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1.
Int J Mol Sci ; 22(15)2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34360726

RESUMO

Fungal diseases pose a major threat to ornamental plants, with an increasing percentage of pathogen-driven host losses. In ornamental plants, management of the majority of fungal diseases primarily depends upon chemical control methods that are often non-specific. Host basal resistance, which is deficient in many ornamental plants, plays a key role in combating diseases. Despite their economic importance, conventional and molecular breeding approaches in ornamental plants to facilitate disease resistance are lagging, and this is predominantly due to their complex genomes, limited availability of gene pools, and degree of heterozygosity. Although genetic engineering in ornamental plants offers feasible methods to overcome the intrinsic barriers of classical breeding, achievements have mainly been reported only in regard to the modification of floral attributes in ornamentals. The unavailability of transformation protocols and candidate gene resources for several ornamental crops presents an obstacle for tackling the functional studies on disease resistance. Recently, multiomics technologies, in combination with genome editing tools, have provided shortcuts to examine the molecular and genetic regulatory mechanisms underlying fungal disease resistance, ultimately leading to the subsequent advances in the development of novel cultivars with desired fungal disease-resistant traits, in ornamental crops. Although fungal diseases constitute the majority of ornamental plant diseases, a comprehensive overview of this highly important fungal disease resistance seems to be insufficient in the field of ornamental horticulture. Hence, in this review, we highlight the representative mechanisms of the fungal infection-related resistance to pathogens in plants, with a focus on ornamental crops. Recent progress in molecular breeding, genetic engineering strategies, and RNAi technologies, such as HIGS and SIGS for the enhancement of fungal disease resistance in various important ornamental crops, is also described.


Assuntos
Resistência à Doença/genética , Fungos Mitospóricos/crescimento & desenvolvimento , Melhoramento Vegetal , Doenças das Plantas , Plantas Geneticamente Modificadas , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/microbiologia
2.
Int J Mol Sci ; 22(15)2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34360554

RESUMO

Leaf angle and grain size are important agronomic traits affecting rice productivity directly and/or indirectly through modulating crop architecture. OsBC1, as a typical bHLH transcription factor, is one of the components comprising a complex formed with LO9-177 and OsBUL1 contributing to modulation of rice leaf inclination and grain size. In the current study, two homologues of OsBC1, OsBCL1 and OsBCL2 were functionally characterized by expressing them under the control of OsBUL1 promoter, which is preferentially expressed in the lamina joint and the spikelet of rice. Increased leaf angle and grain length with elongated cells in the lamina joint and the grain hull were observed in transgenic rice containing much greater gibberellin A3 (GA3) levels than WT, demonstrating that both OsBCL1 and OsBCL2 are positive regulators of cell elongation at least partially through increased GA biosynthesis. Moreover, the cell elongation was likely due to cell expansion rather than cell division based on the related gene expression and, the cell elongation-promoting activities of OsBCL1 and OsBCL2 were functional in a dicot species, Arabidopsis.


Assuntos
Regulação da Expressão Gênica de Plantas , Oryza/anatomia & histologia , Fenótipo , Folhas de Planta/anatomia & histologia , Proteínas de Plantas/metabolismo , Regiões Promotoras Genéticas , Oryza/genética , Oryza/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Transdução de Sinais
4.
Cell Rep ; 31(9): 107717, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32492426

