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1.
Plant Mol Biol ; 104(4-5): 529-548, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32876816

RESUMO

KEY MESSAGE: This research provides comprehensive insight into the molecular networks and molecular mechanisms underlying D. officinale flower development. Flowers are complex reproductive organs and play a crucial role in plant propagation, while also providing sustenance for insects and natural bioactive metabolites for humans. However, knowledge about gene regulation and floral metabolomes in flowers is limited. In this study, we used an important orchid species (Dendrobium officinale), whose flowers can be used to make herbal tea, to perform transcriptome sequencing and metabolic profiling of early- and medium-stage flower buds, as well as opened flowers, to provide comprehensive insight into the molecular mechanisms underlying flower development. A total of 8019 differentially expressed genes (DEGs) and 239 differentiated metabolites were found. The transcription factors that were identified and analyzed belong exclusively to the MIKC-type MADS-box proteins and auxin responsive factors that are known to be involved in flower development. The expression of genes involved in chlorophyll and carotenoid biosynthesis strongly matched the metabolite accumulation patterns. The genes related to flavonoid and polysaccharide biosynthesis were active during flower development. Interestingly, indole-3-acetic acid and abscisic acid, whose trend of accumulation was inverse during flower development, may play an important role in this process. Collectively, the identification of DEGs and differentiated metabolites could help to illustrate the regulatory networks and molecular mechanisms important for flower development in this orchid.


Assuntos
Dendrobium/crescimento & desenvolvimento , Dendrobium/genética , Dendrobium/metabolismo , Flores/crescimento & desenvolvimento , Ácido Abscísico/metabolismo , Carotenoides/metabolismo , Clorofila/metabolismo , Flavonoides/metabolismo , Flores/genética , Flores/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/metabolismo , Proteínas de Domínio MADS/genética , Filogenia , Proteínas de Plantas/genética , Polissacarídeos/metabolismo
2.
Plant Physiol Biochem ; 154: 612-621, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32912492

RESUMO

Salicylic acid (SA) is a well-known priming agent that is widely used to protect plants against stressing agents, including heavy metals as Pb. A better understanding of the mechanisms that enable plants to counteract Pb toxicity would help to select strategies for land reclamation programs. Here we used a metallicolous population of Zygophyllum fabago to assess the extent to which SA pretreatment modulates Pb-induced changes in phenol metabolism and stress-related phytohormone levels in roots and leaves. Our data revealed that accumulation of different phytohormones, lignin, soluble and wall-bound phenolics as well as peroxidase (PRX) activity in Pb-stressed plants differed after SA-pretreatment. Exposure to Pb led to the induction of soluble and cell wall-bound PRX activities, particularly those involved in the oxidation of coniferyl alcohol and ferulic acid, while pretreatment with SA reduced the Pb-induced stimulation of PRX activities in roots but increased them in leaves. SA-treatment by itself induced accumulation of ABA and the JA-precursor 12-oxo-phytodienoic acid (OPDA) in the roots. Pb in turn inhibited these SA-induced effects with the exception of OPDA accumulation that was primed by the pretreatment. The SA treatment also induced accumulation of OPDA in leaves but suppressed the accumulation of JA-Ile although with relatively small absolute changes. Notably, Pb-induced accumulation of ABA was primed in the leaves of SA-pretreated plants. Together our data suggest that priming of OPDA accumulation in the roots and of ABA in the leaves by SA-pretreatment may play important regulatory roles, possibly via regulating PRX activities, for Pb stress in plants.


Assuntos
Ácido Abscísico/metabolismo , Ácidos Graxos Insaturados/metabolismo , Chumbo/efeitos adversos , Fenóis/análise , Ácido Salicílico , Zygophyllum/efeitos dos fármacos , Reguladores de Crescimento de Planta/farmacologia , Folhas de Planta , Raízes de Plantas , Ácido Salicílico/farmacologia , Estresse Fisiológico
3.
PLoS One ; 15(9): e0238381, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881942

RESUMO

Small fructans improve plant tolerance for cold stress. However, the underlying molecular mechanisms are poorly understood. Here, we have demonstrated that the small fructan tetrasaccharide nystose improves the cold stress tolerance of primary rice roots. Roots developed from seeds soaked in nystose showed lower browning rate, higher root activity, and faster growth compared to seeds soaked in water under chilling stress. Comparative proteomics analysis of nystose-treated and control roots identified a total of 497 differentially expressed proteins. GO classification and KEGG pathway analysis documented that some of the upregulated differentially expressed proteins were implicated in the regulation of serine/threonine protein phosphatase activity, abscisic acid-activated signaling, removal of superoxide radicals, and the response to oxidative stress and defense responses. Western blot analysis indicated that nystose promotes the growth of primary rice roots by increasing the level of RSOsPR10, and the cold stress-induced change in RSOsPR10levelis regulated by jasmonate, salicylic acid, and abscisic acid signaling pathways in rice roots. Furthermore, OsMKK4-dependentmitogen-activated protein kinase signaling cascades may be involved in the nystose-induced cold tolerance of primary rice roots. Together, these results indicate that nystose acts as an immunostimulator of the response to cold stress by multiple signaling pathways.


