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1.
Int J Mol Sci ; 22(24)2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34948084

RESUMO

A Raffinose family oligosaccharides (RFOs) is one of the major translocated sugars in the vascular bundle of cucumber, but little RFOs can be detected in fruits. Alpha-galactosidases (α-Gals) catalyze the first catabolism step of RFOs. Six α-Gal genes exist in a cucumber genome, but their spatial functions in fruits remain unclear. Here, we found that RFOs were highly accumulated in vascular tissues. In phloem sap, the stachyose and raffinose content was gradually decreased, whereas the content of sucrose, glucose and fructose was increased from pedicel to fruit top. Three alkaline forms instead of acid forms of α-Gals were preferentially expressed in fruit vascular tissues and alkaline forms have stronger RFO-hydrolysing activity than acid forms. By inducible gene silencing of three alkaline forms of α-Gals, stachyose was highly accumulated in RNAi-CsAGA2 plants, while raffinose and stachyose were highly accumulated in RNAi-CsAGA1 plants. The content of sucrose, glucose and fructose was decreased in both RNAi-CsAGA1 and RNAi-CsAGA2 plants after ß-estradiol treatment. In addition, the fresh- and dry-weight of fruits were significantly decreased in RNAi-CsAGA1 and RNAi-CsAGA2 plants. In cucurbitaceous plants, the non-sweet motif within the promoter of ClAGA2 is widely distributed in the promoter of its homologous genes. Taken together, we found RFOs hydrolysis occurred in the vascular tissues of fruits. CsAGA1 and CsAGA2 played key but partly distinct roles in the hydrolysis of RFOs.


Assuntos
Cucumis sativus/enzimologia , Frutas/enzimologia , Oligossacarídeos/metabolismo , Rafinose/metabolismo , alfa-Galactosidase/metabolismo , Cucumis sativus/metabolismo , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Floema/enzimologia , Floema/metabolismo , Regiões Promotoras Genéticas , Especificidade por Substrato , alfa-Galactosidase/genética
2.
Mol Plant Pathol ; 22(11): 1317-1331, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34355485

RESUMO

RNA-dependent RNA polymerases (RDRs) regulate important aspects of plant development and resistance to pathogens. The role of RDRs in virus resistance has been demonstrated using siRNA signal amplification and through the methylation of viral genomes. Cucumber (Cucumis sativus) has four RDR1 genes that are differentially induced during virus infection: CsRDR1a, CsRDR1b, and duplicated CsRDR1c1/c2. The mode of action of CsRDR1s during viral infection is unknown. Transient expression of the cucumber mosaic virus (CMV)-2b protein (the viral suppressor of RNA silencing) in cucumber protoplasts induced the expression of CsRDR1c, but not of CsRDR1a/1b. Results from the yeast two-hybrid system showed that CsRDR1 proteins interacted with CMV-2b and this was confirmed by bimolecular fluorescence complementation assays. In protoplasts, CsRDR1s localized in the cytoplasm as punctate spots. Colocalization experiments revealed that CsRDR1s and CMV-2b were uniformly dispersed throughout the cytoplasm, suggesting that CsRDR1s are redistributed as a result of interactions. Transient overexpression of individual CsRDR1a/1b genes in protoplasts reduced CMV accumulation, indicating their antiviral role. However, overexpression of CsRDR1c in protoplasts resulted in relatively higher accumulation of CMV and CMVΔ2b. In single cells, CsRDR1c enhances viral replication, leading to CMV accumulation and blocking secondary siRNA amplification of CsRDR1c by CMV-2b protein. This suggests that CMV-2b acts as both a transcription factor that induces CsRDR1c (controlling virus accumulation) and a suppressor of CsRDR1c activity.


Assuntos
Cucumis sativus , Cucumovirus , Doenças das Plantas/virologia , RNA Polimerase Dependente de RNA , Proteínas Virais , Cucumis sativus/enzimologia , Cucumis sativus/virologia , Cucumovirus/patogenicidade , Protoplastos
3.
Int J Mol Sci ; 22(12)2021 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-34205396

RESUMO

Members of the lectin receptor-like kinase (LecRLKs) family play a vital role in innate plant immunity. Few members of the LecRLKs family have been characterized in rice and Arabidopsis, respectively. However, little literature is available about LecRLKs and their role against fungal infection in cucumber. In this study, 60 putative cucumber LecRLK (CsLecRLK) proteins were identified using genome-wide analysis and further characterized into L-type LecRLKs (24) and G-type LecRLKs (36) based on domain composition and phylogenetic analysis. These proteins were allocated to seven cucumber chromosomes and found to be involved in the expansion of the CsLecRLK gene family. Subcellular localization of CsaLecRLK9 and CsaLecRLK12 showed green fluorescence signals in the plasma membrane of leaves. The transcriptional profiling of CsLecRLK genes showed that L-type LecRLKs exhibited functional redundancy as compared to G-type LecRLKs. The qRT-PCR results indicated that both L- and G-type LecRLKs showed significant response against plant growth-promoting fungi (PGPF-Trichoderma harzianum Rifai), powdery mildew pathogen (PPM-Golovinomyces orontii (Castagne) V.P. Heluta), and combined (PGPF+PPM) treatments. The findings of this study contribute to a better understanding of the role of cucumber CsLecRLK genes in response to PGPF, PPM, and PGPF+PPM treatments and lay the basis for the characterization of this important functional gene family.


