scholarly journals The MicroRNA miR773 Is Involved in the Arabidopsis Immune Response to Fungal Pathogens

2018 ◽  
Vol 31 (2) ◽  
pp. 249-259 ◽  
Author(s):  
Raquel Salvador-Guirao ◽  
Patricia Baldrich ◽  
Detlef Weigel ◽  
Ignacio Rubio-Somoza ◽  
Blanca San Segundo
Keyword(s):  
Fungal Pathogens ◽  
Adaptive Responses ◽  
Defense Gene Expression ◽  
Pathogen Infection ◽  
Defense Gene ◽  
Biotic Stresses ◽  
Molecular Pattern ◽  
Pathogen Challenge ◽  
Wide Range ◽  
Resistance To Infection

MicroRNAs (miRNAs) are 21- to 24-nucleotide short noncoding RNAs that trigger gene silencing in eukaryotes. In plants, miRNAs play a crucial role in a wide range of developmental processes and adaptive responses to abiotic and biotic stresses. In this work, we investigated the role of miR773 in modulating resistance to infection by fungal pathogens in Arabidopsis thaliana. Interference with miR773 activity by target mimics (in MIM773 plants) and concomitant upregulation of the miR773 target gene METHYLTRANSFERASE 2 (MET2) increased resistance to infection by necrotrophic (Plectosphaerrella cucumerina) and hemibiotrophic (Fusarium oxysporum, Colletototrichum higginianum) fungal pathogens. By contrast, both MIR773 overexpression and MET2 silencing enhanced susceptibility to pathogen infection. Upon pathogen challenge, MIM773 plants accumulated higher levels of callose and reactive oxygen species than wild-type plants. Stronger induction of defense-gene expression was also observed in MIM773 plants in response to fungal infection. Expression analysis revealed an important reduction in miR773 accumulation in rosette leaves of plants upon elicitor perception and pathogen infection. Taken together, our results show not only that miR773 mediates pathogen-associated molecular pattern-triggered immunity but also demonstrate that suppression of miR773 activity is an effective approach to improve disease resistance in Arabidopsis plants.

scholarly journals Phosphate-induced resistance to pathogen infection in Arabidopsis

2021 ◽  
Author(s):  
Beatriz Val Torregrosa ◽  
Mireia Bundo ◽  
Hector Martin Cardoso ◽  
Marcel Bach Pages ◽  
Tzyy Jen Chiou ◽  
...  
Keyword(s):  
Immune Responses ◽  
Fungal Pathogens ◽  
Oxygen Species ◽  
Loss Of Function ◽  
Wild Type ◽  
Pathogen Infection ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
Resistance To Infection ◽  
Hormonal Signalling

In nature, plants are concurrently exposed to a number of abiotic and biotic stresses. Our understanding of convergence points between responses to combined biotic/abiotic stress pathways remains, however, rudimentary. Here we show that MIR399 overexpression, loss-of-function of PHO2 (PHOSPHATE2), or treatment with high Pi, is accompanied by an increase in phosphate (Pi) content and accumulation of reactive oxygen species (ROS) in Arabidopsis thaliana. High Pi plants (e.g. miR399 overexpressor, pho2 mutant, and plants grown under high Pi supply) exhibited resistance to infection by necrotrophic and hemibiotrophic fungal pathogens. In the absence of pathogen infection, the expression level of genes in the salicylic acid (SA)- and jasmonic acid (JA)-dependent signaling pathways was higher in high Pi plants compared to wild type plants, which is consistent with increased levels of SA and JA in non-infected high Pi plants. During infection, an opposite regulation in the two branches of the JA pathway (ERF1/PDF1.2 and MYC2/VSP2) occurs in high Pi plants. Thus, while the ERF1-PDF1 branch positively responds to fungal infection, the MYC2/VSP2 branch is negatively regulated during pathogen infection in high Pi plants. This study supports that Pi accumulation promotes resistance to infection by fungal pathogens in Arabidopsis, while providing a basis to better understand crosstalk between Pi signaling and hormonal signalling pathways for modulation of plant immune responses.

scholarly journals NITROGEN LIMITATION ADAPTATION functions as a negative regulator of Arabidopsis immunity

2021 ◽  
Author(s):  
Beatriz Val Torregrosa ◽  
Mireia Bundo ◽  
Tzyy Jen Chiou ◽  
Victor Flors ◽  
Blanca San Segundo
Keyword(s):  
Immune Responses ◽  
Transcriptional Activation ◽  
Fungal Pathogens ◽  
Nitrogen Limitation ◽  
Negative Regulator ◽  
Loss Of Function ◽  
Wild Type ◽  
Pathogen Infection ◽  
Fungal Elicitors ◽  
Resistance To Infection

