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1.
BMC Plant Biol ; 19(1): 345, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31390991

RESUMO

BACKGROUND: Aquaporin (AQP) proteins comprise a group of membrane intrinsic proteins (MIPs) that are responsible for transporting water and other small molecules, which is crucial for plant survival under stress conditions including salt stress. Despite the vital role of AQPs, little is known about them in cucumber (Cucumis sativus L.). RESULTS: In this study, we identified 39 aquaporin-encoding genes in cucumber that were separated by phylogenetic analysis into five sub-families (PIP, TIP, NIP, SIP, and XIP). Their substrate specificity was then assessed based on key amino acid residues such as the aromatic/Arginine (ar/R) selectivity filter, Froger's positions, and specificity-determining positions. The putative cis-regulatory motifs available in the promoter region of each AQP gene were analyzed and results revealed that their promoter regions contain many abiotic related cis-regulatory elements. Furthermore, analysis of previously released RNA-seq data revealed tissue- and treatment-specific expression patterns of cucumber AQP genes (CsAQPs). Three aquaporins (CsTIP1;1, CsPIP2;4, and CsPIP1;2) were the most transcript abundance genes, with CsTIP1;1 showing the highest expression levels among all aquaporins. Subcellular localization analysis in Nicotiana benthamiana epidermal cells revealed the diverse and broad array of sub-cellular localizations of CsAQPs. We then performed RNA-seq to identify the expression pattern of CsAQPs under salt stress and found a general decreased expression level of root CsAQPs. Moreover, qRT-PCR revealed rapid changes in the expression levels of CsAQPs in response to diverse abiotic stresses including salt, polyethylene glycol (PEG)-6000, heat, and chilling stresses. Additionally, transient expression of AQPs in N. benthamiana increased leaf water loss rate, suggesting their potential roles in the regulation of plant water status under stress conditions. CONCLUSIONS: Our results indicated that CsAQPs play important roles in response to salt stress. The genome-wide identification and primary function characterization of cucumber aquaporins provides insight to elucidate the complexity of the AQP gene family and their biological functions in cucumber.


Assuntos
Aquaporinas/fisiologia , Cucumis sativus/genética , Proteínas de Plantas/fisiologia , Aquaporinas/genética , Aquaporinas/metabolismo , Cucumis sativus/metabolismo , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Peróxido de Hidrogênio/metabolismo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética , Transcriptoma , Água/metabolismo
2.
BMC Plant Biol ; 19(1): 371, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31438856

RESUMO

BACKGROUND: Propamocarb (PM) is one of the main pesticides used for controlling cucumber downy mildew. However, due to its volatility and internal absorption, PM can easily form pesticide residues on cucumber fruits that seriously endanger human health and pollute the environment. The breeding of new cucumber varieties with a low abundance of PM residues via genetic methods constitutes an effective strategy for reducing pesticide residues and improving cucumber safety and quality. To help elucidate the molecular mechanism resulting in a low PM residue abundance in cucumber, we used the cucumber cultivar 'D0351' (which has the lowest PM residue content) as the test material and identified genes related to low PM residue abundance through high-throughput tag-sequencing (Tag-Seq). RESULTS: CsMAPEG was constitutively expressed and showed both varietal and organizational differences. This gene was strongly expressed in 'D0351'. The expression levels of CsMAPEG in different cucumber tissues under PM stress were as follows: fruit>leaf>stem>root. CsMAPEG can respond to salicylic acid (SA), gibberellin (GA) and Corynespora cassiicola Wei (Cor) stress and thus plays an important regulatory role in plant responses to abiotic and biological stresses. The PM residue abundance in the fruits of CsMAPEG-overexpressing plants was lower than those found in antisense CsMAPEG plants and wild-type plants at all tested time points. The results revealed that CsMAPEG played a positive role in reducing the PM residue abundance. A CsMAPEG sense construct increased the contents of SOD, POD and GST in cucumber fruits, enhanced the degradation and metabolism of PM in cucumber, and thus effectively reduced the pesticide residue abundance in cucumber fruits. CONCLUSIONS: The expression patterns of CsMAPEG in cucumber cultivars with high and low pesticide residue abundances and a transgenic verification analysis showed that CsMAPEG can actively respond to PM stress and effectively reduce the PM residue abundance in cucumber fruits. The results of this study will help researchers further elucidate the mechanism responsible for a low PM residue abundance in cucumber and lay a foundation for the breeding of new agricultural cucumber varieties with low pesticide residue abundances.


