Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 82
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int J Mol Sci ; 23(15)2022 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-35955654

RESUMO

Global warming and drought stress are expected to have a negative impact on agricultural productivity. Desiccation-tolerant species, which are able to tolerate the almost complete desiccation of their vegetative tissues, are appropriate models to study extreme drought tolerance and identify novel approaches to improve the resistance of crops to drought stress. In the present study, to better understand what makes resurrection plants extremely tolerant to drought, we performed transmission electron microscopy and integrative large-scale proteomics, including organellar and phosphorylation proteomics, and combined these investigations with previously published transcriptomic and metabolomics data from the resurrection plant Haberlea rhodopensis. The results revealed new evidence about organelle and cell preservation, posttranscriptional and posttranslational regulation, photosynthesis, primary metabolism, autophagy, and cell death in response to desiccation in H. rhodopensis. Different protective intrinsically disordered proteins, such as late embryogenesis abundant (LEA) proteins, thaumatin-like proteins (TLPs), and heat shock proteins (HSPs), were detected. We also found a constitutively abundant dehydrin in H. rhodopensis whose phosphorylation levels increased under stress in the chloroplast fraction. This integrative multi-omics analysis revealed a systemic response to desiccation in H. rhodopensis and certain targets for further genomic and evolutionary studies on DT mechanisms and genetic engineering towards the improvement of drought tolerance in crops.


Assuntos
Craterostigma , Lamiales , Craterostigma/genética , Dessecação , Secas , Proteômica
2.
Int J Mol Sci ; 23(15)2022 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-35897721

RESUMO

WRKY transcription factors (TFs), one of the largest transcription factor families in plants, play an important role in abiotic stress responses. The resurrection plant, Myrothamnus flabellifolia, has a strong tolerance to dehydration, but only a few WRKY proteins related to abiotic stress response have been identified and functionally characterized in M. flabellifolia. In this study, we identified an early dehydration-induced gene, MfWRKY40, of M. flabellifolia. The deduced MfWRKY40 protein has a conserved WRKY motif but lacks a typical zinc finger motif in the WRKY domain and is localized in the nucleus. To investigate its potential roles in abiotic stresses, we overexpressed MfWRKY40 in Arabidopsis and found that transgenic lines exhibited better tolerance to both drought and salt stresses. Further detailed analysis indicated that MfWRKY40 promoted primary root length elongation and reduced water loss rate and stomata aperture (width/length) under stress, which may provide Arabidopsis the better water uptake and retention abilities. MfWRKY40 also facilitated osmotic adjustment under drought and salt stresses by accumulating more osmolytes, such as proline, soluble sugar, and soluble protein. Additionally, the antioxidation ability of transgenic lines was also significantly enhanced, represented by higher chlorophyll content, less malondialdehyde and reactive oxygen species accumulations, as well as higher antioxidation enzyme activities. All these results indicated that MfWRKY40 might positively regulate tolerance to drought and salinity stresses. Further investigation on the relationship of the missing zinc finger motif of MfWRKY40 and its regulatory role is necessary to obtain a better understanding of the mechanism underlying the excellent drought tolerance of M. flabellifolia.


Assuntos
Arabidopsis , Craterostigma , Arabidopsis/metabolismo , Craterostigma/genética , Desidratação , Secas , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Estresse Salino , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Água/metabolismo
3.
Int J Mol Sci ; 23(14)2022 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-35887237

RESUMO

Drought and salinity have become major environmental problems that affect the production of agriculture, forestry and horticulture. The identification of stress-tolerant genes from plants adaptive to harsh environments might be a feasible strategy for plant genetic improvement to address the challenges brought by global climate changes. In this study, a dehydration-upregulated gene MfWRKY7 of resurrection Plant Myrothamnusflabellifolia, encoding a group IId WRKY transcription factor, was cloned and characterized. The overexpression of MfWRKY7 in Arabidopsis increased root length and tolerance to drought and NaCl at both seedling and adult stages. Further investigation indicated that MfWRKY7 transgenic plants had higher contents of chlorophyll, proline, soluble protein, and soluble sugar but a lower water loss rate and malondialdehyde content compared with wild-type plants under both drought and salinity stresses. Moreover, the higher activities of antioxidant enzymes and lower accumulation of O2- and H2O2 in MfWRKY7 transgenic plants were also found, indicating enhanced antioxidation capacity by MfWRKY7. These findings showed that MfWRKY7 may function in positive regulation of responses to drought and salinity stresses, and therefore, it has potential application value in genetic improvement of plant tolerance to abiotic stress.