Assuntos
Cucumis sativus/enzimologia , Erysiphe/imunologia , Imunidade Vegetal , Proteínas Quinases/genética , Estresse Fisiológico , Cromossomos de Plantas , Cucumis sativus/genética , Cucumis sativus/imunologia , Perfilação da Expressão Gênica , Genes de Plantas , Família Multigênica , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas Quinases/metabolismo
4.
Theor Appl Genet ; 134(8): 2639-2652, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34091695

RESUMO

KEY MESSAGE: The elongated hypocotyl1 (elh1) mutant in cucumber is due to a mutation in CsHY2, which is a homolog of the Arabidopsis HY2 encoding the phytochromobilin (PΦB) synthase for phytochrome biosynthesis Hypocotyl length is a critical determinant in establishing high quality seedlings for successful cucumber production, but knowledge on the molecular regulation of hypocotyl growth in cucumber is very limited. Here, we reported identification and characterization of a cucumber elongated hypocotyl 1 (elh1) mutant. We found that the longer hypocotyl in elh1 was due to longitudinal growth of hypocotyl cells. With fine mapping, the elh1 locus was delimited to a 20.9-kb region containing three annotated genes; only one polymorphism was identified in this region between two parental lines, which was a non-synonymous SNP (G28153633A) in the third exon of CsHY2 (CsGy1G030000) that encodes a phytochromobilin (PΦB) synthase. Uniqueness of the mutant allele at CsHY2 was verified in natural cucumber populations. Ectopic expression of CsHY2 in Arabidopsis hy2-1 long-hypocotyl mutant led to reduced hypocotyl length. The PΦB protein was targeted to the chloroplast. The expression levels of CsHY2 and five phytochrome genes CsPHYA1, CsPHYA2, CsPHYB, CsPHYC and CsPHYE were all significantly down-regulated while several cell elongation related genes were up-regulated in elh1 mutant compared to wild-type cucumber, which are correlated with dynamic hypocotyl elongation in the mutant. RNA-seq analysis in the WT and mutant revealed differentially expressed genes involved in porphyrin and chlorophyll metabolisms, cell elongation and plant hormone signal transduction pathways. This is the first report to characterize and clone the CsHY2 gene in cucumber. This work reveals the important of CsHY2 in regulating hypocotyl length and extends our understanding of the roles of CsHY2 in cucumber.


Assuntos
Cucumis sativus/crescimento & desenvolvimento , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Hipocótilo/crescimento & desenvolvimento , Mutação , Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Cucumis sativus/enzimologia , Cucumis sativus/genética , Hipocótilo/enzimologia , Hipocótilo/genética , Oxirredutases/genética , Fenótipo , Proteínas de Plantas/genética
5.
Plant Cell ; 33(2): 306-321, 2021 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-33793793

RESUMO

Unisexual flowers provide a useful system for studying plant sex determination. In cucumber (Cucumis sativus L.), three major Mendelian loci control unisexual flower development, Female (F), androecious [a; 1-aminocyclopropane-1-carboxylate {ACC} synthase 11, acs11], and Monoecious (M; ACS2), referred to here as the Female, Androecious, Monoecious (FAM) model, in combination with two genes, gynoecious (g, the WIP family C2H2 zinc finger transcription factor gene WIP1) and the ethylene biosynthetic gene ACC oxidase 2 (ACO2). The F locus, conferring gynoecy and the potential for increasing fruit yield, is defined by a 30.2-kb tandem duplication containing three genes. However, the gene that determines the Female phenotype, and its mechanism, remains unknown. Here, we created a set of mutants and revealed that ACS1G is responsible for gynoecy conferred by the F locus. The duplication resulted in ACS1G acquiring a new promoter and expression pattern; in plants carrying the F locus duplication, ACS1G is expressed early in floral bud development, where it functions with ACO2 to generate an ethylene burst. The resulting ethylene represses WIP1 and activates ACS2 to initiate gynoecy. This early ACS1G expression bypasses the need for ACS11 to produce ethylene, thereby establishing a dominant pathway for female floral development. Based on these findings, we propose a model for how these ethylene biosynthesis genes cooperate to control unisexual flower development in cucumber.


