Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.997
Filtrar
1.
Ecotoxicol Environ Saf ; 201: 110778, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32480161

RESUMO

Field peas (Pisum sativum L.) are widely cultivated throughout the world as a cool season grain and forage crop. Boron (B) toxicity is caused by high B concentration in the soil or irrigation water, and is particularly problematic in medium or heavier textured soil types with moderate alkalinity and low annual rainfall. Previous studies have indicated that B-toxicity increases oxidative stress in plants, and B-tolerance has been considered an important target in field pea plant breeding programmes. Inducers of tolerance may be a promising alternative for plant breeding. Little research has been conducted on the combined use of silicon (Si) and salicylic acid (SA) to remediate B-toxicity in field peas. The present study revealed the physiological and biochemical plant responses of applying Si + SA under B-toxicity (15 mg B L-1) on two Brazilian field pea cultivars (Iapar 83 and BRS Forrageira). A semi-hydroponic experiment was conducted using a completely randomized factorial design (2 × 5): with two field pea cultivars and five treatments which were formed by individual and combined applications of Si and SA under B-toxicity plus a control (control, B, B + Si, B + SA, and B + Si + SA). Si (2 mmol L-1) was applied to plants in two forms (root and leaf), while for SA (36 µmol L-1) only foliar applications were applied. Our results demonstrated that the combined use of exogenous Si + SA in field peas increased tolerance to B-toxicity through an intensified antioxidant plant defence system, resulting in a better regulation of reactive oxygen species (ROS) production and degradation. It significantly increased total chlorophyll and carotenoids contents, the activities of major antioxidant enzymes, and reduced MDA and H2O2 contents, resulting in increased fresh shoot and total plant dry biomass. The application of Si + SA alleviated the inhibitory effects of boron toxicity in field peas, resulting in greater plant growth by preventing oxidative membrane damage through an increased tolerance to B-excess within the plant tissue. Therefore, the use of Si + SA is an important and sustainable strategy to alleviate B-toxicity in field pea cultivation.


Assuntos
Antioxidantes/metabolismo , Boro/toxicidade , Ervilhas/fisiologia , Ácido Salicílico/metabolismo , Silício/metabolismo , Poluentes do Solo/toxicidade , Brasil , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ervilhas/efeitos dos fármacos , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo
2.
PLoS Genet ; 16(6): e1008873, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32584819

RESUMO

The regulation of leaf size has been studied for decades. Enhancement of post-mitotic cell expansion triggered by impaired cell proliferation in Arabidopsis is an important process for leaf size regulation, and is known as compensation. This suggests a key interaction between cell proliferation and cell expansion during leaf development. Several studies have highlighted the impact of this integration mechanism on leaf size determination; however, the molecular basis of compensation remains largely unknown. Previously, we identified extra-small sisters (xs) mutants which can suppress compensated cell enlargement (CCE) via a specific defect in cell expansion within the compensation-exhibiting mutant, angustifolia3 (an3). Here we revealed that one of the xs mutants, namely xs2, can suppress CCE not only in an3 but also in other compensation-exhibiting mutants erecta (er) and fugu2. Molecular cloning of XS2 identified a deleterious mutation in CATION CALCIUM EXCHANGER 4 (CCX4). Phytohormone measurement and expression analysis revealed that xs2 shows hyper activation of the salicylic acid (SA) response pathway, where activation of SA response can suppress CCE in compensation mutants. All together, these results highlight the regulatory connection which coordinates compensation and SA response.


Assuntos
Antiporters/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Reguladores de Crescimento de Planta/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Ácido Salicílico/metabolismo , Proteínas de Arabidopsis/genética , Cálcio/metabolismo , Cátions Bivalentes/metabolismo , Crescimento Celular , Proliferação de Células/genética , Regulação da Expressão Gênica de Plantas , Mutação com Perda de Função , Tamanho do Órgão/genética , Folhas de Planta/citologia , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , Transdução de Sinais/genética
4.
Food Chem ; 327: 126992, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32447133

RESUMO

The influence mechanism of different withering methods (CK, indoor natural spreading; LTD, low-temperature plus dark; LTY, low-temperature plus yellow-light; LTCD, low-temperature plus CO2) on non-volatile compounds in postharvest tea leaves was investigated by UHPLC-Q-TOF/MS-based non-targeted metabolomic and transcriptomic analyses. Compared with CK, low-temperature withering could slow down polyphenol oxidation by inhibiting polyphenol oxidase activity and keeping the expression of genes for flavanol synthesis. After withering, the proteinaceous amino acid content increased significantly, especially for LTCD and LTY, mainly due to increased peptidase activity and up-regulation of genes involved in the biosynthesis of valine, leucine, aspartic acid, glutamic acid, phenylalanine, and proline. Moreover, LTCD and LTY enhanced the synthesis of γ-aminobutyric acid and metabolism of phenylalanine-methyl salicylate and tryptophan-indole, respectively. Meanwhile, the transformation of theobromine to caffeine was accelerated under low-temperature withering. This research provides ageneticmetabolicbasis for the application of low-temperature withering to actual green tea processing.