Assuntos
Arabidopsis , Craterostigma , Arabidopsis/metabolismo , Craterostigma/genética , Secas , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Cloreto de Sódio/metabolismo , Estresse Fisiológico/genética
4.
Int J Mol Sci ; 23(7)2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35408906

RESUMO

Ramonda serbica Panc. is an ancient resurrection plant able to survive a long desiccation period and recover metabolic functions upon watering. The accumulation of protective late embryogenesis abundant proteins (LEAPs) is a desiccation tolerance hallmark. To propose their role in R. serbica desiccation tolerance, we structurally characterised LEAPs and evaluated LEA gene expression levels in hydrated and desiccated leaves. By integrating de novo transcriptomics and homologues LEAP domains, 318 R. serbica LEAPs were identified and classified according to their conserved motifs and phylogeny. The in silico analysis revealed that hydrophilic LEA4 proteins exhibited an exceptionally high tendency to form amphipathic α-helices. The most abundant, atypical LEA2 group contained more hydrophobic proteins predicted to fold into the defined globular domains. Within the desiccation-upregulated LEA genes, the majority encoded highly disordered DEH1, LEA1, LEA4.2, and LEA4.3 proteins, while the greatest portion of downregulated genes encoded LEA2.3 and LEA2.5 proteins. While dehydrins might chelate metals and bind DNA under water deficit, other intrinsically disordered LEAPs might participate in forming intracellular proteinaceous condensates or adopt amphipathic α-helical conformation, enabling them to stabilise desiccation-sensitive proteins and membranes. This comprehensive LEAPs structural characterisation is essential to understanding their function and regulation during desiccation aiming at crop drought tolerance improvement.


Assuntos
Craterostigma , Dessecação , Desenvolvimento Embrionário , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Água/metabolismo
5.
J Exp Bot ; 73(5): 1566-1580, 2022 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-34747457

RESUMO

A group of vascular plants called homoiochlorophyllous resurrection plants evolved unique capabilities to protect their photosynthetic machinery against desiccation-induced damage. This study examined whether the ontogenetic status of the resurrection plant Craterostigma pumilum has an impact on how the plant responds to dehydration at the thylakoid membrane level to prepare cells for the desiccated state. Thus, younger plants (<4 months) were compared with their older (>6 months) counterparts. Ultrastructural analysis provided evidence that younger plants suppressed senescence-like programs that are realized in older plants. During dehydration, older plants degrade specific subunits of the photosynthetic apparatus such as the D1 subunit of PSII and subunits of the cytochrome b6f complex. The latter leads to a controlled down-regulation of linear electron transport. In contrast, younger plants increased photoprotective high-energy quenching mechanisms and maintained a high capability to replace damaged D1 subunits. It follows that depending on the ontogenetic state, either more degradation-based or more photoprotective mechanisms are employed during dehydration of Craterostigma pumilum.


Assuntos
Craterostigma , Fotossíntese , Craterostigma/fisiologia , Desidratação/fisiopatologia , Transporte de Elétrons , Fotossíntese/fisiologia , Tilacoides/fisiologia
6.
Cells ; 10(9)2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34571944

RESUMO

The remarkable desiccation tolerance of the vegetative tissues in the resurrection species Craterostigma plantagineum (Hochst.) is favored by its unique cell wall folding mechanism that allows the ordered and reversible shrinking of the cells without damaging neither the cell wall nor the underlying plasma membrane. The ability to withstand extreme drought is also maintained in abscisic acid pre-treated calli, which can be cultured both on solid and in liquid culture media. Cell wall research has greatly advanced, thanks to the use of inhibitors affecting the biosynthesis of e.g., cellulose, since they allowed the identification of the compensatory mechanisms underlying habituation. Considering the innate cell wall plasticity of C. plantagineum, the goal of this investigation was to understand whether habituation to the cellulose biosynthesis inhibitors dichlobenil and isoxaben entailed or not identical mechanisms as known for non-resurrection species and to decipher the cell wall proteome of habituated cells. The results showed that exposure of C. plantagineum calli/cells triggered abnormal phenotypes, as reported in non-resurrection species. Additionally, the data demonstrated that it was possible to habituate Craterostigma cells to dichlobenil and isoxaben and that gene expression and protein abundance did not follow the same trend. Shotgun and gel-based proteomics revealed a common set of proteins induced upon habituation, but also identified candidates solely induced by habituation to one of the two inhibitors. Finally, it is hypothesized that alterations in auxin levels are responsible for the increased abundance of cell wall-related proteins upon habituation.