Assuntos
Cucumis sativus/enzimologia , Cucumis sativus/genética , Flores/enzimologia , Flores/genética , Liases/genética , Sequência de Aminoácidos , Regulação da Expressão Gênica de Plantas , Loci Gênicos , Genoma de Planta , Genótipo , Glucuronidase/metabolismo , Liases/química , Fenótipo , Plantas Geneticamente Modificadas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
6.
Theor Appl Genet ; 134(7): 2023-2034, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33683399

RESUMO

KEY MESSAGE: By the strategy of bulked segregant analysis sequencing combined with genetic mapping, CsDWF5, which encodes 7 dehydrocholesterol reductase that involved in brassinosteroids biosynthesis, was identified as the candidate gene for cpa. Dwarf architecture is one of the most important breeding goals in crops. The biosynthesis and signal transduction of brassinosteroids (BRs) have a great impact on plant growth and development including plant architecture. Here, we identified a compact plant architecture (cpa) mutant from an EMS-induced cucumber population. cpa displayed the extremely dwarf phenotype with shortened internode and petiole, darkened and wrinkled leaf. Genetic analysis revealed that cpa was caused by a single recessive gene. By the strategy of bulked segregant analysis sequencing combined with genetic mapping, CsDWF5, encoding a 7-dehydrocholesterol reductase that involved in sterol biosynthesis, was identified as the candidate gene for cpa. One single nucleotide mutation (G→A) in splicing site causing 3-bp insertion (TAG) was found in the first base of the sixth intron of CsDWF5 in cpa, which furtherly resulted in the frameshift mutation and got a premature stop codon. The expression of CsDWF5 gene was significantly down regulated in different tissues of the cpa mutant compared with that in wild type. The phenotype of cpa could be partially recovered by exogenous BR treatment. Transcriptome analysis identified 1096 genes that exhibited differential expression between the cpa mutant and wild type. KEGG enrichment analysis indicated that differentially expressed genes were significantly enriched in BR biosynthesis and plant-pathogen interaction pathways. These results provide perspectives on the molecular mechanisms underlying the dwarfing phenotype in cucumber.


Assuntos
Brassinosteroides/biossíntese , Cucumis sativus/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/genética , Sequência de Aminoácidos , Mapeamento Cromossômico , Códon sem Sentido , Cucumis sativus/enzimologia , Mutação da Fase de Leitura , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Genes Recessivos , Fenótipo
7.
Theor Appl Genet ; 134(4): 979-991, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33558986

RESUMO

KEY MESSAGE: CsSh5.1, which controls hypocotyl elongation under high temperature conditions in cucumber, was mapped to a 57.1 kb region on chromosome 5 containing a candidate gene encoding a xyloglucan galactosyltransferase. Hypocotyl growth is a vital process in seedling establishment. Hypocotyl elongation after germination relies more on longitudinal cell elongation than cell division. Cell elongation is largely determined by the extensibility of the cell wall. Here, we identified a spontaneous mutant in cucumber (Cucumis sativus L.), sh5.1, which exhibits a temperature-insensitive short hypocotyl phenotype. Genetic analysis showed that the phenotype of sh5.1 was controlled by a recessive nuclear gene. CsSh5.1 was mapped to a 57.1 kb interval on chromosome 5, containing eight predicted genes. Sequencing analysis revealed that the Csa5G171710 is the candidate gene of CsSh5.1, which was further confirmed via co-segregation analysis and genomic DNA sequencing in natural cucumber variations. The result indicated that hypocotyl elongation might be controlled by this gene. CsSh5.1 encodes a xyloglucan galactosyltransferase that specifically adds galactose to xyloglucan and forms galactosylated xyloglucans, which determine the strength and extensibility of the cell walls. CsSh5.1 expression in wild-type (WT) hypocotyl was significantly higher than that in sh5.1 hypocotyl under high temperature, suggesting its important role in hypocotyl cell elongation under high temperature. The identification of CsSh5.1 is helpful for elucidating the function of xyloglucan galactosyltransferase in cell wall expansion and understanding the mechanism of hypocotyl elongation in cucumber.


Assuntos
Mapeamento Cromossômico/métodos , Cucumis sativus/crescimento & desenvolvimento , Galactosiltransferases/metabolismo , Regulação da Expressão Gênica de Plantas , Glucanos/metabolismo , Hipocótilo/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Xilanos/metabolismo , Cromossomos de Plantas/genética , Cucumis sativus/enzimologia , Cucumis sativus/genética , Galactosiltransferases/genética , Perfilação da Expressão Gênica , Hipocótilo/enzimologia , Hipocótilo/genética , Proteínas de Plantas/genética
8.
Int J Mol Sci ; 23(1)2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35008600

RESUMO

Vacuolar invertase (VI) can irreversibly degrade sucrose into glucose and fructose and involve in plants abiotic-stress-tolerance. Cucumber (Cucumis sativus L.) is susceptible to drought stress, especially during the seedling stage. To date, the involvement of VI in drought tolerance in cucumber seedlings is in urgent need of exploration. In the present study, a cucumber vacuolar invertase gene, CsVI2, was isolated and functionally characterized. The results showed that (1) CsVI2 showed vacuolar invertase activity both in vivo and in vitro; (2) the transcript level of CsVI2, along with VI activity, was significantly induced by drought stress. Moreover, the expression of sucrose synthase 3 (CsSUS3) was increased and that of sucrose phosphate synthase 1 (CsSPS1) was decreased after exposure to drought stress, which was followed by an increase in sucrose synthase activity and a decrease in sucrose phosphate synthase activity; (3) CsVI2-overexpressing transformed cucumber seedlings showed enhanced vacuolar invertase activity and drought tolerance and 4) protein-protein interaction modelling indicated that a cucumber invertase inhibitor, CsINVINH3, can interact with CsVI2. In summary, the results indicate that CsVI2 as an invertase can regulate sucrose metabolism and enhance drought stress in cucumber seedlings.