Background: Phosphorus is an important macronutrient required for plant growth and development. It is absorbed through the roots in the form of inorganic phosphate (Pi). To cope with Pi limitation, plants have evolved an array of adaptive mechanisms to facilitate Pi acquisition and protect them from stress caused by Pi starvation. The NITROGEN LIMITATION ADAPTION (NLA) gene plays a key role in the regulation of phosphate starvation responses (PSR), its expression being regulated by the microRNA miR827. Stress caused by Pi limiting conditions might also affect the plant response to pathogen infection. However, cross-talk between phosphate signaling pathways and immune responses remains unclear. Results: In this study, we investigated whether NLA plays a role in Arabidopsis immunity. We show that loss-of-function of NLA and MIR827 overexpression causes an increase in phosphate (Pi) content which results in resistance to infection by the fungal pathogen Plectosphaerella cucumerina. The nla mutant plants accumulated callose in their leaves, a response that is also observed in wild-type plants that have been treated with high Pi. We also show that pathogen infection and treatment with fungal elicitors is accompanied by transcriptional activation of MIR827 and down-regulation of NLA. Upon pathogen challenge, nla plants exhibited higher levels of the phytoalexin camalexin compared to wild type plants. Camalexin level also increases in wild type plants treated with high Pi. Furthermore, the nla mutant plants accumulated salicylic acid (SA) and jasmonic acid (JA) in the absence of pathogen infection whose levels further increased upon pathogen. Conclusions: This study shows that NLA acts as a negative regulator of Arabidopsis immunity. Overaccumulation of Pi in nla plants positively affects resistance to infection by fungal pathogens. This piece of information reinforces the idea of signaling convergence between Pi and immune responses for the regulation of disease resistance in Arabidopsis.

scholarly journals ARCHIPELAGO: A Dedicated Resource for Exploiting Past, Present, and Future Genomic Data on Disease Resistance Regulation in Rice

2008 ◽  
Vol 21 (7) ◽  
pp. 869-878 ◽  
Author(s):  
E. Vergne ◽  
E. Ballini ◽  
G. Droc ◽  
D. Tharreau ◽  
J.-L. Nottéghem ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Genome Structure ◽  
Defense Genes ◽  
Defense Gene Expression ◽  
Specific Expression ◽  
Defense Gene ◽  
Biotic Stresses ◽  
Qtl Cloning ◽  
Pathogenesis Related ◽  
Micro Level

Large amounts of expression data dealing with biotic stresses in rice have been produced in the past 5 years. Here, we extensively review approximately 70 publications and gather together information on more than 2,500 genes of the rice defense arsenal. This information was integrated into the OryGenesDB database. Several genes (e.g., metallothioneins and PBZ1) appear to be hallmarks of rice–pathogen interactions. Cross-referencing this information with the rice kinome highlighted some defense genes and kinases as possible central nodes of regulation. Cross referencing defense gene expression and quantitative trait loci (QTL) information identified some candidate genes for QTL. Overall, pathogenesis-related genes and disease regulators were found to be statistically associated with disease QTL. At the genomic level, we observed that some regions are richer than others and that some chromosomes (e.g., 11 and 12), which contain a lot of resistance gene analogs, have a low content of defense genes. Finally, we show that classical defense genes and defense-related genes such as resistance genes are preferentially organized in clusters. These clusters are not always coregulated and individual paralogs can show specific expression patterns. Thus, the rice defense arsenal has an ARCHIPELAGO-like genome structure at the macro and micro level. This resource opens new possibilities for marker-assisted selection and QTL cloning.

scholarly journals Early Pep-13-induced immune responses are SERK3A/B-dependent in potato

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Linda Nietzschmann ◽  
Karin Gorzolka ◽  
Ulrike Smolka ◽  
Andreas Matern ◽  
Lennart Eschen-Lippold ◽  
...  
Keyword(s):  
Immune Responses ◽  
Defense Responses ◽  
Defense Gene Expression ◽  
Kinase Activation ◽  
Defense Gene ◽  
Potato Plants ◽  
Molecular Pattern ◽  
Hydroxycinnamic Acid Amides ◽  
Untargeted Metabolite Profiling ◽  
Blight Disease