Assuntos
Camellia sinensis/metabolismo , Chá/metabolismo , Cafeína/metabolismo , Camellia sinensis/genética , Cor , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Metabolômica , Folhas de Planta/genética , Folhas de Planta/metabolismo , Polifenóis/metabolismo , Ácido Salicílico/metabolismo , Chá/genética
5.
Nucleic Acids Res ; 48(11): 5953-5966, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32396165

RESUMO

The modification of histones by acetyl groups has a key role in the regulation of chromatin structure and transcription. The Arabidopsis thaliana histone acetyltransferase GCN5 regulates histone modifications as part of the Spt-Ada-Gcn5 Acetyltransferase (SAGA) transcriptional coactivator complex. GCN5 was previously shown to acetylate lysine 14 of histone 3 (H3K14ac) in the promoter regions of its target genes even though GCN5 binding did not systematically correlate with gene activation. Here, we explored the mechanism through which GCN5 controls transcription. First, we fine-mapped its GCN5 binding sites genome-wide and then used several global methodologies (ATAC-seq, ChIP-seq and RNA-seq) to assess the effect of GCN5 loss-of-function on the expression and epigenetic regulation of its target genes. These analyses provided evidence that GCN5 has a dual role in the regulation of H3K14ac levels in their 5' and 3' ends of its target genes. While the gcn5 mutation led to a genome-wide decrease of H3K14ac in the 5' end of the GCN5 down-regulated targets, it also led to an increase of H3K14ac in the 3' ends of GCN5 up-regulated targets. Furthermore, genome-wide changes in H3K14ac levels in the gcn5 mutant correlated with changes in H3K9ac at both 5' and 3' ends, providing evidence for a molecular link between the depositions of these two histone modifications. To understand the biological relevance of these regulations, we showed that GCN5 participates in the responses to biotic stress by repressing salicylic acid (SA) accumulation and SA-mediated immunity, highlighting the role of this protein in the regulation of the crosstalk between diverse developmental and stress-responsive physiological programs. Hence, our results demonstrate that GCN5, through the modulation of H3K14ac levels on its targets, controls the balance between biotic and abiotic stress responses and is a master regulator of plant-environmental interactions.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Histona Acetiltransferases/metabolismo , Histonas/metabolismo , Homeostase , Lisina/metabolismo , Ácido Salicílico/metabolismo , Regiões 5' não Traduzidas/genética , Acetilação , Arabidopsis/imunologia , Histonas/química , Lisina/química , Imunidade Vegetal/genética , Regiões Promotoras Genéticas/genética , Transcrição Genética
6.
PLoS One ; 15(4): e0231426, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32271848

RESUMO

Demand for agricultural crop continues to escalate in response to increasing population and damage of prime cropland for cultivation. Research interest is diverted to utilize soils with marginal plant production. Moisture stress has negative impact on crop growth and productivity. The plant growth promoting rhizobacteria (PGPR) and plant growth regulators (PGR) are vital for plant developmental process under moisture stress. The current study was carried out to investigate the effect of PGPR and PGRs (Salicylic acid and Putrescine) on the physiological activities of chickpea grown in sandy soil. The bacterial isolates were characterized based on biochemical characters including Gram-staining, P-solubilisation, antibacterial and antifungal activities and catalases and oxidases activities and were also screened for the production of indole-3-acetic acid (IAA), hydrogen cyanide (HCN) and ammonia (NH3). The bacterial strains were identified as Bacillus subtilis, Bacillus thuringiensis and Bacillus megaterium based on the results of 16S-rRNA gene sequencing. Chickpea seeds of two varieties (Punjab Noor-2009 and 93127) differing in sensitivity to drought were soaked for 3 h before sowing in fresh grown cultures of isolates. Both the PGRs were applied (150 mg/L), as foliar spray on 20 days old seedlings of chickpea. Moisture stress significantly reduced the physiological parameters but the inoculation of PGPR and PGR treatment effectively ameliorated the adverse effects of moisture stress. The result showed that chickpea plants treated with PGPR and PGR significantly enhanced the chlorophyll, protein and sugar contents. Shoot and root fresh (81%) and dry weights (77%) were also enhanced significantly in the treated plants. Leaf proline content, lipid peroxidation and antioxidant enzymes (CAT, APOX, POD and SOD) were increased in reaction to drought stress but decreased due to PGPR. The plant height (61%), grain weight (41%), number of nodules (78%) and pod (88%), plant yield (76%), pod weight (53%) and total biomass (54%) were higher in PGPR and PGR treated chickpea plants grown in sandy soil. It is concluded from the present study that the integrative use of PGPR and PGRs is a promising method and eco-friendly strategy for increasing drought tolerance in crop plants.