Assuntos
Cucumis sativus/enzimologia , Secas , Estresse Fisiológico , Sacarose/metabolismo , beta-Frutofuranosidase/metabolismo , Sequência de Aminoácidos , Cucumis sativus/metabolismo , Cucumis sativus/fisiologia , Regulação da Expressão Gênica de Plantas , Glucosiltransferases/genética , Modelos Moleculares , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Conformação Proteica , Plântula/metabolismo , Alinhamento de Sequência , beta-Frutofuranosidase/química
9.
Genes (Basel) ; 13(1)2021 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-35052402

RESUMO

Cucumber (Cucumis sativus L.) is an important vegetable crop worldwide, and Fusarium wilt (FW), caused by Fusarium oxysporum f. sp. cucumerinum (Foc), severely restricts cucumber growth and yield. Accumulating lines of evidence indicate that chitinases play important roles in attacking the invading fungal pathogens through catalyzing their cell wall degradation. Here, we identified the chitinase (Chi) genes in cucumber and further screened the FW-responsive genes via a comparative transcriptome analysis and found that six common genes were predominantly expressed in roots but also significantly upregulated after Foc infection. Expression verification further conformed that Chi2 and Chi14 were obviously induced by Foc as well as by hormone treatments, compared with the controls. The purified Chi2 and Chi14 proteins significantly affected the growth of Foc in vitro, compared with the controls. Knockdown of Chi2 in cucumber by virus-induced gene silencing (VIGS) increased susceptibility to FW, compared with the Chi14-silenced and control plants, and silencing of Chi2 drastically impaired gene activation in the jasmonic acid pathway, suggesting that the Chi2 gene might play positive roles in cucumber FW defense and, therefore, can provide a gene resource for developing cucumber-FW-resistance breeding programs.


Assuntos
Quitinases/metabolismo , Cucumis sativus/imunologia , Resistência à Doença/genética , Fusarium/fisiologia , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/imunologia , Proteínas de Plantas/metabolismo , Quitinases/genética , Cucumis sativus/enzimologia , Cucumis sativus/genética , Cucumis sativus/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Transcriptoma
10.
Planta ; 252(5): 75, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33026530

RESUMO

MAIN CONCLUSION: Exogenous SA treatment at appropriate concentrations promotes adventitious root formation in cucumber hypocotyls, via competitive inhibiting the IAA-Asp synthetase activity of CsGH3.5, and increasing the local free IAA level. Adventitious root formation is critical for the cutting propagation of horticultural plants. Indole-3-acetic acid (IAA) has been shown to play a central role in regulating this process, while for salicylic acid (SA), its exact effects and regulatory mechanism have not been elucidated. In this study, we showed that exogenous SA treatment at the concentrations of both 50 and 100 µM promoted adventitious root formation at the base of the hypocotyl of cucumber seedlings. At these concentrations, SA could induce the expression of CYCLIN and Cyclin-dependent Kinase (CDK) genes during adventitious rooting. IAA was shown to be involved in SA-induced adventitious root formation in cucumber hypocotyls. Exposure to exogenous SA led to a slight increase in the free IAA content, and pre-treatment with the auxin transport inhibitor 1-naphthylphthalamic acid (NPA) almost completely abolished the inducible effects of SA on adventitious root number. SA-induced IAA accumulation was also associated with the enhanced expression of Gretchen Hagen3.5 (CsGH3.5). The in vitro enzymatic assay indicated that CsGH3.5 has both IAA- and SA-amido synthetase activity and prefers aspartate (Asp) as the amino acid conjugate. The Asp concentration dictated the functional activity of CsGH3.5 on IAA. Both affinity and catalytic efficiency (Kcat/Km) increased when the Asp concentration increased from 0.3 to 1 mM. In contrast, CsGH3.5 showed equal catalytic efficiency for SA at low and high Asp concentrations. Furthermore, SA functioned as a competitive inhibitor of the IAA-Asp synthetase activity of CsGH3.5. During adventitious formation, SA application indeed repressed the IAA-Asp levels in the rooting zone. These data show that SA plays an inducible role in adventitious root formation in cucumber through competitive inhibition of the auxin conjugation enzyme CsGH3.5. SA reduces the IAA conjugate levels, thereby increasing the local free IAA level and ultimately enhancing adventitious root formation.