Assuntos
Carbamatos/farmacologia , Cucumis sativus/genética , Fungicidas Industriais/farmacologia , Genes de Plantas , Resíduos de Praguicidas , Clonagem Molecular , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/enzimologia , Cucumis sativus/fisiologia , Perfilação da Expressão Gênica , Vetores Genéticos , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transformação Genética
3.
BMC Plant Biol ; 19(1): 225, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31146677

RESUMO

BACKGROUND: Suboptimal root zone temperature (RZT) causes a remarkable reduction in growth of horticultural crops during winter cultivation under greenhouse production. However, limited information is available on the effects of suboptimal RZT on nitrogen (N) metabolism in cucumber seedlings. The aim of this study is to investigate the effects of 24-Epibrassinolide (EBR) on nitrate and ammonium flux rate, N metabolism, and transcript levels of NRT1 family genes under suboptimal RZT in cucumber seedlings. RESULTS: Suboptimal RZT (LT) negatively affected on cucumber growth and proportionately decreased EBR contents, bleeding rate, root activity, enzyme activities of nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), and glutamate synthase (GOGAT), nitrate (NO3-) influx rate, ammonium (NH4+) efflux rate, and transcript levels of nitrate transporter (NRT1) encoding genes. However, exogenous EBR reduced the harmful effects of suboptimal RZT and increased endogenous EBR contents, bleeding rate, root activity, enzyme activities of NR, NiR, GS, and GOGAT, NH4+ and NO3- flux rates and contents, and N accumulation. EBR-treated seedlings also upregulated the transcript levels of nitrate transporters CsNRT1.1, CsNRT1.2A, CsNRT1.2B, CsNRT1.2C, CsNRT1.3, CsNRT1.4A, CsNRT1.5B, CsNRT1.5C, CsNRT1.9, and CsNRT1.10, and downregulated CsNRT1.5A and CsNRT1.8. LT treatment upregulated the expression level of CsNRT1.5A, while exogenous BZR application downregulated the expression level of NRT1 genes. CONCLUSION: These results indicate that exogenous application of EBR alleviated the harmful effects of suboptimal RZT through changes in N metabolism, NH4+ and NO3- flux rates, and NRT1 gene expression, leading to improved cucumber seedlings growth. Our study provides the first evidence of the role of EBR in the response to suboptimal RZT in cucumber, and can be used to improve vegetable production.


Assuntos
Compostos de Amônio/metabolismo , Brassinosteroides/metabolismo , Cucumis sativus/genética , Nitratos/metabolismo , Proteínas de Plantas/genética , Esteroides Heterocíclicos/metabolismo , Transcrição Genética , Cucumis sativus/metabolismo , Família Multigênica , Nitrogênio/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Temperatura Ambiente
4.
BMC Plant Biol ; 19(1): 243, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31174472

RESUMO

BACKGROUND: Green flesh color, resulting from the accumulation of chlorophyll, is one of the most important commercial traits for the fruits. The genetic network regulating green flesh formation has been studied in tomato, melon and watermelon. However, little is known about the inheritance and molecular basis of green flesh in cucumber. This study sought to determine the main genomic regions associated with green flesh. Three F2 and two BC1 populations derived from the 9110Gt (cultivated cucumber, green flesh color) and PI183967 (wild cucumber, white flesh color) were used for the green flesh genetic analysis. Two F2 populations of them were further employed to do the map construction and quantitative trait loci (QTL) study. Also, a core cucumber germplasms population was used to do the GWAS analysis. RESULTS: We identified three indexes, flesh color (FC), flesh extract color (FEC) and flesh chlorophyll content (FCC) in three environments. Genetic analysis indicated that green flesh color in 9110Gt is controlled by a major-effect QTL. We developed two genetic maps with 192 and 174 microsatellite markers respectively. Two novel inversions in Chr1 were identified between cultivated and wild cucumbers. The major-effect QTL, qgf5.1, was identified using FC, FEC and FCC index in all different environments used. In addition, the same qgf5.1, together with qgf3.1, was identified via GWAS. Further investigation of two candidate regions using pairwise LD correlations, combined with genetic diversity of qgf5.1 in natural populations, it was found that Csa5G021320 is the candidate gene of qgf5.1. Geographical distribution revealed that green flesh color formation could be due to the high latitude, which has longer day time to produce the photosynthesis and chlorophyll synthesis during cucumber domestication and evolution. CONCLUSIONS: We first reported the cucumber green flesh color is a quantitative trait. We detected two novel loci qgf5.1 and qgf3.1, which regulate the green flesh formation in cucumber. The QTL mapping and GWAS approaches identified several candidate genes for further validation using functional genomics or forward genetics approaches. Findings from the present study provide a new insight into the genetic control of green flesh in cucumber.


Assuntos
Cucumis sativus/fisiologia , Estudo de Associação Genômica Ampla , Fenótipo , Pigmentação/genética , Locos de Características Quantitativas/genética , Mapeamento Cromossômico , Cor , Cucumis sativus/genética , Redes Reguladoras de Genes/fisiologia
5.
Comput Biol Chem ; 80: 341-350, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31082717

RESUMO

MADS-box genes comprise a family of transcription factors that function in the growth and development of plants. To obtain insights into their evolution in watermelon (Citrullus lanatus), we carried out a genome-wide analysis and identified 39 MADS-box genes. These genes were classified into MIKCc (25), MIKC*(3), Mα (5), Mß (3), and Mγ (3) clades according to their phylogenetic relationship with Arabidopsis thaliana and Cucumis sativus; moreover, these 25 genes in the MIKC clade could be classified into 13 subfamilies, and the Flowering Locus C (FLC) subfamily is absent in watermelon. Analysis of the conserved gene motifs showed similar motifs among clades. Continuing chromosomal localizations analysis indicated that MADS-box genes were distributed across 11 chromosomes in watermelon, and these genes were conditioned to be differentially expressed during plant growth and development. This research provides information that will aid further investigations into the evolution of the MADS-box gene family in plants.