Assuntos
Resposta ao Choque Frio/efeitos dos fármacos , Oligossacarídeos/farmacologia , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteômica/métodos , Transdução de Sinais/efeitos dos fármacos , Ácido Abscísico/metabolismo , Cromatografia Líquida de Alta Pressão , Resposta ao Choque Frio/genética , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Oryza/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Oxilipinas/metabolismo , Fenótipo , Proteínas de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Ácido Salicílico/metabolismo , Transdução de Sinais/genética , Espectrometria de Massas em Tandem
4.
Nature ; 585(7826): 569-573, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32846426

RESUMO

Perception of biotic and abiotic stresses often leads to stomatal closure in plants1,2. Rapid influx of calcium ions (Ca2+) across the plasma membrane has an important role in this response, but the identity of the Ca2+ channels involved has remained elusive3,4. Here we report that the Arabidopsis thaliana Ca2+-permeable channel OSCA1.3 controls stomatal closure during immune signalling. OSCA1.3 is rapidly phosphorylated upon perception of pathogen-associated molecular patterns (PAMPs). Biochemical and quantitative phosphoproteomics analyses reveal that the immune receptor-associated cytosolic kinase BIK1 interacts with and phosphorylates the N-terminal cytosolic loop of OSCA1.3 within minutes of treatment with the peptidic PAMP flg22, which is derived from bacterial flagellin. Genetic and electrophysiological data reveal that OSCA1.3 is permeable to Ca2+, and that BIK1-mediated phosphorylation on its N terminus increases this channel activity. Notably, OSCA1.3 and its phosphorylation by BIK1 are critical for stomatal closure during immune signalling, and OSCA1.3 does not regulate stomatal closure upon perception of abscisic acid-a plant hormone associated with abiotic stresses. This study thus identifies a plant Ca2+ channel and its activation mechanisms underlying stomatal closure during immune signalling, and suggests specificity in Ca2+ influx mechanisms in response to different stresses.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/imunologia , Arabidopsis/metabolismo , Canais de Cálcio/metabolismo , Cálcio/metabolismo , Imunidade Vegetal , Estômatos de Plantas/imunologia , Estômatos de Plantas/metabolismo , Ácido Abscísico/metabolismo , Padrões Moleculares Associados a Patógenos/imunologia , Padrões Moleculares Associados a Patógenos/metabolismo , Fosforilação , Ligação Proteica , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais
5.
Gene ; 758: 144942, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32640309

RESUMO

WUSCHEL-related homeobox4 (WOX4) plays important roles in vascular formation and adventitious root (AR) development. Here, we cloned the WOX4 from the AR of Larix kaempferi, whose cDNA is 1452 bp in length and encodes 483 amino acids. LkWOX4 is mainly expressed in the layer formation area of the stem at 10 days after cutting and its expression levels in the middles and ends of the ARs were higher than that in the AR tips. The fused protein LkWOX4-GFP localized in the nucleus. The heterologous overexpression of LkWOX4 in 84 K poplar significantly increased AR numbers and decreased AR lengths. In LkWOX4 plants, the endogenous jasmonic acid and abscisic acid contents significantly decreased in stems, while the auxin, jasmonic acid and abscisic acid contents significantly increased in ARs. RNA-Seq of those LkWOX4 overexpression poplar plants showed that the expression of plant hormone signaling genes (ARF2, ARF3, ARF7 and ARF18), rooting-related transcription factors (WOX5, LBD29 and SCR) and root development-related genes (CYCD3, GRF1 and TAA1) were affected. Moreover, we found that LkWOX4 interacts with LkPAT18, LkACBP6, and LkCIP7 using yeast two hybrid screening. Thus, we found LkWOX4 involves in the AR initiation and development, which might be regulated through the IAA, JA and ABA signaling pathways.