Assuntos
Cucumis sativus , Hipocótilo , Ácido Salicílico , Cucumis sativus/enzimologia , Cucumis sativus/crescimento & desenvolvimento , Ativação Enzimática/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas , Hipocótilo/enzimologia , Hipocótilo/crescimento & desenvolvimento , Ligases/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Ácido Salicílico/farmacologia
11.
Plant Physiol Biochem ; 156: 333-344, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32998100

RESUMO

Transglutaminase (TGase) is inextricably associated with plant growth and development. However, the mechanism by which TGase enhances salt tolerance of higher plants under salt stress is poorly understood. In this study, we investigated the effects of NaCl stress and exogenous o-phenanthroline (o-Phen, a metalloprotease inhibitor) on TGase activity, chlorophyll fluorescence parameters, carbohydrates contents, the reactive oxygen species (ROS) scavenging system, and endogenous polyamines (PAs) contents of salt-sensitive 'Jinyou No. 4' and salt-tolerant 'Inbred Line 9930' cucumber. Salt stress significantly inhibited plant growth of the two cultivars, as well as hindered carbohydrates transport, which was more evident in the salt-sensitive cultivar. TGase activity and expression, ROS scavenging capacity, and bound PAs content were up-regulated by salt stress to some extent, which was more distinct in the salt-tolerant cucumber cultivar. However, o-Phen treatment significantly inhibited TGase expression, and further decreased plant growth and the actual photochemical efficiency of photosystem II in the two cultivars. In addition, application of o-Phen significantly decreased endogenous PAs content in leaves of 'Jinyou No. 4' and 'Inbred Line 9930' seedlings by 9.60% and 42.32% under NaCl stress, respectively. These results suggested that high activity of TGase increases the salt stress tolerance of cucumber plants by increasing endogenous PAs content and ROS scavenging capacity, and promoting carbon assimilation and photosynthetic products.


Assuntos
Cucumis sativus/enzimologia , Tolerância ao Sal , Transglutaminases/fisiologia , Clorofila , Cucumis sativus/fisiologia , Fotossíntese , Folhas de Planta , Plântula
12.
Int J Biol Macromol ; 162: 1825-1838, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32814103

RESUMO

In recent years, exploration of biopolymer-based materials to avoid hazardous chemicals in agriculture has gained enormous importance for sustainable crop improvement. In the present study, chitosan a biopolymer derived from crab-shell was used in different concentrations as priming agent to cucumber seeds and were evaluated for its effect to enhance plant growth parameters as well as its ability to induce resistance against powdery mildew disease. Among the treatments, seeds-primed with 2.5 mg/mL exhibited early seedling germination of 90% and vigour of 2665 and also remarkably enhanced the cucumber growth parameters which might be fairly attributed to the stimulation of phytohormones content in primed plants over the controls. More importantly, under greenhouse conditions a significant induced disease protection of 66.6% against powdery mildew disease was noticed in chitosan-pretreated plants at 2.5 mg/mL. The induced resistant plants also showed a significant deposition of lignin, callose and H2O2. Notably, polyphenol oxidase, phenylalanine ammonia-lyase, peroxidase and glucanase defense-responsive enzymes were upregulated in chitosan-primed plants. Considered together, these results determine that the susceptible cucumber cultivar elicits immunity after perception of priming with chitosan to upregulate phytohormones and synthesize defense-responsive enzymes, thereby induce resistance against powdery mildew disease and strengthen the growth-promotion of cucumber plants.


Assuntos
Quitosana/farmacologia , Cucumis sativus , Resistência à Doença/efeitos dos fármacos , Fungos/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Sementes , Animais , Braquiúros/química , Cucumis sativus/enzimologia , Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/microbiologia , Proteínas de Plantas/metabolismo , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Plântula/microbiologia , Sementes/crescimento & desenvolvimento , Sementes/microbiologia
13.
Planta ; 252(1): 9, 2020 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-32602044

RESUMO

MAIN CONCLUSION: NO was involved in H2-induced adventitious rooting by regulating the protein and gene expressions of PM H+-ATPase and 14-3-3. Simultaneously, the interaction of PM H+-ATPase and 14-3-3 protein was also involved in this process. Hydrogen gas (H2) and nitric oxide (NO) have been shown to be involved in plant growth and development. The results in this study revealed that NO was involved in H2-induced adventitious root formation. Western blot (WB) analysis showed that the protein abundances of plasma membrane H+-ATPase (PM H+-ATPase) and 14-3-3 protein were increased after H2, NO, H2 plus NO treatments, whereas their protein abundances were down regulated when NO scavenger carboxy-2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTI O) was added. Moreover, the mRNA abundances of the HA3 and 14-3-3(7) gene as well as the activities of PM H+-ATPase (EC 3.6.1.35) and H+ pump were in full agreement with the changes of protein abundance. Phosphorylation of PM H+-ATPase and the interaction of PM H+-ATPase and 14-3-3 protein were detected by co-immunoprecipitation analysis. H2 and NO significantly up regulated the phosphorylation of PM H+-ATPase and the interaction of PM H+-ATPase and 14-3-3 protein. Conversely, the stimulation of PM H+-ATPase phosphorylation and protein interaction were significantly diminished by cPTIO. Protein interaction activator fusicoccin (FC) and inhibitor adenosine monophosphate (AMP) of PM H+-ATPase and 14-3-3 were used in this study, and the results showed that FC significantly increased the abundances of PM H+-ATPase and 14-3-3, while AMP showed opposite trends. We further proved the critical roles of PM H+-ATPase and 14-3-3 protein interaction in NO-H2-induced adventitious root formation. Taken together, our results suggested that NO might be involved in H2-induced adventitious rooting by regulating the expression and the interaction of PM H+-ATPase and 14-3-3 protein.


