Phytophthora cinnamomi is one of the most invasive tree pathogens that devastates wild and cultivated forests. Due to its wide host range, knowledge of the infection process at the molecular level is lacking for most of its tree hosts. To expand the repertoire of studied Phytophthora-woody plant interactions and identify molecular mechanisms that can facilitate discovery of novel ways to control its spread and damaging effects, we focused on the interaction between P. cinnamomi and sweet chestnut (Castanea sativa), an economically important tree for the wood processing industry. By using a combination of proteomics, metabolomics, and targeted hormonal analysis, we mapped the effects of P. cinnamomi attack on stem tissues immediately bordering the infection site and away from it. P. cinnamomi led to a massive reprogramming of the chestnut proteome and accumulation of the stress-related hormones salicylic acid (SA) and jasmonic acid (JA), indicating that stem inoculation can be used as an easily accessible model system to identify novel molecular players in P. cinnamomi pathogenicity.
- MeSH
- cyklopentany metabolismus MeSH
- dřevo MeSH
- Fagaceae metabolismus mikrobiologie MeSH
- homeostáza MeSH
- kořeny rostlin MeSH
- kyselina salicylová metabolismus MeSH
- metabolomika MeSH
- nemoci rostlin mikrobiologie MeSH
- oxylipiny metabolismus MeSH
- Phytophthora patogenita MeSH
- proteomika MeSH
- regulátory růstu rostlin metabolismus MeSH
- signální transdukce MeSH
- vazebná místa MeSH
- výpočetní biologie MeSH
- Publikační typ
- časopisecké články MeSH
Alterations of hydrogen peroxide (H2O2) levels have a profound impact on numerous signaling cascades orchestrating plant growth, development, and stress signaling, including programmed cell death. To expand the repertoire of known molecular mechanisms implicated in H2O2 signaling, we performed a forward chemical screen to identify small molecules that could alleviate the photorespiratory-induced cell death phenotype of Arabidopsisthaliana mutants lacking H2O2-scavenging capacity by peroxisomal catalase2. Here, we report the characterization of pakerine, an m-sulfamoyl benzamide from the sulfonamide family. Pakerine alleviates the cell death phenotype of cat2 mutants exposed to photorespiration-promoting conditions and delays dark-induced senescence in wild-type Arabidopsis leaves. By using a combination of transcriptomics, metabolomics, and affinity purification, we identified abnormal inflorescence meristem 1 (AIM1) as a putative protein target of pakerine. AIM1 is a 3-hydroxyacyl-CoA dehydrogenase involved in fatty acid β-oxidation that contributes to jasmonic acid (JA) and salicylic acid (SA) biosynthesis. Whereas intact JA biosynthesis was not required for pakerine bioactivity, our results point toward a role for β-oxidation-dependent SA production in the execution of H2O2-mediated cell death.
- MeSH
- Arabidopsis cytologie účinky léků genetika metabolismus MeSH
- buněčná smrt účinky léků MeSH
- buněčné dýchání účinky léků genetika MeSH
- cyklopentany metabolismus MeSH
- fotosyntéza účinky léků genetika MeSH
- fyziologický stres MeSH
- hydroponie metody MeSH
- kyselina salicylová metabolismus MeSH
- listy rostlin cytologie účinky léků metabolismus MeSH
- meristém cytologie účinky léků metabolismus MeSH
- multienzymové komplexy genetika metabolismus MeSH
- oxylipiny metabolismus MeSH
- peroxid vodíku antagonisté a inhibitory farmakologie MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin * MeSH
- rostlinné buňky účinky léků metabolismus MeSH
- semena rostlinná účinky léků MeSH
- signální transdukce MeSH
- stanovení celkové genové exprese MeSH
- sulfonamidy chemická syntéza farmakologie MeSH
- transkriptom MeSH
- výpočetní biologie metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Salicylic acid (SA) is a very simple phenolic compound (a C7H6O3 compound composed of an aromatic ring, one carboxylic and a hydroxyl group) and this simplicity contrasts with its high versatility and the involvement of SA in several plant processes either in optimal conditions or in plants facing environmental cues, including heavy metal (HM) stress. Nowadays, a huge body of evidence has unveiled that SA plays a pivotal role as plant growth regulator and influences intra- and inter-plant communication attributable to its methyl ester form, methyl salicylate, which is highly volatile. Under stress, including HM stress, SA interacts with other plant hormones (e.g., auxins, abscisic acid, gibberellin) and promotes the stimulation of antioxidant compounds and enzymes thereby alerting HM-treated plants and helping in counteracting HM stress. The present literature survey reviews recent literature concerning the roles of SA in plants suffering from HM stress with the aim of providing a comprehensive picture about SA and HM, in order to orientate the direction of future research on this topic.