Assuntos
Benzamidas/farmacologia , Parede Celular/metabolismo , Craterostigma/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Nitrilas/farmacologia , Proteínas de Plantas/metabolismo , Proteoma/metabolismo , Membrana Celular/metabolismo , Parede Celular/efeitos dos fármacos , Craterostigma/efeitos dos fármacos , Craterostigma/crescimento & desenvolvimento , Secas , Herbicidas/farmacologia , Proteínas de Plantas/genética , Proteoma/análise , Proteoma/efeitos dos fármacos
7.
Genome Biol Evol ; 13(8)2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34165527

RESUMO

Acanthochlamys bracteata (Velloziaceae) is a resurrection plant with cold tolerance. Herein, a chromosome-level reference genome of A. bracteata based on Nanopore, Illumina, and Hi-C data is reported. The high-quality assembled genome was 197.97 Mb, with a scaffold N50 value of 8.64 Mb and a contig N50 value of 6.96 Mb. We annotated 23,509 protein-coding genes. Eight contracted gene families and three expanded gene families were detected. Repeat sequences accounted for approximately 28.63% of the genome. The LEA1 and Dehydrin gene families, which are involved in desiccation resistance, expanded in A. bracteata. We identified genes involved in chilling tolerance, COLD1.


Assuntos
Craterostigma , Cromossomos , Craterostigma/genética , Genoma , Genoma de Planta , Filogenia , Sequências Repetitivas de Ácido Nucleico
8.
Acta Biochim Pol ; 68(2): 277-286, 2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-33979512

RESUMO

Haberlea rhodopensis is a paleolithic tertiary relict species that belongs to the unique group of resurrection plants sharing remarkable tolerance to desiccation. When exposed to severe drought stress, this species shows an ability to maintain structural integrity of its deactivated photosynthetic apparatus, which easily reactivates upon rehydration. In addition to its homoiochlorophyllous nature, the resurrection capability of H. rhodopensis is of particular importance to the global climate change mitigation. In this study, we sequenced, assembled, and analyzed the mitochondrial (mt) genome of H. rhodopensis for the first time. The master circle has a typical circular structure of 484 138 bp in length with a 44.1% GC content in total. The mt genome of H. rhodopensis contains 59 genes in total, including 35 protein-coding, 21 tRNAs, and 3 rRNAs genes. 7 tandem repeats and 85 simple sequence repeats (SSRs) are distributed throughout the mt genome. The alignment of 20 plant mt genomes confirms the phylogenetic position of H. rhodopensis in the Lamiales order. Our comprehensive analysis of the complete mt genome of H. rhodopensis is a significant addition to the limited database of organelle genomes of resurrection species. Comparative and phylogenetic analysis provides valuable information for a better understanding of mitochondrial molecular evolution in plants.


Assuntos
Craterostigma/genética , Genoma Mitocondrial , Craterostigma/metabolismo , Desidratação/metabolismo , Secas , Genes de Plantas , Lamiales/genética , Lamiales/metabolismo , Fotossíntese , Filogenia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Sequências de Repetição em Tandem , Água
9.
Plant J ; 107(2): 377-398, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33901322

RESUMO

The resurrection plant Craterostigma plantagineum possesses an extraordinary capacity to survive long-term desiccation. To enhance our understanding of this phenomenon, complementary transcriptome, soluble proteome and targeted metabolite profiling was carried out on leaves collected from different stages during a dehydration and rehydration cycle. A total of 7348 contigs, 611 proteins and 39 metabolites were differentially abundant across the different sampling points. Dynamic changes in transcript, protein and metabolite levels revealed a unique signature characterizing each stage. An overall low correlation between transcript and protein abundance suggests a prominent role for post-transcriptional modification in metabolic reprogramming to prepare plants for desiccation and recovery. The integrative analysis of all three data sets was performed with an emphasis on photosynthesis, photorespiration, energy metabolism and amino acid metabolism. The results revealed a set of precise changes that modulate primary metabolism to confer plasticity to metabolic pathways, thus optimizing plant performance under stress. The maintenance of cyclic electron flow and photorespiration, and the switch from C3 to crassulacean acid metabolism photosynthesis, may contribute to partially sustain photosynthesis and minimize oxidative damage during dehydration. Transcripts with a delayed translation, ATP-independent bypasses, alternative respiratory pathway and 4-aminobutyric acid shunt may all play a role in energy management, together conferring bioenergetic advantages to meet energy demands upon rehydration. This study provides a high-resolution map of the changes occurring in primary metabolism during dehydration and rehydration and enriches our understanding of the molecular mechanisms underpinning plant desiccation tolerance. The data sets provided here will ultimately inspire biotechnological strategies for drought tolerance improvement in crops.


