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1.
Plant Sci ; 287: 110173, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481204

RESUMO

Anthocyanins are responsible for red, purple, and pink pigmentation of flowers in Cymbidium hybrids. Although anthocyanin content in all floral organs increases with flower development, they increase markedly in the tepals compared with the labella or columns. Using next-generation sequencing technology, we identified three anthocyanin biosynthesis regulatory genes, CyMYB1, CybHLH1, and CybHLH2, from Cymbidium 'Mystique'. Yeast two-hybrid analysis showed that the CyMYB1 protein can form a heterodimer with either CybHLH1 or CybHLH2. In the tepals, the expression level of CyMYB1 increased as the flower developed, whereas the high expression level of CyMYB1 was detected at the early flower developmental stages in the labella and columns, remaining constant until increasing at the late developmental stage. These expression profiles of CyMYB1 positively correlated with the profiles of anthocyanin accumulation in the tepals. When Cymbidium Sazanami 'Champion' was grown at 30 °C/25 °C, reduced anthocyanin levels were observed, specifically in the tepals, compared with those in flowers grown at 20 °C/15 °C. The transcription of CyMYB1 in the tepals was suppressed at high temperatures, and the expressions of CyDFR and CyANS were also synchronously suppressed. This study revealed that CyMYB1 activates the transcription of CyDFR and CyANS and regulates the temporal- and temperature-dependent anthocyanin accumulation in Cymbidium tepals.


Assuntos
Antocianinas/biossíntese , Flores/metabolismo , Regulação da Expressão Gênica de Plantas , Orchidaceae/metabolismo , Flavonoides/metabolismo , Genes de Plantas/genética , Sequenciamento de Nucleotídeos em Larga Escala , Orchidaceae/genética , Filogenia , Proteínas de Plantas/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Temperatura Ambiente , Fatores de Transcrição/metabolismo , Transcriptoma
2.
Plant Sci ; 287: 110166, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481226

RESUMO

In angiosperms, cyclic electron flow (CEF) around photosystem I (PSI) is more important for photoprotection under fluctuating light than under constant light. However, the underlying mechanism is not well known. In the present study, we measured the CEF activity, P700 redox state and electrochromic shift signal upon a sudden transition from low to high light in wild-type plants of Arabidopsis thaliana and Bletilla striata (Orchidaceae). Within the first 20 s after transition from low to high light, P700 was highly reduced in both species, which was accompanied with a sufficient proton gradient (ΔpH) across the thylakoid membranes. Meanwhile, the level of CEF activation was elevated. After transition from low to high light for 60 s, the plants generated an optimal ΔpH. Under such condition, PSI was highly oxidized and the level of CEF activation decreased to the steady state. Furthermore, the CEF activation was positively correlated to the P700 reduction ratio. These results indicated that upon a sudden transition from low to high light, the insufficient ΔpH led to the over-reduction of PSI electron carriers, which in turn stimulated the CEF around PSI. This transient stimulation of CEF not only favored the rapid ΔpH formation but also accepted electrons from PSI, thus protecting PSI at donor and acceptor sides. These findings provide new insights into the important role of CEF in regulation of photosynthesis under fluctuating light.


Assuntos
Arabidopsis/metabolismo , Transporte de Elétrons , Orchidaceae/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Arabidopsis/efeitos da radiação , Clorofila/metabolismo , Relação Dose-Resposta à Radiação , Transporte de Elétrons/efeitos da radiação , Luz , Orchidaceae/efeitos da radiação , Complexo de Proteína do Fotossistema I/efeitos da radiação
3.
BMC Plant Biol ; 19(1): 337, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375064

RESUMO

BACKGROUND: Cymbidium goeringii belongs to the Orchidaceae, which is one of the most abundant angiosperm families. Cymbidium goeringii consist with high economic value and characteristics include fragrance and multiple flower colors. Floral scent is one of the important strategies for ensuring fertilization. However, limited genetic data is available in this non-model plant, and little known about the molecular mechanism responsible for floral scent in this orchid. Transcriptome and expression profiling data are needed to identify genes and better understand the biological mechanisms of floral scents in this species. Present transcriptomic data provides basic information on the genes and enzymes related to and pathways involved in flower secondary metabolism in this plant. RESULTS: In this study, RNA sequencing analyses were performed to identify changes in gene expression and biological pathways related scent metabolism. Three cDNA libraries were obtained from three developmental floral stages: closed bud, half flowering stage and full flowering stage. Using Illumina technique 159,616,374 clean reads were obtained and were assembled into 85,868 final unigenes (average length 1194 nt), 33.85% of which were annotated in the NCBI non redundant protein database. Among this unigenes 36,082 were assigned to gene ontology and 23,164 were combined with COG groups. Total 33,417 unigenes were assigned in 127 pathways according to the Kyoto Encyclopedia of Genes and Genomes pathway database. According these transcriptomic data we identified number of candidates genes which differentially expressed in different developmental stages of flower related to fragrance biosynthesis. In q-RT-PCR most of the fragrance related genes highly expressed in half flowering stage. CONCLUSIONS: RNA-seq and DEG data provided comprehensive gene expression information at the transcriptional level that could be facilitate the molecular mechanisms of floral biosynthesis pathways in three developmental phase's flowers in Cymbidium goeringii, moreover providing useful information for further analysis on C. goeringii, and other plants of genus Cymbidium.


