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1.
BMC Plant Biol ; 19(1): 547, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31823722

RESUMO

BACKGROUND: Infestation of the phytotoxic aphid Schizaphis graminum can rapidly induce leaf chlorosis in susceptible plants, but this effect is not observed with the nonphytotoxic aphid Sitobion avenae. However, few studies have attempted to identify the different defence responses induced in wheat by S. graminum and S. avenae feeding and the mechanisms underlying the activation of chlorosis by S. graminum feeding. RESULTS: S. graminum feeding significantly reduced the chlorophyll content of wheat leaves, and these effects were not observed with S. avenae. A transcriptomic analysis showed that the expression levels of genes involved in the salicylic acid, jasmonic acid and ethylene signalling defence pathways were significantly upregulated by both S. avenae and S. graminum feeding; however, more plant defence genes were activated by S. graminum feeding than S. avenae feeding. The transcript levels of genes encoding cell wall-modifying proteins were significantly increased after S. graminum feeding, but only a few of these genes were induced by S. avenae. Furthermore, various reactive oxygen species-scavenging genes, such as 66 peroxidase (POD) and 8 ascorbate peroxidase (APx) genes, were significantly upregulated after S. graminum feeding, whereas only 15 POD and one APx genes were induced by S. avenae feeding. The activity of four antioxidant enzymes was also significantly upregulated by S. graminum feeding. Cytological examination showed that S. graminum feeding induced substantial hydrogen peroxide (H2O2) accumulation in wheat leaves. The chlorosis symptoms and the loss of chlorophyll observed in wheat leaves after S. graminum feeding were reduced and inhibited by the scavenging of H2O2 by dimethylthiourea, which indicated that H2O2 plays important role in the induction of chlorosis by S. graminum feeding. CONCLUSIONS: S. graminum and S. avenae feeding induces the JA, SA and ET signalling pathways, but S. graminum activated stronger plant defence responses than S. avenae. S. graminum feeding triggers strong ROS-scavenging activity and massive H2O2 production in wheat leaves, and the accumulation of H2O2 induced by S. graminum feeding is involved in the activation of chlorosis in wheat leaves. These results enhance our understanding of mechanisms underlying aphid-wheat interactions and provide clues for the development of aphid-resistant wheat varieties.


Assuntos
Afídeos/fisiologia , Genes de Plantas/fisiologia , Herbivoria , Transcriptoma , Triticum/fisiologia , Animais , Cadeia Alimentar , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Redes e Vias Metabólicas , Folhas de Planta/fisiologia , Especificidade da Espécie , Triticum/genética
2.
J Plant Physiol ; 243: 153021, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31639534

RESUMO

Kiwifruit (Actinidia chinensis var. deliciosa (A. Chev) A. Chev.) is a widely cultivated crop due to the nutritional value of its fruits. Its commercialization is related to the fruit size, which is directly linked with the number of seeds and, consequently, with pollination. In this dioecious species pollination is dependent on a short effective pollination period which is related to a Programmed Cell Death (PCD) process. At the same time, this PCD process allows the growth of many pollen tubes. Several studies suggest that ethylene can play an important role in PCD in a number of systems. In this report, we determined the full sequence of the AcACS gene, encoding the enzyme that catalyses a rate-limiting step of the ethylene synthesis. Next, we monitored the expression pattern of this gene as well as of other genes involved in ethylene synthesis (ACO2-5) and signalling (AdERS1a, AdERS1b, AdETR1, AdETR2, AdETR3, AdCTR1, AdCTR2, AdEIL1) in pollinated and non-pollinated stigmatic arms of kiwifruit female flowers. The relative expression patterns observed for AcACS, ACOs and ethylene perception and signalling genes (AdERS1, AdETR1, AdCTR1 and AdEIL1) showed that they are expressed before anthesis. After anthesis, expression of the studied genes was detected earlier in pollinated than in non-pollinated stigmatic arms, as it was previously determined for PCD hallmarks. In addition, the expression pattern of the studied genes showed a clear relationship with the PCD hallmarks described in a previous report in the secretory tissue both in non-pollinated stigmatic arms (related to the short EPP in this species) and in pollinated ones (related to the growth of many pollen tubes during progamic phase). Overall, these results suggest an involvement of ethylene with PCD contributing to the high reproductive success of this species.