Assuntos
Agricultura , Bacillaceae/fisiologia , Cicer/crescimento & desenvolvimento , Reguladores de Crescimento de Planta/farmacologia , Amônia/metabolismo , Bacillaceae/genética , Bacillaceae/isolamento & purificação , Bacillus megaterium/genética , Bacillus megaterium/isolamento & purificação , Bacillus subtilis/genética , Bacillus subtilis/isolamento & purificação , Bacillus subtilis/fisiologia , Biomassa , Clorofila/análise , Cicer/efeitos dos fármacos , Cicer/metabolismo , Ácidos Indolacéticos/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Reguladores de Crescimento de Planta/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Putrescina/metabolismo , Putrescina/farmacologia , RNA Ribossômico 16S/química , RNA Ribossômico 16S/metabolismo , Chuva , Ácido Salicílico/metabolismo , Ácido Salicílico/farmacologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Microbiologia do Solo
7.
Artigo em Inglês | MEDLINE | ID: mdl-32348929

RESUMO

Grain filling is the final determinant of yield, and this process is susceptible to abiotic stresses. Salicylic acid (SA) regulates grain filling in rice plants. A comparative proteomic study was conducted to understand how SA mediates grain filling under soil drying (SD) condition. Zhefu802 and its near-isogenic line (NIL) were planted in pots in an artificial chamber. SA (100 mg L-1) was applied, followed by SD treatment (with a water potential of -30 to -35 kPa) at anthesis. The results showed that the grain yield and grain weight significantly decreased under SD in Zhefu802, but not in its NIL variety. SD also decreased expression of photosynthesis-related proteins in grains of Zhefu802, which resulted in its poorer drought resistance. Furthermore, the decreased grain filling rate rather than the grain size explained the observed decreased grain weight and grain yield under SD. Interestingly, these reductions were reversed by SA. Expression of proteins involved in glycolysis/TCA circle, starch and sucrose metabolism, antioxidation and detoxication, oxidative phosphorylation, transcription, translation, and signal transduction, were significantly down-regulated under SD and were significantly up-regulated in response to SA. The expression of these proteins was examined at transcriptional level and similar results were obtained. Inhibited expression of these proteins and related pathways contributed to the observed decrease in the grain filling rate of Zhefu802, and application of SA up-regulated expression of these proteins to improve grain weight. The findings of this study provide new insights into grain filling regulation by SA, and offer the scientific foundation for cultivation practice.


Assuntos
Grão Comestível , Oryza , Proteoma , Ácido Salicílico , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Oryza/genética , Oryza/metabolismo , Proteômica , Ácido Salicílico/metabolismo , Solo/química
8.
PLoS Biol ; 18(3): e3000671, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32203514

RESUMO

Domesticated crops with high yield and quality are frequently susceptible to pathogen attack, whereas enhancement of disease resistance generally compromises crop yield. The underlying mechanisms of how plant development and disease resistance are coordinately programed remain elusive. Here, we showed that the basic Helix-Loop-Helix (bHLH) transcription factor Cucumis sativus Irregular Vasculature Patterning (CsIVP) was highly expressed in cucumber vascular tissues. Knockdown of CsIVP caused severe vasculature disorganization and abnormal organ morphogenesis. CsIVP directly binds to vascular-related regulators YABBY5 (CsYAB5), BREVIPEDICELLUS (CsBP), and AUXIN/INDOLEACETIC ACIDS4 (CsAUX4) and promotes their expression. Knockdown of CsYAB5 resulted in similar phenotypes as CsIVP-RNA interference (RNAi) plants, including disturbed vascular configuration and abnormal organ morphology. Meanwhile, CsIVP-RNAi plants were more resistant to downy mildew and accumulated more salicylic acid (SA). CsIVP physically interacts with NIM1-INTERACTING1 (CsNIMIN1), a negative regulator in the SA signaling pathway. Thus, CsIVP is a novel vasculature regulator functioning in CsYAB5-mediated organ morphogenesis and SA-mediated downy mildew resistance in cucumber.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/imunologia , Proteínas de Plantas/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Cucumis sativus/classificação , Cucumis sativus/genética , Resistência à Doença/genética , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/metabolismo , Morfogênese , Filogenia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Proteínas de Plantas/genética , Feixe Vascular de Plantas/genética , Feixe Vascular de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Ligação Proteica , Ácido Salicílico/metabolismo , Transdução de Sinais/genética
9.
Ecotoxicol Environ Saf ; 192: 110254, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32007746

