scholarly journals Endophytic Actinobacteria Induce Defense Pathways in Arabidopsis thaliana

2008 ◽  
Vol 21 (2) ◽  
pp. 208-218 ◽  
Author(s):  
V. M. Conn ◽  
A. R. Walker ◽  
C. M. M. Franco
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Salicylic Acid ◽  
Systemic Acquired Resistance ◽  
Quantitative Polymerase Chain Reaction ◽  
In Planta ◽  
Defense Gene Expression ◽  
Streptomyces Sp ◽  
Endophytic Actinobacteria

Endophytic actinobacteria, isolated from healthy wheat tissue, which are capable of suppressing a number wheat fungal pathogens both in vitro and in planta, were investigated for the ability to activate key genes in the systemic acquired resistance (SAR) or the jasmonate/ethylene (JA/ET) pathways in Arabidopsis thaliana. Inoculation of A. thaliana (Col-0) with selected endophytic strains induced a low level of SAR and JA/ET gene expression, measured using quantitative polymerase chain reaction. Upon pathogen challenge, endophyte-treated plants demonstrated a higher abundance of defense gene expression compared with the non-endophyte-treated controls. Resistance to the bacterial pathogen Erwinia carotovora subsp. carotovora required the JA/ET pathway. On the other hand, resistance to the fungal pathogen Fusarium oxysporum involved primarily the SAR pathway. The endophytic actinobacteria appear to be able to “prime” both the SAR and JA/ET pathways, upregulating genes in either pathway depending on the infecting pathogen. Culture filtrates of the endophytic actinobacteria were investigated for the ability to also activate defense pathways. The culture filtrate of Micromonospora sp. strain EN43 grown in a minimal medium resulted in the induction of the SAR pathway; however, when grown in a complex medium, the JA/ET pathway was activated. Further analysis using Streptomyces sp. strain EN27 and defense-compromised mutants of A. thaliana indicated that resistance to E. carotovora subsp. carotovora occurred via an NPR1-independent pathway and required salicylic acid whereas the JA/ET signaling molecules were not essential. In contrast, resistance to F. oxysporum mediated by Streptomyces sp. strain EN27 occurred via an NPR1-dependent pathway but also required salicylic acid and was JA/ET independent.

scholarly journals The Arabidopsis mediator complex subunit 8 regulates oxidative stress responses

2021 ◽  
Author(s):  
Huaming He ◽  
Jordi Denecker ◽  
Katrien Van Der Kelen ◽  
Patrick Willems ◽  
Robin Pottie ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Stress Responses ◽  
Negative Regulator ◽  
Mediator Complex ◽  
Defense Gene Expression ◽  
A Genome ◽  
Oxidative Stress Responses

Abstract Signaling events triggered by hydrogen peroxide (H2O2) regulate plant growth and defense by orchestrating a genome-wide transcriptional reprogramming. However, the specific mechanisms that govern H2O2-dependent gene expression are still poorly understood. Here, we identify the Arabidopsis Mediator complex subunit MED8 as a regulator of H2O2 responses. The introduction of the med8 mutation in a constitutive oxidative stress genetic background (catalase-deficient, cat2) was associated with enhanced activation of the salicylic acid pathway and accelerated cell death. Interestingly, med8 seedlings were more tolerant to oxidative stress generated by the herbicide methyl viologen (MV) and exhibited transcriptional hyperactivation of defense signaling, in particular salicylic acid- and jasmonic acid-related pathways. The med8-triggered tolerance to MV was manipulated by the introduction of secondary mutations in salicylic acid and jasmonic acid pathways. In addition, analysis of the Mediator interactome revealed interactions with components involved in mRNA processing and microRNA biogenesis, hence expanding the role of Mediator beyond transcription. Notably, MED8 interacted with the transcriptional regulator NEGATIVE ON TATA-LESS, NOT2, to control the expression of H2O2-inducible genes and stress responses. Our work establishes MED8 as a component regulating oxidative stress responses and demonstrates that it acts as a negative regulator of H2O2-driven activation of defense gene expression.

scholarly journals Does Bromelain-Cisplatin Combination Afford In-Vitro Synergistic Anticancer Effects on Human Prostatic Carcinoma Cell Line, PC3?