Assuntos
Proteínas de Homeodomínio/genética , Larix/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Organogênese Vegetal/genética , Fatores de Transcrição/genética , Ácido Abscísico/metabolismo , Clonagem Molecular , Ciclopentanos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Regulação da Expressão Gênica de Plantas/genética , Ácidos Indolacéticos/metabolismo , Larix/genética , Meristema/genética , Oxilipinas/metabolismo , Transdução de Sinais/genética
6.
PLoS One ; 15(7): e0235795, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645115

RESUMO

To investigate the growth, physiological changes and mechanism of drought resistance of Camellia oleifera GWu-2 under drought stress conditions, changes in the main growth and physiological indices of GWu-2 under different water gradients were studied. Factor analysis was used to study the differences between indicators under different water gradients, and correlation analysis was implemented to analyze the relationship between different factors. We observed that the growth state, enzyme secretion, stomatal morphology and leaf osmotic adjustment substances were significantly affected by drought stress. In particular, increases in leaf abscisic acid (ABA), indole acetic acid (IAA) and methyl jasmonate (MeJA) contents under drought stress were negatively correlated with the stomatal opening degree, and the ratio of ZR/GA3 was significantly correlated with the growth and physiological indicators of GWu-2, indicating that different hormones respond differently to drought stress and have different functions in the growth regulation and drought resistance of GWu-2. We concluded that the drought resistance mechanism of GWu-2 was controlled by maintaining root growth to obtain the necessary water, increasing the contents of osmotic substances of leaves to maintain water holding capacity, reducing the transpiration of water by increasing leaf ABA, IAA and MeJA content to close stomata and reducing the damage caused by drought by increasing the activity of superoxide dismutase (SOD).


Assuntos
Aclimatação , Camellia/fisiologia , Ácido Abscísico/metabolismo , Acetatos/metabolismo , Camellia/crescimento & desenvolvimento , Ciclopentanos/metabolismo , Secas , Ácidos Indolacéticos/metabolismo , Oxilipinas/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Estômatos de Plantas/crescimento & desenvolvimento , Estômatos de Plantas/fisiologia , Estresse Fisiológico , Água/metabolismo
7.
Gene ; 760: 144990, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32721476

RESUMO

The MYB transcription factors are involved in the regulation of plant secondary metabolism, cell development and morphogenesis, and stress response. Here, a full-length, 816-bp NtMYB4a cDNA, which encodes a protein comprising 271 amino acids, was isolated from tobacco leaves. Phylogenetic analysis revealed that NtMYB4a is most similar to Nicotiana. attenuata MYB4, followed by Eriobotrya japonica MYB4, and NtMYB4a clustered with transcriptional activators rather than repressors. Subcellular localization assays showed that NtMYB4 localized in the nucleus, membrane, and cytoplasm. Expression analyses revealed differential expression of NtMYB4a among different tissues and organs and between different developmental stages, with most expression occurring in the stems and leaves during the full-bloom stage. Moreover, NtMYB4a expression was induced by cold, NaCl, PEG, abscisic acid, methyl jasmonate, and dark stressors, and the expression patterns and maximum expression levels varied with the type of stress. Overexpression of NtMYB4a upregulated NtPAL, Nt4CL, NtCHS, NtCHI, NtF3H, NtDFR, NtANS, and NtUFGT, which resulted in increased anthocyanin content in the tobacco corolla and darker colors. However, CRISPR/Cas9-mediated knockout of NtMYB4a downregulated NtPAL, NtC4H, Nt4CL, NtCHS, NtCHI, NtF3H, NtANS, and NtUFGT, which resulted in reduced anthocyanin content, and lighter corolla colors. These results indicated that NtMYB4a positively regulates anthocyanin biosynthesis and is involved in abiotic stress responses in tobacco plants.


Assuntos
Tabaco/metabolismo , Fatores de Transcrição/isolamento & purificação , Fatores de Transcrição/metabolismo , Ácido Abscísico/metabolismo , Sequência de Aminoácidos , Antocianinas/biossíntese , Regulação da Expressão Gênica de Plantas/genética , Filogenia , Folhas de Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Estresse Fisiológico/genética , Tabaco/genética , Fatores de Transcrição/genética , Ativação Transcricional/genética
8.
PLoS One ; 15(7): e0236530, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32706831

RESUMO

Apple trees grafted on different rootstock types, including vigorous rootstock (VR), dwarfing interstock (DIR), and dwarfing self-rootstock (DSR), are widely planted in production, but the molecular determinants of tree branch architecture growth regulation induced by rootstocks are still not well known. In this study, the branch growth phenotypes of three combinations of 'Fuji' apple trees grafted on different rootstocks (VR: Malus baccata; DIR: Malus baccata/T337; DSR: T337) were investigated. The VR trees presented the biggest branch architecture. The results showed that the sugar content, sugar metabolism-related enzyme activities, and hormone content all presented obvious differences in the tender leaves and buds of apple trees grafted on these rootstocks. Transcriptomic profiles of the tender leaves adjacent to the top buds allowed us to identify genes that were potentially involved in signaling pathways that mediate the regulatory mechanisms underlying growth differences. In total, 3610 differentially expressed genes (DEGs) were identified through pairwise comparisons. The screened data suggested that sugar metabolism-related genes and complex hormone regulatory networks involved the auxin (IAA), cytokinin (CK), abscisic acid (ABA) and gibberellic acid (GA) pathways, as well as several transcription factors, participated in the complicated growth induction process. Overall, this study provides a framework for analysis of the molecular mechanisms underlying differential tree branch growth of apple trees grafted on different rootstocks.