Assuntos
Citrullus/genética , Genes de Plantas , Proteínas de Domínio MADS/genética , Proteínas de Plantas/genética , Arabidopsis/genética , Cucumis sativus/genética , Expressão Gênica , Perfilação da Expressão Gênica , Proteínas de Domínio MADS/classificação , Filogenia , Proteínas de Plantas/classificação , Transcriptoma
6.
Food Chem ; 290: 308-315, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31000051

RESUMO

To provide precision management of cucumber under protected cultivation, the relationships between environmental factors and daily increment of aroma in two lines were analyzed during development, using Pearson correlation and stepwise regression. Irrespective of the line tested, the daily increment of volatile compounds and C6 aldehydes were positively correlated with average daily light intensity (X1), while the daily increment of C9 aldehydes was negatively correlated with average daily relative humidity (X4) and average daytime relative humidity (X7). X1 was considered as the most significant environmental factor which affected the daily increment of volatile compounds in both lines, X7 was the environmental factor which affected the daily increment of C9 aldehydes most in No.14-1, and X1 and X4 were the factors which affected the daily increment of C6 aldehydes and C9 aldehydes most in No.26. A range of environmental factors was forecast for the maximal daily increment of volatile compounds.


Assuntos
Cucumis sativus/química , Compostos Orgânicos Voláteis/análise , Aldeídos/química , Cucumis sativus/genética , Cucumis sativus/crescimento & desenvolvimento , Frutas/química , Frutas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Genótipo , Umidade , Luz , Análise de Regressão
7.
Gene ; 707: 117-125, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31034942

RESUMO

Light is fundamental for plants in growth and development, with regulating by integration of photoreceptors, hormones, and transcription factors. In this study, the cucumber seedlings were supplemented with different ratios of red and blue light (1R1B, 2R1B, 1R2B and weak daylight as control), with triggering change of phenotype, and gene expression profiles of CsPHYs and CsCRYs, CsGAs/BRs, and CsPIFs in hypocotyls. The cucumber seedling growth was significantly improved by supplemental light quality as compared with CK, and the seedlings in 2R1B were the stoutest, with obviously shortening hypocotyls, and higher dry weight and seedlings index at two-leaf stage. The gene expression of photoreceptor and hormone, including CsPHYA, CsPHYB, CsCRY1, CsGA20ox1, CsGA20ox2, CsGA3ox1, was significantly up-regulated in hypocotyl under different supplemental light conditions. The cucumber seedlings silenced by pTRV2-PIF4 had an obvious shortened hypocotyl. The expression level of CsCRY1, CsGA20ox1 and CsGA3ox1 was markedly down-regulation, whereas CsPHYA and CsPHYB expression increased observably and CsGA20ox2 expression was not dramatically difference in pTRV2-PIF4-infected seedlings. Thus, cucumber seedlings hypocotyl elongation was regulated by different supplemental light through crosstalk of photoreceptor, GAs, PIFs, and increasing ratio of red light could promote suppression of hypocotyl elongation.


Assuntos
Cucumis sativus/crescimento & desenvolvimento , Hipocótilo/crescimento & desenvolvimento , Proteínas de Plantas/genética , Plântula/genética , Criptocromos/genética , Cucumis sativus/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Hipocótilo/genética , Oxigenases de Função Mista/genética , Fenótipo , Fotoperíodo , Fitocromo/genética
8.
BMC Plant Biol ; 19(1): 157, 2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31023214

RESUMO

BACKGROUND: Pedicel orientation can affect the female flower orientation and seed yield in cucumber. A spontaneous mutant possessing upward growth of pedicels was identified in the wild type inbred strain 9930 and named upward-pedicel (up). The morphological and genetic analyses of up were performed in this study. In order to clone the up gene, 933 F2 individuals and 524 BC1 individuals derived from C-8-6 (WT) and up were used for map-based cloning. RESULTS: up was mapped to a 35.2 kb physical interval on chromosome 1, which contains three predicted genes. Sequencing analysis revealed that a 5-bp deletion was found in the second exon of Csa1G535800, and it led to a frameshift mutation resulting in a premature stop codon. The candidate gene of CsUp (Csa1G535800) was further confirmed via genomic and cDNA sequencing in biparental and natural cucumber populations. Sequencing data showed that a 4-bp deletion was found in the sixth exon of Csa1G535800 in CGN19839, another inbred line, and there was also a mutation of an amino acid in Csa1G535800 that could contribute to the upward growth of pedicels in CGN19839. Moreover, it was found that Csa1G535800 exhibited strong expression in the pedicel of WT, suggesting its important role in development of pedicel orientation. Thus, Csa1G535800 was considered to be the candidate gene of CsUp. CONCLUSIONS: CsUp encodes an Auxilin-like protein and controls pedicel orientation in cucumber. The identification of CsUp may help us to understand the mechanism of pedicel orientation development and allow for investigation of novel functions of Auxilin-like proteins in cucumber.


Assuntos
Auxilinas/genética , Mapeamento Cromossômico , Cucumis sativus/genética , Genes de Plantas , Estudos de Associação Genética , Mutação/genética , Sequência de Aminoácidos , Sequência de Bases , Segregação de Cromossomos , Cromossomos de Plantas/genética , Cruzamentos Genéticos , Regulação da Expressão Gênica de Plantas , Genes Recessivos , Loci Gênicos , Fenótipo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Característica Quantitativa Herdável , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
9.
BMC Plant Biol ; 19(1): 164, 2019 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-31029105

RESUMO

BACKGROUND: Circular RNAs (circRNAs) are 3'-5' head-to-tail covalently closed non-coding RNA that have been proved to play essential roles in many cellular and developmental processes. However, no information relate to cucumber circRNAs is available currently, especially under salt stress condition. RESULTS: In this study, we sequenced circRNAs in cucumber and a total of 2787 were identified, with 1934 in root and 44 in leaf being differentially regulated under salt stress. Characteristics analysis of these circRNAs revealed following features: most of them are exon circRNAs (79.51%) and they prefer to arise from middle exon(s) of parent genes (2035/2516); moreover, most of circularization events (88.3%) use non-canonical-GT/AG splicing signals; last but not least, pairing-driven circularization is not the major way to generate cucumber circRNAs since very few circRNAs (18) contain sufficient flanking complementary sequences. Annotation and enrichment analysis of both parental genes and target mRNAs were launched to uncover the functions of differentially expressed circRNAs induced by salt stress. The results showed that circRNAs may be paly roles in salt stress response by mediating transcription, signal transcription, cell cycle, metabolism adaptation, and ion homeostasis related pathways. Moreover, circRNAs may function to regulate proline metabolisms through regulating associated biosynthesis and degradation genes. CONCLUSIONS: The present study identified large number of cucumber circRNAs and function annotation revealed their possible biological roles in response to salt stress. Our findings will lay a solid foundation for further structure and function studies of cucumber circRNAs.


Assuntos
Cucumis sativus/genética , Cucumis sativus/fisiologia , RNA de Plantas/genética , RNA/genética , Estresse Salino/genética , Sequência de Bases , Biomassa , Cucumis sativus/crescimento & desenvolvimento , Éxons/genética , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Redes Reguladoras de Genes , Genes de Plantas , Transporte de Íons , MicroRNAs/genética , MicroRNAs/metabolismo , Anotação de Sequência Molecular , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/metabolismo
10.
Ecotoxicol Environ Saf ; 174: 245-254, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30831473

RESUMO

Salinity decreases the yield and quality of crops. Silicon (Si) has been widely reported to have beneficial effects on plant growth and development under salt stress. However, the mechanism is still poorly understood. In an attempt to identify genes or gene networks that may be orchestrated to improve salt tolerance of cucumber plants, we sequenced the transcriptomes of both control and salt-stressed cucumber leaves in the presence or absence of added Si. Seedlings of cucumber 'JinYou 1' were subjected to salt stress (75 mM NaCl) without or with addition of 0.3 mM Si. Plant growth, photosynthetic gas exchange and transcriptomic dynamics were investigated. The results showed that Si addition improved the growth and photosynthetic performance of cucumber seedlings under salt stress. The comparative transcriptome analysis revealed that Si played an important role in shaping the transcriptome of cucumber: the expressions of 1469 genes were altered in response to Si treatment in the control conditions, and these genes were mainly involved in ion transport, hormone and signal transduction, biosynthetic and metabolic processes, and stress and defense responses. Under salt stress alone, 1482 genes with putative functions associated with metabolic processes and responses to environmental stimuli have changed their expression levels. Si treatment shifted the transcriptome of salt-stressed cucumber back to that of the control, as evidenced that among the 708 and 774 genes that were up- or down-regulated under salt stress, a large majority of them (609 and 595, respectively) were reverted to the normal expression levels. These results suggest that Si may act as an elicitor to precondition cucumber plants and induce salt tolerance. The study may help us understand the mechanism for silicon-mediated salt tolerance and provide a theoretical basis for silicon application in crop production in saline soils.


Assuntos
Cucumis sativus/efeitos dos fármacos , Estresse Salino/efeitos dos fármacos , Silicatos/farmacologia , Transcriptoma/efeitos dos fármacos , Cucumis sativus/genética , Cucumis sativus/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Modelos Teóricos , Fotossíntese/efeitos dos fármacos , Fotossíntese/genética , Desenvolvimento Vegetal/efeitos dos fármacos , Desenvolvimento Vegetal/genética , Salinidade , Estresse Salino/genética , Tolerância ao Sal/efeitos dos fármacos , Tolerância ao Sal/genética , Cloreto de Sódio/administração & dosagem
11.
Int J Mol Sci ; 20(5)2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-30823363

RESUMO

Calcium and ethylene are essential in plant growth and development. In this study, we investigated the effects of calcium and ethylene on adventitious root formation in cucumber explants under salt stress. The results revealed that 10 µM calcium chloride (CaCl2) or 0.1 µM ethrel (ethylene donor) treatment have a maximum biological effect on promoting the adventitious rooting in cucumber under salt stress. Meanwhile, we investigated that removal of ethylene suppressed calcium ion (Ca2+)-induced the formation of adventitious root under salt stress indicated that ethylene participates in this process. Moreover, the application of Ca2+ promoted the activities of 1-aminocyclopropane-l-carboxylic acid synthase (ACS) and ACC Oxidase (ACO), as well as the production of 1-aminocyclopropane-l-carboxylic acid (ACC) and ethylene under salt stress. Furthermore, we discovered that Ca2+ greatly up-regulated the expression level of CsACS3, CsACO1 and CsACO2 under salt stress. Meanwhile, Ca2+ significantly down-regulated CsETR1, CsETR2, CsERS, and CsCTR1, but positively up-regulated the expression of CsEIN2 and CsEIN3 under salt stress; however, the application of Ca2+ chelators or channel inhibitors could obviously reverse the effects of Ca2+ on the expression of the above genes. These results indicated that Ca2+ played a vital role in promoting the adventitious root development in cucumber under salt stress through regulating endogenous ethylene synthesis and activating the ethylene signal transduction pathway.


Assuntos
Cálcio/metabolismo , Cucumis sativus/metabolismo , Etilenos/metabolismo , Raízes de Plantas/metabolismo , Estresse Salino , Cucumis sativus/genética , Cucumis sativus/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Transdução de Sinais
12.
Theor Appl Genet ; 132(5): 1505-1521, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30710191

RESUMO

KEY MESSAGE: QTL-seq analysis identified three major QTLs conferring subgynoecy in cucumbers. Furthermore, sequence and expression analyses predicted candidate genes controlling subgynoecy. The cucumber (Cucumis sativus L.) is a typical monoecious having individual male and female flowers, and sex differentiation is an important developmental process that directly affects its fruit yield. Subgynoecy represents a sex form with a high degree of femaleness and would have alternative use as gynoecy under limited resource conditions. Recently, many studies have been reported that QTL-seq, which integrates the advantages of bulked segregant analysis and high-throughput whole-genome resequencing, can be a rapid and cost-effective way of mapping QTLs. Segregation analysis in the F2 and BC1 populations derived from a cross between subgynoecious LOSUAS and monoecious BMB suggested the quantitative nature of subgynoecy in cucumbers. Both genome-wide SNP profiling of subgynoecious and monoecious bulks constructed from F2 and BC1 plants consistently identified three significant genomic regions, one on chromosome 3 (sg3.1) and another two on short and long arms of chromosome 1 (sg1.1 and sg1.2). Classical QTL analysis using the F2 confirmed sg3.1 (R2 = 42%), sg1.1 (R2 = 29%) and sg1.2 (R2 = 18%) as major QTLs. These results revealed the unique genetic inheritance of subgynoecious line LOSUAS through two distinct major QTLs, sg3.1 and sg1.1, which mainly increase degree of femaleness, while another QTL, sg1.2, contributes to decrease it. This study demonstrated that QTL-seq allows rapid and powerful detection of QTLs using preliminary generation mapping populations such as F2 or BC1 population and further that the identified QTLs could be useful for molecular breeding of cucumber lines with high yield potential.


Assuntos
Cucumis sativus/genética , Locos de Características Quantitativas , Cucumis sativus/crescimento & desenvolvimento , Flores/genética , Flores/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Fenótipo , Desenvolvimento Vegetal/genética , Polimorfismo de Nucleotídeo Único , Reprodução
13.
Theor Appl Genet ; 132(4): 1223-1233, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30758532

RESUMO

KEY MESSAGE: We used a mitochondrial (mt) mutant of cucumber to document rare maternal transmission of mt polymorphisms and demonstrate that polymorphisms can become more prevalent and sort to progenies to increase mt DNA diversity. The mitochondrial (mt) DNAs of most angiosperms show maternal inheritance, although relatively rare biparental or paternal transmission has been documented. The mt DNAs of plants in the genus Cucumis (family Cucurbitaceae) are paternally transmitted in intra- and interspecific crosses. MSC16 is an inbred line of cucumber (Cucumis sativus) with a mitochondrially associated mosaic (MSC) phenotype. MSC16 was crossed as the male parent to wild-type cultivar Calypso, and hybrid progenies were evaluated for the wild-type phenotype in order to screen for rare maternal or biparental transmission of the mt DNA. We then used standard and droplet digital (dd) PCR to study the transmission of polymorphic mt markers across three generations. We observed evidence for occasional maternal and biparental transmission of the mt DNA in cucumber. The transmission of specific regions of the maternal mt DNA could be as high as 17.8%, although the amounts of these maternal regions were often much lower relative to paternally transmitted regions. Different combinations of maternal and paternal mt polymorphisms were detected in progenies across generations, indicating that relatively rare maternal regions can be transmitted to progenies and become predominant to increase mt DNA diversity over generations.


Assuntos
Cucumis sativus/genética , DNA Mitocondrial/genética , Polimorfismo Genético , Núcleo Celular/genética , Cruzamentos Genéticos , DNA de Plantas/genética , Marcadores Genéticos , Genótipo , Mitocôndrias/genética
14.
Int J Mol Sci ; 20(4)2019 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-30791389

RESUMO

Transglutaminase (TGase) is a regulator of posttranslational modification of protein that provides physiological protection against diverse environmental stresses in plants. Nonetheless, the mechanisms of TGase-mediated salt tolerance remain largely unknown. Here, we found that the transcription of cucumber TGase (CsTGase) was induced in response to light and during leaf development, and the CsTGase protein was expressed in the chloroplast and the cell wall. The overexpression of the CsTGase gene effectively ameliorated salt-induced photoinhibition in tobacco plants, increased the levels of chloroplast polyamines (PAs) and enhanced the abundance of D1 and D2 proteins. TGase also induced the expression of photosynthesis related genes and remodeling of thylakoids under normal conditions. However, salt stress treatment reduced the photosynthesis rate, PSII and PSI related genes expression, D1 and D2 proteins in wild-type (WT) plants, while these effects were alleviated in CsTGase overexpression plants. Taken together, our results indicate that TGase-dependent PA signaling protects the proteins of thylakoids, which plays a critical role in plant response to salt stress. Thus, overexpression of TGase may be an effective strategy for enhancing resistance to salt stress of salt-sensitive crops in agricultural production.


Assuntos
Cucumis sativus/genética , Expressão Gênica , Tabaco/genética , Transglutaminases/genética , Biomassa , Cloroplastos/genética , Cloroplastos/metabolismo , Cloroplastos/ultraestrutura , Cucumis sativus/enzimologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Imuno-Histoquímica , Fotossíntese , Folhas de Planta/genética , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , Tolerância ao Sal , Estresse Fisiológico , Tilacoides/metabolismo , Tabaco/metabolismo , Transglutaminases/metabolismo
15.
Plant Mol Biol ; 99(6): 535-544, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30707394

RESUMO

KEY MESSAGE: In this study, we first linked the signal molecule H2S with cucurbitacin C, which can cause the bitter taste of cucumber leaves and fruit, and specifically discuss its molecular mechanism. Cucurbitacin C (CuC), a triterpenoid secondary metabolite, enhances the resistance of cucumber plants to pathogenic bacteria and insect herbivores, but results in bitter-tasting fruits. CuC can be induced in some varieties of cucumber on exposure to plant stressors. The gasotransmitter hydrogen sulfide (H2S) participates in multiple physiological processes relating to plant stress resistance. This study focused on the effect of H2S on low temperature-induced CuC synthesis in cucumber. The results showed that treatment of cucumber leaves at 4 °C for 12 h enhanced the content and production rate of H2S and increased the expression of genes encoding enzymes involved in H2S generation, Csa2G034800.1 (CsaLCD), Csa1G574800.1 (CsaDES1), and Csa1G574810.1 (CsaDES2). In addition, treatment at 4 °C or with exogenous H2S upregulated the expression of CuC synthetase-encoding genes and the resulting CuC content in cucumber leaves, whereas pretreatment with hypotaurine (HT, a H2S scavenger) before treatment at 4 °C offset these effects. In vitro, H2S could increase the S-sulfhydration level of His-Csa5G156220 and His-Csa5G157230 (both bHLH transcription factors), as well as their binding activity to the promoter of Csa6G088690, which encodes the key synthetase for CuC generation. H2S pretreatment enhanced the cucumber leaves resistance to the Phytophthora melonis. Together, these results demonstrated that H2S acts as a positive regulator of CuC synthesis as a result of the modification of proteins by S-sulfhydration, also providing indirect evidence for the role of H2S in improving the resistance of plants to abiotic stresses and biotic stresses by regulating the synthesis of secondary metabolites.


Assuntos
Temperatura Baixa , Cucumis sativus/metabolismo , Sulfeto de Hidrogênio/metabolismo , Triterpenos/metabolismo , Cucumis sativus/genética , Cucumis sativus/parasitologia , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas/genética , Phytophthora/patogenicidade , Folhas de Planta/metabolismo , Metabolismo Secundário/genética , Estresse Fisiológico
16.
Plant Sci ; 279: 59-69, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30709494

RESUMO

The cucumber (Cucumis sativus L.), an economically important vegetable crop, is often infected by Pseudoperonospora cubensis (P. cubensis), which results in inhibited growth and reduced yield. WRKY transcription factors (TFs) play critical roles in plant disease resistance. However, little is known about the function of WRKY TFs in cucumber downy mildew resistance. In this study, we reported that CsWRKY50, a cucumber WRKY subgroup Ⅱc TF localized in the nucleus, plays an important role in cucumber defense responses to downy mildew. In addition, several putative cis-acting elements involved in abiotic stress responsiveness were also identified in the CsWRKY50 promoter. Expression analysis revealed that CsWRKY50 can be induced by P. cubensis infection, abiotic stress and diverse signaling molecules. The overexpression of CsWRKY50 in cucumber enhanced the resistance of the plant to the fungal pathogen P. cubensis. In addition, less ROS accumulated in 35S:CsWRKY50 transgenic plants infected by the pathogen due to the higher expression levels of antioxidant enzymes. Importantly, after P. cubensis infection, the transcript levels of several hormone-related defense genes were also upregulated in transgenic plants, including SA- and JA-responsive genes and SA-synthesis genes. Collectively, our results indicate that CsWRKY50 positively regulates cucumber disease resistance to P. cubensis via multiple signaling pathways.


Assuntos
Cucumis sativus/imunologia , Peronospora , Doenças das Plantas/microbiologia , Proteínas de Plantas/fisiologia , Fatores de Transcrição/fisiologia , Cucumis sativus/genética , Cucumis sativus/metabolismo , Cucumis sativus/microbiologia , Regulação da Expressão Gênica de Plantas/imunologia , Genes de Plantas , Filogenia , Doenças das Plantas/imunologia , Imunidade Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Alinhamento de Sequência , Análise de Sequência de DNA , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
17.
Arch Virol ; 164(4): 1121-1134, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30799510

RESUMO

Cucumber green mottle mosaic virus (CGMMV) is an important pathogen of cucumber (Cucumis sativus). The molecular mechanisms mediating host-pathogen interactions are likely to be strongly influenced by microRNAs (miRNAs), which are known to regulate gene expression during the disease cycle. This study focused on 14 miRNAs (miR159, miR169, miR172, miR838, miR854, miR5658, csa-miRn1-3p, csa-miRn2-3p, csa-miRn3-3p, csa-miRn4-5p, csa-miRn5-5p, csa-miRn6-3p, csa-miRn7-5p and csa-miRn8-3p) and their target genes. The data collected was used to construct a regulatory network of miRNAs and target genes associated with cucumber-CGMMV interactions, which identified 608 potential target genes associated with all of the miRNAs except csa-miRn7-5p. Five of the miRNAs (miR159, miR838, miR854, miR5658 and csa-miRn6-3p) were found to be mutually linked by target genes, while another eight (miR169, miR172, csa-miRn1-3p, csa-miRn2-3p, csa-miRn3-3p, csa-miRn4-5p, csa-miRn5-5p and csa-miRn8-3p) formed subnetworks that did not display any connectivity with other miRNAs or their target genes. Reverse transcription quantitative real-time PCR (RT-qPCR) was used to analyze the expression levels of the different miRNAs and their putative target genes in leaf, stem and root samples of cucumber over a 42-day period after inoculation with CGMMV. A positive correlation was found between some of the miRNAs and their respective target genes, although for most, the response varied greatly depending on the time point, indicating that additional factors are likely to be involved in the interaction between cucumber miRNAs and their target genes. Several miRNAs, including miR159 and csa-miRn6-3p, were linked to target genes that have been associated with plant responses to disease. A model linking miRNAs, their targets and downstream biological processes is proposed to indicate the roles of these miRNAs in the cucumber-CGMMV pathosystem.


Assuntos
Cucumis sativus/genética , MicroRNAs/genética , Doenças das Plantas/virologia , RNA de Plantas/genética , Tobamovirus/fisiologia , Cucumis sativus/metabolismo , Cucumis sativus/virologia , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Interações Hospedeiro-Patógeno , MicroRNAs/metabolismo , Doenças das Plantas/genética , Folhas de Planta/metabolismo , Folhas de Planta/virologia , RNA de Plantas/metabolismo , Tobamovirus/genética
18.
BMC Genomics ; 20(1): 144, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30777003