RESUMO

The direct interactions of bacterial membranes and polycyclic aromatic hydrocarbons (PAHs) strongly influence the biological processes, such as metabolic activity and uptake of substrates due to changes in membrane lipids. However, the elucidation of adaptation mechanisms as well as membrane phospholipid alterations in the presence of phenanthrene (PHE) from α-proteobacteria has not been fully explored. This study was conducted to define the degradation efficiency of PHE by Sphingopyxis soli strain KIT-001 in a newly isolated from Jeonju river sediments and to characterize lipid profiles in the presence of PHE in comparison to cells grown on glucose using quantitative lipidomic analysis. This strain was able to respectively utilize 1-hydroxy-2-naphthoic acid and salicylic acid as sole carbon source and approximately 90% of PHE (50 mg/L) was rapidly degraded via naphthalene route within 1 day incubation. In the cells grown on PHE, strain KIT-001 appeared to dynamically change profiles of metabolite and lipid in comparison to cells grown on glucose. The levels of primary metabolites, phosphatidylethanolamines (PE), and phosphatidic acids (PA) were significantly decreased, whereas the levels of phosphatidylcholines (PC) and phosphatidylglycerols (PG) were significantly increased. The adaptation mechanism of Sphingopyxis sp. regarded mainly the accumulation of bilayer forming lipids and anionic lipids to adapt more quickly under restricted nutrition and toxicity condition. Hence, these findings are conceivable that strain KIT-001 has a good adaptive ability and biodegradation for PHE through the alteration of phospholipids, and will be helpful for applications for effective bioremediation of PAHs-contaminated sites.


Assuntos
Fenantrenos/metabolismo , Fosfolipídeos/metabolismo , Sphingomonadaceae/metabolismo , Biodegradação Ambiental , Sedimentos Geológicos/microbiologia , Lipidômica , Metabolômica , Naftalenos/metabolismo , Naftóis/metabolismo , Fosfolipídeos/química , Ácido Salicílico/metabolismo , Sphingomonadaceae/isolamento & purificação
10.
Proc Natl Acad Sci U S A ; 117(7): 3867-3873, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-32024752

RESUMO

In plants, enhanced defense often compromises growth and development, which is regarded as trade-offs between growth and defense. Here we identified a gene, OsALDH2B1, that functions as a master regulator of the growth-defense trade-off in rice. OsALDH2B1 has its primary function as an aldehyde dehydrogenase and a moonlight function as a transcriptional regulator. Loss of function of OsALDH2B1 greatly enhanced resistance to broad-spectrum pathogens, including fungal blast, bacterial leaf blight, and leaf streak, but caused severe phenotypic changes such as male sterility and reduced plant size, grain size, and number. We showed that its primary function as a mitochondrial aldehyde dehydrogenase conditions male fertility. Its moonlight function of transcriptional regulation, featuring both repressing and activating activities, regulates a diverse range of biological processes involving brassinolide, G protein, jasmonic acid, and salicylic acid signaling pathways. Such regulations cause large impacts on the morphology and immunity of rice plants. The versatile functions of OsALDH2B1 provide an example of the genic basis of growth-defense trade-offs in plants.


Assuntos
Aldeído Desidrogenase/imunologia , Regulação da Expressão Gênica de Plantas , Oryza/crescimento & desenvolvimento , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/imunologia , Aldeído Desidrogenase/genética , Ciclopentanos/metabolismo , Resistência à Doença , Magnaporthe/fisiologia , Oryza/genética , Oryza/metabolismo , Oryza/microbiologia , Oxilipinas/metabolismo , Doenças das Plantas/genética , Proteínas de Plantas/genética , Ácido Salicílico/metabolismo
11.
Artigo em Inglês | MEDLINE | ID: mdl-32005380

RESUMO

The soil-born vascular disease Verticillium wilt, which is caused by fungal pathogen Verticillium dahliae, is a devastating disease of cotton worldwide. In the last decade, a large number of genes have been found to participate in cotton-V. dahliae interactions, but the detailed mechanisms of cotton resistance to V. dahliae remain unclear. Here, we functionally characterized MPK3, a MAPK gene from cotton. MPK3 was induced in the roots of both resistant and susceptible cotton cultivars by V. dahliae inoculation. Transgenic cotton and tobacco with constitutively higher GbMPK3 expression conferred higher V. dahliae susceptibility, while MPK3 knockdown in cotton has limited effect on cotton resistance to V. dahliae. Expression profiling revealed that SA-mediated defense pathway genes (WRKY70, PR1, and PR5) accumulated after V. dahliae inoculation in roots of both wild-type and transgenic cotton, and the expression levels of these genes were higher in GbMPK3-overexpressing plants than in wild-type plants, indicating that GbMPK3 upregulation may reduce plant resistance to V. dahliae through regulating salicylic acid signaling transduction.