Assuntos
Actinidia/fisiologia , Apoptose/genética , Etilenos/biossíntese , Expressão Gênica/fisiologia , Genes de Plantas/fisiologia , Transdução de Sinais/genética , Actinidia/genética , Perfilação da Expressão Gênica
3.
Planta ; 250(6): 1897-1910, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31485773

RESUMO

MAIN CONCLUSION: A homologue of the ribosomal protein L22e, Rpf84, regulates root nodule symbiosis by mediating the infection process of rhizobia and preventing bacteroids from degradation in Robinia pseudoacacia. Ribosomal proteins (RPs) are known to have extraribosomal functions, including developmental regulation and stress responses; however, the effects of RPs on symbiotic nodulation of legumes are still unclear. Ribosomal protein 22 of the large 60S subunit (RPL22), a non-typical RP that is only found in eukaryotes, has been shown to function as a tumour suppressor in animals. Here, a homologue of RPL22, Rpf84, was identified from the leguminous tree R. pseudoacacia. Subcellular localization assays showed that Rpf84 was expressed in the cytoplasm and nucleus. Knockdown of Rpf84 by RNA interference (RNAi) technology impaired the infection process and nodule development. Compared with the control, root and stem length, dry weight and nodule number per plant were drastically decreased in Rpf84-RNAi plants. The numbers of root hair curlings, infection threads and nodule primordia were also significantly reduced. Ultrastructure analyses showed that Rpf84-RNAi nodules contained fewer infected cells with fewer bacteria. In particular, remarkable deformation of bacteroids and fusion of multiple symbiosomes occurred in infected cells. By contrast, overexpression of Rpf84 promoted nodulation, and the overexpression nodules maintained a larger infection/differentiation region and had more infected cells filled with bacteroids than the control at 45 days post inoculation, suggesting a retarded ageing process in nodules. These results indicate for the first time that RP regulates the symbiotic nodulation of legumes and that RPL22 may function in initiating the invasion of rhizobia and preventing bacteroids from degradation in R. pseudoacacia.


Assuntos
Genes de Plantas/genética , Proteínas de Plantas/genética , Nodulação/genética , Subunidades Ribossômicas Maiores/genética , Robinia/genética , Clonagem Molecular , Genes de Plantas/fisiologia , Proteínas de Plantas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Subunidades Ribossômicas Maiores/fisiologia , Robinia/crescimento & desenvolvimento , Robinia/fisiologia , Nódulos Radiculares de Plantas/crescimento & desenvolvimento , Nódulos Radiculares de Plantas/metabolismo , Simbiose/genética , Transcriptoma
4.
J Plant Physiol ; 241: 153014, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31487619

RESUMO

Tuberization in potato is governed by many intrinsic and extrinsic factors. Various molecular signals, such as red light photoreceptor (StPHYB), BEL1-like transcription factor (StBEL5), CYCLING DOF FACTOR1 (StCDF1), StCO1/2 (CONSTANS1/2) and StSP6A (Flowering Locus T orthologue), function as crucial regulators during the photoperiod-dependent tuberization pathway. StCDF1 induces tuberization by increasing StSP6A levels via StCO1/2 suppression. Although the circadian clock proteins, GIGANTEA (StGI) and FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (StFKF1), are reported as StCDF1 interactors, how the StCDF1 gene is regulated in potato is unknown. The BEL-KNOX heterodimer regulates key tuberization genes through tandem TGAC core motifs in their promoters. A recent study reported the presence of six tandem TGAC core motifs in the StCDF1 promoter, suggesting possible regulation of StCDF1 by StBEL5. In our study, we observed a positive correlation between StBEL5 and StCDF1 expression, whereas StCDF1 and its known repressor, StFKF1, showed a negative correlation for the tested tissue types. To investigate the StBEL5-StCDF1 interaction, we generated transgenic potato promoter lines containing a wild-type or mutated (deletion of six tandem TGAC sites) StCDF1 promoter fused to GUS. Wild-type promoter transgenic lines exhibited widespread GUS activity, whereas this activity was absent in the mutated promoter transgenic lines. Moreover, StBEL5 and StCDF1 transcript levels were significantly higher in the stolon-to-tuber stages under short-day conditions compared to long-day conditions. Using wild-type and mutated prStCDF1 as baits in Y1H assays, we further demonstrated that StBEL5 interacts with the StCDF1 promoter through tandem TGAC motifs, indicating direct regulation of StCDF1 by StBEL5 in potato.


Assuntos
Proteínas de Plantas/metabolismo , Solanum tuberosum/metabolismo , Fatores de Transcrição/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Genes de Plantas/fisiologia , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Solanum tuberosum/genética , Solanum tuberosum/fisiologia , Estresse Fisiológico , Sequências de Repetição em Tandem/genética , Sequências de Repetição em Tandem/fisiologia , Fatores de Transcrição/fisiologia , Transcriptoma/genética , Técnicas do Sistema de Duplo-Híbrido
5.
Plant Sci ; 287: 110180, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481194