Assuntos
Regulação da Expressão Gênica de Plantas , Malus/genética , Transdução de Sinais/genética , Açúcares/metabolismo , Ácido Abscísico/análise , Ácido Abscísico/metabolismo , Cromatografia Líquida de Alta Pressão , Citocininas/análise , Citocininas/metabolismo , Flores/genética , Flores/metabolismo , Giberelinas/análise , Giberelinas/metabolismo , Ácidos Indolacéticos/análise , Ácidos Indolacéticos/metabolismo , Malus/crescimento & desenvolvimento , Fenótipo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/genética , Caules de Planta/fisiologia , RNA de Plantas/genética , RNA de Plantas/metabolismo , Açúcares/análise , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , alfa-Glucosidases/genética , alfa-Glucosidases/metabolismo
9.
Plant Mol Biol ; 104(1-2): 39-53, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32564178

RESUMO

Plants are exposed to various environmental cues that lead to reactive oxygen species (ROS) accumulation. ROS production and detoxification are tightly regulated to maintain balance. Although studies of glucose (Glc) are always accompanied by ROS in animals, the role of Glc in respect of ROS in plants is unclear. We isolated gsm2 (Glc-hypersensitive mutant 2), a mutant with a notably chlorotic-cotyledon phenotype. The chloroplast-localized GSM2 was characterized as a transaldolase in the pentose phosphate pathway. With 3% Glc treatment, fewer or no thylakoids were observed in gsm2 cotyledon chloroplasts than in wild-type cotyledon chloroplasts, suggesting that GSM2 is required for chloroplast protection under stress. gsm2 also showed evaluated accumulation of ROS with 3% Glc treatment and was more sensitive to exogenous H2O2 than the wild type. Gene expression analysis of the antioxidant enzymes in gsm2 revealed that chloroplast damage to gsm2 cotyledons results from the accumulation of excessive ROS in response to Glc. Moreover, the addition of diphenyleneiodonium chloride or phenylalanine can rescue Glc-induced chlorosis in gsm2 cotyledons. This work suggests that GSM2 functions to maintain ROS balance in response to Glc during early seedling growth and sheds light on the relationship between Glc, the pentose phosphate pathway and ROS.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Homeostase , RNA Helicases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transaldolase/metabolismo , Ácido Abscísico/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Clorofila/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Cotilédone/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação , Glucuronidase/metabolismo , Peróxido de Hidrogênio/metabolismo , Via de Pentose Fosfato/genética , Via de Pentose Fosfato/fisiologia , Fenótipo , RNA Helicases/genética , RNA de Plantas/genética , RNA de Plantas/isolamento & purificação , Plântula/genética , Plântula/metabolismo , Transaldolase/genética
10.
Plant Mol Biol ; 103(4-5): 545-560, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32504260

RESUMO

KEY MESSAGE: OsGTγ-2, a trihelix transcription factor, is a positive regulator of rice responses to salt stress by regulating the expression of ion transporters. Salinity stress seriously restricts rice growth and yield. Trihelix transcription factors (GT factors) specifically bind to GT elements and play a diverse role in plant morphological development and responses to abiotic stresses. In our previous study, we found that the GT-1 element (GAAAAA) is a key element in the salinity-induced OsRAV2 promoter. Here, we identified a rice OsGTγ family member, OsGTγ-2, which directly interacted with the GT-1 element in the OsRAV2 promoter. OsGTγ-2 specifically targeted the nucleus, was mainly expressed in roots, sheathes, stems and seeds, and was induced by salinity, osmotic and oxidative stresses and abscisic acid (ABA). The seed germination rate, seedling growth and survival rate under salinity stress was improved in OsGTγ-2 overexpressing lines (PZmUbi::OsGTγ-2). In contrast, CRISPR/Cas9-mediated OsGTγ-2 knockout lines (osgtγ-2) showed salt-hypersensitive phenotypes. In response to salt stress, different Na+ and K+ acclamation patterns were observed in PZmUbi::OsGTγ-2 lines and osgtγ-2 plants were observed. The molecular mechanism of OsGTγ-2 in rice salt adaptation was also investigated. Several major genes responsible for ion transporting, such as the OsHKT2; 1, OsHKT1; 3 and OsNHX1 were transcriptionally regulated by OsGTγ-2. A subsequent yeast one-hybrid assay and EMSA indicated that OsGTγ-2 directly interacted with the promoters of OsHKT2; 1, OsNHX1 and OsHKT1; 3. Taken together, these results suggest that OsGTγ-2 is an important positive regulator involved in rice responses to salt stress and suggest a potential role for OsGTγ-2 in regulating salinity adaptation in rice.