RESUMO

Flowering of many plant species depends on interactions between basic leucine zipper (bZIP) transcription factors and systemically transported florigen proteins. Members of the genus Arabidopsis contain two of these bZIPs, FD and FDP, which we show have largely complementary expression patterns in shoot apices before and during flowering. CRISPR-Cas9-induced null mutants for FDP flower slightly earlier than wild-type, whereas fd mutants are late flowering. Identical G-box sequences are enriched at FD and FDP binding sites, but only FD binds to genes involved in flowering and only fd alters their transcription. However, both proteins bind to genes involved in responses to the phytohormone abscisic acid (ABA), which controls developmental and stress responses. Many of these genes are differentially expressed in both fd and fdp mutant seedlings, which also show reduced ABA sensitivity. Thus, florigen-interacting bZIPs have distinct functions in flowering dependent on their expression patterns and, at earlier stages in development, play common roles in phytohormone signaling.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Florígeno/metabolismo , Ácido Abscísico/farmacologia , Arabidopsis/genética , Proteínas de Arabidopsis/classificação , Proteínas de Arabidopsis/genética , Fatores de Transcrição de Zíper de Leucina Básica/classificação , Fatores de Transcrição de Zíper de Leucina Básica/genética , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Sistemas CRISPR-Cas/genética , Flores/genética , Flores/metabolismo , Edição de Genes , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genótipo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Proteínas de Domínio MADS/genética , Proteínas de Domínio MADS/metabolismo , Mutagênese , Filogenia , Plantas Geneticamente Modificadas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
5.
Plants (Basel) ; 9(6)2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32481726

RESUMO

Biotechnological approaches have been used to modify the floral color, size, and fragrance of ornamental plants, as well as to increase disease resistance and vase life. Together with the advancement of whole genome sequencing technologies, new plant breeding techniques have rapidly emerged in recent years. Compared to the early versions of gene editing tools, such as meganucleases (MNs), zinc fingers (ZFNs), and transcription activator-like effector nucleases (TALENs), clustered regularly interspaced short palindromic repeat (CRISPR) is capable of altering a genome more efficiently and with higher accuracy. Most recently, new CRISPR systems, including base editors and prime editors, confer reduced off-target activity with improved DNA specificity and an expanded targeting scope. However, there are still controversial issues worldwide for the recognition of genome-edited plants, including whether genome-edited plants are genetically modified organisms and require a safety evaluation process. In the current review, we briefly summarize the current progress in gene editing systems and also introduce successful/representative cases of the CRISPR system application for the improvement of ornamental plants with desirable traits. Furthermore, potential challenges and future prospects in the use of genome-editing tools for ornamental plants are also discussed.

6.
Plants (Basel) ; 9(4)2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32340222

RESUMO

Internode elongation is one of the key agronomic traits determining a plant's height and biomass. However, our understanding of the molecular mechanisms controlling internode elongation is still limited in crop plant species. Here, we report the functional identification of an atypical basic helix-loop-helix transcription factor (OsbHLH073) through gain-of-function studies using overexpression (OsbHLH073-OX) and activation tagging (osbhlh073-D) lines of rice. The expression of OsbHLH073 was significantly increased in the osbhlh073-D line. The phenotype of osbhlh073-D showed semi-dwarfism due to deficient elongation of the first internode and poor panicle exsertion. Transgenic lines overexpressing OsbHLH073 confirmed the phenotype of the osbhlh073-D line. Exogenous gibberellic acid (GA3) treatment recovered the semi-dwarf phenotype of osbhlh073-D plants at the seedling stage. In addition, quantitative expression analysis of genes involving in GA biosynthetic and signaling pathway revealed that the transcripts of rice ent-kaurene oxidases 1 and 2 (OsKO1 and OsKO2) encoding the GA biosynthetic enzyme were significantly downregulated in osbhlh073-D and OsbHLH073-OX lines. Yeast two-hybrid and localization assays showed that the OsbHLH073 protein is a nuclear localized-transcriptional activator. We report that OsbHLH073 participates in regulating plant height, internode elongation, and panicle exsertion by regulating GA biosynthesis associated with the OsKO1 and OsKO2 genes.