Assuntos
Cucumis sativus/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Óxido Nítrico/farmacologia , ATPases Translocadoras de Prótons/metabolismo , Transdução de Sinais/efeitos dos fármacos , Membrana Celular/enzimologia , Cucumis sativus/enzimologia , Cucumis sativus/crescimento & desenvolvimento , Glicosídeos/metabolismo , Hidrogênio/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Raízes de Plantas/crescimento & desenvolvimento , ATPases Translocadoras de Prótons/genética
14.
Nat Plants ; 6(7): 809-822, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32665652

RESUMO

Axillary meristem development determines both plant architecture and crop yield; this critical process is regulated by the PROLIFERATING CELL FACTORS (TCP) family of transcription factors. Although TCP proteins bind primarily to promoter regions, some also target gene bodies for expression activation. However, the underlying regulatory mechanism remains unknown. Here we show that TEN, a TCP from cucumber (Cucumis sativus L.), controls the identity and mobility of tendrils. Through its C terminus, TEN binds at intragenic enhancers of target genes; its N-terminal domain functions as a non-canonical histone acetyltransferase (HAT) to preferentially act on lysine 56 and 122 of the histone H3 globular domain. This HAT activity is responsible for chromatin loosening and host-gene activation. The N termini of all tested CYCLOIDEA and TEOSINTE BRANCHED 1-like TCP proteins contain an intrinsically disordered region; despite their sequence divergence, they have conserved HAT activity. This study identifies a non-canonical class of HATs and provides a mechanism by which modification at the H3 globular domain is integrated with the transcription process.


Assuntos
Histona Acetiltransferases/fisiologia , Proteínas de Plantas/fisiologia , Fatores de Transcrição/fisiologia , Sítios de Ligação , Cucumis sativus/enzimologia , Cucumis sativus/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Genes de Plantas/fisiologia , Histona Acetiltransferases/metabolismo
15.
Plant Sci ; 296: 110492, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32540011

RESUMO

Transglutaminases (TGases), mediators of the transamidation of specific proteins by polyamines (PA), play critical roles in PA metabolism in animals, but their functions and regulatory mechanisms are largely unknown in plants. In this study, we demonstrated that TGase from cucumber played a protective role in the regulation of PA metabolism under salt stress. The expression of TGase was induced by salt stress in cucumber. Ectopic overexpression of cucumber TGase in tobacco conferred enhanced tolerance to salt stress based on both external symptoms and membrane integrity. Overexpression lines maintained high levels of PAs under salt stress, suggesting that PAs played a vital role in TGase-induced salt tolerance. In contrast, the levels of Na+ content in the wild-type (WT) plants increased, while they decreased in the overexpression plants. The expression levels of several genes related to ion exchange enhanced, and the Na+/K+ ratio decreased by increased TGase activity under salt stress. The activities of the proton-pump ATPase (H+-ATPase), vacuolar H+-ATPase (V-ATPase) and vacuolar H+-pyrophosphatase (PPase) were higher in the overexpression lines than in WT plants under salt stress. Moreover, the malondialdehyde (MDA) and H2O2 contents were significantly lower in the overexpression lines than in WT plants, accompanied by increased antioxidant enzyme activity. Taken together, these findings demonstrate that TGase plays protective roles in response to salt stress, which may promote plant survival by regulating PA metabolism and the Na+/K+ balance under salt stress.


Assuntos
Poliaminas/metabolismo , Plantas Tolerantes a Sal/genética , Tabaco/genética , Transglutaminases/metabolismo , Antioxidantes/metabolismo , Clonagem Molecular , Cucumis sativus/enzimologia , Cucumis sativus/genética , Cucumis sativus/metabolismo , Cucumis sativus/fisiologia , Expressão Ectópica do Gene , Genes de Plantas/genética , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Potássio/metabolismo , Plantas Tolerantes a Sal/metabolismo , Plantas Tolerantes a Sal/fisiologia , Sódio/metabolismo , Tabaco/metabolismo , Tabaco/fisiologia , Transglutaminases/genética , Transglutaminases/fisiologia
16.
Artigo em Inglês | MEDLINE | ID: mdl-32464332