Assuntos
Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Gossypium/genética , Ácido Salicílico/metabolismo , Transdução de Sinais , Verticillium/fisiologia , Gossypium/metabolismo , Gossypium/microbiologia , Lycopersicon esculentum/genética , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/microbiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/microbiologia
12.
Artigo em Inglês | MEDLINE | ID: mdl-32005389

RESUMO

Salicylic acid (SA) plays an important role in the response of plants to abiotic stresses. Starvation stress affects plant cell metabolic activities, which further limits the normal growth and development of plants. It was reported that SA might play a regulatory role in the process of plant against starvation stress, but the mechanism involved in this process is still unclear. Thus, in this study, the transgenic plants overexpressing a SA binding protein 2 (SABP2) gene were exposed to starvation stress and the transgenic lines showed starvation-tolerant phenotype. Compared with wild-type (WT) plants, transgenic plants showed better growth status under poor-nutrition stress. Transgenic plants also showed more vigorous roots than WT plants. Physiological tests indicated that the transgenic plants showed higher relative water content (RWC), chlorophyll content, photosynthetic capacity, endogenous SA content, and lower ROS level compared to WT plants. Transcriptome analysis of tobacco plants identified 3, 748 differentially expressed genes (DEGs) between transgenic and WT plants under starvation stress. These DEGs are mainly involved in glycolysis/gluconeogenesis pathway group, MAPK signaling pathway group and plant hormone signal transduction pathway group. As determined by qPCR, up-regulated expression of fifteen genes such as abscisic acid receptor PYR1-like gene (NtPYR1-like), bidirectional sugar transporter N3-like gene (NtSWEETN3-like) and superoxide dismutase [Fe] chloroplastic-like gene (NtFeSOD-like), etc., was observed in transgenic plants under poor-nutrition stress which was in accordance with RNA-sequencing results. The modified pathways involved in plant hormone signaling are thought to be at least one of the main causes of the increased starvation tolerance of transgenic tobacco plants with altered SA homeostasis.


Assuntos
Esterases/genética , Regulação da Expressão Gênica de Plantas , Nutrientes/metabolismo , Proteínas de Plantas/genética , Ácido Salicílico/metabolismo , Tabaco/fisiologia , Esterases/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Estresse Fisiológico/genética , Tabaco/genética
13.
BMC Plant Biol ; 20(1): 16, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31914927

RESUMO

BACKGROUND: Food contamination with Salmonella enterica and enterohemorrhagic Escherichia coli is among the leading causes of foodborne illnesses worldwide and crop plants are associated with > 50% of the disease outbreaks. However, the mechanisms underlying the interaction of these human pathogens with plants remain elusive. In this study, we have explored plant resistance mechanisms against these enterobacteria and the plant pathogen Pseudomonas syringae pv. tomato (Pst) DC3118, as an opportunity to improve food safety. RESULTS: We found that S. enterica serovar Typhimurium (STm) transcriptionally modulates stress responses in Arabidopsis leaves, including induction of two hallmark processes of plant defense: ROS burst and cell wall modifications. Analyses of plants with a mutation in the potentially STm-induced gene EXO70H4 revealed that its encoded protein is required for stomatal defense against STm and E. coli O157:H7, but not against Pst DC3118. In the apoplast however, EXO70H4 is required for defense against STm and Pst DC3118, but not against E. coli O157:H7. Moreover, EXO70H4 is required for callose deposition, but had no function in ROS burst, triggered by all three bacteria. The salicylic acid (SA) signaling and biosynthesis proteins NPR1 and ICS1, respectively, were involved in stomatal and apoplastic defense, as well as callose deposition, against human and plant pathogens. CONCLUSIONS: The results show that EXO70H4 is involved in stomatal and apoplastic defenses in Arabidopsis and suggest that EXO70H4-mediated defense play a distinct role in guard cells and leaf mesophyll cells in a bacteria-dependent manner. Nonetheless, EXO70H4 contributes to callose deposition in response to both human and plant pathogens. NPR1 and ICS1, two proteins involved in the SA signaling pathway, are important to inhibit leaf internalization and apoplastic persistence of enterobacteria and proliferation of phytopathogens. These findings highlight the existence of unique and shared plant genetic components to fight off diverse bacterial pathogens providing specific targets for the prevention of foodborne diseases.


Assuntos
Proteínas de Arabidopsis , Escherichia coli O157 , Glucanos/metabolismo , Imunidade Vegetal , Salmonella enterica , Proteínas de Transporte Vesicular , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Parede Celular/metabolismo , Escherichia coli O157/metabolismo , Escherichia coli O157/patogenicidade , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Humanos , Transferases Intramoleculares/metabolismo , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Imunidade Vegetal/fisiologia , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Estômatos de Plantas/metabolismo , Pseudomonas syringae/metabolismo , Pseudomonas syringae/patogenicidade , Espécies Reativas de Oxigênio/metabolismo , Ácido Salicílico/metabolismo , Salmonella enterica/metabolismo , Salmonella enterica/patogenicidade , Transdução de Sinais , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo
14.
BMC Plant Biol ; 20(1): 38, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992205