7.
BMC Plant Biol ; 20(1): 53, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32013867

RESUMO

BACKGROUND: Floral transition initiates reproductive development of plants and occurs in response to environmental and endogenous signals. In Arabidopsis thaliana, this process is accelerated by several environmental cues, including exposure to long days. The photoperiod-dependent promotion of flowering involves the transcriptional induction of FLOWERING LOCUS T (FT) in the phloem of the leaf. FT encodes a mobile protein that is transported from the leaves to the shoot apical meristem, where it forms part of a regulatory complex that induces flowering. Whether FT also has biological functions in leaves of wild-type plants remains unclear. RESULTS: In order to address this issue, we first studied the leaf transcriptomic changes associated with FT overexpression in the companion cells of the phloem. We found that FT induces the transcription of SWEET10, which encodes a bidirectional sucrose transporter, specifically in the leaf veins. Moreover, SWEET10 is transcriptionally activated by long photoperiods, and this activation depends on FT and one of its earliest target genes SUPPRESSOR OF CONSTANS OVEREXPRESSION 1 (SOC1). The ectopic expression of SWEET10 causes early flowering and leads to higher levels of transcription of flowering-time related genes in the shoot apex. CONCLUSIONS: Collectively, our results suggest that the FT-signaling pathway activates the transcription of a sucrose uptake/efflux carrier during floral transition, indicating that it alters the metabolism of flowering plants as well as reprogramming the transcription of floral regulators in the shoot meristem.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Proteínas de Domínio MADS/genética , Proteínas de Membrana Transportadoras/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Flores/genética , Proteínas de Domínio MADS/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Transcriptoma
8.
Int J Mol Sci ; 21(3)2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32050562

RESUMO

Orchids are one of the most significant plants that have ecologically adapted to every habitat on earth. Orchids show a high level of variation in their floral morphologies, which makes them popular as ornamental plants in the global market. Floral scent and color are key traits for many floricultural crops. Volatile organic compounds (VOCs) play vital roles in pollinator attraction, defense, and interaction with the environment. Recent progress in omics technology has led to the isolation of genes encoding candidate enzymes responsible for the biosynthesis and regulatory circuits of plant VOCs. Uncovering the biosynthetic pathways and regulatory mechanisms underlying the production of floral scents is necessary not only for a better understanding of the function of relevant genes but also for the generation of new cultivars with desirable traits through molecular breeding approaches. However, little is known about the pathways responsible for floral scents in orchids because of their long life cycle as well as the complex and large genome; only partial terpenoid pathways have been reported in orchids. Here, we review the biosynthesis and regulation of floral volatile compounds in orchids. In particular, we focused on the genes responsible for volatile compounds in various tissues and developmental stages in Cymbidium orchids. We also described the emission of orchid floral volatiles and their function in pollination ecology. Taken together, this review will provide a broad scope for the study of orchid floral scents.


Assuntos
Regulação da Expressão Gênica de Plantas , Orchidaceae/genética , Compostos Orgânicos Voláteis/metabolismo , Evolução Molecular , Flores/genética , Flores/metabolismo , Orchidaceae/metabolismo
9.
Plants (Basel) ; 9(1)2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31861279

RESUMO

Type-2 diabetes mellitus is one of the most prevalent metabolic diseases in the world, and is characterized by hyperglycemia (i.e., high levels of glucose in the blood). Alpha-glucosidases are enzymes in the digestive tract that hydrolyze carbohydrates into glucose. One strategy that has been developed to treat type-2 diabetes is inhibition of the activity of alpha-glucosidases using synthetic drugs. However, these inhibitors are usually associated with gastrointestinal side effects. Therefore, the development of inhibitors from natural products offers an alternative option for the control of hyperglycemia. In recent years, various studies have been conducted to identify alpha-glucosidases inhibitors from natural sources such as plants, and many candidates have transpired to be secondary metabolites including alkaloids, flavonoids, phenols, and terpenoids. In this review, we focus on the alpha-glucosidases inhibitors found in common vegetable crops and the major classes of phytochemicals responsible for the inhibitory activity, and also as potential/natural drug candidates for the treatment of type-2 diabetes mellitus. In addition, possible breeding strategies for production of improved vegetable crops with higher content of the inhibitors are also described.