RESUMO

The CYP74B subfamily of fatty acid hydroperoxide transforming cytochromes P450 includes the most common plant enzymes. All CYP74Bs studied yet except the CYP74B16 (flax divinyl ether synthase, LuDES) and the CYP74B33 (carrot allene oxide synthase, DcAOS) are 13-hydroperoxide lyases (HPLs, synonym: hemiacetal synthases). The results of present work demonstrate that additional products (except the HPL products) of fatty acid hydroperoxides conversion by the recombinant StHPL (CYP74B3, Solanum tuberosum), MsHPL (CYP74B4v1, Medicago sativa), and CsHPL (CYP74B6, Cucumis sativus) are epoxyalcohols. MsHPL, StHPL, and CsHPL converted the 13-hydroperoxides of linoleic (13-HPOD) and α-linolenic acids (13-HPOT) primarily to the chain cleavage products. The minor by-products of 13-HPOD and 13-HPOT conversions by these enzymes were the oxiranyl carbinols, 11-hydroxy-12,13-epoxy-9-octadecenoic and 11-hydroxy-12,13-epoxy-9,15-octadecadienoic acid. At the same time, all enzymes studied converted 9-hydroperoxides into corresponding oxiranyl carbinols with HPL by-products. Thus, the results showed the additional epoxyalcohol synthase activity of studied CYP74B enzymes. The 13-HPOD conversion reliably resulted in smaller yields of the HPL products and bigger yields of the epoxyalcohols compared to the 13-HPOT transformation. Overall, the results show the dualistic HPL/EAS behaviour of studied CYP74B enzymes, depending on hydroperoxide isomerism and unsaturation.


Assuntos
Cucumis sativus/enzimologia , Sistema Enzimático do Citocromo P-450/química , Peróxidos Lipídicos/química , Proteínas de Plantas/química , Solanum tuberosum/enzimologia , Clonagem Molecular , Cucumis sativus/genética , Sistema Enzimático do Citocromo P-450/genética , Proteínas de Plantas/genética , RNA de Plantas , Proteínas Recombinantes/química , Solanum tuberosum/genética
17.
Int J Mol Sci ; 21(9)2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32397623

RESUMO

Fusaric acid (FA), the fungal toxin produced by Fusarium oxysporum, plays a predominant role in the virulence and symptom development of Fusarium wilt disease. As mineral nutrients can be protective agents against Fusarium wilt, hydroponic experiments employing zinc (Zn) and copper (Cu) followed by FA treatment were conducted in a glasshouse. FA exhibited strong phytotoxicity on cucumber plants, which was reversed by the addition of Zn or Cu. Thus, Zn or Cu dramatically reduced the wilt index, alleviated the leaf or root cell membrane injury and mitigated against the FA inhibition of plant growth and photosynthesis. Cucumber plants grown with Zn exhibited decreased FA transportation to shoots and a 17% increase in toxicity mitigation and showed minimal hydrogen peroxide, lipid peroxidation level with the increased of antioxidant enzymes activity in both roots and leaves. Cucumber grown with additional Cu absorbed less FA but showed more toxicity mitigation at 20% compared to with additional Zn and exhibited decreased hydrogen peroxide level and increased antioxidant enzymes activity. Thus, adding Zn or Cu can decrease the toxicity of the FA by affecting the absorption or transportation of the FA in plants and mitigate toxicity possibly through chelation. Zn and Cu modify the antioxidant system to scavenge hydrogen peroxide for suppressing FA induction of oxidative damage. Our experiments could provide a theoretical basis for the direct application of micro-fertilizer as protective agents in farming.


Assuntos
Antioxidantes/metabolismo , Cobre/farmacologia , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/metabolismo , Ácido Fusárico/toxicidade , Doenças das Plantas/prevenção & controle , Zinco/farmacologia , Cobre/metabolismo , Cucumis sativus/enzimologia , Ácido Fusárico/metabolismo , Fusarium/metabolismo , Peróxido de Hidrogênio/metabolismo , Micotoxinas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Doenças das Plantas/microbiologia , Doenças das Plantas/terapia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Caules de Planta/efeitos dos fármacos , Caules de Planta/metabolismo , Zinco/metabolismo
18.
Ecotoxicol Environ Saf ; 193: 110351, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32109583

RESUMO

Microcystins (MCs) have become an important global environmental issue, causing oxidative stress, which is an important toxic mechanism for MCs in plants. However, the regulating mechanism of antioxidative enzymes in plants in adapting to MCs stress remains unclear. We studied the dynamic effects of MCs at different concentrations (5, 10, 50 and 100 µg/L) in rice and cucumber seedlings on relative growth rate (RGR), and reactive oxygen species and malondialdehyde (MDA) content, and antioxidative enzyme activities, during a stress period (MCs exposed for 1, 3, 5 and 7 d) and recovery period (7 d). During the stress period, MCs at 5 µg/L inhibited RGR in cucumber and promoted RGR in rice. The contents of superoxide anion (O2·-), hydrogen peroxide (H2O2) and MDA increased and RGR declined in both crops with time and intensity of MCs stress. For cucumber, all these parameters responded earlier to MCs stress, and O2·-, MDA and RGR were more responsive to MCs stress than in rice. Moreover, catalase (CAT) and peroxidase (POD), and the relative expressions of CAT genes increased in both crops at 5-100 µg/L MCs, whereas relative expression of POD genes increased only in cucumber. Diversely, superoxide dismutase (SOD) response to MCs in cucumber leaves was later than for rice. MCs at 100 µg/L decreased the relative expression of SOD genes in cucumber but did not change SOD activity. During the recovery period, all the above indicators in both crops were higher than the control and lower than in the stress period. Conversely, RGR was lower than in the control and higher than in the stress period, except for cucumber which was lower, and MDA content higher than the stress period at 100 µg/L MCs. Overall, these results indicated that cucumber was more sensitive to MCs than rice, and SOD, CAT and POD play an important role in plant response to MCs stress.