AbstractPotato plants treated with the pathogen-associated molecular pattern Pep-13 mount salicylic acid- and jasmonic acid-dependent defense responses, leading to enhanced resistance against Phytophthora infestans, the causal agent of late blight disease. Recognition of Pep-13 is assumed to occur by binding to a yet unknown plasma membrane-localized receptor kinase. The potato genes annotated to encode the co-receptor BAK1, StSERK3A and StSERK3B, are activated in response to Pep-13 treatment. Transgenic RNAi-potato plants with reduced expression of both SERK3A and SERK3B were generated. In response to Pep-13 treatment, the formation of reactive oxygen species and MAP kinase activation, observed in wild type plants, is highly reduced in StSERK3A/B-RNAi plants, suggesting that StSERK3A/B are required for perception of Pep-13 in potato. In contrast, defense gene expression is induced by Pep-13 in both control and StSERK3A/B-depleted plants. Altered morphology of StSERK3A/B-RNAi plants correlates with major shifts in metabolism, as determined by untargeted metabolite profiling. Enhanced levels of hydroxycinnamic acid amides, typical phytoalexins of potato, in StSERK3A/B-RNAi plants are accompanied by significantly decreased levels of flavonoids and steroidal glycoalkaloids. Thus, altered metabolism in StSERK3A/B-RNAi plants correlates with the ability of StSERK3A/B-depleted plants to mount defense, despite highly decreased early immune responses.

scholarly journals Fungal LysM effectors that comprise two LysM domains bind chitin through intermolecular dimerization

2020 ◽  
Author(s):  
Hui Tian ◽  
Gabriel L. Fiorin ◽  
Anja Kombrink ◽  
Jeroen R. Mesters ◽  
Bart P.H.J. Thomma
Keyword(s):  
Fungal Pathogens ◽  
Plant Immunity ◽  
Effector Proteins ◽  
Broad Host Range ◽  
Fungal Cell ◽  
Mould Fungus ◽  
Colletotrichum Higginsianum ◽  
Molecular Pattern ◽  
Wide Range ◽  
Binding Groove

SUMMARYChitin is a polymer of β-(1,4)-linked N-acetyl-D-glucosamine (GlcNAc) and a major structural component of fungal cell walls that acts as a microbe-associated molecular pattern (MAMP) that can be recognized by plant cell surface-localized pattern recognition receptors (PRRs) to activate a wide range of immune responses. In order to deregulate chitin-induced plant immunity and successfully establish their infection, many fungal pathogens secrete effector proteins with LysM domains. We previously determined that two of the three LysM domains of the LysM effector Ecp6 from the tomato leaf mould fungus Cladosporium fulvum cooperate to form a chitin-binding groove that binds chitin with ultra-high affinity, allowing to outcompete host PRRs for chitin binding. In this study, we describe functional and structural analyses aimed to investigate whether LysM effectors that contain two LysM domains bind chitin through intramolecular or intermolecular LysM dimerization. To this end, we focus on MoSlp1 from the rice blast fungus Magnaporthe oryzae, Vd2LysM from the broad host range vascular wilt fungus Verticillium dahliae, and ChElp1 and ChElp2 from the Brassicaceae anthracnose fungus Colletotrichum higginsianum. We show that these LysM effectors bind chitin through intermolecular LysM dimerization, allowing the formation of polymeric complexes that may precipitate in order to eliminate the presence of chitin oligomers at infection sites to suppress activation of chitin-induced plant immunity. In this manner, many fungal pathogens are able to subvert chitin-triggered immunity in their plant hosts.

scholarly journals Cyclic Lipopeptides of Bacillus amyloliquefaciens subsp. plantarum Colonizing the Lettuce Rhizosphere Enhance Plant Defense Responses Toward the Bottom Rot Pathogen Rhizoctonia solani

2015 ◽  
Vol 28 (9) ◽  
pp. 984-995 ◽  
Author(s):  
Soumitra Paul Chowdhury ◽  
Jenny Uhl ◽  
Rita Grosch ◽  
Sylvia Alquéres ◽  
Sabrina Pittroff ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Plant Defense ◽  
Bacillus Amyloliquefaciens ◽  
Defense Responses ◽  
Disease Suppression ◽  
Plant Defense Responses ◽  
Defense Gene Expression ◽  
Defense Gene ◽  
Pathogen Challenge ◽  
Bottom Rot