Assuntos
Craterostigma/metabolismo , Craterostigma/anatomia & histologia , Craterostigma/fisiologia , Desidratação , Perfilação da Expressão Gênica , Redes e Vias Metabólicas/fisiologia , Fotossíntese , Folhas de Planta/anatomia & histologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Proteínas de Plantas/metabolismo , Proteômica
10.
Planta ; 253(5): 92, 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33821335

RESUMO

MAIN CONCLUSION: The cell wall protein CpWAK1 interacts with pectin, participates in decoding cell wall signals, and induces different downstream responses. Cell wall-associated protein kinases (WAKs) are transmembrane receptor kinases. In the desiccation-tolerant resurrection plant Craterostigma plantagineum, CpWAK1 has been shown to be involved in stress responses and cell expansion by forming a complex with the C. plantagineum glycine-rich protein1 (CpGRP1). This prompted us to extend the studies of WAK genes in C. plantagineum. The phylogenetic analyses of WAKs from C. plantagineum and from other species suggest that these genes have been duplicated after species divergence. Expression profiles indicate that CpWAKs are involved in various biological processes, including dehydration-induced responses and SA- and JA-related reactions to pathogens and wounding. CpWAK1 shows a high affinity for "egg-box" pectin structures. ELISA assays revealed that the binding of CpWAKs to pectins is modulated by CpGRP1 and it depends on the apoplastic pH. The formation of CpWAK multimers is the prerequisite for the CpWAK-pectin binding. Different pectin extracts lead to opposite trends of CpWAK-pectin binding in the presence of Ca2+ at pH 8. These observations demonstrate that CpWAKs can potentially discriminate and integrate cell wall signals generated by diverse stimuli, in concert with other elements, such as CpGRP1, pHapo, Ca2+[apo], and via the formation of CpWAK multimers.


Assuntos
Parede Celular/metabolismo , Craterostigma/enzimologia , Meio Ambiente , Pectinas/metabolismo , Proteínas Quinases/metabolismo , Filogenia
11.
Int J Mol Sci ; 22(7)2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33918442

RESUMO

While human extracellular vesicles (EVs) have attracted a big deal of interest and have been extensively characterized over the last years, plant-derived EVs and nanovesicles have earned less attention and have remained poorly investigated. Although a series of investigations already revealed promising beneficial health effects and drug delivery properties, adequate (pre)clinical studies are rare. This fact might be caused by a lack of sources with appropriate qualities. Our study introduces plant cell suspension culture as a new and well controllable source for plant EVs. Plant cells, cultured in vitro, release EVs into the growth medium which could be harvested for pharmaceutical applications. In this investigation we characterized EVs and nanovesicles from distinct sources. Our findings regarding secondary metabolites indicate that these might not be packaged into EVs in an active manner but enriched in the membrane when lipophilic enough, since apparently lipophilic compounds were associated with nanovesicles while more hydrophilic structures were not consistently found. In addition, protein identification revealed a possible explanation for the mechanism of EV cell wall passage in plants, since cell wall hydrolases like 1,3-ß-glucosidases, pectinesterases, polygalacturonases, ß-galactosidases and ß-xylosidase/α-L-arabinofuranosidase 2-like are present in plant EVs and nanovesicles which might facilitate cell wall transition. Further on, the identified proteins indicate that plant cells secrete EVs using similar mechanisms as animal cells to release exosomes and microvesicles.