RESUMO

Although the genes controlling chloroplast development play important roles in plant responses to environmental stresses, the molecular mechanisms remain largely unclear. In this study, an Arabidopsis mutant dpg1 (delayed pale-greening1) with a chloroplast development defect was studied. By using quantitative RT-PCR and histochemical GUS assays, we demonstrated that AtDPG1 was mainly expressed in the green tissues of Arabidopsis seedlings and could be induced by salt stress. Phenotypic analysis showed that mutation in AtDPG1 lead to an enhanced sensitivity to salt stress in Arabidopsis seedlings. Further studies demonstrated that disruption of the AtDPG1 in Arabidopsis increases its sensitivity to salt stress in an ABA-dependent manner. Moreover, expression levels of various stress-responsive and ABA signal-related genes were remarkably altered in the dpg1 plants under NaCl treatment. Notably, the transcript levels of ABI4 in dpg1 mutant increased more significantly than that in wild type plants under salt conditions. The seedlings of dpg1/abi4 double mutant exhibited stronger resistance to salt stress after salt treatment compared with the dpg1 single mutant, suggesting that the salt-hypersensitive phenotype of dpg1 seedlings could be rescued via loss of ABI4 function. These results reveal that AtDPG1 is involved in the salt stress response of Arabidopsis seedling through ABI4.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/metabolismo , Genes de Plantas/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Plântula/metabolismo , Fatores de Transcrição/fisiologia , Ácido Abscísico/metabolismo , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Estresse Salino , Plântula/fisiologia , Fatores de Transcrição/metabolismo , Transcriptoma
6.
Plant Sci ; 287: 110181, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481212

RESUMO

The flavonoid compound anthocyanin is an important plant metabolite with nutritional and aesthetic value as well as anti-oxidative capacity. MYB transcription factors are key regulators of anthocyanin biosynthesis in plants. In pepper (Capsicum annuum), the CaAn2 gene, encoding an R2R3 MYB transcription factor, regulates anthocyanin biosynthesis. However, no functional study or structural analysis of functional and dysfunctional CaAn2 alleles has been performed. Here, to elucidate the function of CaAn2, we generated transgenic Nicotiana benthamiana and Arabidopsis thaliana plants expressing CaAn2. All of the tissues in these plants were purple. Promoter analysis of CaAn2 in purple C. annuum 'KC00134' plants revealed the insertion of a non-long terminal repeat (LTR) retrotransposon designated Ca-nLTR-A. To determine the promoter activity and functional domain of Ca-nLTR-A, various constructs carrying different domains of Ca-nLTR-A fused with GUS were transformed into N. benthamiana. Promoter analysis showed that the 3' untranslated region (UTR) of the second open reading frame of Ca-nLTR-A is responsible for CaAn2 expression in 'KC00134'. Sequence analysis of Ca-nLTR-A identified transcription factor binding sites known to regulate anthocyanin biosynthesis. This study indicates that insertion of a non-LTR retrotransposon in the promoter may activate expression of CaAn2 by recruiting transcription factors at the 3' UTR and thus provides the first example of exaptation of a non-LTR retrotransposon into a new promoter in plants.


Assuntos
Antocianinas/biossíntese , Capsicum/metabolismo , Proteínas de Plantas/metabolismo , Retroelementos/fisiologia , Fatores de Transcrição/metabolismo , Antocianinas/metabolismo , Arabidopsis , Capsicum/genética , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Genes de Plantas/fisiologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Retroelementos/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tabaco , Técnicas do Sistema de Duplo-Híbrido
7.
Plant Sci ; 287: 110168, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481214

RESUMO

Tiller production in grass species is controlled by both axillary bud initiation and bud outgrowth, which may be regulated by plant hormones. However, how gibberellic acid (GA) affects tillering in perennial grass species is still unclear. This study aims to elucidate the roles and the underlying mechanisms of GA in regulating tiller development. Tall fescue seedlings were treated with different concentrations of GA3 by foliar application, dose-dependent inhibitory effects of GA on tiller production were observed. GA3 (25 µM) slowed down the transition from axillary buds to tillers by specifically inhibiting the outgrowth of axillary buds. GA-inhibition of tillering were not related to endogenous content for auxin or strigolactone, but was mainly due to the antagonistic interaction with cytokinins (CK), as shown by the decreased CK content and up-regulation expression of CK degradation genes in GA3-treated plants. Furthermore, GA could act through regulating the expression of FaTB1 specifically expressed in axillary buds to repress bud outgrowth. These results provide insights for the regulatory mechanisms of GA for tiller bud outgrowth through crosstalks with CK and signaling of FaTB1 expression.