10.
Front Plant Sci ; 10: 1258, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31649713

RESUMO

Orchids comprise one of the largest, most highly evolved angiosperm families, and form an extremely peculiar group of plants. Various orchids are available through traditional breeding and micro-propagation since they are valuable as potted plants and/or cut flowers in horticultural markets. The flowering of orchids is generally influenced by environmental signals such as temperature and endogenous developmental programs controlled by genetic factors as is usual in many flowering plant species. The process of floral transition is connected to the flower developmental programs that include floral meristem maintenance and floral organ specification. Thanks to advances in molecular and genetic technologies, the understanding of the molecular mechanisms underlying orchid floral transition and flower developmental processes have been widened, especially in several commercially important orchids such as Phalaenopsis, Dendrobium and Oncidium. In this review, we consolidate recent progress in research on the floral transition and flower development of orchids emphasizing representative genes and genetic networks, and also introduce a few successful cases of manipulation of orchid flowering/flower development through the application of molecular breeding or biotechnology tools.

11.
Plant Biotechnol (Tokyo) ; 35(3): 273-279, 2018 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31819733

RESUMO

Recently, two rice genes, OsAPETALA2 (OsAP2) and OsWRKY24 have been reported to be positive regulators involved in increased lamina inclination and grain size through cell elongation. Here, we found that the two genes have tightly linked expression patterns and functional convergence in rice, and are also likely to play an opposite role in Arabidopsis. Overexpression of the two rice transcription factors in Arabidopsis caused smaller plant size with reduced cell size, and the expression of a series of genes encoding expansins and xyloglucan endotransglucosylase/hydrolases (XTHs) involved in cell elongation was reduced. However, transgenic Arabidopsis expressing OsWRKY24-SRDX as a synthetic chimeric repressor displayed indistinguishable phenotypes from wild-type plants. Moreover, the subcellular localization pattern of OsWRKY24 in Arabidopsis was different from that in rice. Thus, we demonstrate an example of transcription factors from one species playing distinct roles in different plant species.

12.
Front Plant Sci ; 8: 1253, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28769958

RESUMO

Oryza sativa BRASSINOSTEROID UPREGULATED1 LIKE1 (OsBUL1) positively affects lamina inclination and grain size. OsBUL1 knock-out (osbul1) plants as well as transgenic rice with reduced level of OsBUL1 expression produce erect leaves and small grains. Here, we identified a putative downstream gene of OsBUL1, OsBUL1 DOWNSTREAM GENE1 (OsBDG1) encoding a small protein with short leucine-rich-repeats by cDNA microarray analyses in the lamina joint and panicles of wild-type and osbul1 plants. Transgenic rice plants with increased OsBDG1 expression exhibit increased leaf angle and grain size, which is similar to an OsBDG1 activation tagging line whereas double stranded RNA interference (dsRNAi) lines for OsBDG1 knock-down generate erect leaves with smaller grains. Moreover, transgenic rice expressing OsBDG1 under the control of OsBUL1 promoter also shows enlarged leaf bending and grain size phenotypes. Two genes, OsAP2 (OsAPETALA2) and OsWRKY24 were identified as being upregulated transcriptional activators in the lamina joint of pOsBUL1:OsBDG1 plants and induced expression of the two genes driven by OsBUL1 promoter caused increased lamina inclination and grain size in rice. Thus, our work demonstrates that a series of genes showing expression cascades are involved in the promotion of cell elongation in lamina joints and functionally cause increased lamina inclination.

13.
Plant Signal Behav ; 12(5): e1322245, 2017 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-28448202

RESUMO

Genetic pathways relevant to flowering of Arabidopsis are under the control of environmental cues such as day length and temperatures, and endogenous signals including phytohormones and developmental aging. However, genes and even regulatory pathways for flowering identified in crops show divergence from those of Arabidopsis and often do not have functional equivalents to Arabidopsis and/or existing species- or genus-specific regulators and show modified or novel pathways. Orchids are the largest, most highly evolved flowering plants, and form an extremely peculiar group of plants. Here, we briefly summarize the flowering pathways of Arabidopsis, rice and wheat and present them alongside recent discoveries/progress in orchid flowering and flower developmental processes including our transgenic Phalaenopsis orchids for LEAFY overexpression. Potential biotechnological applications in flowering/flower development of orchids with potential target genes are also discussed from an interactional and/or comparative viewpoint.