Assuntos
Flores/metabolismo , Genes de Plantas/genética , Odorantes , Orchidaceae/genética , Acetatos/metabolismo , Ciclopentanos/metabolismo , Farneseno Álcool/metabolismo , Flores/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas/fisiologia , Orchidaceae/metabolismo , Oxilipinas/metabolismo , Filogenia , Análise de Sequência de RNA , Sesquiterpenos/metabolismo , Terpenos/metabolismo
4.
Molecules ; 24(13)2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31323985

RESUMO

Seven novel norcycloartane glycosides, maryloside A-G (1-7), were isolated from the leaves of Cymbidium Great Flower 'Marylaurencin', along with a known norcycloartane glycoside, cymbidoside (8). These structures were determined on the basis of mainly NMR experiments as well as chemical degradation and X-ray crystallographic analysis. The isolated compounds (1-6 and 8) were evaluated for the inhibitory activity on lipopolysaccharide (LPS) and interferon-γ (IFN-γ)-stimulated nitric oxide (NO) production in RAW 264.7 cells. Consequently, 1 and 3 exhibited moderate activity.


Assuntos
Flores/química , Glicosídeos/química , Orchidaceae/química , Folhas de Planta/química , Sobrevivência Celular , Flores/metabolismo , Glicosídeos/isolamento & purificação , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , Óxido Nítrico/biossíntese , Orchidaceae/metabolismo , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Folhas de Planta/metabolismo
5.
J Chem Ecol ; 45(5-6): 464-473, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31111291

RESUMO

Different enantiomers of chiral compounds within floral perfumes usually trigger distinct responses in insects; however, this has frequently been neglected in studies investigating semiochemicals in plant-pollinator interactions. Approximately 1000 neotropical plants produce floral perfumes as the only reward for pollinators, i.e. male euglossine bees. The chiral compound carvone epoxide is a key component of the scent bouquet of many perfume-rewarding plants that are pollinated by males of Eulaema. Here, we tested the biological activity of the four carvone epoxide stereoisomers to four Eulaema species occurring in the Atlantic Rainforest of NE-Brazil. We determined the stereochemistry of carvone epoxide in the floral scent of several Catasetum species, tested whether the antennae of bees respond differentially to these stereoisomers and investigated if there is a behavioural preference for any of the stereoisomers. We found that 1) Catasetum species emit only the (-)-trans-stereoisomer of carvone epoxide, 2) for E. atleticana and E. niveofasciata antennal responses to the (-)-trans-carvone epoxide were significantly stronger than those to (-)-cis-carvone epoxide, 3) the strength and pattern of antennal responses to all 4 stereoisomers (separately tested) did not differ among Eulaema species, and 4) there were significant differences in attractiveness of the four stereoisomers to the bees species with the (-)-trans-stereoisomer being particularly attractive. We assume (-)-trans-carvone epoxide to be the dominant isomer in perfume-rewarding plants pollinated by Eulaema. The universal occurrence of carvone epoxide in Catasetum species pollinated by Eulaema, suggests that this compound has evolved in perfume-rewarding as a specific attractant for Eulaema bees as pollinators.


Assuntos
Abelhas/fisiologia , Monoterpenos/química , Animais , Comportamento Animal/efeitos dos fármacos , Cromatografia Gasosa , Compostos de Epóxi/química , Flores/química , Flores/metabolismo , Masculino , Monoterpenos/farmacologia , Orchidaceae/química , Orchidaceae/metabolismo , Estereoisomerismo
6.
BMC Genomics ; 20(1): 125, 2019 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-30744548