Assuntos
Vesículas Extracelulares/ultraestrutura , Magnoliopsida/metabolismo , Metabolismo Secundário , Técnicas de Cultura de Células , Células Cultivadas , Craterostigma , Fosfolipídeos/metabolismo , Proteoma
12.
J Exp Bot ; 72(7): 2600-2610, 2021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33483750

RESUMO

Resurrection plants are vascular species able to sustain extreme desiccation in their vegetative tissues. Despite its potential interest, the role of leaf anatomy in CO2 diffusion and photosynthesis under non-stressed conditions has not been explored in these species. Net CO2 assimilation (An) and its underlying diffusive, biochemical, and anatomical determinants were assessed in 10 resurrection species from diverse locations, including ferns, and homoiochlorophyllous and poikilochlorophyllous angiosperms. Data obtained were compared with previously published results in desiccation-sensitive ferns and angiosperms. An in resurrection plants was mostly driven by mesophyll conductance to CO2 (gm) and limited by CO2 diffusion. Resurrection species had a greater cell wall thickness (Tcw) than desiccation-sensitive plants, a feature associated with limited CO2 diffusion in the mesophyll, but also greater chloroplast exposure to intercellular spaces (Sc), which usually leads to higher gm. This combination enabled a higher An per Tcw compared with desiccation-sensitive species. Resurrection species possess unusual anatomical features that could confer stress tolerance (thick cell walls) without compromising the photosynthetic capacity (high chloroplast exposure). This mechanism is particularly successful in resurrection ferns, which display higher photosynthesis than their desiccation-sensitive counterparts.


Assuntos
Craterostigma , Dióxido de Carbono/metabolismo , Parede Celular , Cloroplastos/metabolismo , Células do Mesofilo , Fotossíntese , Folhas de Planta
13.
Phytochem Anal ; 32(4): 521-529, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33034094

RESUMO

INTRODUCTION: Craterostigma plantagineum and Lindernia brevidens are resurrection plants, so these plants can tolerate desiccation of their vegetative tissues. Different components and mechanisms contribute to desiccation tolerance and secondary plant metabolites, like phenolic compounds, may play a role during these processes. OBJECTIVES: Secondary plant metabolites of the two resurrection plants, C. plantagineum and L. brevidens as well as the closely related desiccation sensitive species, L. subracemosa, were investigated regarding the polyphenol profile. MATERIAL AND METHODS: Secondary plant compounds were extracted with acidified methanol and analysed with ultra-high-performance liquid chromatography electrospray ionisation mass spectrometry (UHPLC-ESI-MS). Phenolic compounds were identified by comparing of ultraviolet (UV) and MSn -spectra with published data. All compounds were quantified as verbascoside equivalents by external calibration at the compound specific wavelength. RESULTS: In total, eight compounds that belong to the subclass of phenylethanoid glycosides and one flavone, luteolin hexoside pentoside, were identified. Two of these compounds exhibited a fragmentation pattern, which is closely related to phenylethanoid glycosides. The predominantly synthesised phenylethanoid in all of the three plant species and in every stage of hydration was verbascoside. The total content of phenolic compounds during the three stages of hydration, untreated, desiccated, and rehydrated revealed differences especially between C. plantagineum and L. brevidens as the latter one lost almost all phenolic compounds during rehydration. CONCLUSION: The amount of verbascoside correlates with the degree of desiccation tolerance and verbascoside might play a role in the protective system in acting as an antioxidant.


Assuntos
Craterostigma , Dessecação
14.
Plant Sci ; 302: 110698, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33288011

RESUMO

Phosphatidylcholine is a major phospholipid which is shown to be involved in stress adaptation. Phosphatidylcholine increased during dehydration in Craterostigma plantagineum, and therefore we characterized CTP:phosphocholine cytidylyltransferase (CpCCT1), a key regulatory enzyme for phosphatidylcholine synthesis in plants. The CpCCT1 gene from the resurrection plant C. plantagineum was cloned and the amino acid sequence was compared with homologs from other species including yeast and rat. CCT proteins have conserved catalytic and membrane-binding domains while the N-terminal and C-terminal domains have diverged. The tissue specific expression analysis indicated that CpCCT1 is expressed in all tested tissues and it is induced by dehydration and in response to 0.5 M NaCl solutions. In plants exposed to low temperature in the dark, the CpCCT1 transcript increased after 4 h at 4 °C. CpCCT1 expression also increased during mannitol and sorbitol treatments in a concentration dependent manner. Phytohormones such as abscisic acid and indole-3-acetic acid also trigged transcript accumulation. Comparisons of transcript and protein accumulations for different treatments (except for dehydration) suggest transcriptional and translational control mechanisms. Analysis of promoter activity and polysome occupancy suggest that CpCCT1 gene expression is mainly under translational regulation during dehydration.