2020 ◽  
Vol 9 ◽  
pp. 1749
Author(s):  
Fatemeh Amini Chermahini ◽  
Elham Raeisi ◽  
Mathias Hossain Aazami ◽  
Abbas Mirzaei ◽  
Esfandiar Heidarian ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Viability ◽  
Cell Line ◽  
Colony Formation ◽  
Prostatic Carcinoma ◽  
Carcinoma Cell ◽  
Quantitative Polymerase Chain Reaction ◽  
Chemotherapeutic Agents ◽  
Carcinoma Cell Line

Background: Bromelain enhances anticancer impacts to chemotherapeutic agents. The question as to whether bromelain does promote in-vitro cytotoxic and proapoptotic effects of cisplatin on human prostatic carcinoma PC3 cell line was investigated. Materials and Methods: PC3 (human prostatic carcinoma) cells were treated either single or in combination with bromelain and/or cisplatin. MTT, clonogenic assay, flow cytometry and real-time quantitative polymerase chain reaction were used to investigate cell viability, colony formation, proapoptotic potential and p53 gene expression, respectively. Results: Cisplatin (IC10) combined with bromelain (IC40) significantly affected PC3 cell viability, inhibited colony formation, as well increased p53 proapoptotic gene expression compared to cisplatin single treatment. Nevertheless, bromelain-cisplatin chemoherbal combination did not display any additive proapoptotic effect compared to single treatments. Conclusion: Bromelain-cisplatin chemoherbal combination demonstrated synergistic in-vitro anticancer effect on human prostatic carcinoma cell line, PC3, that drastically reduced required cisplatin dose. [GMJ.2020;9:e1749]

scholarly journals Characterization of the early response of Arabidopsis thaliana to Dickeya dadantii infection using expression profiling

2018 ◽  
Author(s):  
Frédérique Van Gijsegem ◽  
Frédérique Bitton ◽  
Anne-Laure Laborie ◽  
Yvan Kraepiel ◽  
Jacques Pédron
Keyword(s):  
Arabidopsis Thaliana ◽  
Early Stage ◽  
Plant Defence ◽  
Plant Responses ◽  
Type I ◽  
In Planta ◽  
Secretion Systems ◽  
Dickeya Dadantii ◽  
A Genome

AbstractTo draw a global view of plant responses to interactions with the phytopathogenic enterobacterale Dickeya dadantii, a causal agent of soft rot diseases on many plant species, we analysed the early Arabidopsis responses to D. dadantii infection. We performed a genome-wide analysis of the Arabidopsis thaliana transcriptome during D. dadantii infection and conducted a genetic study of identified responses.A limited set of genes related to plant defence or interactions with the environment were induced at an early stage of infection, with an over-representation of genes involved in both the metabolism of indole glucosinolates (IGs) and the jasmonate (JA) defence pathway. Bacterial type I and type II secretion systems are required to trigger the induction of IG and JA-related genes while the type III secretion system appears to partially inhibit these defence pathways. Using Arabidopsis mutants impaired in JA biosynthesis or perception, we showed that induction of some IG metabolism genes was COI1-dependent but, surprisingly, JA-independent. Moreover, characterisation of D. dadantii disease progression in Arabidopsis mutants impaired in JA or IG pathways showed that JA triggers an efficient plant defence response that does not involve IGs.The induction of the IG pathway by bacterial pathogens has been reported several times in vitro. This study shows for the first time, that this induction does indeed occur in planta, but also that this line of defence is ineffective against D. dadantii infection, in contrast to its role to counteract herbivorous or fungal pathogen attacks.

scholarly journals Biochemical characteristics of AtFAR2, a fatty acid reductase from Arabidopsis thaliana that reduces fatty acyl-CoA and -ACP substrates into fatty alcohols

2016 ◽  
Vol 63 (3) ◽  
Author(s):  
Thuy T. P. Doan ◽  
Anders S. Carlsson ◽  
Sten Stymne ◽  
Per Hofvander
Keyword(s):  
Arabidopsis Thaliana ◽  
Fatty Acid ◽  
Fatty Acyl ◽  
Fatty Alcohols ◽  
Abnormal Development ◽  
In Planta ◽  
Alcohol Production ◽  
Genes Encoding ◽  
In Vitro Data