RESUMO

BACKGROUND: Cymbidium faberi, one of the most famous oriental orchids, has a distinct flower scent, which increases its economic value. However, the molecular mechanism of the flower scent biosynthesis was unclear prior to this study. Methyl jasmonate (MeJA) is one of the main volatile organic compounds (VOC) produced by the flowers of C. faberi. In this study, unigene 79,363 from comparative transcriptome analysis was selected for further investigation. RESULTS: A transcriptome comparison between blooming and withered flowers of C. faberi yielded a total of 9409 differentially expressed genes (DEGs), 558 of which were assigned to 258 pathways. The top ten pathways included α-linolenic acid metabolism, pyruvate metabolism and fatty acid degradation, which contributed to the conversion of α-linolenic acid to MeJA. One of the DEGs, jasmonic acid carboxyl methyltransferase (CfJMT, Unigene 79,363) was highly expressed in the blooming flower of C. faberi, but was barely detected in leaves and roots. Although the ectopic expression of CfJMT in tomato could not increase the MeJA content, the expression levels of endogenous MeJA biosynthesis genes were influenced, especially in the wound treatment, indicating that CfJMT may participate in the response to abiotic stresses. CONCLUSION: This study provides a basis for elucidating the molecular mechanism of flower scent biosynthesis in C. faberi, which is beneficial for the genetically informed breeding of new cultivars of the economically valuable oriental orchids.


Assuntos
Flores/metabolismo , Perfilação da Expressão Gênica , Metiltransferases/genética , Odorantes , Orchidaceae/genética , Orchidaceae/metabolismo , Orchidaceae/enzimologia , Orchidaceae/fisiologia , Regiões Promotoras Genéticas/genética , Estresse Fisiológico , Regulação para Cima
7.
Plant Physiol Biochem ; 135: 341-347, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30605871

RESUMO

Light energy is essential for carbon metabolism in plants, as well as controlling the transport of metabolites between the organs. While terrestrial plants have a distinct structural and functional separation between the light exposed aerial parts and the non-exposed roots, epiphytic plants, such as orchids, have shoots and roots simultaneously fully exposed to light. The roots of orchids differ mainly from non-orchidaceous plants in their ability to photosynthesize. Since the roots of Catasetum fimbriatum can synthesize auxin which is acropetally transported to the shoot region, we decided to investigate whether: (1) light treatment of C. fimbriatum roots raises the auxin levels in the plant; and (2) distinct auxin concentrations can change the source-sink relationships, altering the amounts of sugars and organic acids in leaves, pseudobulbs and roots. Among the organs studied, the roots accumulated the highest concentrations of indole-3-acetic-acid (IAA); and when roots were exposed to light, IAA accumulated in the leaves. However, when polar auxin transport (PAT) was blocked with N-(1-Naphthyl)phthalamic acid (NPA) treatment, a significant accumulation of sugars and organic acids occurred in the pseudobulbs and leaves, respectively, suggesting that auxin flux from roots to shoots was involved in carbon partitioning of the aerial organs. Considering that C. fimbriatum plants lose all their leaves seasonally, it is possible the roots are a substituting influence on the growth and development of this orchid during its leafless period.


Assuntos
Carbono/metabolismo , Ácidos Indolacéticos/metabolismo , Orchidaceae/metabolismo , Raízes de Plantas/metabolismo , Animais , Frutose/metabolismo , Glucose/metabolismo , Luz , Orchidaceae/efeitos da radiação , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos da radiação , Sacarase/metabolismo
8.
Phytochemistry ; 156: 176-183, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30312933

RESUMO

Phenylalanine ammonia lyase (PAL) is the first enzyme of phenylpropanoid pathway. In the present study, a full-length PAL transcript from Vanda coerulea Griff. ex Lindl. (Family: Orchidaceae) was isolated and characterized. It was found that complete PAL transcript of V. coerulea (VcPAL; Gene Bank no. MG745168) contained 2175 bp with the open reading frame (ORF) of 2112 bp, encoding 703 amino acid residues. The multiple sequence alignment showed that VcPAL protein had 81% identity with that of the orchid, Bromheadia finlaysoniana. Phylogenetic analysis also disclosed that VcPAL shared the same evolutionary relationship with PAL proteins of other orchid species and to be closely related to that of other angiosperm species as well. The three-dimensional structure of VcPAL was found to be homo-tetrameric in nature consisting of four identical subunits with a molecular mass of 75 kDa per subunit. In silico characterization revealed the deduced protein to be a stable protein, comprising three major functional domains as reported in PAL proteins of other species. The transcription profiling of VcPAL exhibited the highest expression level to be present in the in vitro - raised leaf and root samples as compared to that of the ex vitro plant. The differential expression of VcPAL transcript was observed to be up-regulated by different types of abiotic stresses like wounding, cold, UV-B, salinity, and down-regulated by dark treatment. The study also exhibited that the VcPAL enzyme activity was directly proportional to the gene expression after the tissues were subjected to salinity and wounding stresses wherein a 1.7- fold increase in the enzyme activity was recorded in the leaf tissues exposed to salinity stress. A positive correlation could be found between the enzyme activity and the accumulation of phenylpropanoids such as total phenolic and flavonoid contents with R2 = 0.85 and 0.842 respectively.