Assuntos
Colina-Fosfato Citidililtransferase/metabolismo , Craterostigma/enzimologia , Proteínas de Plantas/metabolismo , Colina-Fosfato Citidililtransferase/genética , Colina-Fosfato Citidililtransferase/fisiologia , Clonagem Molecular , Craterostigma/genética , Desidratação , Regulação da Expressão Gênica de Plantas , Fosfatidilcolinas/metabolismo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Alinhamento de Sequência
15.
Planta ; 252(5): 84, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33044571

RESUMO

MAIN CONCLUSION: CpGLP1 belongs to the large group of germin-like proteins and comprises a cell wall-localized protein which has superoxide dismutase activity and may contribute towards ROS metabolism and cell wall folding during desiccation. The plant cell wall is a dynamic matrix and its plasticity is essential for cell growth and processing of environmental signals to cope with stresses. A few so-called resurrection plants like Craterostigma plantagineum survive desiccation by implementing protection mechanisms. In C. plantagineum, the cell wall shrinks and folds upon desiccation to avoid mechanical and oxidative damage which contributes to cell integrity. Despite the high toxic potential, ROS are important molecules for cell wall remodeling processes as they participate in enzymatic reactions and act as signaling molecules. Here we analyzed the C. plantagineum germin-like protein 1 (CpGLP1) to understand its contribution to cell wall folding and desiccation tolerance. The analysis of the CpGLP1 sequence showed that this protein does not fit into the current GLP classification and forms a new group within the Linderniaceae. CpGLP1 transcripts accumulate in leaves in response to dehydration and ABA, and mannitol treatments transiently induce CpGLP1 transcript accumulation supporting the participation of CpGLP1 in desiccation-related processes. CpGLP1 protein from cell wall protein extracts followed transcript accumulation and protein preparations from bacteria overexpressing CpGLP1 showed SOD activity. In agreement with cell wall localization, CpGLP1 interacts with pectins which have not been reported for GLP proteins. Our data support a role for CpGLP1 in the ROS metabolism related to the control of cell wall plasticity during desiccation in C. plantagineum.


Assuntos
Craterostigma , Desidratação , Glicoproteínas , Proteínas de Plantas , Superóxido Dismutase , Parede Celular/genética , Craterostigma/enzimologia , Craterostigma/genética , Desidratação/genética , Dessecação , Glicoproteínas/genética , Glicoproteínas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Superóxido Dismutase/metabolismo
16.
Int J Mol Sci ; 21(8)2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32344614

RESUMO

Phytochrome-interacting factors (PIFs), a subfamily of basic helix-loop-helix (bHLH) transcription factors (TFs), play critical roles in regulating plant growth and development. The resurrection plant Myrothamnus flabellifolia possesses a noteworthy tolerance to desiccation, but no PIFs related to the response to abiotic stress have been functionally studied. In this study, a dehydration-inducible PIF gene, MfPIF1, was cloned and characterized. Subcellular localization assay revealed that MfPIF1 is localized predominantly in the nucleus. Overexpression of MfPIF1 in Arabidopsis thaliana led to enhanced drought and salinity tolerance, which was attributed to higher contents of chlorophyll, proline (Pro), soluble protein, and soluble sugar, activities of antioxidant enzymes as well as lower water loss rate, malondialdehyde (MDA) content, and reactive oxygen species (ROS) accumulation in transgenic lines compared with control plants. Moreover, MfPIF1 decreased stomatal aperture after drought and abscisic acid (ABA) treatment, and increased expression of both ABA biosynthesis and ABA-responsive genes including NCED3, P5CS, and RD29A. Overall, these results indicated that MfPIF1 may act as a positive regulator to drought and salinity responses, and therefore could be considered as a potential gene for plant genetic improvement of drought and salinity tolerance.


Assuntos
Arabidopsis/fisiologia , Secas , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Salinidade , Estresse Fisiológico , Traqueófitas/genética , Sequência de Aminoácidos , Antioxidantes/metabolismo , Clonagem Molecular , Craterostigma/genética , Fitocromo/metabolismo , Proteínas de Plantas/química , Transporte Proteico , Tolerância ao Sal
17.
New Phytol ; 226(3): 741-759, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32017123