Assuntos
Cucumis sativus/efeitos dos fármacos , Microcistinas/toxicidade , Oryza/efeitos dos fármacos , Antioxidantes/metabolismo , Catalase/genética , Catalase/metabolismo , Cucumis sativus/enzimologia , Cucumis sativus/genética , Cucumis sativus/crescimento & desenvolvimento , Expressão Gênica/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Oryza/enzimologia , Oryza/genética , Oryza/crescimento & desenvolvimento , Estresse Oxidativo , Peroxidase/genética , Peroxidase/metabolismo , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/enzimologia , Plântula/genética , Plântula/metabolismo , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo
19.
Int J Mol Sci ; 22(1)2020 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-33396869

RESUMO

The leaf is an important photosynthetic organ and plays an essential role in the growth and development of plants. Leaf color mutants are ideal materials for studying chlorophyll metabolism, chloroplast development, and photosynthesis. In this study, we identified an EMS-induced mutant, yl2.1, which exhibited yellow cotyledons and true leaves that did not turn green with leaf growth. The yl2.1 locus was controlled by a recessive nuclear gene. The CsYL2.1 was mapped to a 166.7-kb genomic region on chromosome 2, which contains 24 predicted genes. Only one non-synonymous single nucleotide polymorphism (SNP) was found between yl2.1 and wt-WD1 that was located in Exon 7 of Csa2G263900, resulting in an amino acid substitution. CsYL2.1 encodes a plastid isoform of triose phosphate isomerase (pdTPI), which catalyzes the reversible conversion of dihydroxyacetone phosphate (DHAP) to glyceraldehyde-3-phosphate (GAP) in chloroplasts. CsYL2.1 was highly expressed in the cotyledons and leaves. The mesophyll cells of the yl2.1 leaves contained reduced chlorophyll and abnormal chloroplasts. Correspondingly, the photosynthetic efficiency of the yl2.1 leaves was impaired. Identification of CsYL2.1 is helpful in elucidating the function of ptTPI in the chlorophyll metabolism and chloroplast development and understanding the molecular mechanism of this leaf color variant in cucumber.


Assuntos
Cucumis sativus/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Mutação , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Plastídeos/enzimologia , Triose-Fosfato Isomerase/metabolismo , Clorofila/metabolismo , Cloroplastos/metabolismo , Cor , Cucumis sativus/enzimologia , Cucumis sativus/genética , Genes Recessivos , Isoenzimas , Fenótipo , Folhas de Planta/enzimologia , Folhas de Planta/genética , Proteínas de Plantas/genética , Triose-Fosfato Isomerase/genética
20.
Chemosphere ; 243: 125308, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31722261

RESUMO

Cadmium level is continuously increasing in agricultural soils mainly due to anthropogenic activities. Cadmium is one of the most phytotoxic metals in the soils. The present study investigates the possible role of 2-hydroxymelatonin (2-OHMT) in assuagement of Cd-toxicity in cucumber (Cucumis sativus L.) plants. 2-OHMT is an important metabolite produced through interaction of melatonin with oxygenated compounds. Cadmium stress decreased the activity of antioxidant enzymes and polyamines. However, exogenously applied 2-OHMT enhanced plant growth attributes including photosynthetic rate, intercellular CO2 concentration, stomatal conductance and transpiration rate in treated plants. In addition, 2-OHMT induced enhancement of the activity of PAs biosynthesizing enzymes (putrescine, spermidine and spermine) in conjunction with reduction in activity of polyamine oxidase (PAO). 2-OHMT mitigated Cd stress through up-regulation in expression of stress related CS-ERS gene along with the amplified activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in treated seedlings. The improved activity of antioxidant scavengers played central role in reduction of hydrogen peroxide (H2O2), electrolyte leakage (EL) and malondialdehyde (MDA) in plants under Cd stress. Recent findings also advocate the positive correlation between PAs and ethylene, as both possess common precursor. The current study reveals that priming seeds with 2-OHMT reduces Cd-toxicity and makes it possible to cultivate cucumber in Cd-contaminated areas. Future experiments will perhaps help in elucidation of 2-OHMT intervened stress mitigation procedure in C. sativus crop. Furthermore, research with reference to potential of 2-OHMT for stress alleviation in other horticultural and agronomic crops will assist in enhancement of crop productivity.


Assuntos
Cádmio/toxicidade , Cucumis sativus/metabolismo , Melatonina/farmacologia , Plântula/metabolismo , Antioxidantes/metabolismo , Cádmio/metabolismo , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/enzimologia , Melatonina/análogos & derivados , Melatonina/metabolismo , Poliaminas/metabolismo , Plântula/efeitos dos fármacos , Plântula/enzimologia , Sementes/metabolismo
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