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1.
BMC Plant Biol ; 21(1): 376, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34399701

RESUMO

BACKGROUND: Glycolytic pathway is common in all plant organs, especially in oxygen-deficient tissues. Phosphofructokinase (PFK) is a rate-limiting enzyme in the glycolytic pathway and catalyses the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate. Cassava (M. esculenta) root is a huge storage organ with low amount of oxygen. However, less is known about the functions of PFK from M. esculenta (MePFK). We conducted a systematic analysis of MePFK genes to explore the function of the MePFK gene family under hypoxic stress. RESULTS: We identified 13 MePFK genes and characterised their sequence structure. The phylogenetic tree divided the 13 genes into two groups: nine were MePFKs and four were pyrophosphate-fructose-6-phosphate phosphotransferase (MePFPs). We confirmed by green fluorescent protein fusion protein expression that MePFK03 and MePFPA1 were localised in the chloroplast and cytoplasm, respectively. The expression profiles of the 13 MePFKs detected by quantitative reverse transcription polymerase chain reaction revealed that MePFK02, MePFK03, MePFPA1, MePFPB1 displayed higher expression in leaves, root and flower. The expression of MePFK03, MePFPA1 and MePFPB1 in tuber root increased gradually with plant growth. We confirmed that hypoxia occurred in the cassava root, and the concentration of oxygen was sharply decreasing from the outside to the inside root. The expression of MePFK03, MePFPA1 and MePFPB1 decreased with the decrease in the oxygen concentration in cassava root. Waterlogging stress treatment showed that the transcript level of PPi-dependent MePFP and MeSuSy were up-regulated remarkably and PPi-dependent glycolysis bypass was promoted. CONCLUSION: A systematic survey of phylogenetic relation, molecular characterisation, chromosomal and subcellular localisation and cis-element prediction of MePFKs were performed in cassava. The expression profiles of MePFKs in different development stages, organs and under waterlogging stress showed that MePFPA1 plays an important role during the growth and development of cassava. Combined with the transcriptional level of MeSuSy, we found that pyrophosphate (PPi)-dependent glycolysis bypass was promoted when cassava was under waterlogging stress. The results would provide insights for further studying the function of MePFKs under hypoxic stress.


Assuntos
Genoma de Planta , Manihot/enzimologia , Manihot/genética , Fosfofrutoquinases/genética , Fosfofrutoquinases/metabolismo , Cloroplastos/enzimologia , Mapeamento Cromossômico , Cromossomos de Plantas , Sequência Conservada , Citoplasma/enzimologia , Éxons , Flores/enzimologia , Íntrons , Família Multigênica , Oxigênio/metabolismo , Filogenia , Folhas de Planta/enzimologia , Raízes de Plantas/enzimologia , Regiões Promotoras Genéticas , Estresse Fisiológico/genética , Transcriptoma
2.
Nat Microbiol ; 6(7): 852-864, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34194036

RESUMO

The plant microbiota consists of a multitude of microorganisms that can affect plant health and fitness. However, it is currently unclear how the plant shapes its leaf microbiota and what role the plant immune system plays in this process. Here, we evaluated Arabidopsis thaliana mutants with defects in different parts of the immune system for an altered bacterial community assembly using a gnotobiotic system. While higher-order mutants in receptors that recognize microbial features and in defence hormone signalling showed substantial microbial community alterations, the absence of the plant NADPH oxidase RBOHD caused the most pronounced change in the composition of the leaf microbiota. The rbohD knockout resulted in an enrichment of specific bacteria. Among these, we identified Xanthomonas strains as opportunistic pathogens that colonized wild-type plants asymptomatically but caused disease in rbohD knockout plants. Strain dropout experiments revealed that the lack of RBOHD unlocks the pathogenicity of individual microbiota members driving dysbiosis in rbohD knockout plants. For full protection, healthy plants require both a functional immune system and a microbial community. Our results show that the NADPH oxidase RBOHD is essential for microbiota homeostasis and emphasizes the importance of the plant immune system in controlling the leaf microbiota.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/microbiologia , Homeostase , Microbiota , NADPH Oxidases/metabolismo , Arabidopsis/enzimologia , Arabidopsis/imunologia , Proteínas de Arabidopsis/genética , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/patogenicidade , Fenômenos Fisiológicos Bacterianos , Genótipo , NADPH Oxidases/genética , Fenótipo , Imunidade Vegetal/genética , Folhas de Planta/enzimologia , Folhas de Planta/imunologia , Folhas de Planta/microbiologia
3.
Int J Mol Sci ; 22(14)2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-34299202