Assuntos
Aclimatação/fisiologia , Proteínas de Ligação a DNA/metabolismo , Oryza/fisiologia , Estresse Salino/fisiologia , Tolerância ao Sal/genética , Fatores de Transcrição/metabolismo , Ácido Abscísico/metabolismo , Aclimatação/genética , Adaptação Fisiológica , Sistemas CRISPR-Cas , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/crescimento & desenvolvimento , Desenvolvimento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Salinidade , Plântula/genética , Sementes/metabolismo , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Estresse Fisiológico/genética , Simportadores/metabolismo , Fatores de Transcrição/genética
11.
PLoS Genet ; 16(6): e1008892, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32569316

RESUMO

Nicotinamide adenine dinucleotide (NAD) is an essential coenzyme that has emerged as a central hub linking redox equilibrium and signal transduction in living organisms. The homeostasis of NAD is required for plant growth, development, and adaption to environmental cues. In this study, we isolated a chilling hypersensitive Arabidopsis thaliana mutant named qs-2 and identified the causal mutation in the gene encoding quinolinate synthase (QS) critical for NAD biosynthesis. The qs-2 mutant is also hypersensitive to salt stress and abscisic acid (ABA) but resistant to drought stress. The qs-2 mutant accumulates a reduced level of NAD and over-accumulates reactive oxygen species (ROS). The ABA-hypersensitivity of qs-2 can be rescued by supplementation of NAD precursors and by mutations in the ABA signaling components SnRK2s or RBOHF. Furthermore, ABA-induced over-accumulation of ROS in the qs-2 mutant is dependent on the SnRK2s and RBOHF. The expression of QS gene is repressed directly by ABI4, a transcription factor in the ABA response pathway. Together, our findings reveal an unexpected interplay between NAD biosynthesis and ABA and stress signaling, which is critical for our understanding of the regulation of plant growth and stress responses.


Assuntos
Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Complexos Multienzimáticos/genética , Reguladores de Crescimento de Planta/metabolismo , Estresse Fisiológico/genética , Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/isolamento & purificação , Proteínas de Arabidopsis/metabolismo , Retroalimentação Fisiológica , Perfilação da Expressão Gênica , Complexos Multienzimáticos/isolamento & purificação , Complexos Multienzimáticos/metabolismo , Mutação , NAD/biossíntese , NADPH Oxidases/metabolismo , Plantas Geneticamente Modificadas , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Transdução de Sinais/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/isolamento & purificação , Fatores de Transcrição/metabolismo
12.
PLoS One ; 15(5): e0232750, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32369520

RESUMO

The rare earth element lanthanum (La) has been proven to be beneficial for plant growth with a low concentration, and abscisic acid (ABA) which is a plant hormone also can regulate plant growth. In the present study, we investigated the germination and seedling growth of switchgrass (Panicum virgatum L.) under La (10 µM), ABA (10 µM) and La + ABA treatments. The results showed that La, ABA and La + ABA treatments could not significantly affect the germination and shoot length as compared to the control (P>0.05). However, La treatment increased the root activity and chlorophyll content, and ABA treatment enhanced root length and root activity (P<0.05). La + ABA treatments demonstrated that La could not significantly alleviate the promotion of ABA in root length, while ABA reversed the increase of chlorophyll content caused by La. The coregulation of La and ABA on chlorophyll content was further explored by in vitro experiments and quantum chemical calculations. In vitro experiments revealed that La, ABA, and La + ABA treatments reduced the absorbance of chlorophyll, and quantum chemical calculations indicated that the reduction of absorbance was caused by the reactions between La, ABA and chlorophyll. In vivo and in vitro experiments, together with quantum chemical calculations, demonstrated that both ABA and La could stimulate the production of chlorophyll, while they also could react with chlorophyll to produce La-monochlorophyll, La-bischlorophyll, and ABA adsorbed chlorophyll, which had lower absorbance. La + ABA treatment significantly decreased the chlorophyll content in vivo. This phenomenon was due to the fact that La and ABA formed LaABA compound, which markedly reduced the concentrations of ABA and La, and the effect of promoting chlorophyll production was overcome by the effect of reducing chlorophyll absorbance.