Assuntos
Citocininas/metabolismo , Festuca/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas/fisiologia , Reguladores de Crescimento de Planta/fisiologia , Brotos de Planta/crescimento & desenvolvimento , Citocininas/fisiologia , Festuca/genética , Festuca/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/genética , Giberelinas , Brotos de Planta/metabolismo , Receptor Cross-Talk
8.
Plant Sci ; 287: 110179, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481215

RESUMO

Stigmatic mucilage plays a crucial role in pollen-grain adhesion on the stigma in flowering plants. Little information is available regarding mucilage biosynthesis in orchid plants. In the present study, stigmatic mucilage is rich in galactose-containing polysaccharides, mainly consisted of galactose and arabinose in Dendrobium officinale. Thirteen galactosyltransferases involved in biosynthesis of the ß-1,3-galactose linkage polysaccharides, belonging to the CAZY GT31 family, were identified from D. officinale genome. A positive correlation between the mucilage content and the DoGALT2 expression at different stages was observed. DoGALT2 expressed overall sampled tissues with the highest in D. officinale stigmatic mucilage that contributes to pollen adhesion and elongation. DoGALT2 was targeted to Golgi, and had a GALT domain (PF01762) that was homologous to the characterized GALT2 in Arabidopsis. Compared to wild-type Arabidopsis, DoGALT2 overexpressing plants showed a higher content of galactose and galactose-containing alcohol-insoluble residues, and enhanced tolerance to abiotic stress. DoGALT2 complemented Arabidopsis GALT2 mutant (galt2-1), with an equivalent galactose with wild-type Arabidopsis but significantly higher than galt2-1. These findings provide evidence that DoGALT2 might be involved in regulating the biosynthesis of galactose-containing polysaccharides during D. officinale pollen development.


Assuntos
Dendrobium/enzimologia , Flores/enzimologia , Galactosiltransferases/metabolismo , Genes de Plantas/fisiologia , Mucilagem Vegetal/biossíntese , Proteínas de Plantas/metabolismo , Arabidopsis , Clonagem Molecular , Dendrobium/genética , Dendrobium/metabolismo , Flores/química , Flores/metabolismo , Galactose/metabolismo , Galactosiltransferases/genética , Mucilagem Vegetal/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Polissacarídeos/análise , Transcriptoma
9.
Plant Sci ; 287: 110175, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481217

RESUMO

Plant root systems ensure the efficient absorption of water and nutrients and provide anchoring into the soil. Although root systems are a highly plastic set of traits that vary both between and among species, the basic root system morphology is controlled by inherent genetic factors. TCP20 has been identified as a key regulator of root development in plants, and yet its underlying mechanism has not been fully elucidated, especially in chrysanthemum. We found that overexpression of the CmTCP20 gene promoted both adventitious and lateral root development in chrysanthemum. To get further insight into the molecular mechanisms controlling root system development, we conducted a study employing tandem mass tag proteomic to characterize the differential root system development proteomes from CmTCP20-overexpressing and wild-type chrysanthemum root samples. Of the proteins identified, 234 proteins were found to be differentially abundant (>1.5-fold cut off, p < 0.05) in CmTCP20-overexpressing versus wild-type chrysanthemum root samples. Functional enrichment analysis indicated that the CmTCP20 gene may participate in "phytohormone signal transduction". Our findings provide a valuable perspective on the mechanisms of both adventitious and lateral root development via CmTCP20 modulation at the proteome level in chrysanthemum.


Assuntos
Chrysanthemum/metabolismo , Genes de Plantas/fisiologia , Raízes de Plantas/crescimento & desenvolvimento , Clorofila/metabolismo , Cromatografia Líquida de Alta Pressão , Chrysanthemum/genética , Chrysanthemum/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/metabolismo , Fotossíntese , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Proteômica , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
PLoS One ; 14(9): e0222530, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31539385

RESUMO

Quantitative real-time PCR (qRT-PCR) is an efficient method to estimate the gene expression levels but the accuracy of its result largely depends on the stability of the reference gene. Many studies have reported considerable variation in the expression of reference genes (RGs) in different tissue and conditions. Therefore, screening for appropriate RGs with stable expression is crucial for functional analysis of the target gene. Two closely related crucifers Brassica juncea (cultivated) and Camelina sativa (wild) respond differently towards various abiotic and biotic stress where C. sativa exhibits higher tolerance to various stress. Comparative gene expression analysis of the target genes between two such species is the key approach to understand the mechanism of a plant's response to stress. However, using an unsuitable RG can lead to misinterpretation of expression levels of the target gene in such studies. In this investigation, the stability of seven candidate RGs including traditional housekeeping genes (HKGs) and novel candidate RGs were identified across diverse sample sets of B. juncea and C. sativa representing- hormone treated, wounded, Alternaria brassicae inoculated and combination treated samples (exogenous hormone treatment followed by A. brassicae inoculation). In this investigation, we identified stable RGs in both the species and the most suitable RGs to perform an unbiased comparative gene expression analysis between B. juncea and C. sativa. Results revealed that TIPS41 and PP2A were identified as the overall best performing RGs in both the species. However, the most suitable RG for each sample subset representing different condition must be individually selected. In Hormone treated and wounded samples TIPS41 expressed stably in both the species and in A. brassicae inoculated and combination treatment performance of PP2A was the best. In this study, for the first time, we have identified and validated stable reference gene in C. sativa for accurate normalization of gene expression data.