Assuntos
Flores/crescimento & desenvolvimento , Flores/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Biotecnologia , Flores/genética , Regulação da Expressão Gênica de Plantas , Orchidaceae/genética , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/metabolismo , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo
14.
EMBO J ; 36(7): 904-918, 2017 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-28270524

RESUMO

Seasonal reproduction in many organisms requires detection of day length. This is achieved by integrating information on the light environment with an internal photoperiodic time-keeping mechanism. Arabidopsis thaliana promotes flowering in response to long days (LDs), and CONSTANS (CO) transcription factor represents a photoperiodic timer whose stability is higher when plants are exposed to light under LDs. Here, we show that PSEUDO RESPONSE REGULATOR (PRR) proteins directly mediate this stabilization. PRRs interact with and stabilize CO at specific times during the day, thereby mediating its accumulation under LDs. PRR-mediated stabilization increases binding of CO to the promoter of FLOWERING LOCUS T (FT), leading to enhanced FT transcription and early flowering under these conditions. PRRs were previously reported to contribute to timekeeping by regulating CO transcription through their roles in the circadian clock. We propose an additional role for PRRs in which they act upon CO protein to promote flowering, directly coupling information on light exposure to the timekeeper and allowing recognition of LDs.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Proteínas de Ligação a DNA/metabolismo , Flores/efeitos da radiação , Luz , Fatores de Transcrição/metabolismo
15.
Sci Rep ; 7: 44477, 2017 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-28290557

RESUMO

Key flowering genes, FD and FD PARALOGUE (FDP) encoding bZIP transcription factors that interact with a FLOWERING LOCUS T (FT) in Arabidopsis were ectopically expressed in rice since we found AtFD and AtFDP also interact with HEADING DATE 3a (Hd3a) and RICE FLOWERING LOCUS T 1 (RFT1). Transgenic rice plants overexpressing AtFD and AtFDP caused reduction in plant height and spikelet size with decreased expression of genes involved in cell elongation without significant flowering time alteration in spite of increased expression of OsMADS14 and OsMADS15, rice homologues of APETALA1 (AP1) in the leaves. Simultaneous overexpression of AtFD and AtFDP enhanced phenotypes seen with overexpression of either single gene while transgenic rice plants expressing AtFD or AtFDP under the control of phloem-specific Hd3a promoter were indistinguishable from wild-type rice. Candidate genes responsible for the phenotypes were identified by comparison of microarray hybridization and their expression pattern was also examined in WT and transgenic rice plants. It has so far not been reported that AtFD and AtFDP affect cell elongation in plants, and our findings provide novel insight into the possible roles of AtFD and AtFDP in the mesophyll cells of plants, and potential genetic tools for manipulation of crop architecture.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Oryza/genética , Plantas Geneticamente Modificadas/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos/genética , Arabidopsis/anatomia & histologia , Arabidopsis/crescimento & desenvolvimento , Expressão Ectópica do Gene/genética , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Oryza/anatomia & histologia , Oryza/crescimento & desenvolvimento , Fenótipo , Fotoperíodo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/anatomia & histologia , Plantas Geneticamente Modificadas/crescimento & desenvolvimento
16.
Plant Signal Behav ; 12(1): e1274482, 2017 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-28029278

RESUMO

The architecture determining grain production in rice is mainly affected by factors such as lamina angle, tillering, plant height and panicle morphology. In particular, leaf angle, the degree of bending between the leaf blade and leaf sheath directly affects crop architecture and grain yields. Balancing activities between the 2 antagonistic groups of proteins, atypical helix-loop-helix (HLH) and basic HLH (bHLH) proteins have been regarded as one of the major molecular machineries regulating lamina angles through the control of cell elongation in the lamina joint of rice. Recently, formation of a complex consisting of atypical HLH protein, OsBUL1, a KxDL motif-containing protein, LO9-177 and a bHLH protein, OsBC1 has been reported to play a positive role in lamina inclination of rice unraveling a novel layer of cell elongation control in rice lamina joint. Here, we demonstrate a trimeric complex formation in rice cells by a combination of BiFC and FRET-FLIM assays.