RESUMO

Rice spotted leaf mutants are helpful to investigate programmed cell death (PCD) and defense response pathways in plants. Using a map-based cloning strategy, we characterized novel rice spotted leaf mutation splHM143 that encodes a 7-hydroxymethyl chlorophyll a reductase (OsHCAR). The wild-type (WT) allele could rescue the mutant phenotype, as evidenced by complementation analysis. OsHCAR was constitutively expressed at all rice tissues tested and its expression products localized to chloroplasts. The mutant exhibited PCD and leaf senescence with increased H2O2 (hydrogen peroxide) accumulation, increased of ROS (reactive oxygen species) scavenging enzymes activities and TUNEL (terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling) -positive nuclei, upregulation of PCD related genes, decreased chlorophyll (Chl) contents, downregulation of photosynthesis-related genes, and upregulation of senescence-associated genes. Besides, the mutant exhibited enhanced bacterial blight resistance with significant upregulation of defense response genes. Knockout lines of OsHCAR exhibited spotted leaf phenotype, cell death, leaf senescence, and showed increased resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo) coupled with upregulation of five pathogenesis-related marker genes. The overexpression of OsHCAR resulted in increased susceptibility to Xoo with decreased expression of pathogenesis-related marker genes. Altogether, our findings revealed that OsHCAR is involved in regulating cell death and defense response against bacterial blight pathogen in rice.


Assuntos
Resistência à Doença/imunologia , Oryza/imunologia , Oxirredutases/metabolismo , Doenças das Plantas/imunologia , Folhas de Planta/imunologia , Proteínas de Plantas/metabolismo , Xanthomonas/fisiologia , Clorofila/análogos & derivados , Clorofila/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/enzimologia , Oryza/crescimento & desenvolvimento , Oxirredutases/genética , Doenças das Plantas/microbiologia , Folhas de Planta/enzimologia , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética
4.
Biochemistry (Mosc) ; 86(7): 878-886, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34284711

RESUMO

The effects of superoxide dismutase (SOD) inhibitors, diethyldithiocarbamate (DDC), triethylenetetramine (trien), and their combination with glucose on cells of the epidermis from pea leaves of different age (rapidly growing young leaves and slowly growing old leaves) was investigated. DDC and trien caused death of the guard cells as determined by destruction of their nuclei. Glucose did not affect destruction of the nuclei induced by SOD inhibitors in the cells from old leaves, but intensified it in the cells from young leaves. 2-Deoxyglucose, an inhibitor of glycolysis, and propyl gallate, SOD-mimic and antioxidant, suppressed destruction of the nuclei that was caused by SOD inhibitors and glucose in cells of the epidermis from the young, but not from the old leaves. Glucose and trien stimulated, and propyl gallate reduced generation of reactive oxygen species (ROS) in the pea epidermis as determined by the fluorescence of 2',7'-dichlorofluorescein (DCF). Carbonyl cyanide m-chlorophenylhydrazone (CCCP), a protonophoric uncoupler of oxidative and photosynthetic phosphorylation, suppressed the DCF fluorescence in the guard cells. Treatment of the cells with CCCP followed by its removal with washing increased destruction of the nuclei caused by SOD inhibitors and glucose. In young leaves, CCCP was less effective than in old ones. The findings demonstrate the effects of SOD inhibitors and glucose on the cell death and generation of ROS and could indicate glycolysis-dependent ROS production.


Assuntos
Ditiocarb/farmacologia , Glucose/metabolismo , Ervilhas/efeitos dos fármacos , Epiderme Vegetal/efeitos dos fármacos , Espécies Reativas de Oxigênio , Superóxido Dismutase/antagonistas & inibidores , Trientina/farmacologia , Morte Celular , Quelantes/farmacologia , Inibidores Enzimáticos/farmacologia , Glucose/farmacologia , Ervilhas/enzimologia , Ervilhas/metabolismo , Ervilhas/fisiologia , Epiderme Vegetal/enzimologia , Epiderme Vegetal/metabolismo , Epiderme Vegetal/fisiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia
5.
Int J Mol Sci ; 22(9)2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34067069

RESUMO

Banana (Musa spp.), one of the most important fruits worldwide, is generally cold sensitive. In this study, by using the cold-sensitive banana variety Tianbaojiao (Musa acuminate) as the study material, we investigated the effects of Piriformospora indica on banana cold resistance. Seedlings with and without fungus colonization were subjected to 4 °C cold treatment. The changes in plant phenotypes, some physiological and biochemical parameters, chlorophyll fluorescence parameters, and the expression of eight cold-responsive genes in banana leaves before and after cold treatment were measured. Results demonstrated that P. indica colonization reduced the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2) but increased the activities of superoxide dismutase (SOD) and catalase (CAT) and the contents of soluble sugar (SS) and proline. Noteworthily, the CAT activity and SS content in the leaves of P. indica-colonized banana were significant (p < 0.05). After 24 h cold treatment, the decline in maximum photochemistry efficiency of photosystem II (Fv/Fm), photochemical quenching coefficient (qP), efficient quantum yield [Y(II)], and photosynthetic electron transport rate (ETR) in the leaves of P. indica-colonized banana was found to be lower than in the non-inoculated controls (p < 0.05). Moreover, although the difference was not significant, P. indica colonization increased the photochemical conversion efficiency and electron transport rate and alleviated the damage to the photosynthetic reaction center of banana leaves under cold treatment to some extent. Additionally, the expression of the most cold-responsive genes in banana leaves was significantly induced by P. indica during cold stress (p < 0.05). It was concluded that P. indica confers banana with enhanced cold resistance by stimulating antioxidant capacity, SS accumulation, and the expression of cold-responsive genes in leaves. The results obtained from this study are helpful for understanding the P. indica-induced cold resistance in banana.


Assuntos
Basidiomycota/fisiologia , Temperatura Baixa , Resistência à Doença , Endófitos/fisiologia , Musa/enzimologia , Basidiomycota/crescimento & desenvolvimento , Catalase/metabolismo , Clorofila/metabolismo , Contagem de Colônia Microbiana , Eletrólitos/metabolismo , Fluorescência , Regulação da Expressão Gênica de Plantas , Musa/genética , Musa/microbiologia , Peroxidase/metabolismo , Fenótipo , Folhas de Planta/enzimologia , Folhas de Planta/microbiologia , Folhas de Planta/fisiologia , Superóxido Dismutase/metabolismo
6.
Mol Plant Pathol ; 22(7): 786-799, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33955635

RESUMO

Pattern-triggered immunity (PTI) is typically initiated in plants by recognition of pathogen- or damage-associated molecular patterns (PAMP/DAMPs) by cell surface-localized pattern recognition receptors (PRRs). Here, we investigated the role in PTI of Arabidopsis thaliana brassinosteroid-signalling kinases 7 and 8 (BSK7 and BSK8), which are members of the receptor-like cytoplasmic kinase subfamily XII. BSK7 and BSK8 localized to the plant cell periphery and interacted in yeast and in planta with FLS2, but not with other PRRs. Consistent with a role in FLS2 signalling, bsk7 and bsk8 single and bsk7,8 double mutant plants were impaired in several immune responses induced by flg22, but not by other PAMP/DAMPs. These included resistance to Pseudomonas syringae and Botrytis cinerea, reactive oxygen species accumulation, callose deposition at the cell wall, and expression of the defence-related gene PR1, but not activation of MAP kinases and expression of the FRK1 and WRKY29 genes. bsk7, bsk8, and bsk7,8 plants also displayed enhanced susceptibility to P. syringae and B. cinerea. Finally, BSK7 and BSK8 variants mutated in their myristoylation site or in the ATP-binding site failed to complement defective phenotypes of the corresponding mutants, suggesting that localization to the cell periphery and kinase activity are critical for BSK7 and BSK8 functions. Together, these findings demonstrate that BSK7 and BSK8 play a role in PTI initiated by recognition of flg22 by interacting with the FLS2 immune receptor.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Botrytis/fisiologia , Doenças das Plantas/imunologia , Imunidade Vegetal , Pseudomonas syringae/fisiologia , Arabidopsis/enzimologia , Arabidopsis/microbiologia , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Brassinosteroides/metabolismo , Membrana Celular/metabolismo , Glucanos/metabolismo , Mutação com Perda de Função , Doenças das Plantas/microbiologia , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/microbiologia , Folhas de Planta/fisiologia , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Receptores de Reconhecimento de Padrão , Transdução de Sinais
7.
Int J Mol Sci ; 22(6)2021 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-33805821

RESUMO

Drought is the most serious abiotic stress, which significantly reduces crop productivity. The phytohormone ABA plays a pivotal role in regulating stomatal closing upon drought stress. Here, we characterized the physiological function of AtBBD1, which has bifunctional nuclease activity, on drought stress. We found that AtBBD1 localized to the nucleus and cytoplasm, and was expressed strongly in trichomes and stomatal guard cells of leaves, based on promoter:GUS constructs. Expression analyses revealed that AtBBD1 and AtBBD2 are induced early and strongly by ABA and drought, and that AtBBD1 is also strongly responsive to JA. We then compared phenotypes of two AtBBD1-overexpression lines (AtBBD1-OX), single knockout atbbd1, and double knockout atbbd1/atbbd2 plants under drought conditions. We did not observe any phenotypic difference among them under normal growth conditions, while OX lines had greatly enhanced drought tolerance, lower transpirational water loss, and higher proline content than the WT and KOs. Moreover, by measuring seed germination rate and the stomatal aperture after ABA treatment, we found that AtBBD1-OX and atbbd1 plants showed significantly higher and lower ABA-sensitivity, respectively, than the WT. RNA sequencing analysis of AtBBD1-OX and atbbd1 plants under PEG-induced drought stress showed that overexpression of AtBBD1 enhances the expression of key regulatory genes in the ABA-mediated drought signaling cascade, particularly by inducing genes related to ABA biosynthesis, downstream transcription factors, and other regulatory proteins, conferring AtBBD1-OXs with drought tolerance. Taken together, we suggest that AtBBD1 functions as a novel positive regulator of drought responses by enhancing the expression of ABA- and drought stress-responsive genes as well as by increasing proline content.


Assuntos
Ácido Abscísico/metabolismo , Adaptação Fisiológica/genética , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Endonucleases/genética , Regulação da Expressão Gênica de Plantas , Ácido Abscísico/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/enzimologia , Proteínas de Arabidopsis/agonistas , Proteínas de Arabidopsis/antagonistas & inibidores , Proteínas de Arabidopsis/metabolismo , Núcleo Celular/metabolismo , Ciclopentanos/metabolismo , Ciclopentanos/farmacologia , Citoplasma/metabolismo , Secas , Endonucleases/antagonistas & inibidores , Endonucleases/metabolismo , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Oxilipinas/metabolismo , Oxilipinas/farmacologia , Células Vegetais/efeitos dos fármacos , Células Vegetais/enzimologia , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/genética , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/enzimologia , Estômatos de Plantas/genética , Plantas Geneticamente Modificadas , Prolina/metabolismo , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Água/metabolismo
8.
Plant J ; 106(2): 301-313, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33735498

RESUMO

The leaf vascular bundle sheath cells (BSCs) that tightly envelop the leaf veins, are a selective and dynamic barrier to xylem sap water and solutes radially entering the mesophyll cells. Under normal conditions, xylem sap pH below 6 is presumably important for driving and regulating the transmembranal solute transport. Having discovered recently a differentially high expression of a BSC proton pump, AHA2, we now test the hypothesis that it regulates the xylem sap pH and leaf radial water fluxes. We monitored the xylem sap pH in the veins of detached leaves of wild-type Arabidopsis, AHA mutants and aha2 mutants complemented with AHA2 gene solely in BSCs. We tested an AHA inhibitor (vanadate) and stimulator (fusicoccin), and different pH buffers. We monitored their impact on the xylem sap pH and the leaf hydraulic conductance (Kleaf ), and the effect of pH on the water osmotic permeability (Pf ) of isolated BSCs protoplasts. We found that AHA2 is necessary for xylem sap acidification, and in turn, for elevating Kleaf . Conversely, AHA2 knockdown, which alkalinized the xylem sap, or, buffering its pH to 7.5, reduced Kleaf , and elevating external pH to 7.5 decreased the BSCs Pf . All these showed a causative link between AHA2 activity in BSCs and leaf radial hydraulic water conductance.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Folhas de Planta/fisiologia , ATPases Translocadoras de Prótons/metabolismo , Xilema/fisiologia , Arabidopsis/enzimologia , Arabidopsis/metabolismo , Concentração de Íons de Hidrogênio , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Estômatos de Plantas/citologia , Estômatos de Plantas/enzimologia , Estômatos de Plantas/fisiologia , Transpiração Vegetal/fisiologia , Xilema/enzimologia , Xilema/metabolismo
9.
Plant Physiol ; 185(2): 352-368, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33721894

RESUMO

KLU, encoded by a cytochrome P450 CYP78A family gene, generates an important-albeit unknown-mobile signal that is distinct from the classical phytohormones. Multiple lines of evidence suggest that KLU/KLU-dependent signaling functions in several vital developmental programs, including leaf initiation, leaf/floral organ growth, and megasporocyte cell fate. However, the interactions between KLU/KLU-dependent signaling and the other classical phytohormones, as well as how KLU influences plant physiological responses, remain poorly understood. Here, we applied in-depth, multi-omics analysis to monitor transcriptome and metabolome dynamics in klu-mutant and KLU-overexpressing Arabidopsis plants. By integrating transcriptome sequencing data and primary metabolite profiling alongside phytohormone measurements, our results showed that cytokinin signaling, with its well-established function in delaying leaf senescence, was activated in KLU-overexpressing plants. Consistently, KLU-overexpressing plants exhibited significantly delayed leaf senescence and increased leaf longevity, whereas the klu-mutant plants showed early leaf senescence. In addition, proline biosynthesis and catabolism were enhanced following KLU overexpression owing to increased expression of genes associated with proline metabolism. Furthermore, KLU-overexpressing plants showed enhanced drought-stress tolerance and reduced water loss. Collectively, our work illustrates a role for KLU in positively regulating leaf longevity and drought tolerance by synergistically activating cytokinin signaling and promoting proline metabolism. These data promote KLU as a potential ideal genetic target to improve plant fitness.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Sistema Enzimático do Citocromo P-450/metabolismo , Citocininas/metabolismo , Metaboloma , Reguladores de Crescimento de Plantas/metabolismo , Transdução de Sinais , Transcriptoma , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Sistema Enzimático do Citocromo P-450/genética , Secas , Expressão Gênica , Genômica , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/fisiologia , Prolina/metabolismo , Estresse Fisiológico
10.
Int J Mol Sci ; 22(4)2021 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-33670070

RESUMO

The present study aimed to investigate the enzymatic potential of Silybum marianum leaves to bioconvert phenolic acids produced in S. marianum callus into silymarin derivatives as chemopreventive agent. Here we demonstrate that despite the fact that leaves of S. marianum did not accumulate silymarin themselves, expanding leaves had the full capacity to convert di-caffeoylquinic acid to silymarin complex. This was proven by HPLC separations coupled with electrospray ionization mass spectrometry (ESI-MS) analysis. Soaking the leaf discs with S. marianum callus extract for different times revealed that silymarin derivatives had been formed at high yield after 16 h. Bioconverted products displayed the same retention time and the same mass spectra (MS or MS/MS) as standard silymarin. Bioconversion was achieved only when using leaves of a specific age, as both very young and old leaves failed to produce silymarin from callus extract. Only medium leaves had the metabolic capacity to convert callus components into silymarin. The results revealed higher activities of enzymes of the phenylpropanoid pathway in medium leaves than in young and old leaves. It is concluded that cotyledon-derived callus efficiently produces compounds that can be bio-converted to flavonolignans in leaves tissue of S. marianum.


Assuntos
Cardo-Mariano/química , Compostos Fitoquímicos/farmacologia , Folhas de Planta/química , Silimarina/farmacologia , Extratos Vegetais/química , Folhas de Planta/enzimologia , Espectrometria de Massas por Ionização por Electrospray , Temperatura
11.
Plant Physiol ; 185(2): 441-456, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33580795

RESUMO

Age-dependent changes in reactive oxygen species (ROS) levels are critical in leaf senescence. While H2O2-reducing enzymes such as catalases and cytosolic ASCORBATE PEROXIDASE1 (APX1) tightly control the oxidative load during senescence, their regulation and function are not specific to senescence. Previously, we identified the role of ASCORBATE PEROXIDASE6 (APX6) during seed maturation in Arabidopsis (Arabidopsis thaliana). Here, we show that APX6 is a bona fide senescence-associated gene. APX6 expression is specifically induced in aging leaves and in response to senescence-promoting stimuli such as abscisic acid (ABA), extended darkness, and osmotic stress. apx6 mutants showed early developmental senescence and increased sensitivity to dark stress. Reduced APX activity, increased H2O2 level, and altered redox state of the ascorbate pool in mature pre-senescing green leaves of the apx6 mutants correlated with the early onset of senescence. Using transient expression assays in Nicotiana benthamiana leaves, we unraveled the age-dependent post-transcriptional regulation of APX6. We then identified the coding sequence of APX6 as a potential target of miR398, which is a key regulator of copper redistribution. Furthermore, we showed that mutants of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE7 (SPL7), the master regulator of copper homeostasis and miR398 expression, have a higher APX6 level compared with the wild type, which further increased under copper deficiency. Our study suggests that APX6 is a modulator of ROS/redox homeostasis and signaling in aging leaves that plays an important role in developmental- and stress-induced senescence programs.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Ascorbato Peroxidases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Ácido Abscísico/metabolismo , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Ascorbato Peroxidases/genética , Cobre/deficiência , Proteínas de Ligação a DNA/genética , Escuridão , Homeostase , Peróxido de Hidrogênio/metabolismo , MicroRNAs/genética , Oxirredução , Reguladores de Crescimento de Plantas/metabolismo , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Fatores de Tempo , Tabaco/enzimologia , Tabaco/genética , Tabaco/fisiologia , Fatores de Transcrição/genética
12.
Nat Commun ; 12(1): 735, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33531490

RESUMO

Nitrogen (N) and carbon (C) are essential elements for plant growth and crop yield. Thus, improved N and C utilisation contributes to agricultural productivity and reduces the need for fertilisation. In the present study, we find that overexpression of a single rice gene, Oryza sativa plasma membrane (PM) H+-ATPase 1 (OSA1), facilitates ammonium absorption and assimilation in roots and enhanced light-induced stomatal opening with higher photosynthesis rate in leaves. As a result, OSA1 overexpression in rice plants causes a 33% increase in grain yield and a 46% increase in N use efficiency overall. As PM H+-ATPase is highly conserved in plants, these findings indicate that the manipulation of PM H+-ATPase could cooperatively improve N and C utilisation, potentially providing a vital tool for food security and sustainable agriculture.


Assuntos
Membrana Celular/metabolismo , Oryza/enzimologia , Oryza/metabolismo , Proteínas de Plantas/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Compostos de Amônio/metabolismo , Transporte Biológico , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Oryza/fisiologia , Fotossíntese/genética , Fotossíntese/fisiologia , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia
13.
Int J Mol Sci ; 22(2)2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33477636

RESUMO

Soybean (Glycine max L.) is a major crop providing important source for protein and oil for human life. Low phosphate (LP) availability is a critical limiting factor affecting soybean production. Soybean plants develop a series of strategies to adapt to phosphate (Pi) limitation condition. However, the underlying molecular mechanisms responsible for LP stress response remain largely unknown. Here, we performed a label-free quantification (LFQ) analysis of soybean leaves grown under low and high phosphate conditions. We identified 267 induced and 440 reduced differential proteins from phosphate-starved leaves. Almost a quarter of the LP decreased proteins are involved in translation processes, while the LP increased proteins are accumulated in chlorophyll biosynthetic and carbon metabolic processes. Among these induced proteins, an enolase protein, GmENO2a was found to be mostly induced protein. On the transcriptional level, GmENO2a and GmENO2b, but not GmENO2c or GmENO2d, were dramatically induced by phosphate starvation. Among 14 enolase genes, only GmENO2a and GmENO2b genes contain the P1BS motif in their promoter regions. Furthermore, GmENO2b was specifically induced in the GmPHR31 overexpressing soybean plants. Our findings provide molecular insights into how soybean plants tune basic carbon metabolic pathway to adapt to Pi deprivation through the ENO2 enzymes.


Assuntos
Adaptação Fisiológica/genética , Fosfopiruvato Hidratase/genética , Proteômica , Soja/genética , Regulação da Expressão Gênica de Plantas/genética , Fosfatos/metabolismo , Fosfopiruvato Hidratase/metabolismo , Folhas de Planta/enzimologia , Folhas de Planta/genética , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Soja/enzimologia
14.
Sci Rep ; 11(1): 46, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420129

RESUMO

The stems of bioenergy sorghum hybrids at harvest are > 4 m long, contain > 40 internodes and account for ~ 80% of harvested biomass. In this study, bioenergy sorghum hybrids were grown at four planting densities (~ 20,000 to 132,000 plants/ha) under field conditions for 60 days to investigate the impact shading has on stem growth and biomass accumulation. Increased planting density induced a > 2-fold increase in sorghum internode length and a ~ 22% decrease in stem diameter, a typical shade avoidance response. Shade-induced internode elongation was due to an increase in cell length and number of cells spanning the length of internodes. SbGA3ox2 (Sobic.003G045900), a gene encoding the last step in GA biosynthesis, was expressed ~ 20-fold higher in leaf collar tissue of developing phytomers in plants grown at high vs. low density. Application of GA3 to bioenergy sorghum increased plant height, stem internode length, cell length and the number of cells spanning internodes. Prior research showed that sorghum plants lacking phytochrome B, a key photoreceptor involved in shade signaling, accumulated more GA1 and displayed shade avoidance phenotypes. These results are consistent with the hypothesis that increasing planting density induces expression of GA3-oxidase in leaf collar tissue, increasing synthesis of GA that stimulates internode elongation.


Assuntos
Giberelinas/metabolismo , Oxigenases de Função Mista/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Caules de Planta/crescimento & desenvolvimento , Sorghum/metabolismo , Metabolismo Energético , Regulação da Expressão Gênica de Plantas , Folhas de Planta/enzimologia , Caules de Planta/metabolismo , Sorghum/crescimento & desenvolvimento , Sorghum/fisiologia
15.
Biomolecules ; 11(2)2021 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-33503885

RESUMO

Lipoxygenases are widespread enzymes that catalyze oxidation of polyunsaturated fatty acids (linoleic, linolenic, and arachidonic acid) to produce hydroperoxides. Lipoxygenase reactions can be desirable, but also lipoxygenases can react in undesirable ways. Most of the products of lipoxygenase reactions are aromatic compounds that can affect food properties, especially during long-term storage. Lipoxygenase action on unsaturated fatty acids could result in off-flavor/off-odor development, causing food spoilage. In addition, lipoxygenases are present in the human body and play an important role in stimulation of inflammatory reactions. Inflammation is linked to many diseases, such as cancer, stroke, and cardiovascular and neurodegenerative diseases. This review summarized recent research on plant families and species that can inhibit lipoxygenase activity.


Assuntos
Ácidos Graxos Insaturados/química , Inflamação/tratamento farmacológico , Inibidores de Lipoxigenase/farmacologia , Oxigênio/química , Extratos Vegetais/farmacologia , Animais , Araquidonato 15-Lipoxigenase/biossíntese , Araquidonato 5-Lipoxigenase/biossíntese , Ácido Araquidônico , Ácidos Graxos , Flores/enzimologia , Humanos , Peróxido de Hidrogênio/química , Concentração Inibidora 50 , Lipoxigenase/metabolismo , Inibidores de Lipoxigenase/química , Oxirredução , Folhas de Planta/enzimologia , Polifenóis/química
16.
Int J Mol Sci ; 22(2)2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33445552

RESUMO

Production of a volatile phenylpropene; eugenol in sweet basil is mostly associated with peltate glandular trichomes (PGTs) found aerially. Currently only one eugenol synthase (EGS), ObEGS1 which belongs to PIP family is identified from sweet basil PGTs. Reports of the presence of eugenol in roots led us to analyse other EGSs in roots. We screened for all the PIP family reductase transcripts from the RNA-Seq data. In vivo functional characterization of all the genes in E. coli showed their ability to produce eugenol and were termed as ObEGS2-8. Among all, ObEGS1 displayed highest expression in PGTs and ObEGS4 in roots. Further, eugenol was produced only in the roots of soil-grown plants, but not in roots of aseptically-grown plants. Interestingly, eugenol production could be induced in roots of aseptically-grown plants under elicitation suggesting that eugenol production might occur as a result of environmental cues in roots. The presence of ObEGS4 transcript and protein in aseptically-grown plants indicated towards post-translational modifications (PTMs) of ObEGS4. Bioinformatics analysis showed possibility of phosphorylation in ObEGS4 which was further confirmed by in vitro experiment. Our study reveals the presence of multiple eugenol synthases in sweet basil and provides new insights into their diversity and tissue specific regulation.


Assuntos
Eugenol/metabolismo , Ocimum basilicum/fisiologia , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Raízes de Plantas/enzimologia , Tricomas/enzimologia , Sequência de Aminoácidos , Eugenol/química , Cromatografia Gasosa-Espectrometria de Massas , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Imuno-Histoquímica , Ocimum basilicum/química , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/química , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/genética , Folhas de Planta/química , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Fenômenos Fisiológicos Vegetais , Regiões Promotoras Genéticas , Sequências Reguladoras de Ácido Nucleico , Tabaco/fisiologia
17.
Plant Physiol Biochem ; 160: 211-217, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33515970

RESUMO

Citrate is an important intermediate product for the biosynthesis of several metabolites in plants. As two important organs of the citrus plant, fruits and leaves have their own metabolites characteristics; among them, citrate is normally high in fruit juice sacs (JS) and low in leaves. In this study, citrate content and transcript levels of citrate synthesis, transport, storage, and utilization related genes were compared between leaves and fruit JS of Citrus reticulata cv. 'Huagan No. 2', C. grandis cv. 'Hirado Buntan', and C. sinensis cv. 'Anliu'. Results indicated that the citrate content in fruit JS was significantly higher than in leaves of each cultivar. Only the relative mRNA levels of a P-type proton pump gene, CsPH8, was significantly lower in leaves than in fruit JS of three citrus cultivars, while other genes related to citrate biosynthesis, transport, storage, and utilization were highly expressed in leaves as compared to fruit JS. Furthermore, CsPH8 transient and stable transformation in leaves indicated that the change in citrate content is highly consistent with the change of CsPH8 transcript levels. Taken together, our results strongly suggest that the low accumulation of citrate in citrus leaves is mainly due to the low expression level of CsPH8; additionally, the high level of expression of citrate-utilizing genes would prevent citrate accumulation in the leaf organ.


Assuntos
Ácido Cítrico/análise , Citrus , ATPases do Tipo-P/genética , Folhas de Planta/química , Proteínas de Plantas/genética , Citrus/enzimologia , Citrus/genética , Regulação da Expressão Gênica de Plantas , Folhas de Planta/enzimologia
18.
Plant Cell Rep ; 40(2): 361-374, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33392730

RESUMO

KEY MESSAGE: MANNANASE7 gene in Brassica napus L. encodes a hemicellulose which located at cell wall or extracellular space and dehiscence-resistance can be manipulated by altering the expression of MANNANASE7. Silique dehiscence is an important physiological process in plant reproductive development, but causes heavy yield loss in crops. The lack of dehiscence-resistant germplasm limits the application of mechanized harvesting and greatly restricts the rapeseed (Brassica napus L.) production. Hemicellulases, together with cellulases and pectinases, play important roles in fruit development and maturation. The hemicellulase gene MANNANASE7 (MAN7) was previously shown to be involved in the development and dehiscence of Arabidopsis (Arabidopsis thaliana) siliques. Here, we cloned BnaA07g12590D (BnMAN7A07), an AtMAN7 homolog from rapeseed, and demonstrate its function in the dehiscence of rapeseed siliques. We found that BnMAN7A07 was expressed in both vegetative and reproductive organs and significantly highly expressed in leaves, flowers and siliques where the abscission or dehiscence process occurs. Subcellular localization experiment showed that BnMAN7A07 was localized in the cell wall. The biological activity of the BnMAN7A07 protein isolated and purified through prokaryotic expression system was verified to catalyse the decomposition of xylan into xylose. Phenotypic studies of RNA interference (RNAi) lines revealed that down-regulation of BnMAN7A07 in rapeseed could significantly enhance silique dehiscence-resistance. In addition, the expression of upstream silique development regulators is altered in BnMAN7A07-RNAi plants, suggesting that a possible feedback regulation mechanism exists in the regulation network of silique dehiscence. Our results demonstrate that dehiscence-resistance can be manipulated by altering the expression of hemicellulase gene BnMAN7A07, which could provide an available genetic resource for breeding practice in rapeseed which is beneficial to mechanized harvest.