Assuntos
Ácido Abscísico/metabolismo , Clorofila/metabolismo , Lantânio/metabolismo , Panicum/crescimento & desenvolvimento , Reguladores de Crescimento de Planta/metabolismo , Plântula/crescimento & desenvolvimento , Germinação , Panicum/metabolismo , Plântula/metabolismo
13.
Chemosphere ; 256: 127157, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32470740

RESUMO

Microcystins released by cyanobacteria affect crop growth and productivity, and even food safety. Plant hormones play a vital role in regulating growth, development and stress response in plants. Therefore, we studied the response of hormones including abscisic acid (ABA), indole-3-acetic acid (IAA), Zeatin (ZT) and gibberellin (GA3) as well as hormone balances (IAA/ABA, ZT/ABA and GA/ABA) to cyanobacterial extract containing microcystins (1, 10, 100 and 1000 µg/L) during stress and recovery periods. Low concentration microcystins (1 µg/L) promoted growth of rice seedlings by increasing levels of IAA, ZT and GA3 and maintaining hormone balances. In addition, the up-regulation of OsYUCCA1 increased IAA level in rice roots by promoting IAA biosynthesis. High concentrations microcystins (10, 100 or1000 µg/L) inhibited growth of rice seedlings by reducing levels of IAA, ZT and GA3 and ratios of IAA/ABA, ZT/ABA and GA/ABA due to increased ABA level. The increase in ABA in rice seedlings induced by high concentrations MCs was resulted from up-regulation of OsNCED1, OsNCED3, OsNCED4 and OsZEP to enhance ABA biosynthesis, and was controlled by up-regulating expression levels of OsABAox1-3 for enhancing ABA catabolism as negative feedback. The highest concentration of MCs (1000 µg/L) caused irreversible damage to metabolisms of IAA and ABA, partly resulting in unrecoverable inhibition on rice growth. All results demonstrate that "low-concentration promotion and high-concentration inhibition" of microcystins was associated with changes in hormone levels and balances by affecting their metabolisms, and could be helpful for guiding agricultural irrigation with microcystin contaminated water.


Assuntos
Cianobactérias/metabolismo , Microcistinas/toxicidade , Oryza/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Plântula/metabolismo , Ácido Abscísico/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/microbiologia , Extratos Vegetais , Raízes de Plantas/metabolismo , Zeatina/metabolismo
14.
Gene ; 753: 144803, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32446917

RESUMO

R2R3-type MYBs are a key group of regulatory factors that control diverse developmental processes and stress tolerance in plants. Soybean is a major legume crop with the richness of seed protein and edible vegetable oil, and 244 R2R3-type MYBs have been identified in soybean. However, the knowledge regarding their functional roles has been greatly limited as yet. In this study, a novel R2R3-type MYB (GmMYB81) was functionally characterized in soybean, and it is closely related to two abiotic stress-associated regulators (AtMYB44 and AtMYB77). GmMYB81 transcripts not only differentially accumulated in soybean tissues and during embryo development, but also were significantly enhanced by drought, salt and cold stress. Histochemical GUS assay in Arabidopsis indicated that GmMYB81 promoter showed high activity in seedlings, rosette leaves, inflorescences, silique wall, mature anthers, roots, and germinating seeds. Further investigation indicated that over-expression of GmMYB81 in Arabidopsis caused auxin-associated phenotypes, including small flower and silique, more branch, and weakened apical dominance. Moreover, over-expression of GmMYB81 significantly elevated the rates of seed germination and green seedling under salt and drought stress, indicating that GmMYB81 might confer plant tolerance to salt and drought stress during seed germination. Additionally, protein interaction analysis showed that GmMYB81 interacts with the abiotic stress regulator GmSGF14l. Further observation indicated that they displayed similar expression patterns under drought and salt stress, suggesting GmMYB81 and GmSGF14l might cooperatively affect stress tolerance. These findings will facilitate future investigations of the regulatory mechanisms of GmMYB81 in response to plant stress tolerance, especially seed germination under abiotic stresses.


Assuntos
Proteínas de Arabidopsis/genética , Soja/genética , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Ácido Abscísico/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Secas , Fabaceae/genética , Flores/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Germinação/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Estresse Salino/genética , Tolerância ao Sal/genética , Sementes/metabolismo , Fatores de Transcrição/metabolismo
15.
Gene ; 753: 144802, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32454178

RESUMO

Synchronous and timely regulation of multiple genes results in an effective defense response that decides the fate of the host when challenged with pathogens or unexpected changes in environmental conditions. One such gene, which is downregulated in response to multiple bacterial pathogens, is a putative nonspecific lipid transfer protein (nsLTP) of unknown function that we have named DISEASE RELATED NONSPECIFIC LIPID TRANSFER PROTEIN 1 (DRN1). We show that upon pathogen challenge, DRN1 is strongly downregulated, while a putative DRN1-targeting novel microRNA (miRNA) named DRN1 Regulating miRNA (DmiR) is reciprocally upregulated. Furthermore, we provide evidence that DRN1 is required for defense against bacterial and fungal pathogens as well as for normal seedling growth under salinity stress. Although nsLTP family members from different plant species are known to be a significant source of food allergens and are often associated with antimicrobial properties, our knowledge on the biological functions and regulation of this gene family is limited. Our current work not only sheds light on the mechanism of regulation but also helps in the functional characterization of DRN1, a putative nsLTP family member of hitherto unknown function.