Assuntos
Oryza/metabolismo , Células Vegetais/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Transferência Ressonante de Energia de Fluorescência , Regulação da Expressão Gênica de Plantas
17.
Plant Physiol ; 173(1): 688-702, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27879391

RESUMO

Rice atypical HLH protein Oryza sativa BRASSINOSTEROID UPREGULATED 1-LIKE1 (OsBUL1) is preferentially expressed in the lamina joint where it controls cell elongation and positively affects leaf angles. OsBUL1 knockout mutant (osbul1) and transgenic rice for double-stranded RNA interference (dsRNAi) of OsBUL1 produced erect leaves with smaller grains, whereas OsBUL1 overexpressors and an activation tagging line of OsBUL1 exhibited increased lamina inclination and grain size. Moreover, OsBUL1 expression was induced by brassinolide (BL) and osbul1 did not respond to BL treatment. To understand the molecular network of OsBUL1 function in rice, we isolated a novel OsBUL1-interacting protein, LO9-177, an uncharacterized protein containing a KxDL motif, and functionally studied it with respect to the lamina inclination and grain size of rice. OsBUL1 COMPLEX1 (OsBC1) is a basic helix-loop-helix (bHLH) transcriptional activator that interacts with OsBUL1 only in the presence of LO9-177 forming a possible trimeric complex for cell elongation in the lamina joint of rice. Expression of OsBC1 is also upregulated by BL and has a similar pattern to that of OsBUL1 Transgenic rice plants expressing OsBC1 under the control of OsBUL1 promoter showed increased grain size as well as leaf bending, while transgenic lines for dsRNAi and/or expressing a dominant repressor form of OsBC1 displayed reduced plant height and grain size. Together, these results demonstrated that a novel protein complex consisting of OsBUL1, LO9-177, and OsBC1 is associated with the HLH-bHLH system, providing new insight into the molecular functional network based on HLH-bHLH proteins for cell elongation.


Assuntos
Oryza/fisiologia , Folhas de Planta/anatomia & histologia , Proteínas de Plantas/metabolismo , Sementes/fisiologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Brassinosteroides/metabolismo , Regulação da Expressão Gênica de Plantas , Técnicas de Inativação de Genes , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Folhas de Planta/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Sementes/genética , Transdução de Sinais , Esteroides Heterocíclicos/metabolismo , Transativadores/genética , Transativadores/metabolismo
18.
Plant Cell Physiol ; 56(11): 2234-47, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26493518

RESUMO

The plant-specific transcription factor LEAFY (LFY) is considered to be a master regulator of flower development in the model plant, Arabidopsis. This protein plays a dual role in plant growth, integrating signals from the floral inductive pathways and acting as a floral meristem identity gene by activating genes for floral organ development. Although LFY occupies an important position in flower development, the functional divergence of LFY homologs has been demonstrated in several plants including monocots and gymnosperms. In particular, the functional roles of LFY genes from orchid species such as Phalaenopsis that contain unique floral morphologies with distinct expression patterns of floral organ identity genes remain elusive. Here, PhapLFY, an ortholog of Arabidopsis LFY from Phalaenopsis aphrodite subsp. formosana, a Taiwanese native monopodial orchid, was isolated and characterized through analyses of expression and protein activity. PhapLFY transcripts accumulated in the floral primordia of developing inflorescences, and the PhapLFY protein had transcriptional autoactivation activity forming as a homodimer. Furthermore, PhapLFY rescues the aberrant floral phenotypes of Arabidopsis lfy mutants. Overexpression of PhapLFY alone or together with PhapFT1, a P. aphrodite subsp. formosana homolog of Arabidopsis FLOWERING LOCUS T (FT) in rice, caused precocious heading. Consistently, a higher Chl content in the sepals and morphological changes in epidermal cells were observed in the floral organs of PhapLFY knock-down orchids generated by virus-induced gene silencing. Taken together, these results suggest that PhapLFY is functionally distinct from RICE FLORICAULA/LEAFY (RFL) but similar to Arabidopsis LFY based on phenotypes of our transgenic Arabidopsis and rice plants.