RESUMO

BACKGROUD: Many Gram-negative bacteria use N-acyl-homoserine lactones (AHLs) to communicate each other and to coordinate their collective behaviors. Recently, accumulating evidence shows that host plants are able to sense and respond to bacterial AHLs. Once primed, plants are in an altered state that enables plant cells to more quickly and/or strongly respond to subsequent pathogen infection or abiotic stress. RESULTS: In this study, we report that pretreatment with N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL) confers resistance against the pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 (PstDC3000) in Arabidopsis. Pretreatment with 3OC8-HSL and subsequent pathogen invasion triggered an augmented burst of hydrogen peroxide, salicylic acid accumulation, and fortified expression of the pathogenesis-related genes PR1 and PR5. Upon PstDC3000 challenge, plants treated with 3OC8-HSL showed increased activities of defense-related enzymes including peroxidase, catalase, phenylalanine ammonialyase, and superoxide dismutase. In addition, the 3OC8-HSL-primed resistance to PstDC3000 in wild-type plants was impaired in plants expressing the bacterial NahG gene and in the npr1 mutant. Moreover, the expression levels of isochorismate synthases (ICS1), a critical salicylic acid biosynthesis enzyme, and two regulators of its expression, SARD1 and CBP60g, were potentiated by 3OC8-HSL pretreatment followed by pathogen inoculation. CONCLUSIONS: Our data indicate that 3OC8-HSL primes the Arabidopsis defense response upon hemibiotrophic bacterial infection and that 3OC8-HSL-primed resistance is dependent on the SA signaling pathway. These findings may help establish a novel strategy for the control of plant disease.


Assuntos
4-Butirolactona/análogos & derivados , Arabidopsis , Imunidade Vegetal/efeitos dos fármacos , Pseudomonas syringae/patogenicidade , Ácido Salicílico/metabolismo , 4-Butirolactona/farmacologia , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Ligação a Calmodulina/efeitos dos fármacos , Proteínas de Ligação a Calmodulina/genética , Proteínas de Ligação a Calmodulina/metabolismo , Genes de Plantas , Transferases Intramoleculares/efeitos dos fármacos , Transferases Intramoleculares/genética , Transferases Intramoleculares/metabolismo , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Percepção de Quorum/fisiologia , Transdução de Sinais/efeitos dos fármacos
15.
BMC Genomics ; 21(1): 28, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31914917

RESUMO

BACKGROUND: Fusarium circinatum, the causal agent of pitch canker disease, poses a serious threat to several Pinus species affecting plantations and nurseries. Although Pinus pinaster has shown moderate resistance to F. circinatum, the molecular mechanisms of defense in this host are still unknown. Phytohormones produced by the plant and by the pathogen are known to play a crucial role in determining the outcome of plant-pathogen interactions. Therefore, the aim of this study was to determine the role of phytohormones in F. circinatum virulence, that compromise host resistance. RESULTS: A high quality P. pinaster de novo transcriptome assembly was generated, represented by 24,375 sequences from which 17,593 were full length genes, and utilized to determine the expression profiles of both organisms during the infection process at 3, 5 and 10 days post-inoculation using a dual RNA-sequencing approach. The moderate resistance shown by Pinus pinaster at the early time points may be explained by the expression profiles pertaining to early recognition of the pathogen, the induction of pathogenesis-related proteins and the activation of complex phytohormone signaling pathways that involves crosstalk between salicylic acid, jasmonic acid, ethylene and possibly auxins. Moreover, the expression of F. circinatum genes related to hormone biosynthesis suggests manipulation of the host phytohormone balance to its own benefit. CONCLUSIONS: We hypothesize three key steps of host manipulation: perturbing ethylene homeostasis by fungal expression of genes related to ethylene biosynthesis, blocking jasmonic acid signaling by coronatine insensitive 1 (COI1) suppression, and preventing salicylic acid biosynthesis from the chorismate pathway by the synthesis of isochorismatase family hydrolase (ICSH) genes. These results warrant further testing in F. circinatum mutants to confirm the mechanism behind perturbing host phytohormone homeostasis.


Assuntos
Fusarium/patogenicidade , Pinus/genética , Pinus/microbiologia , Transcriptoma/genética , Ciclopentanos/metabolismo , Oxilipinas/metabolismo , Doenças das Plantas/microbiologia , Ácido Salicílico/metabolismo
16.
J Biotechnol ; 309: 113-130, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31935417

