
Pathogenicity Tests ◽  
Different Parts

Verticillium longisporum is an economically important vascular pathogen of Brassicaceae crops in different parts of the world. V. longisporum is a diploid hybrid that consists of three different lineages, each of which originated from a separate hybridization event between two different sets of parental species. We used 20 isolates representing the three V. longisporum lineages and the relative V. dahliae, and performed pathogenicity tests on 11 different hosts, including artichoke, cabbage, cauliflower, cotton, eggplant, horseradish, lettuce, linseed, oilseed rape (canola), tomato, and watermelon. V. longisporum was overall more virulent on the Brassicaceae crops than V. dahliae, which was more virulent than V. longisporum across the non-Brassicaceae crops. There were differences in virulence between the three V. longisporum lineages. V. longisporum lineage A1/D1 was the most virulent lineage on oilseed rape, and V. longisporum lineage A1/D2 was the most virulent lineage on cabbage and horseradish. We also found that on the non-Brassicaceae hosts eggplant, tomato, lettuce, and watermelon, V. longisporum was more or equally virulent than V. dahliae. This suggests that V. longisporum may have a wider potential host range than currently appreciated.

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