Assuntos
Orchidaceae/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Clonagem Molecular , Flores/metabolismo , Expressão Gênica , Mutação , Orchidaceae/genética , Oryza/genética , Filogenia , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Fatores de Transcrição/genética
19.
Plant Physiol ; 169(3): 2187-99, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26417007

RESUMO

Flowers form on the flanks of the shoot apical meristem (SAM) in response to environmental and endogenous cues. In Arabidopsis (Arabidopsis thaliana), the photoperiodic pathway acts through FLOWERING LOCUS T (FT) to promote floral induction in response to day length. A complex between FT and the basic leucine-zipper transcription factor FD is proposed to form in the SAM, leading to activation of APETALA1 and LEAFY and thereby promoting floral meristem identity. We identified mutations that suppress FT function and recovered a new allele of the homeodomain transcription factor PENNYWISE (PNY). Genetic and molecular analyses showed that ectopic expression of BLADE-ON-PETIOLE1 (BOP1) and BOP2, which encode transcriptional coactivators, in the SAM during vegetative development, confers the late flowering of pny mutants. In wild-type plants, BOP1 and BOP2 are expressed in lateral organs close to boundaries of the SAM, whereas in pny mutants, their expression occurs in the SAM. This ectopic expression lowers FD mRNA levels, reducing responsiveness to FT and impairing activation of APETALA1 and LEAFY. We show that PNY binds to the promoters of BOP1 and BOP2, repressing their transcription. These results demonstrate a direct role for PNY in defining the spatial expression patterns of boundary genes and the significance of this process for floral induction by FT.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Proteínas Repressoras/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Flores/genética , Flores/crescimento & desenvolvimento , Flores/fisiologia , Proteínas de Homeodomínio/genética , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/fisiologia , Mutação , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , RNA Mensageiro/genética , Proteínas Repressoras/genética , Reprodução , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
20.
Plant J ; 84(3): 451-63, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26358558

RESUMO

Seasonal flowering involves responses to changes in day length. In Arabidopsis thaliana, the CONSTANS (CO) transcription factor promotes flowering in the long days of spring and summer. Late flowering in short days is due to instability of CO, which is efficiently ubiquitinated in the dark by the CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) E3 ligase complex. Here we show that CO is also phosphorylated. Phosphorylated and unphosphorylated forms are detected throughout the diurnal cycle but their ratio varies, with the relative abundance of the phosphorylated form being higher in the light and lower in the dark. These changes in relative abundance require COP1, because in the cop1 mutant the phosphorylated form is always more abundant. Inactivation of the PHYTOCHROME A (PHYA), CRYPTOCHROME 1 (CRY1) and CRYPTOCHROME 2 (CRY2) photoreceptors in the phyA cry1 cry2 triple mutant most strongly reduces the amount of the phosphorylated form so that unphosphorylated CO is more abundant. This effect is caused by increased COP1 activity, as it is overcome by introduction of the cop1 mutation in the cop1 phyA cry1 cry2 quadruple mutant. Degradation of CO is also triggered in red light, and as in darkness this increases the relative abundance of unphosphorylated CO. Finally, a fusion protein containing truncated CO protein including only the carboxy-terminal region was phosphorylated in transgenic plants, locating at least one site of phosphorylation in this region. We propose that CO phosphorylation contributes to the photoperiodic flowering response by enhancing the rate of CO turnover via activity of the COP1 ubiquitin ligase.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Proteínas de Ligação a DNA/metabolismo , Flores/fisiologia , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Sequência de Aminoácidos , Proteínas de Arabidopsis/genética , Criptocromos/genética , Criptocromos/metabolismo , Proteínas de Ligação a DNA/genética , Escuridão , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Fosforilação , Fotoperíodo , Fitocromo A/genética , Fitocromo A/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Proteólise , Fatores de Transcrição/genética , Ubiquitina-Proteína Ligases/genética
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