Fatty alcohols and derivatives are important for proper deposition of a functional pollen wall. Mutations in specific genes encoding fatty acid reductases (FAR) responsible for fatty alcohol production cause abnormal development of pollen. A disrupted AtFAR2 (MS2) gene in Arabidopsis thaliana results in pollen developing an abnormal exine layer and a reduced fertility phenotype. AtFAR2 has been shown to be targeted to chloroplasts and in a purified form to be specific for acyl-ACP substrates. Here, we present data on the in vitro and in planta characterizations of AtFAR2 from A. thaliana and show that this enzyme has the ability to use both, C16:0-ACP and C16:0-CoA, as substrates to produce C16:0-alcohol. Our results further show that AtFAR2 is highly similar in properties and substrate specificity to AtFAR6 for which in vitro data has been published, and which is also a chloroplast localized enzyme. This suggests that although AtFAR2 is the major enzyme responsible for exine layer functionality, AtFAR6 might provide functional redundancy to AtFAR2.

Expression of ERG11 and efflux pump genes CDR1, CDR2 and SNQ2 in voriconazole susceptible and resistant Candida glabrata strains

2019 ◽  
Vol 58 (1) ◽  
pp. 30-38
Author(s):  
Patricia Navarro-Rodríguez ◽  
Adela Martin-Vicente ◽  
Loida López-Fernández ◽  
Josep Guarro ◽  
Javier Capilla
Keyword(s):  
Gene Expression ◽  
Candida Glabrata ◽  
Efflux Pump ◽  
Expression Profiles ◽  
Quantitative Polymerase Chain Reaction ◽  
Clear Correlation ◽  
Synonymous Mutations ◽  
First Time

AbstractCandida glabrata causes difficult to treat invasive candidiasis due to its antifungal resistance, mainly to azoles. The aim of the present work was to study the role of the genes ERG11, CDR1, CDR2, and SNQ2 on the resistance to voriconazole (VRC) in a set of C. glabrata strains with known in vitro and in vivo susceptibility to this drug. Eighteen clinical isolates of C. glabrata were exposed in vitro to VRC, and the expression of the cited genes was quantified by real time quantitative polymerase chain reaction (q-PCR). In addition, the ERG11 gene was amplified and sequenced to detect possible mutations. Ten synonymous mutations were found in 15 strains, two of them being reported for the first time; however, no amino acid changes were detected. ERG11 and CDR1 were the most expressed genes in all the strains tested, while the expression of CDR2 and SNQ2 was modest. Our results show that gene expression does not directly correlate with the VRC MIC. In addition, the expression profiles of ERG11 and efflux pump genes did not change consistently after exposure to VRC. Although individual analysis did not result in a clear correlation between MIC and gene expression, we did observe an increase in ERG11 and CDR1 expression in resistant strains. It is of interest that considering both in vitro and in vivo results, the slight increase in such gene expression correlates with the observed resistance to VRC.

scholarly journals Gene Involved in Transcriptional Activation of the hrp Regulatory Gene hrpG in Xanthomonas oryzae pv. oryzae

2006 ◽  
Vol 188 (11) ◽  
pp. 4158-4162 ◽  
Author(s):  
Seiji Tsuge ◽  
Takeshi Nakayama ◽  
Shinsaku Terashima ◽  
Hirokazu Ochiai ◽  
Ayako Furutani ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plant Pathogen ◽  
Transcriptional Activation ◽  
Regulatory Gene ◽  
Xanthomonas Oryzae ◽  
In Planta

ABSTRACT A novel regulatory gene, trh, which is involved in hrp gene expression, is identified in the plant pathogen Xanthomonas oryzae pv. oryzae. In the trh mutant, expression of HrpG, which is a key regulator for hrp gene expression, is reduced both under the in vitro hrp-inducing condition and in planta.