- MeSH
- antioxidancia metabolismus MeSH
- fyziologický stres MeSH
- kyselina salicylová chemie metabolismus MeSH
- metabolické sítě a dráhy MeSH
- molekulární struktura MeSH
- oxidační stres MeSH
- reaktivní formy kyslíku metabolismus MeSH
- rostliny účinky léků metabolismus MeSH
- těžké kovy škodlivé účinky chemie metabolismus MeSH
- vystavení vlivu životního prostředí * škodlivé účinky MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Plants, like other multicellular organisms, survive through a delicate balance between growth and defense against pathogens. Salicylic acid (SA) is a major defense signal in plants, and the perception mechanism as well as downstream signaling activating the immune response are known. Here, we identify a parallel SA signaling that mediates growth attenuation. SA directly binds to A subunits of protein phosphatase 2A (PP2A), inhibiting activity of this complex. Among PP2A targets, the PIN2 auxin transporter is hyperphosphorylated in response to SA, leading to changed activity of this important growth regulator. Accordingly, auxin transport and auxin-mediated root development, including growth, gravitropic response, and lateral root organogenesis, are inhibited. This study reveals how SA, besides activating immunity, concomitantly attenuates growth through crosstalk with the auxin distribution network. Further analysis of this dual role of SA and characterization of additional SA-regulated PP2A targets will provide further insights into mechanisms maintaining a balance between growth and defense.
- MeSH
- Arabidopsis růst a vývoj fyziologie MeSH
- imunita rostlin MeSH
- kořeny rostlin růst a vývoj metabolismus MeSH
- kyselina salicylová metabolismus MeSH
- kyseliny indoloctové metabolismus MeSH
- proteinfosfatasa 2 metabolismus MeSH
- proteiny huseníčku metabolismus MeSH
- signální transdukce * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The phytohormone salicylic acid (SA) has a crucial role in plant physiology. Its role is best described in the context of plant response to pathogen attack. During infection, SA is rapidly accumulated throughout the green tissues and is important for both local and systemic defences. However, some genetic/metabolic variations can also result in SA overaccumulation in plants, even in basal conditions. To date, more than forty Arabidopsis thaliana mutants have been described as having enhanced endogenous SA levels or constitutively activated SA signalling pathways. In this study, we established a collection of mutants containing different SA levels due to diverse genetic modifications and distinct gene functions. We chose prototypic SA-overaccumulators (SA-OAs), such as bon1-1, but also "non-typical" ones such as exo70b1-1; the selection of OA is accompanied by their crosses with SA-deficient lines. Here, we extensively studied the plant development and SA level/signalling under various growth conditions in soil and in vitro, and showed a strong negative correlation between rosette size, SA content and PR1/ICS1 transcript signature. SA-OAs (namely cpr5, acd6, bon1-1, fah1/fah2 and pi4kβ1β2) had bigger rosettes under high light conditions, whereas WT plants did not. Our data provide new insights clarifying a link between SA and plant behaviour under environmental stresses. The presented SA mutant collection is thus a suitable tool to shed light on the mechanisms underlying trade-offs between growth and defence in plants.
- MeSH
- Arabidopsis genetika metabolismus mikrobiologie MeSH
- interakce hostitele a patogenu MeSH
- kyselina salicylová metabolismus MeSH
- mutace * MeSH
- nemoci rostlin genetika mikrobiologie MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin * MeSH
- regulátory růstu rostlin metabolismus MeSH
- signální transdukce genetika MeSH
- vývoj rostlin genetika MeSH
- Publikační typ
- časopisecké články MeSH
MAIN CONCLUSION: The level of resistance induced in different tomato genotypes after β-CRY treatment correlated with the upregulation of defence genes, but not sterol binding and involved ethylene and jasmonic acid signalling. Elicitins, a family of small proteins secreted by Phytophthora and Pythium spp., are the most well-known microbe-associated molecular patterns of oomycetes, a lineage of fungus-like organisms that include many economically significant crop pathogens. The responses of tomato plants to elicitin INF1 produced by Phytophthora infestans have been studied extensively. Here, we present studies on the responses of three tomato genotypes to β-cryptogein (β-CRY), a potent elicitin secreted by Phytophthora cryptogea that induces hypersensitive response (HR) cell death in tobacco plants and confers greater resistance to oomycete infection than acidic elicitins like INF1. We also studied β-CRY mutants impaired in sterol binding (Val84Phe) and interaction with the binding site on tobacco plasma membrane (Leu41Phe), because sterol binding was suggested to be important in INF1-induced resistance. Treatment with β-CRY or the Val84Phe mutant induced resistance to powdery mildew caused by the pathogen Pseudoidium neolycopersici, but not the HR cell death observed in tobacco and potato plants. The level of resistance induced in different tomato genotypes correlated with the upregulation of defence genes including defensins, β-1,3-glucanases, heveins, chitinases, osmotins, and PR1 proteins. Treatment with the Leu41Phe mutant did not induce this upregulation, suggesting similar elicitin recognition in tomato and tobacco. However, here β-CRY activated ethylene and jasmonic acid signalling, but not salicylic acid signalling, demonstrating that elicitins activate different downstream signalling processes in different plant species. This could potentially be exploited to enhance the resistance of Phytophthora-susceptible crops.
- MeSH
- cyklopentany metabolismus MeSH
- ethyleny metabolismus MeSH
- fungální proteiny metabolismus MeSH
- interakce hostitele a patogenu MeSH
- kyselina salicylová metabolismus MeSH
- listy rostlin metabolismus mikrobiologie MeSH
- nemoci rostlin mikrobiologie MeSH
- oxylipiny metabolismus MeSH
- peroxid vodíku metabolismus MeSH
- Phytophthora MeSH
- Pythium MeSH
- reaktivní formy kyslíku metabolismus MeSH
- regulátory růstu rostlin metabolismus MeSH
- signální transdukce * MeSH
- Solanum lycopersicum metabolismus mikrobiologie fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
The integrity of the actin cytoskeleton is essential for plant immune signalling. Consequently, it is generally assumed that actin disruption reduces plant resistance to pathogen attack. Here, we demonstrate that actin depolymerization induced a dramatic increase in salicylic acid (SA) levels in Arabidopsis thaliana. Transcriptomic analysis showed that the SA pathway was activated due to the action of isochorismate synthase (ICS). The effect was also confirmed in Brassica napus. This raises the question of whether actin depolymerization could, under particular conditions, lead to increased resistance to pathogens. Thus, we explored the effect of pretreatment with actin-depolymerizing drugs on the resistance of Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae, and on the resistance of an important crop Brassica napus to its natural fungal pathogen Leptosphaeria maculans. In both pathosystems, actin depolymerization activated the SA pathway, leading to increased plant resistance. To our best knowledge, we herein provide the first direct evidence that disruption of the actin cytoskeleton can actually lead to increased plant resistance to pathogens, and that SA is crucial to this process.
- MeSH
- aktiny metabolismus MeSH
- Arabidopsis metabolismus mikrobiologie MeSH
- Ascomycota patogenita MeSH
- Brassica napus metabolismus mikrobiologie MeSH
- intramolekulární transferasy metabolismus MeSH
- kyselina salicylová metabolismus MeSH
- nemoci rostlin mikrobiologie MeSH
- proteiny huseníčku metabolismus MeSH
- Pseudomonas syringae patogenita MeSH
- regulace genové exprese u rostlin fyziologie MeSH
- signální transdukce fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Singlet oxygen produced from triplet excited chlorophylls in photosynthesis is a signal molecule that can induce programmed cell death (PCD) through the action of the OXIDATIVE STRESS INDUCIBLE 1 (OXI1) kinase. Here, we identify two negative regulators of light-induced PCD that modulate OXI1 expression: DAD1 and DAD2, homologs of the human antiapoptotic protein DEFENDER AGAINST CELL DEATH. Overexpressing OXI1 in Arabidopsis (Arabidopsis thaliana) increased plant sensitivity to high light and induced early senescence of mature leaves. Both phenomena rely on a marked accumulation of jasmonate and salicylate. DAD1 or DAD2 overexpression decreased OXI1 expression, jasmonate levels, and sensitivity to photooxidative stress. Knock-out mutants of DAD1 or DAD2 exhibited the opposite responses. Exogenous applications of jasmonate upregulated salicylate biosynthesis genes and caused leaf damage in wild-type plants but not in the salicylate biosynthesis mutant Salicylic acid induction-deficient2, indicating that salicylate plays a crucial role in PCD downstream of jasmonate. Treating plants with salicylate upregulated the DAD genes and downregulated OXI1 We conclude that OXI1 and DAD are antagonistic regulators of cell death through modulating jasmonate and salicylate levels. High light-induced PCD thus results from a tight control of the relative activities of these regulating proteins, with DAD exerting a negative feedback control on OXI1 expression.
- MeSH
- apoptóza genetika účinky záření MeSH
- Arabidopsis cytologie genetika metabolismus MeSH
- biosyntetické dráhy účinky léků genetika účinky záření MeSH
- cyklopentany metabolismus farmakologie MeSH
- fosfolipasy A1 genetika metabolismus MeSH
- kyselina salicylová metabolismus farmakologie MeSH
- listy rostlin cytologie genetika metabolismus MeSH
- mutace MeSH
- oxylipiny metabolismus farmakologie MeSH
- protein-serin-threoninkinasy genetika metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin účinky léků účinky záření MeSH
- regulátory růstu rostlin metabolismus farmakologie MeSH
- singletový kyslík metabolismus MeSH
- stanovení celkové genové exprese metody MeSH
- světlo MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Citrus canker, caused by Xanthomonas axonopodis pv. citri ('Xac'), is an important quarantine disease in citrus crops. Arbuscular mycorrhizal fungi (AMF) form symbiotic interactions with host plants and further affect their disease resistance, possibly by modulating the activity of salicylic acid (SA), a key phytohormone in disease resistance. Common mycorrhizal networks (CMNs) can interconnect plants, but it is not yet clear whether CMNs promote resistance to citrus canker and, if so, whether SA signaling is involved in this process. To test this possibility, we used a two-chambered rootbox to establish CMNs between trifoliate orange (Poncirus trifoliata) seedlings in chambers inoculated (treated) or not (neighboring) with the AMF, Paraglomus occultum. A subset of the AMF-inoculated seedlings were also inoculated with Xac (+AMF+Xac). At 2 d post-inoculation (dpi), compared with the +AMF-Xac treatment, neighboring seedlings in +AMF+Xac treatment had lower expression levels of the SA biosynthetic genes, PtPAL, PtEPS1, and PtPBS3, but higher SA levels, which attributed to the upregulation of PtPAL and PtPBS3 in treated seedlings and the transfer of SA, via CMNs, to the neighboring seedlings. At 4 dpi, the pathogenesis-related (PR) protein genes, PtPR1, PtPR4, and PtPR5, and the transcriptional regulatory factor gene, PtNPR1, were activated in neighboring seedlings of +AMF+Xac treatment. At 9 dpi, root phenylalanine ammonia-lyase activity and total soluble phenol and lignin concentrations increased in neighboring seedlings of +AMF+Xac treatment, likely due to the linkage and signal transfer, via CMNs. These findings support the hypothesis that CMNs transfer the SA signal from infected to neighboring healthy seedlings, to activate defense responses and affording protection to neighboring plants against citrus canker infection.
Thorium is natural actinide metal with potential use in nuclear energetics. Contamination by thorium, originated from mining activities or spills, represents environmental risk due to its radioactivity and chemical toxicity. A promising approach for cleaning of contaminated areas is phytoremediation, which need to be based, however, on detail understanding of the thorium effects on plants. In this study we investigated transcriptomic response of tobacco roots exposed to 200μM thorium for one week. Thorium application resulted in up-regulation of 152 and down-regulation of 100 genes (p-value <0.01, fold change ≥2). The stimulated genes were involved in components of jasmonic acid and salicylic acid signaling pathways and various abiotic (e.g. oxidative stress) and biotic stress (e.g. pathogens, wounding) responsive genes. Further, up-regulation of phosphate starvation genes and down-regulation of genes involved in phytic acid biosynthesis indicated that thorium disturbed phosphate uptake or signaling. Also expression of iron responsive genes was influenced. Negative regulation of several aquaporins indicated disturbance of water homeostasis. Genes potentially involved in thorium transport could be zinc-induced facilitator ZIF2, plant cadmium resistance PCR2, and ABC transporter ABCG40. This study provides the first insight at the processes in plants exposed to thorium.
- MeSH
- cyklopentany metabolismus MeSH
- down regulace MeSH
- fosfáty chemie MeSH
- fyziologický stres účinky léků MeSH
- kadmium metabolismus MeSH
- kořeny rostlin metabolismus MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- kyselina salicylová metabolismus MeSH
- listy rostlin metabolismus MeSH
- oxidační stres MeSH
- oxylipiny metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- regulace genové exprese u rostlin * MeSH
- stanovení celkové genové exprese MeSH
- tabák účinky léků MeSH
- thorium farmakologie MeSH
- transkriptom * MeSH
- upregulace MeSH
- železo chemie MeSH
- Publikační typ
- časopisecké články MeSH