RESUMO

BACKGROUND: Trichoderma spp. are effective biocontrol agents for many plant pathogens, thus the mechanism of Trichoderma-induced plant resistance is not fully understood. In this study, a novel Trichoderma strain was identified, which could promote plant growth and reduce the disease index of gray mold caused by Botrytis cinerea in cucumber. To assess the impact of Trichoderma inoculation on the plant response, a multi-omics approach was performed in the Trichoderma-inoculated cucumber plants through the analyses of the plant transcriptome, proteome, and phytohormone content. RESULTS: A novel Trichoderma strain was identified by morphological and molecular analysis, here named T. longibrachiatum H9. Inoculation of T. longibrachiatum H9 to cucumber roots promoted plant growth in terms of root length, plant height, and fresh weight. Root colonization of T. longibrachiatum H9 in the outer layer of epidermis significantly inhibited the foliar pathogen B. cinerea infection in cucumber. The plant transcriptome and proteome analyses indicated that a large number of differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were identified in cucumber plants 96 h post T. longibrachiatum H9 inoculation. Up-regulated DEGs and DEPs were mainly associated with defense/stress processes, secondary metabolism, and phytohormone synthesis and signaling, including jasmonic acid (JA), ethylene (ET) and salicylic acid (SA), in the T. longibrachiatum H9-inoculated cucumber plants in comparison to untreated plants. Moreover, the JA and SA contents significantly increased in cucumber plants with T. longibrachiatum H9 inoculation. CONCLUSIONS: Application of T. longibrachiatum H9 to the roots of cucumber plants effectively promoted plant growth and significantly reduced the disease index of gray mold caused by B. cinerea. The analyses of the plant transcriptome, proteome and phytohormone content demonstrated that T. longibrachiatum H9 mediated plant systemic resistance to B. cinerea challenge through the activation of signaling pathways associated with the phytohormones JA/ET and SA in cucumber.


Assuntos
Cucumis sativus/metabolismo , Cucumis sativus/microbiologia , Ciclopentanos/metabolismo , Resistência à Doença , Etilenos/metabolismo , Oxilipinas/metabolismo , Doenças das Plantas/microbiologia , Ácido Salicílico/metabolismo , Transdução de Sinais , Trichoderma , Biomarcadores , Cucumis sativus/genética , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno , Doenças das Plantas/genética , Proteômica , Transcriptoma , Trichoderma/fisiologia
19.
Ecotoxicol Environ Saf ; 171: 435-442, 2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-30639869

RESUMO

High-affinity K+ (HKT) gene family is regulated the transport of Na+ and maintain the balance between Na+ and K+ in the process of plant growth, development and response to abiotic stress. Despite this fact, systemic and comprehensive studies on HKT in multiply plants remains unknown. A total of 29 HKT genes distributed on nine species were identified. Phylogenetic tree analysis results indicated that HKT genes were divided into five homology subfamilies. Combining structural analysis with protein contains five highly conservative motifs, HKT family has similar gene structures and special gene characteristics. Finally, the expression patterns of HKT showed two different dramatic changes in different organs and tissues under different salt stress in multiply plants. This study has many implications for research into the comparative genomics analysis of HTK gene family, which revealed regulation mechanism of HKT genes, is valuable for understanding development and response to abiotic stress in plant.


Assuntos
Regulação da Expressão Gênica de Plantas , Genoma de Planta , Proteínas de Plantas/genética , Estresse Salino , Fatores de Transcrição/genética , Sequência de Aminoácidos , Citrus sinensis/genética , Coffea/genética , Cucumis sativus/genética , Estruturas Genéticas , Lycopersicon esculentum/genética , Proteínas de Plantas/metabolismo , Populus/genética , Alinhamento de Sequência , Sorghum/genética , Soja/genética , Vitis/genética , Zea mays/genética
20.
Photochem Photobiol Sci ; 18(2): 424-433, 2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30628617

RESUMO

Expression of cucumber (Cucumis sativus) genes encoding the phenylpropanoid and flavonoid biosynthetic enzymes phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), and chalcone synthase (CHS), was studied under control light conditions (photosynthetically active radiation, PAR) in root, stem, and leaf. Furthermore, the expression was quantified in leaves illuminated with PAR and supplemental ultraviolet-A (315-400 nm) or ultraviolet-B (280-315 nm) radiation. The expression patterns of all twelve CsPAL, three CsC4H, and three CsCHS genes were established. Among the genes regulated by UV two general expression patterns emerge. One pattern applies to genes primarily regulated by enriched UV-A illumination (pattern 1). Another pattern (pattern 2) was found for the genes regulated by enriched UV-B. Three of the pattern 2 genes (CsPAL4, CsPAL10, and CsCHS2) displayed a particular sub-pattern (pattern 2b) with transcription enriched by at least 30-fold. In contrast to the other genes studied, the promoters of the genes regulated according to pattern 2b contained a combination of a number of cis-acting regulatory elements (MREs, ACEs, and G-boxes) that may be of importance for the particularly high enhancement of expression under UV-B-containing light. The regulation of phenylpropanoid and flavonoid biosynthesis genes in cucumber resembles that of a number of other plants. However, cucumber, due to its greater size, is an attractive species for combining more detailed studies of the morphology, physiological parameters and fine regulation of spatial and temporal expression of key genes. This, in turn, can facilitate the quantitative investigation of the relationships among different promoter motifs, the expression levels of each of these three genes, and metabolite accumulation profiles.


Assuntos
Cucumis sativus/genética , Cucumis sativus/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Genes de Plantas/genética , Propanóis/metabolismo , Raios Ultravioleta , Cucumis sativus/enzimologia , Cucumis sativus/metabolismo , Especificidade de Órgãos , Folhas de Planta/genética , Folhas de Planta/efeitos da radiação
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