RESUMO

Resurrection plants recover physiological functions after complete desiccation. Almost all of them are native to tropical warm environments. However, the Gesneriaceae include four genera, remnant of the past palaeotropical flora, which inhabit temperate mountains. One of these species is additionally freezing-tolerant: Ramonda myconi. We hypothesise that this species has been able to persist in a colder climate thanks to some resurrection-linked traits. To disentangle the physiological mechanisms underpinning multistress tolerance to desiccation and freezing, we conducted an exhaustive seasonal assessment of photosynthesis (gas exchange, limitations to partitioning, photochemistry and galactolipids) and primary metabolism (through metabolomics) in two natural populations at different elevations. R. myconi displayed low rates of photosynthesis, largely due to mesophyll limitation. However, plants were photosynthetically active throughout the year, excluding a reversible desiccation period. Common responses to desiccation and low temperature involved chloroplast protection: enhanced thermal energy dissipation, higher carotenoid to Chl ratio and de-epoxidation of the xanthophyll cycle. As specific responses, antioxidants and secondary metabolic routes rose upon desiccation, while putrescine, proline and a variety of sugars rose in winter. The data suggest conserved mechanisms to cope with photo-oxidation during desiccation and cold events, while additional metabolic mechanisms may have evolved as specific adaptations to cold during recent glaciations.


Assuntos
Craterostigma , Adaptação Fisiológica , Cloroplastos/metabolismo , Dessecação , Fotossíntese , Plantas
19.
Plant J ; 100(4): 661-676, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31350933

RESUMO

Craterostigma plantagineum belongs to the desiccation-tolerant angiosperm plants. Upon dehydration, leaves fold and the cells shrink which is reversed during rehydration. To understand this process changes in cell wall pectin composition, and the role of the apoplastic glycine-rich protein 1 (CpGRP1) were analysed. Cellular microstructural changes in hydrated, desiccated and rehydrated leaf sections were analysed using scanning electron microscopy. Pectin composition in different cell wall fractions was analysed with monoclonal antibodies against homogalacturonan, rhamnogalacturonan I, rhamnogalacturonan II and hemicellulose epitopes. Our data demonstrate changes in pectin composition during dehydration/rehydration which is suggested to affect cell wall properties. Homogalacturonan was less methylesterified upon desiccation and changes were also demonstrated in the detection of rhamnogalacturonan I, rhamnogalacturonan II and hemicelluloses. CpGRP1 seems to have a central role in cell adaptations to water deficit, as it interacts with pectin through a cluster of arginine residues and de-methylesterified pectin presents more binding sites for the protein-pectin interaction than to pectin from hydrated leaves. CpGRP1 can also bind phosphatidic acid (PA) and cardiolipin. The binding of CpGRP1 to pectin appears to be dependent on the pectin methylesterification status and it has a higher affinity to pectin than its binding partner CpWAK1. It is hypothesised that changes in pectin composition are sensed by the CpGRP1-CpWAK1 complex therefore leading to the activation of dehydration-related responses and leaf folding. PA might participate in the modulation of CpGRP1 activity.


Assuntos
Parede Celular/química , Craterostigma/fisiologia , Pectinas/metabolismo , Proteínas de Plantas/metabolismo , Arginina/metabolismo , Parede Celular/metabolismo , Craterostigma/citologia , Desidratação , Ácidos Fosfatídicos/metabolismo , Folhas de Planta/citologia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética
20.
Sci Rep ; 9(1): 3049, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30816196

RESUMO

Haberlea rhodopensis is a resurrection plant with an extremely high desiccation tolerance. Even after long periods of almost full desiccation, its physiological functions are recovered shortly upon re-watering. In order to identify physiological strategies which contribute to its remarkable drought stress tolerance we used near infrared spectroscopy to investigate the state of water in the leaves of this plant and compared it to its relative, non-resurrection plant species Deinostigma eberhardtii. Here we show, using a novel aquaphotomics spectral analysis, that H. rhodopensis performs a dynamic regulation of water molecular structure during dehydration directed at drastic decrease of free water molecules, increase of water molecules with 4 hydrogen bonds, and a massive accumulation of water dimers in the full desiccation stage. Our findings suggest that changes in water structure mirror the changes in major metabolites and antioxidants which together constitute a robust defense system underlying the desiccation tolerance of the resurrection plant, while the water dimer may hold special importance for the "drying without dying" ability.


Assuntos
Aclimatação/fisiologia , Craterostigma/fisiologia , Secas , Água/química , Craterostigma/química , Dessecação , Dimerização , Estrutura Molecular , Folhas de Planta/química , Folhas de Planta/fisiologia , Análise Espectral , Água/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...