The commercially available inoculant Bacillus amyloliquefaciens FZB42 is able to considerably reduce lettuce bottom rot caused by Rhizoctonia solani. To understand the interaction between FZB42 and R. solani in the rhizosphere of lettuce, we used an axenic system with lettuce bacterized with FZB42 and inoculated with R. solani. Confocal laser scanning microscopy showed that FZB42 could delay the initial establishment of R. solani on the plants. To show which secondary metabolites of FZB42 are produced under these in-situ conditions, we developed an ultra-high performance liquid chromatography coupled to time of flight mass spectrometry–based method and identified surfactin, fengycin, and bacillomycin D in the lettuce rhizosphere. We hypothesized that lipopeptides and polyketides play a role in enhancing the plant defense responses in addition to the direct antagonistic effect toward R. solani and used a quantitative real-time polymerase chain reaction–based assay for marker genes involved in defense signaling pathways in lettuce. A significant higher expression of PDF 1.2 observed in the bacterized plants in response to subsequent pathogen challenge showed that FZB42 could enhance the lettuce defense response toward the fungal pathogen. To identify if surfactin or other nonribosomally synthesized secondary metabolites could elicit the observed enhanced defense gene expression, we examined two mutants of FZB42 deficient in production of surfactin and the lipopetides and polyketides, by expression analysis and pot experiments. In the absence of surfactin and other nonribosomally synthesized secondary metabolites, there was no enhanced PDF 1.2–mediated response to the pathogen challenge. Pot experiment results showed that the mutants failed to reduce disease incidence in lettuce as compared with the FZB42 wild type, indicating, that surfactin as well as other nonribosomally synthesized secondary metabolites play a role in the actual disease suppression and on lettuce health. In conclusion, our study showed that nonribosomally synthesized secondary metabolites of FZB42 are actually produced in the lettuce rhizosphere and contribute to the disease suppression by mediating plant defense gene expression toward the pathogen R. solani.

Control of Winged Waterprimrose (Jussiaea decurrens) and Northern Jointvetch (Aeschynomene virginica) with Fungal Pathogens

Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 497-501 ◽  
Author(s):  
C. D. Boyette ◽  
G. E. Templeton ◽  
R. J. Smith
Keyword(s):  
Oryza Sativa ◽  
Glycine Max ◽  
Fungal Pathogens ◽  
Liquid Culture ◽  
Field Experiments ◽  
Colletotrichum Gloeosporioides ◽  
Pathogenic Fungus ◽  
Field Tests ◽  
Wide Range ◽  
Growing Region

An indigenous, host-specific, pathogenic fungus that parasitizes winged waterprimrose [Jussiaea decurrens(Walt.) DC.] is endemic in the rice growing region of Arkansas. The fungus was isolated and identified asColletotrichum gloeosporioides(Penz.) Sacc. f.sp. jussiaeae(CGJ). It is highly specific for parasitism of winged waterprimrose and not parasitic on creeping waterprimrose (J. repensL. var.glabrescensKtze.), rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.], cotton (Gossypium hirsutumL.), or 4 other crops and 13 other weeds. The fungus was physiologically distinct from C.gloeosporioides(Penz.) Sacc. f. sp.aeschynomene(CGA), an endemic anthracnose pathogen of northern jointvetch[Aeschynomene virginica(L.) B.S.P.], as indicated by cross inoculations of both weeds. Culture in the laboratory and inoculation of winged waterprimrose in greenhouse, growth chamber and field experiments indicated that the pathogen was stable, specific, and virulent in a wide range of environments. The pathogen yielded large quantities of spores in liquid culture. It is suitable for control of winged waterprimrose. Winged waterprimrose and northern jointvetch were controlled in greenhouse and field tests by application of spore mixtures of CGJ and CGA at concentrations of 1 to 2 million spores/ml of each fungus in 94 L/ha of water; the fungi did not damage rice or nontarget crops.

scholarly journals Recent Development on Plant Aldehyde Dehydrogenase Enzymes and Their Functions in Plant Development and Stress Signaling

Genes ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 51
Author(s):  
Adesola J. Tola ◽  
Amal Jaballi ◽  
Hugo Germain ◽  
Tagnon D. Missihoun
Keyword(s):  
Plant Development ◽  
Critical Analysis ◽  
Current Knowledge ◽  
Stress Signaling ◽  
Oxygen Species ◽  
Abiotic And Biotic Stresses ◽  
Aldehyde Dehydrogenases ◽  
Biotic Stresses ◽  
Wide Range ◽  
Excessive Accumulation

Abiotic and biotic stresses induce the formation of reactive oxygen species (ROS), which subsequently causes the excessive accumulation of aldehydes in cells. Stress-derived aldehydes are commonly designated as reactive electrophile species (RES) as a result of the presence of an electrophilic α, β-unsaturated carbonyl group. Aldehyde dehydrogenases (ALDHs) are NAD(P)+-dependent enzymes that metabolize a wide range of endogenous and exogenous aliphatic and aromatic aldehyde molecules by oxidizing them to their corresponding carboxylic acids. The ALDH enzymes are found in nearly all organisms, and plants contain fourteen ALDH protein families. In this review, we performed a critical analysis of the research reports over the last decade on plant ALDHs. Newly discovered roles for these enzymes in metabolism, signaling and development have been highlighted and discussed. We concluded with suggestions for future investigations to exploit the potential of these enzymes in biotechnology and to improve our current knowledge about these enzymes in gene signaling and plant development.

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