RESUMO

Salicylic acid (SA) and nitric oxide (NO) are considered as putative plant growth regulators that are involved in the regulation of an array of plant's growth and developmental functions under environmental fluctuations when applied at lower concentrations. The possible involvement of NO in SA induced attenuation of high temperature (HT) induced oxidative stress in plants is however, still vague and need to be explored. Therefore, the present study aimed to investigates the biochemical and physiological changes induced by foliar spray of SA and NO combinations to ameliorate HT induced oxidative stress in Lablab purpureus L. Foliar application of combined SA and NO significantly improved relative water content (27.8 %), photosynthetic pigment content (67.2 %), membrane stability (45 %), proline content (1.0 %), expression of enzymatic antioxidants (7.1-18 %) along with pod yield (1.0 %). Heat Shock Factors (HSFs) play crucial roles in plants abiotic stress tolerance, however there structural and functional classifications in L. purpureus L. is still unknown. So, In-silico approach was also used for functional characterization and homology modelling of HSFs in L. purpureus. The experimental findings depicted that combine effect of SA and NO enhances tolerance in HT stressed L. purpureus L. plants by regulating physiological functions, antioxidants, expression and regulation of stress-responsive genes via transcriptional regulation of heat shock factor.


Assuntos
Biologia Computacional/métodos , Fabaceae/metabolismo , Fatores de Transcrição de Choque Térmico/metabolismo , Temperatura Alta , Óxido Nítrico/metabolismo , Ácido Salicílico/metabolismo , Antioxidantes , Carotenoides/metabolismo , Clorofila/metabolismo , Evolução Molecular , Fabaceae/genética , Radicais Livres , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição de Choque Térmico/genética , Peróxido de Hidrogênio/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Fotossíntese/efeitos dos fármacos , Reguladores de Crescimento de Planta/metabolismo , Prolina/metabolismo , Domínios e Motivos de Interação entre Proteínas , Alinhamento de Sequência , Estresse Fisiológico
17.
Plant Cell Rep ; 39(4): 457-472, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31993730

RESUMO

KEY MESSAGE: Transgenic rice overexpressing PLCP attenuated the virulence of Xanthomonas oryzae pv. oryzae through extensive activation of transduction signal and transcription activities that orchestrate downstream responses including the biosynthesis of secondary metabolites and up-regulation of several pathogenesis-related proteins. High-throughput transcriptome investigations of plant immunity highlight the complexity of gene networks leading to incompatible interaction with the pathogen. Accumulating findings implicate papain-like cysteine proteases (PLCPs) as a central hub in plant defense. While diverse roles of PLCPs in different pathosystems have become more evident, information on gene networks and signaling pathways necessary to orchestrate downstream responses are lacking. To understand the biological significance of cysteine protease against Xanthomonas oryzae pv. oryzae, PLCP overexpression and knockout rice lines were generated. The pathogenicity test revealed the attenuation of Xanthomonas oryzae pv. oryzae race K3a virulence in transgenic lines which is ascribed to high hydrogen peroxide and free salicylic acid accumulation. Next-generation sequencing of RNA from transgenic and wild-type plants identified 1597 combined differentially expressed genes, 1269 of which were exclusively regulated in the transgenic libraries. It was found that PLCP aids rice to circumvent infection through the extensive activation of transduction signal and transcription factors that orchestrate downstream responses, including up-regulation of multiple pathogenesis-related proteins and biosynthesis of secondary metabolites.


Assuntos
Cisteína Endopeptidases/metabolismo , Resistência à Doença/genética , Oryza/enzimologia , Oryza/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Xanthomonas/patogenicidade , Cisteína Endopeptidases/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/imunologia , Técnicas de Inativação de Genes , Ontologia Genética , Genoma de Planta , Sequenciamento de Nucleotídeos em Larga Escala , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/imunologia , Peróxido de Hidrogênio/metabolismo , Oryza/genética , Oryza/imunologia , Doenças das Plantas/imunologia , Plantas Geneticamente Modificadas , Mapeamento de Interação de Proteínas , Interferência de RNA , RNA-Seq , Espécies Reativas de Oxigênio/metabolismo , Ácido Salicílico/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Transcriptoma , Regulação para Cima , Virulência
18.
Artigo em Inglês | MEDLINE | ID: mdl-31958679

RESUMO

Salicylic acid (SA) is involved in several responses associated with plant development and defence against biotic and abiotic stress, but its role on photosynthetic regulation is still under debate. This work investigated energy conversion processes and related gene expression in the brachytic mutant of sunflower lingering hope (linho). This mutant was characterized by a higher ratio between the free SA form and its conjugate form SA O-ß-D-glucoside (SAG) compared to wild type (WT), without significant changes in the endogenous level of abscisic acid and hydrogen peroxide. The mutant showed an inhibition of photosynthesis due to a combination of both stomatal and non-stomatal limitations, although the latter seemed to play a major role. The reduced carboxylation efficiency was associated with a down-regulation of the gene expression for both the large and small subunits of Rubisco and the Rubisco activase enzyme. Moreover, linho showed an alteration of photosystem II (PSII) functionality, with reduced PSII photochemistry, increased PSII excitation pressure and decreased thermal energy dissipation of excessive light energy. These responses were associated with a lower photosynthetic pigments concentration and a reduced expression of genes encoding for light-harvesting chlorophyll a/b binding proteins (i.e. HaLhcA), chlorophyll binding subunits of PSII proteins (i.e. HaPsbS and HaPsbX), phytoene synthase enzyme and a different expression level for genes related to PSII repair cycle, such as HaPsbA and HaPsbD. The concomitant stimulation of respiratory metabolism, suggests that linho activated a coordinate modulation of chloroplast and mitochondria activities to compensate the energy imbalance and regulate energy conversion processes.