Assuntos
Brassicaceae/genética , Genes de Plantas/genética , Mostardeira/genética , Brassicaceae/fisiologia , Genes Essenciais/genética , Genes Essenciais/fisiologia , Genes de Plantas/fisiologia , Mostardeira/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Transcriptoma
11.
Int J Mol Sci ; 20(19)2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31547521

RESUMO

The Auxin/indole-3-acetic acid (Aux/IAA) repressor genes down-regulate the auxin response pathway during many stages of plant and fruit development. In order to determine if and how Aux/IAAs participate in governing texture and hardness in stone fruit maturation, we identified 23 Aux/IAA genes in peach, confirmed by the presence of four conserved domains. In this work, we used fluorescence microscopy with PpIAA-GFP fusion reporters to observe their nuclear localization. We then conducted PCR-based differential expression analysis in "melting" and "stony hard" varieties of peach, and found that in the "melting" variety, nine PpIAAs exhibited peak expression in the S4-3 stage of fruit maturation, with PpIAA33 showing the highest (>120-fold) induction. The expression of six PpIAAs peaked in the S4-2 stage, with PpIAA14 expressed the most highly. Only PpIAA15/16 showed higher expression in the "stony hard" variety than in the "melting" variety, both peaking in the S3 stage. In contrast, PpIAA32 had the highest relative expression in buds, flowers, young and mature leaves, and roots. Our study provides insights into the expression patterns of Aux/IAA developmental regulators in response to auxin during fruit maturation, thus providing insight into their potential development as useful markers for quantitative traits associated with fruit phenotype.


Assuntos
Regulação da Expressão Gênica de Plantas/fisiologia , Genes de Plantas/fisiologia , Ácidos Indolacéticos/metabolismo , Prunus persica , Flores/genética , Flores/metabolismo , Frutas/genética , Frutas/metabolismo , Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla , Folhas de Planta/genética , Folhas de Planta/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Prunus persica/genética , Prunus persica/metabolismo
12.
PLoS One ; 14(9): e0222344, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31550256

RESUMO

Around the world, pansies are one of the most popular garden flowers, but they are generally sensitive to high temperatures, and this limits the practicality of planting them during the warmest days of the year. However, a few pansy germplasms with improved heat tolerance have been discovered or bred, but the mechanisms of their heat resistance are not understood. In this study, we investigated the transcript profiles of a heat-tolerant pansy inbred line, DFM16, in response to high temperatures using RNAseq. Approximately 55.48 Gb of nucleotide data were obtained and assembled into 167,576 unigenes with an average length of 959 bp, of which, 5,708 genes were found to be differentially expressed after heat treatments. Real-time qPCR was performed to validate the expression profiles of the selected genes. Nine metabolic pathways were found to be significantly enriched, in the analysis of the differentially expressed genes. Several potentially interesting genes that encoded putative transcription regulators or key components involving heat shock protein (HSP), heat shock transcription factors (HSF), and antioxidants biosynthesis, were identified. These genes were highlighted to indicate their significance in response to heat stress and will be used as candidate genes to improve pansy heat-tolerance in the future.


Assuntos
Viola/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/fisiologia , Genes de Plantas/genética , Genes de Plantas/fisiologia , Resposta ao Choque Térmico , Temperatura Alta/efeitos adversos , Fenótipo , Reação em Cadeia da Polimerase em Tempo Real , Plântula/metabolismo , Plântula/fisiologia , Transcriptoma/genética , Viola/genética , Viola/fisiologia
13.
Planta ; 250(6): 1955-1965, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31529399

RESUMO

MAIN CONCLUSION: The duplications of the dominantVrn-A1alleles as well as theVRN-B1gene, revealed for the first time, are new sources of polymorphism in polyploid wheat at these agronomically valuable genomic locations. Flowering time is an important trait in wheat breeding. In spring wheat, this feature is mainly determined by the variants and number of the homoeologous dominant VRN1 alleles. Previously, multiplication of the recessive vrn-A1 allele was shown for winter hexaploid wheat (Würschum et al., BMC Genet 29:16-96, 2015). In the present study, VRN1 gene copy-number variation as well as the copy number of VRN-A1 with the alternative exon 4 haplotype were investigated in spring and winter accessions of different tetraploid and hexaploid wheat species. Two ratio tests were optimized based on end-point quantification of PCR fragments and results were verified by a qPCR assay. It was defined that since the genomic environment affects the accessibility of amplified VRN1 regions, the DNA template should be fragmented for proper quantification of VRN1 copy number during PCR-based assays. For the first time, it was shown that the dominant Vrn-A1 alleles are most often duplicated in hexaploid wheat. In tetraploid wheat, both the dominant and recessive alleles were represented as a single haploid copy, and in only two accessions of T. dicoccum, vrn-A1b.3 was duplicated. Multiplication of VRN-A1 was often associated with awnless spikes. Five haploid combinations of the recessive vrn-A1 copies with alternative exon 4 were identified in hexaploid wheat. Finally for the first time, duplication of VRN-B1 was found in hexaploid wheat of T. compactum and T. spelta. These results expand our knowledge of the genetic diversity of VRN1 genes in wheat and provide additional strategies for the manipulation of flowering time in this strategic crop.


Assuntos
Proteínas de Plantas/genética , Poliploidia , Triticum/genética , Alelos , Variações do Número de Cópias de DNA , DNA de Plantas/genética , Eletroforese Capilar , Eletroforese em Gel de Poliacrilamida , Flores/crescimento & desenvolvimento , Genes de Plantas/genética , Genes de Plantas/fisiologia , Proteínas de Plantas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Tetraploidia , Triticum/crescimento & desenvolvimento
14.
J Plant Physiol ; 241: 153034, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31493718

RESUMO

Legumes have the capacity to fix nitrogen in symbiosis with soil bacteria known as rhizobia by the formation of root nodules. However, nitrogen fixation is highly sensitive to soil salinity with a concomitant reduction of the plant yield and soil fertilization. Polycationic aliphatic amines known as polyamines (PAs) have been shown to be involved in the response to a variety of stresses in plants including soil salinity. Therefore, the generation of transgenic plants overexpressing genes involved in PA biosynthesis have been proposed as a promising tool to improve salt stress tolerance in plants. In this work we tested whether the modulation of PAs in transgenic Medicago truncatula plants was advantageous for the symbiotic interaction with Sinorhizobium meliloti under salt stress conditions, when compared to wild type plants. Consequently, we characterized the symbiotic response to salt stress of the homozygous M. truncatula plant line L-108, constitutively expressing the oat adc gene, coding for the PA biosynthetic enzyme arginine decarboxylase, involved in PAs biosynthesis. In a nodulation kinetic assay, nodule number incremented in L-108 plants under salt stress. In addition, these plants at vegetative stage showed higher nitrogenase and nodule biomass and, under salt stress, accumulated proline (Pro) and spermine (Spm) in nodules, while in wt plants, the accumulation of glutamic acid (Glu), γ-amino butyric acid (GABA) and 1-aminocyclopropane carboxylic acid (ACC) (the ethylene (ET) precursor) were the metabolites involved in the salt stress response. Therefore, overexpression of oat adc gene favours the symbiotic interaction between plants of M. truncatula L-108 and S. meliloti under salt stress and the accumulation of Pro and Spm, seems to be the molecules involved in salt stress tolerance.


Assuntos
Carboxiliases/metabolismo , Genes de Plantas/fisiologia , Interações entre Hospedeiro e Microrganismos/fisiologia , Medicago truncatula/microbiologia , Proteínas de Plantas/metabolismo , Prolina/metabolismo , Nódulos Radiculares de Plantas/metabolismo , Estresse Salino/fisiologia , Sinorhizobium meliloti/fisiologia , Espermina/metabolismo , Simbiose , Aminoácidos/metabolismo , Carboxiliases/genética , Catalase/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Interações entre Hospedeiro e Microrganismos/genética , Peróxido de Hidrogênio/metabolismo , Medicago truncatula/genética , Medicago truncatula/metabolismo , Medicago truncatula/fisiologia , Fixação de Nitrogênio/fisiologia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Nódulos Radiculares de Plantas/fisiologia , Simbiose/fisiologia , Transcriptoma
15.
BMC Plant Biol ; 19(1): 398, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31510927

RESUMO

BACKGROUND: High temperature is one of the major abiotic stresses in tomato and greatly reduces fruit yield and quality. Identifying high-temperature stress-responsive (HSR) genes and breeding heat-tolerant varieties is an effective way to address this issue. However, there are few reports on the fine mapping of heat-tolerance quantitative trait locus (QTL) and the identification of HSR genes in tomato. Here, we applied three heat tolerance-related physiological indexes, namely, relative electrical conductivity (REC), chlorophyll content (CC) and maximum photochemical quantum efficiency (Fv/Fm) of PSII (photosystem II), as well as the phenotypic index, the heat injury index (HII), and conventional QTL analysis combined with QTL-seq technology to comprehensively detect heat-tolerance QTLs in tomato seedlings. In addition, we integrated the QTL mapping results with RNA-seq to identify key HSR genes within the major QTLs. RESULTS: A total of five major QTLs were detected: qHII-1-1, qHII-1-2, qHII-1-3, qHII-2-1 and qCC-1-5 (qREC-1-3). qHII-1-1, qHII-1-2 and qHII-1-3 were located, respectively, in the intervals of 1.43, 1.17 and 1.19 Mb on chromosome 1, while the interval of qHII-2-1 was located in the intervals of 1.87 Mb on chromosome 2. The locations observed with conventional QTL mapping and QTL-seq were consistent. qCC-1-5 and qREC-1-3 for CC and REC, respectively, were located at the same position by conventional QTL mapping. Although qCC-1-5 was not detected in QTL-seq analysis, its phenotypic variation (16.48%) and positive additive effect (0.22) were the highest among all heat tolerance QTLs. To investigate the genes involved in heat tolerance within the major QTLs in tomato, RNA-seq analysis was performed, and four candidate genes (SlCathB2, SlGST, SlUBC5, and SlARG1) associated with heat tolerance were finally detected within the major QTLs by DEG analysis, qRT-PCR screening and biological function analysis. CONCLUSIONS: In conclusion, this study demonstrated that the combination of conventional QTL mapping, QTL-seq analysis and RNA-seq can rapidly identify candidate genes within major QTLs for a complex trait of interest to replace the fine-mapping process, thus greatly shortening the breeding process and improving breeding efficiency. The results have important applications for the fine mapping and identification of HSR genes and breeding for improved thermotolerance.