Assuntos
Arabidopsis/genética , Proteínas de Transferência de Fosfolipídeos/genética , Estresse Salino/genética , Ácido Abscísico/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Resistência à Doença/genética , Secas , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Transferência de Fosfolipídeos/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Patologia Vegetal , Plantas Geneticamente Modificadas , Salinidade , Tolerância ao Sal/genética , Plântula/genética , Estresse Fisiológico/genética
16.
Artigo em Inglês | MEDLINE | ID: mdl-32353677

RESUMO

Remobilization of stem water soluble carbohydrates (WSC) can supply crucial carbon resources for grain filling under drought stress, while the regulatory metabolism associated with abscisic acid (ABA) is still limited. Two cultivars, LJ196 (drought-tolerant) and XD18 (drought-prone), were pot-grown under well-watered (WW) and drought-stressed (DS) conditions. Concentrations of WSC components and ABA, and fructan metabolizing enzymes and genes were investigated in peduncle after anthesis. When compared with those under the WW, LJ196 remained higher grain yield and grain-filling rate than XD18 under the DS. During the early period of grain filling (0-14 DAA), DS increased concentrations of total WSC and its components, but thereafter substantially reduced them. The gene expression levels and enzymatic activities of fructan 1-exohydrolases (1-FEH) and fructan 6-exohydrolases (6-FEH) showed similar trends, whereas those of fructan: fructan 1-fructosyltransferase (1-FFT), and sucrose: fructan 6-fructosyltransferase (6-SFT) were depressed and declined over the period of examination. LJ196 still showed higher levels of ABA and fructan metabolizing. The ABA concentration under the DS was positively and significantly correlated with total WSC and fructan concentration, and expression levels of these enzymes and genes as well, with more prominently with those of 6-FEH. Presumably, ABA could enhance fructan hydrolysis by strongly up-regulating the gene expression and enzymatic activity of 6-FEH to accelerate WSC remobilization. However, stem WSC induced by DS could be not fully remobilized to grains, due to its weaker correlation with grain-filling rate and finally indicating lower grain yield. The findings would provide useful information for wheat production under water-deficit environments.


Assuntos
Ácido Abscísico/metabolismo , Metabolismo dos Carboidratos , Secas , Hepatite C Crônica , Triticum , Carboidratos/química , Triticum/enzimologia , Triticum/genética , Água/química
17.
Science ; 368(6488): 266-269, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32299946

RESUMO

Drought alone causes more annual loss in crop yield than all pathogens combined. To adapt to moisture gradients in soil, plants alter their physiology, modify root growth and architecture, and close stomata on their aboveground segments. These tissue-specific responses modify the flux of cellular signals, resulting in early flowering or stunted growth and, often, reduced yield. Physiological and molecular analyses of the model plant Arabidopsis thaliana have identified phytohormone signaling as key for regulating the response to drought or water insufficiency. Here we discuss how engineering hormone signaling in specific cells and cellular domains can facilitate improved plant responses to drought. We explore current knowledge and future questions central to the quest to produce high-yield, drought-resistant crops.


Assuntos
Produtos Agrícolas/fisiologia , Secas , Reguladores de Crescimento de Planta/metabolismo , Água/metabolismo , Ácido Abscísico/metabolismo , Arabidopsis , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Engenharia Genética , Transdução de Sinais
18.
Ecotoxicol Environ Saf ; 196: 110528, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32240865

RESUMO

In plants, tolerance to cadmium (Cd) stress is closely related to indole-3-acetic acid (IAA) and hydrogen peroxide (H2O2). However, it is unclear whether Cd-resistant and -sensitive varieties respond differently to Cd stress. In this study, the effects of dimethylthiourea (DMTU, a H2O2 scavenger) and p-chlorophenoxy isobutyric acid (PCIB, an IAA signaling inhibitor) on root growth, endogenous hormones and antioxidant system were investigated to decipher how DMTU and PCIB treatments alleviate the inhibition of root elongation in Cd-resistant (Commander) and -sensitive (Crossfire III) tall fescue varieties under Cd stress. Both varieties subjected to 10 µM Cd treatments for 12 h presented a substantial decrease in root elongation coupled with a reduction in brassinosteroid (BR) and zeatin riboside (ZR) contents, but the changes in IAA and abscisic acid (ABA) contents under Cd stress were opposite in the two varieties. In addition, the H2O2 content and antioxidant enzyme activities significantly increased in both varieties. However, pretreatment with PCIB or DMTU mitigated the inhibition of root elongation caused by Cd, accompanied by the significant changes of aforementioned physiological parameters. PCIB significantly reduced the IAA content in 'Commander', while DMTU significantly increased the IAA content in 'Crossfire III' and effectively relieved the inhibition of root elongation. But both treatments decreased the Cd-induced H2O2 accumulation. These results indicated that DMTU or PCIB can alleviate the Cd-inhibited root elongation in two varieties whose resistance differed under Cd stress, but they presented differences in the response of hormones, especially IAA, which may be due to the different adaptation mechanisms of two varieties in response to Cd stress.