Assuntos
Regulação da Expressão Gênica de Plantas , Helianthus , Ácido Salicílico , Clorofila/metabolismo , Helianthus/genética , Helianthus/metabolismo , Mutação , Fotossíntese/genética , Complexo de Proteína do Fotossistema II/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Ácido Salicílico/metabolismo
19.
BMC Genomics ; 21(1): 93, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996126

RESUMO

BACKGROUND: Whiteflies are a threat to cassava (Manihot esculenta), an important staple food in many tropical/subtropical regions. Understanding the molecular mechanisms regulating cassava's responses against this pest is crucial for developing control strategies. Pathogenesis-related (PR) protein families are an integral part of plant immunity. With the availability of whole genome sequences, the annotation and expression programs of the full complement of PR genes in an organism can now be achieved. An understanding of the responses of the entire complement of PR genes during biotic stress and to the defense hormones, salicylic acid (SA) and jasmonic acid (JA), is lacking. Here, we analyze the responses of cassava PR genes to whiteflies, SA, JA, and other biotic aggressors. RESULTS: The cassava genome possesses 14 of the 17 plant PR families, with a total of 447 PR genes. A cassava PR gene nomenclature is proposed. Phylogenetic relatedness of cassava PR proteins to each other and to homologs in poplar, rice and Arabidopsis identified cassava-specific PR gene family expansions. The temporal programs of PR gene expression in response to the whitefly (Aleurotrachelus socialis) in four whitefly-susceptible cassava genotypes showed that 167 of the 447 PR genes were regulated after whitefly infestation. While the timing of PR gene expression varied, over 37% of whitefly-regulated PR genes were downregulated in all four genotypes. Notably, whitefly-responsive PR genes were largely coordinately regulated by SA and JA. The analysis of cassava PR gene expression in response to five other biotic stresses revealed a strong positive correlation between whitefly and Xanthomonas axonopodis and Cassava Brown Streak Virus responses and negative correlations between whitefly and Cassava Mosaic Virus responses. Finally, certain associations between PR genes in cassava expansions and response to biotic stresses were observed among PR families. CONCLUSIONS: This study represents the first genome-wide characterization of PR genes in cassava. PR gene responses to six biotic stresses and to SA and JA are demonstrably different to other angiosperms. We propose that our approach could be applied in other species to fully understand PR gene regulation by pathogens, pests and the canonical defense hormones SA and JA.


Assuntos
Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Interações Hospedeiro-Parasita/genética , Manihot/genética , Manihot/parasitologia , Família Multigênica , Transcriptoma , Resistência à Doença/genética , Genótipo , Manihot/efeitos dos fármacos , Manihot/metabolismo , Oryza/genética , Filogenia , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Populus/genética , Populus/metabolismo , Reprodutibilidade dos Testes , Ácido Salicílico/metabolismo , Fatores de Tempo
20.
Mol Plant Microbe Interact ; 33(2): 223-234, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31544656

RESUMO

Streptomycetes are soil-dwelling, filamentous actinobacteria and represent a prominent bacterial clade inside the plant root microbiota. The ability of streptomycetes to produce a broad spectrum of antifungal metabolites suggests that these bacteria could be used to manage plant diseases. Here, we describe the identification of a soil Streptomyces strain named AgN23 which strongly activates a large array of defense responses when applied on Arabidopsis thaliana leaves. AgN23 increased the biosynthesis of salicylic acid, leading to the development of salicylic acid induction deficient 2 (SID2)-dependent necrotic lesions. Size exclusion fractionation of plant elicitors secreted by AgN23 showed that these signals are tethered into high molecular weight complexes. AgN23 mycelium was able to colonize the leaf surface, leading to plant resistance against Alternaria brassicicola infection in wild-type Arabidopsis plants. AgN23-induced resistance was found partially compromised in salicylate, jasmonate, and ethylene mutants. Our data show that Streptomyces soil bacteria can develop at the surface of plant leaves to induce defense responses and protection against foliar fungal pathogens, extending their potential use to manage plant diseases.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Resistência à Doença , Micoses , Streptomyces , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Resistência à Doença/fisiologia , Regulação da Expressão Gênica de Plantas , Mutação , Ácido Salicílico/metabolismo , Microbiologia do Solo , Streptomyces/crescimento & desenvolvimento , Streptomyces/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA