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1.
Plants (Basel) ; 10(9)2021 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-34579478

RESUMO

Plants are frequently exposed to simultaneous abiotic and biotic stresses, a condition that induces complex responses, negatively affects crop productivity and is becoming more exacerbated with current climate change. In this study, we investigated the effects of individual and combined heat and osmotic stresses on Arabidopsis susceptibility to the biotrophic pathogen Pseudomonas syringae pv. tomato (Pst) and the necrotrophic pathogen Botrytiscinerea (Bc). Our data showed that combined abiotic and biotic stresses caused an enhanced negative impact on plant disease resistance in comparison with individual Pst and Bc infections. Pretreating plants with individual heat or combined osmotic-heat stress strongly reduced the expression of many defense genes including pathogenesis-related proteins (PR-1 and PR-5) and the TN-13 gene encoding the TIR-NBS protein, which are involved in disease resistance towards Pst. We also found that combined osmotic-heat stress caused high plant susceptibility to Bc infection and reduced expression of a number of defense genes, including PLANT DEFENSIN 1.3 (PDF1.3), BOTRYTIS SUSCEPTIBLE 1 (BOS1) and THIONIN 2.2 (THI2.2) genes, which are important for disease resistance towards Bc. The impaired disease resistance against both Pst and Bc under combined abiotic stress is associated with reduced expression of cell wall-related genes. Taken together, our data emphasize that the combination of global warming-associated abiotic stresses such as heat and osmotic stresses makes plants more susceptible to pathogen infection, thus threatening future global food security.

3.
Front Plant Sci ; 12: 657451, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33897746

RESUMO

Coprinopsis cinerea lectin 2 (CCL2) is a fucoside-binding lectin from the basidiomycete C. cinerea that is toxic to the bacterivorous nematode Caenorhabditis elegans as well as animal-parasitic and fungivorous nematodes. We expressed CCL2 in Arabidopsis to assess its protective potential toward plant-parasitic nematodes. Our results demonstrate that expression of CCL2 enhances host resistance against the cyst nematode Heterodera schachtii. Surprisingly, CCL2-expressing plants were also more resistant to fungal pathogens including Botrytis cinerea, and the phytopathogenic bacterium Pseudomonas syringae. In addition, CCL2 expression positively affected plant growth indicating that CCL2 has the potential to improve two important agricultural parameters namely biomass production and general disease resistance. The mechanism of the CCL2-mediated enhancement of plant disease resistance depended on fucoside-binding by CCL2 as transgenic plants expressing a mutant version of CCL2 (Y92A), compromised in fucoside-binding, exhibited wild type (WT) disease susceptibility. The protective effect of CCL2 did not seem to be direct as the lectin showed no growth-inhibition toward B. cinerea in in vitro assays. We detected, however, a significantly enhanced transcriptional induction of plant defense genes in CCL2- but not CCL2-Y92A-expressing lines in response to infection with B. cinerea compared to WT plants. This study demonstrates a potential of fungal defense lectins in plant protection beyond their use as toxins.

4.
Biotechnol Biofuels ; 14(1): 61, 2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33685508

RESUMO

BACKGROUND: Textile industry represents one prevalent activity worldwide, generating large amounts of highly contaminated and rich in azo dyes wastewater, with severe effects on natural ecosystems and public health. However, an effective and environmentally friendly treatment method has not yet been implemented, while concurrently, the increasing demand of modern societies for adequate and sustainable energy supply still remains a global challenge. Under this scope, the purpose of the present study was to isolate promising species of yeasts inhabiting wood-feeding termite guts, for combined azo dyes and textile wastewater bioremediation, along with biodiesel production. RESULTS: Thirty-eight yeast strains were isolated, molecularly identified and subsequently tested for desired enzymatic activity, lipid accumulation, and tolerance to lignin-derived metabolites. The most promising species were then used for construction of a novel yeast consortium, which was further evaluated for azo dyes degradation, under various culture conditions, dye levels, as well as upon the addition of heavy metals, different carbon and nitrogen sources, and lastly agro-waste as an inexpensive and environmentally friendly substrate alternative. The novel yeast consortium, NYC-1, which was constructed included the manganese-dependent peroxidase producing oleaginous strains Meyerozyma caribbica, Meyerozyma guilliermondii, Debaryomyces hansenii, and Vanrija humicola, and showed efficient azo dyes decolorization, which was further enhanced depending on the incubation conditions. Furthermore, enzymatic activity, fatty acid profile and biodiesel properties were thoroughly investigated. Lastly, a dye degradation pathway coupled to biodiesel production was proposed, including the formation of phenol-based products, instead of toxic aromatic amines. CONCLUSION: In total, this study might be the first to explore the application of MnP and lipid-accumulating yeasts for coupling dye degradation and biodiesel production.