Interaction of Arabidopsis TGA3 and WRKY53 transcription factors on Cestrum yellow leaf curling virus (CmYLCV) promoter mediates salicylic acid-dependent gene expression in planta

Planta ◽  
2017 ◽  
Vol 247 (1) ◽  
pp. 181-199 ◽  
Author(s):  
Shayan Sarkar ◽  
Abhimanyu Das ◽  
Prashant Khandagale ◽  
Indu B. Maiti ◽  
Sudip Chattopadhyay ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salicylic Acid ◽  
Transcription Factors ◽  
Yellow Leaf ◽  
In Planta ◽  
Leaf Curling

scholarly journals LPIAT, a lyso-Phosphatidylinositol Acyltransferase, Modulates Seed Germination in Arabidopsis thaliana through PIP Signalling Pathways and is Involved in Hyperosmotic Response

2020 ◽  
Vol 21 (5) ◽  
pp. 1654
Author(s):  
Denis Coulon ◽  
Lionel Faure ◽  
Magali Grison ◽  
Stéphanie Pascal ◽  
Valérie Wattelet-Boyer ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Seed Germination ◽  
Lipid Synthesis ◽  
Strong Increase ◽  
In Planta ◽  
Acyltransferase Activity ◽  
Chain Acyl ◽  
Phosphatidylinositol Phosphates ◽  
Mature Seeds

Lyso-lipid acyltransferases are enzymes involved in various processes such as lipid synthesis and remodelling. Here, we characterized the activity of an acyltransferase from Arabidopsis thaliana (LPIAT). In vitro, this protein, expressed in Escherichia coli membrane, displayed a 2-lyso-phosphatidylinositol acyltransferase activity with a specificity towards saturated long chain acyl CoAs (C16:0- and C18:0-CoAs), allowing the remodelling of phosphatidylinositol. In planta, LPIAT gene was expressed in mature seeds and very transiently during seed imbibition, mostly in aleurone-like layer cells. Whereas the disruption of this gene did not alter the lipid composition of seed, its overexpression in leaves promoted a strong increase in the phosphatidylinositol phosphates (PIP) level without affecting the PIP2 content. The spatial and temporal narrow expression of this gene as well as the modification of PIP metabolism led us to investigate its role in the control of seed germination. Seeds from the lpiat mutant germinated faster and were less sensitive to abscisic acid (ABA) than wild-type or overexpressing lines. We also showed that the protective effect of ABA on young seedlings against dryness was reduced for lpiat line. In addition, germination of lpiat mutant seeds was more sensitive to hyperosmotic stress. All these results suggest a link between phosphoinositides and ABA signalling in the control of seed germination

scholarly journals Signaling Crosstalk between Salicylic Acid and Ethylene/Jasmonate in Plant Defense: Do We Understand What They Are Whispering?

2019 ◽  
Vol 20 (3) ◽  
pp. 671 ◽  
Author(s):  
Ning Li ◽  
Xiao Han ◽  
Dan Feng ◽  
Deyi Yuan ◽  
Li-Jun Huang
Keyword(s):  
Salicylic Acid ◽  
Signaling Pathways ◽  
Pseudomonas Syringae ◽  
Defense Response ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Defense Responses ◽  
Host Cells ◽  
Defense Gene Expression ◽  
Signaling Crosstalk

During their lifetime, plants encounter numerous biotic and abiotic stresses with diverse modes of attack. Phytohormones, including salicylic acid (SA), ethylene (ET), jasmonate (JA), abscisic acid (ABA), auxin (AUX), brassinosteroid (BR), gibberellic acid (GA), cytokinin (CK) and the recently identified strigolactones (SLs), orchestrate effective defense responses by activating defense gene expression. Genetic analysis of the model plant Arabidopsis thaliana has advanced our understanding of the function of these hormones. The SA- and ET/JA-mediated signaling pathways were thought to be the backbone of plant immune responses against biotic invaders, whereas ABA, auxin, BR, GA, CK and SL were considered to be involved in the plant immune response through modulating the SA-ET/JA signaling pathways. In general, the SA-mediated defense response plays a central role in local and systemic-acquired resistance (SAR) against biotrophic pathogens, such as Pseudomonas syringae, which colonize between the host cells by producing nutrient-absorbing structures while keeping the host alive. The ET/JA-mediated response contributes to the defense against necrotrophic pathogens, such as Botrytis cinerea, which invade and kill hosts to extract their nutrients. Increasing evidence indicates that the SA- and ET/JA-mediated defense response pathways are mutually antagonistic.

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