Assuntos
Brassica napus/enzimologia , Glicosídeo Hidrolases/metabolismo , Polissacarídeos/metabolismo , Arabidopsis/enzimologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brassica napus/genética , Parede Celular/enzimologia , Regulação para Baixo , Espaço Extracelular/enzimologia , Flores/enzimologia , Flores/genética , Regulação da Expressão Gênica de Plantas , Glicosídeo Hidrolases/genética , Manosidases/genética , Manosidases/metabolismo , Melhoramento Vegetal , Folhas de Planta/enzimologia , Folhas de Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
19.
Photosynth Res ; 147(2): 211-227, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33393063

RESUMO

C4-like plants represent the penultimate stage of evolution from C3 to C4 plants. Although Coleataenia prionitis (formerly Panicum prionitis) has been described as a C4 plant, its leaf anatomy and gas exchange traits suggest that it may be a C4-like plant. Here, we reexamined the leaf structure and biochemical and physiological traits of photosynthesis in this grass. The large vascular bundles were surrounded by two layers of bundle sheath (BS): a colorless outer BS and a chloroplast-rich inner BS. Small vascular bundles, which generally had a single BS layer with various vascular structures, also occurred throughout the mesophyll together with BS cells not associated with vascular tissue. The mesophyll cells did not show a radial arrangement typical of Kranz anatomy. These features suggest that the leaf anatomy of C. prionitis is on the evolutionary pathway to a complete C4 Kranz type. Phosphoenolpyruvate carboxylase (PEPC) and pyruvate, Pi dikinase occurred in the mesophyll and outer BS. Glycine decarboxylase was confined to the inner BS. Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) accumulated in the mesophyll and both BSs. C. prionitis had biochemical traits of NADP-malic enzyme type, whereas its gas exchange traits were close to those of C4-like intermediate plants rather than C4 plants. A gas exchange study with a PEPC inhibitor suggested that Rubisco in the mesophyll could fix atmospheric CO2. These data demonstrate that C. prionitis is not a true C4 plant but should be considered as a C4-like plant.


Assuntos
Dióxido de Carbono/metabolismo , Fotossíntese , Poaceae/fisiologia , Cloroplastos/enzimologia , Cloroplastos/fisiologia , Cloroplastos/ultraestrutura , Glicina Desidrogenase (Descarboxilante)/metabolismo , Malato Desidrogenase/metabolismo , Células do Mesofilo/enzimologia , Células do Mesofilo/fisiologia , Células do Mesofilo/ultraestrutura , Fenótipo , Fosfoenolpiruvato Carboxilase/antagonistas & inibidores , Fosfoenolpiruvato Carboxilase/metabolismo , Folhas de Planta/enzimologia , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Proteínas de Plantas/metabolismo , Poaceae/enzimologia , Poaceae/ultraestrutura , Ribulose-Bifosfato Carboxilase/metabolismo
20.
Appl Biochem Biotechnol ; 193(2): 389-404, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33009584

RESUMO

Proteolytic enzymes are widely distributed in nature, playing essential roles in important biological functions. Recently, the use of plant proteases at the industrial level has mainly increased in the food industry (e.g., cheesemaking, meat tenderizing, and protein hydrolysate production). Current technological and scientific advances in the detection and characterization of proteolytic enzymes have encouraged the search for new natural sources. Thus, this work aimed to explore the milk-clotting and proteolytic properties of different tissues of Vallesia glabra. Aqueous extracts from the leaves, fruits, and seeds of V. glabra presented different protein profiles, proteolytic activity, and milk-clotting activity. The milk-clotting activity increased with temperature (30-65 °C), but this activity was higher in leaf (0.20 MCU/mL) compared with that in fruit and seed extracts (0.12 and 0.11 MCU/mL, respectively) at 50 °C. Proteolytic activity in the extracts assayed at different pH (2.5-12.0) suggested the presence of different types of active proteases, with maximum activity at acidic conditions (4.0-4.5). Inhibitory studies indicated that major activity in V. glabra extracts is related to cysteine proteases; however, the presence of serine, aspartic, and metalloproteases was also evident. The hydrolytic profile of caseins indicated that V. glabra leaves could be used as a rennet substitute in cheesemaking, representing a new and promising source of proteolytic enzymes.


Assuntos
Apocynaceae/enzimologia , Leite/química , Peptídeo Hidrolases/química , Folhas de Planta/enzimologia , Proteínas de Plantas/química , Proteólise , Sementes/enzimologia , Animais , Concentração de Íons de Hidrogênio
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