5.
Nat Nanotechnol ; 16(3): 344-353, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33318639

RESUMO

In plants, pathogen attack can induce an immune response known as systemic acquired resistance that protects against a broad spectrum of pathogens. In the search for safer agrochemicals, silica nanoparticles (SiO2 NPs; food additive E551) have recently been proposed as a new tool. However, initial results are controversial, and the molecular mechanisms of SiO2 NP-induced disease resistance are unknown. Here we show that SiO2 NPs, as well as soluble Si(OH)4, can induce systemic acquired resistance in a dose-dependent manner, which involves the defence hormone salicylic acid. Nanoparticle uptake and action occurred exclusively through the stomata (leaf pores facilitating gas exchange) and involved extracellular adsorption in the air spaces in the spongy mesophyll of the leaf. In contrast to the treatment with SiO2 NPs, the induction of systemic acquired resistance by Si(OH)4 was problematic since high Si(OH)4 concentrations caused stress. We conclude that SiO2 NPs have the potential to serve as an inexpensive, highly efficient, safe and sustainable alternative for plant disease protection.


Assuntos
Arabidopsis/efeitos dos fármacos , Resistência à Doença/genética , Nanopartículas/química , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Doenças das Plantas/genética , Doenças das Plantas/prevenção & controle , Espécies Reativas de Oxigênio/química , Ácido Salicílico/química , Dióxido de Silício/química , Dióxido de Silício/farmacologia
6.
Bioresour Technol ; 323: 124544, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33360721

RESUMO

Lignocellulose biodegradation is limited because of its recalcitrant structure particularly when polluted by toxic and carcinogenic compounds such as creosote oil (CRO). As far as we know, this might be the first report that explores the biodegradation of creosote treated wood (CTW) to serve biomethane production. Two novel CTW-degrading microbial consortia, designated as CTW-1 and CTW-2, were screened and constructed to enhance methane production from CRO-treated pine sawdust. After 12 days of biological pretreatment by CTW-1 and CTW-2, a significant reduction in lignocellulosic content of CTW was recorded; estimated as 49 and 43%, respectively. More than 64 and 91% of cumulative biogas and methane yields were obtained from biodegraded CTW over control. Ecotoxicity of treated and untreated CTW was compared by Microtox test. The biodegraded CTW hydrolysates showed a toxicity decrease of more than 80%, suggesting the promising role of constructed microbial consortia for biofuel production and bioremediation.


Assuntos
Creosoto , Hidrocarbonetos Policíclicos Aromáticos , Biodegradação Ambiental , Metano , Consórcios Microbianos , Madeira
7.
Sci Rep ; 10(1): 9339, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32518329

RESUMO

Biofilm formation and hyphal growth are considered to be the most serious virulence factors of Candida species in blood causing candidemia infections, which are difficult to treat due to the spread of resistant Candida isolates to most antifungal drugs. Therefore, in this study, we investigated the effect of different types and concentrations of selected macroalgal extracts from Cladostephus spongiosus (Phaeophyta), Laurencia papillosa (Rhodophyta), and Codium arabicum (Chlorophyta) in inhibiting those virulence factors of the isolated Candida. Acetone extract of C. spongiosus (AECS) showed a stronger anticandidal activity against the selected strains than ethanol extract. Candida krusei was the highest biofilm producer among the selected isolates. AECS showed an inhibition of C. krusei biofilm formation as well as a reduction in the viability of preformed biofilms. Also, AECS reduced various sugars in the candidal exo-polysaccaride layer (EPS). Scanning electron microscopy (SEM) and light microscopic images revealed an absence of hyphae and an alteration in the morphology of biofilm cells when treated with AECS. Moreover, AECS downregulated the expression of hyphal specific genes, hyphal wall protein 1 (HWP1), Agglutinin-like protein 1 (ALS1) and fourth secreted aspartyl proteinase (SAP4), which confirmed the inhibitory effect of AECS on hyphal growth and biofilm formation. Gas chromatography-mass spectrophotometer (GC-MS) analysis of AECS showed three major compounds, which were non-existent in the ethanol extract, and might be responsible for the anticandidal activity; these revealed compounds were 4-hydroxy-4-methyl-2-pentanone, n-hexadecenoic acid, and phenol, 2-methoxy-4-(2-propenyl). These active compounds of AECS may be promising for future pharmaceutical applications in the treatment of candidemia.


Assuntos
Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Candida/fisiologia , Hifas/efeitos dos fármacos , Hifas/crescimento & desenvolvimento , Alga Marinha/química , Biofilmes/crescimento & desenvolvimento , Candida/crescimento & desenvolvimento , Candida/metabolismo , Polissacarídeos Fúngicos/biossíntese
8.
Plant Signal Behav ; 10(9): e998544, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26375184

RESUMO

Systemic acquired resistance (SAR) is a form of broad-spectrum disease resistance that is induced in response to primary infection and that protects uninfected portions of the plant against secondary infections by related or unrelated pathogens. SAR is associated with an increase in chemical signals that operate in a collective manner to confer protection against secondary infections. These include, the phytohormone salicylic acid (SA), glycerol-3-phosphate (G3P), azelaic acid (AzA) and more recently identified signals nitric oxide (NO) and reactive oxygen species (ROS). NO, ROS, AzA and G3P function in the same branch of the SAR pathway, and in parallel to the SA-regulated branch. NO and ROS function upstream of AzA/G3P and different reactive oxygen species functions in an additive manner to mediate chemical cleavage of the C9 double bond on C18 unsaturated fatty acids to generate AzA. The parallel and additive functioning of various chemical signals provides important new insights in the overlapping pathways leading to SAR.


Assuntos
Arabidopsis/imunologia , Arabidopsis/metabolismo , Resistência à Doença/imunologia , Óxido Nítrico/metabolismo , Doenças das Plantas/imunologia , Espécies Reativas de Oxigênio/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/metabolismo , Modelos Biológicos , Óxido Nítrico Sintase/metabolismo , Doenças das Plantas/microbiologia , Pseudomonas syringae , Transdução de Sinais
9.
Cell Rep ; 7(2): 348-355, 2014 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-24726369

RESUMO

Systemic acquired resistance (SAR) is a form of resistance that protects plants against a broad spectrum of secondary infections. However, exploiting SAR for the protection of agriculturally important plants warrants a thorough investigation of the mutual interrelationships among the various signals that mediate SAR. Here, we show that nitric oxide (NO) and reactive oxygen species (ROS) serve as inducers of SAR in a concentration-dependent manner. Thus, genetic mutations that either inhibit NO/ROS production or increase NO accumulation (e.g., a mutation in S-nitrosoglutathione reductase [GSNOR]) abrogate SAR. Different ROS function additively to generate the fatty-acid-derived azelaic acid (AzA), which in turn induces production of the SAR inducer glycerol-3-phosphate (G3P). Notably, this NO/ROS→AzA→G3P-induced signaling functions in parallel with salicylic acid-derived signaling. We propose that the parallel operation of NO/ROS and SA pathways facilitates coordinated regulation in order to ensure optimal induction of SAR.


Assuntos
Arabidopsis/imunologia , Óxido Nítrico/metabolismo , Imunidade Vegetal , Espécies Reativas de Oxigênio/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ácidos Dicarboxílicos/metabolismo , Glutationa Redutase/genética , Glutationa Redutase/metabolismo , Glicerofosfatos/metabolismo , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase/metabolismo , Pseudomonas syringae/patogenicidade
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