Assuntos
Genes de Plantas/fisiologia , Temperatura Alta , Lycopersicon esculentum/fisiologia , Locos de Características Quantitativas/fisiologia , Termotolerância/genética , Mapeamento Cromossômico , Lycopersicon esculentum/genética , Análise de Sequência de RNA , Estresse Fisiológico
16.
BMC Plant Biol ; 19(1): 401, 2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31510935

RESUMO

BACKGROUND: Small RNAs regulate a wide variety of processes in plants, from organ development to both biotic and abiotic stress response. Being master regulators in genetic networks, their biogenesis and action is a fundamental aspect to characterize in order to understand plant growth and development. Three main gene families are critical components of RNA silencing: DICER-LIKE (DCL), ARGONAUTE (AGO) and RNA-DEPENDENT RNA POLYMERASE (RDR). Even though they have been characterized in other plant species, there is no information about these gene families in Citrus sinensis, one of the most important fruit species from both economical and nutritional reasons. While small RNAs have been implicated in the regulation of multiple aspects of plant growth and development, their role in the abscission process has not been characterized yet. RESULTS: Using genome-wide analysis and a phylogenetic approach, we identified a total of 13 AGO, 5 DCL and 7 RDR genes. We characterized their expression patterns in root, leaf, flesh, peel and embryo samples using RNA-seq data. Moreover, we studied their role in fruit abscission through gene expression analysis in fruit rind compared to abscission zone from samples obtained by laser capture microdissection. Interestingly, we determined that the expression of several RNA silencing factors are down-regulated in fruit abscission zone, being particularly represented gene components of the RNA-dependent DNA Methylation pathway, indicating that repression of this process is necessary for fruit abscission to take place in Citrus sinensis. CONCLUSIONS: The members of these 3 families present characteristic conserved domains and distinct expression patterns. We provide a detailed analysis of the members of these families and improved the annotation of some of these genes based on RNA-seq data. Our data suggests that the RNA-dependent DNA Methylation pathway is involved in the important fruit abscission process in C. sinensis.


Assuntos
Citrus sinensis/fisiologia , Metilação de DNA/fisiologia , Frutas/crescimento & desenvolvimento , Genes de Plantas/fisiologia , Genoma de Planta/fisiologia , Citrus sinensis/genética , Citrus sinensis/crescimento & desenvolvimento , Frutas/genética , Regulação da Expressão Gênica de Plantas , Família Multigênica , Filogenia
17.
J Plant Physiol ; 241: 153001, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31415937

RESUMO

Drought impact on plants is an increasing concern under the climate change scenario. Cowpea (Vigna unguiculata L. Walp.) is considered as one of the most tolerant legume crops to drought, being the search for the best well-adapted genotypes crucial to face the future challenges. Different approaches have been used for differentiating plant responses to drought stress. Plants of four cowpea genotypes were submitted to three watering regimens (a severe and moderate drought stress, and well-watered control) during 15 days, and several physiological, biochemical and molecular parameters were evaluated. Stressed plants revealed commonly-described drought stress characteristics, but not all assayed parameters were useful for discriminating plants with different drought severities or genotypes. The analyses which have contributed most to genotype discrimination were those related with stomatal function, and biochemical markers such as proline and anthocyanin contents. Antioxidant enzymes activities and related genes expression did not differed among genotypes or upon drought stress treatments, suggesting that scavenging enzymes are not involved in the differential ability of cowpea plants to survive under drought stress. This information will be useful to evaluate and use genetic resources, as well as design strategies for breeding cowpea resistance to drought stress.