Assuntos
Cádmio/toxicidade , Ácido Clofíbrico/farmacologia , Festuca/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Tioureia/análogos & derivados , Ácido Abscísico/metabolismo , Adaptação Fisiológica/efeitos dos fármacos , Festuca/crescimento & desenvolvimento , Festuca/metabolismo , Peróxido de Hidrogênio/metabolismo , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Tioureia/farmacologia
19.
PLoS One ; 15(4): e0231117, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32240252

RESUMO

Herbaceous peony (Paeonia lactiflora Pall.) is a popular ornamental and medicinal plant. Taking approximately six to seven months, the seeds germination under natural conditions experiences dual dormancies, which seriously affects horticultural cultivation. Few studies have been conducted on exploring both biological and molecular mechanism that regulates dormancy removal process in hypocotyls double dormant plants. Here, we first measured ABA and GA3 content changes at four key dormancy break stages, and then performed transcriptomic analyses to identify the differentially expressed genes (DEGs) using RNA-seq. We subsequently carried out Quantitative real-time PCR (qRT-PCR) to validate RNA-seq data. ABA content decreased during the whole dormancy removal process and GA3 content exhibited decreasing slightly and then increasing trend. RNA sequencing de novo assembly generated a total of 99,577 unigenes. 20,344 unigenes were differentially expressed in the whole dormancy release process. The qPCR results of 54 selected unigenes were consistent with the FPKM values obtained from RNA-seq. Our results summarize a valuable collection of gene expression profiles characterizing the dormancy release process. The DEGs are candidates for functional analyses of genes affecting the dormancy release, which is a precious resource for the on-going physiological and molecular investigation of seeds dormancy removal in other perennial plants.


Assuntos
Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Paeonia/genética , Dormência de Plantas/genética , Reguladores de Crescimento de Planta/metabolismo , Ácido Abscísico/metabolismo , Giberelinas/metabolismo , Anotação de Sequência Molecular , Transdução de Sinais , Transcriptoma/genética
20.
Chemosphere ; 252: 126486, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32234629

RESUMO

Hydrogen peroxide (H2O2) acts as a significant regulatory component interrelated with signal transduction in plants. The positive role of H2O2 in plants subjected to myriad of abiotic factors has led us to comprehend that it is not only a free radical, generated as a product of oxidative stress, but also helpful in the maintenance of cellular homeostasis in crop plants. Studies over the last two centuries has indicated that H2O2 is a key molecule which regulate photosynthesis, stomatal movement, pollen growth, fruit and flower development and leaf senescence. Exogenously-sourced H2O2 at nanomolar levels functions as a signalling molecule, facilitates seed germination, chlorophyll content, stomatal opening, and delays senescence, while at elevated levels, it triggers oxidative burst to organic molecules, which could lead to cell death. Furthermore, H2O2 is also known to interplay synergistically or antagonistically with other plant growth regulators such as auxins, gibberellins, cytokinins, abscisic acid, jasmonic acid, ethylene and salicylic acid, nitric oxide and Ca2+ (as signalling molecules), and brassinosteroids (steroidal PGRs) under myriad of environmental stresses and thus, mediate plant growth and development and reactions to abiotic factors. The purpose of this review is to specify accessible knowledge on the role and dynamic mechanisms of H2O2 in mediating growth responses and plant resilience to HM stresses, and its crosstalk with other significant PGRs in controlling various processes. More recently, signal transduction by mitogen activated protein kinases and other transcription factors which attenuate HM stresses in plants have also been dissected.


Assuntos
Metais Pesados/toxicidade , Desenvolvimento Vegetal/efeitos dos fármacos , Estresse Fisiológico/fisiologia , Ácido Abscísico/metabolismo , Morte Celular , Clorofila/metabolismo , Citocininas/metabolismo , Homeostase , Peróxido de Hidrogênio/metabolismo , Ácidos Indolacéticos/metabolismo , Metais Pesados/metabolismo , Óxido Nítrico/metabolismo , Fotossíntese , Reguladores de Crescimento de Planta/metabolismo , Plantas/metabolismo , Transdução de Sinais
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