Assuntos
Vigna/fisiologia , Antocianinas/metabolismo , Biomarcadores , Clorofila A/metabolismo , Desidratação , Genes de Plantas/fisiologia , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos/fisiologia , Peroxidase/metabolismo , Fotossíntese/fisiologia , Prolina/metabolismo , Superóxido Dismutase/metabolismo , Transcriptoma/fisiologia , Vigna/genética , Vigna/metabolismo
18.
Plant Physiol Biochem ; 142: 452-459, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31421442

RESUMO

Cold stress can significantly alter the composition and functioning of the major membrane lipids in plants. However, the roles of the sterol component of plant membranes in stress tolerance remain unclear. In the work presented here we investigated the role of sterols in the response of wheat to cold stress. Initial experiments demonstrated that the roots and leaves of wheat seedlings are differentially sensitive to low positive temperatures. In the roots, cold stress induced disturbance of membrane integrity and accumulation of ROS followed by the induction of autophagy. The absence of such changes in leaves suggests that in wheat, the roots are more sensitive to cold than the leaves. The roots display a time-dependent parabolic pattern of cold stress response, characterized by raised levels of sterols and markers of oxidative stress during short-term treatment, and a decline of these parameters after prolonged treatment. MßCD-induced sterol depletion aggravated the negative effects of cold on the roots. In the leaves the changes also displayed parabolic patterns, with significant changes occurring in 24-ethyl sterols and major PLs. Constitutively high levels of sterols, glycolipids and PLs, and up-regulation of TaSMTs in the leaves may provide membrane stability and cold tolerance. Taken together, results suggest that sterols play important roles in the response of wheat seedlings to cold stress.


Assuntos
Membrana Celular/metabolismo , Genes de Plantas/fisiologia , Plântula/metabolismo , Esteróis/biossíntese , Triticum/metabolismo , Resposta ao Choque Frio , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Lipídeos de Membrana/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Plântula/genética , Plântula/fisiologia , Triticum/genética , Triticum/fisiologia
19.
Plant Physiol Biochem ; 142: 500-509, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31445475

RESUMO

Early blight disease of tomato is one of the most devastating biotic stresses worldwide, and in Iran, Alternaria alternata is one of the most predominant species causing the disease. In the current study, a diverse collection of 35 tomato genotypes and implication of 5 SlWRKYs and 7 PR genes as well as enzymatic activity were evaluated on resistant and susceptible cultivars through real-time polymerase chain reaction at transplanting and maturing stages and by measuring product formation using spectrophotometry. The results indicated that the expression of these antifungal genes in 14 genotypes at two growth stages after inoculation with A. alternata highly enhanced by 1-50-fold. There was also significant upregulation of WRKYs and PRs genes among the resistant tomato varieties in comparison to susceptible and control varieties at both stages. These findings demonstrate the varieties that showed increased or decreased SlWRKY1 expression also displayed similar changes in the expression of PR1 and PR2 genes. Furthermore, the differential expression patterns of SlWRKY1 and SlWRKY11 were consistent with PR7 and PDF1.2 expression patterns. The analysis of enzymatic activity of PR2 and PR3 proteins, ß-1,3-glucanase, and chitinase showed the highest level of activity in resistant inoculated genotypes against A. alternata. Therefore, the current findings suggest the possible involvement of these transcription factors in the increased expression of PR genes in response to A. alternata infection.


Assuntos
Alternaria , Resistência à Doença/genética , Lycopersicon esculentum/microbiologia , Doenças das Plantas/microbiologia , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Genes de Plantas/fisiologia , Genótipo , Lycopersicon esculentum/genética , Lycopersicon esculentum/imunologia , Doenças das Plantas/imunologia , Folhas de Planta/microbiologia , Reação em Cadeia da Polimerase em Tempo Real
20.
Plant Physiol Biochem ; 142: 510-518, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31445476

RESUMO

As one of the most popular woody species that blooms in summer, Lagerstroemia speciosa has been used abundantly in urban landscape for its excellent floral beauty. For the first time, we discovered a double-flower variant with all petaloid stamens. To understand the molecular basis of this variation, we contrasted the transcriptomes of single- and double-flower buds at three stamen development stages. In total, 73,536 unigenes were mapped and 30,714 differently expressed genes (DEGs) were identified in the tissues. We focused on the DEGs expressing in both phenotypes and investigated the association of their expression profiles with their functions in transcription pathways. Furthermore, we performed WGCNA and identified co-expressed genes with four floral homeotic genes as hubs (MADS16, Unigene0026169; AP2, Unigene0042732; SOC1, Unigene0046314; AG, Unigene0056437). The expression of these hub genes has been conserved across the three developmental stages but significantly different between the two floral phenotypes. As a result, the robust transcriptional regulation of stamen petaloidy in double flowers was deduced. These findings will help to unravel the regulatory mechanisms of several specific genes, thereby providing a basis to study double-flower molecular breeding in L. speciosa.


Assuntos
Flores/crescimento & desenvolvimento , Lagerstroemia/crescimento & desenvolvimento , Flores/anatomia & histologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas/fisiologia , Lagerstroemia/anatomia & histologia , Reguladores de Crescimento de Planta/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia
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