Assuntos
Orchidaceae/enzimologia , Fenilalanina Amônia-Liase/genética , Transcrição Genética/genética , Sequência de Aminoácidos , Simulação por Computador , Conformação Molecular , Orchidaceae/metabolismo , Fenilalanina Amônia-Liase/química , Fenilalanina Amônia-Liase/metabolismo , Alinhamento de Sequência
9.
PLoS Pathog ; 14(9): e1007288, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30212572

RESUMO

Salicylic acid (SA) is a key phytohormone that mediates a broad spectrum of resistance against a diverse range of viruses; however, the downstream pathway of SA governed antiviral immune response remains largely to be explored. Here, we identified an orchid protein containing A20 and AN1 zinc finger domains, designated Pha13. Pha13 is up-regulated upon virus infection, and the transgenic monocot orchid and dicot Arabidopsis overexpressing orchid Pha13 conferred greater resistance to different viruses. In addition, our data showed that Arabidopsis homolog of Pha13, AtSAP5, is also involved in virus resistance. Pha13 and AtSAP5 are early induced by exogenous SA treatment, and participate in the expression of SA-mediated immune responsive genes, including the master regulator gene of plant immunity, NPR1, as well as NPR1-independent virus defense genes. SA also induced the proteasome degradation of Pha13. Functional domain analysis revealed that AN1 domain of Pha13 is involved in expression of orchid NPR1 through its AN1 domain, whereas dual A20/AN1 domains orchestrated the overall virus resistance. Subcellular localization analysis suggested that Pha13 can be found localized in the nucleus. Self-ubiquitination assay revealed that Pha13 confer E3 ligase activity, and the main E3 ligase activity was mapped to the A20 domain. Identification of Pha13 interacting proteins and substrate by yeast two-hybrid screening revealed mainly ubiquitin proteins. Further detailed biochemical analysis revealed that A20 domain of Pha13 binds to various polyubiquitin chains, suggesting that Pha13 may interact with multiple ubiquitinated proteins. Our findings revealed that Pha13 serves as an important regulatory hub in plant antiviral immunity, and uncover a delicate mode of immune regulation through the coordination of A20 and/or AN1 domains, as well as through the modulation of E3 ligase and ubiquitin chain binding activity of Pha13.


Assuntos
Imunidade Vegetal , Proteínas de Plantas/imunologia , Vírus de Plantas/imunologia , Vírus de Plantas/patogenicidade , Sequência de Aminoácidos , Antivirais/metabolismo , Arabidopsis/imunologia , Arabidopsis/metabolismo , Arabidopsis/virologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/imunologia , Genes de Plantas , Interações Hospedeiro-Patógeno , Modelos Biológicos , Orchidaceae/imunologia , Orchidaceae/metabolismo , Orchidaceae/virologia , Imunidade Vegetal/genética , Imunidade Vegetal/fisiologia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Ligação Proteica , Domínios Proteicos , Ácido Salicílico/metabolismo , Homologia de Sequência de Aminoácidos , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/imunologia , Ubiquitina-Proteína Ligases/metabolismo , Dedos de Zinco
10.
Chem Biodivers ; 15(12): e1800360, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30239121

RESUMO

The study of the main components of the alcoholic extract obtained from Chloraea chrysantha Poepp. led to the isolation of two new dihydrostilbene derivatives together with the known gavilein (3). The new compounds have been assigned as 3-methoxy-5-{2-[3-methoxy-2-(3-methylbut-2-en-1-yl)phenyl]ethyl}phenol (1) and 1-[2-(3,5-dimethoxyphenyl)ethyl]-3-methoxy-2-(3-methylbut-2-en-1-yl)benzene (2). The presence of compounds 1-3 is perfectly in accordance with the current botanical classification of the genus.


Assuntos
Orchidaceae/química , Estilbenos/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Conformação Molecular , Orchidaceae/metabolismo , Estilbenos/isolamento & purificação
11.
Am J Bot ; 105(9): 1595-1600, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30129024

RESUMO

PREMISE OF THE STUDY: The evolution of full mycoheterotrophy is one of the most interesting topics within plant evolution. The leafless orchid Cymbidium macrorhizon is often assumed to be fully mycoheterotrophic even though it has a green stem and fruit capsule. Here, we assessed the trophic status of this species by analyzing the chlorophyll content and the natural 13 C and 15 N abundance in the sprouting and the fruiting season. METHODS: The chlorophyll content was measured in five sprouting and five fruiting individuals of C. macrorhizon that were co-occurring. In addition, their 13 C and 15 N isotopic signatures were compared with those of neighboring autotrophic and partially mycoheterotrophic reference plants. KEY RESULTS: Fruiting individuals of C. macrorhizon were found to contain a remarkable amount of chlorophyll compared to their sprouting counterparts. In addition, the natural abundance of 13 C in the tissues of the fruiting plants was slightly depleted relative to the sprouting ones. Linear two-source mixing model analysis revealed that fruiting C. macrorhizon plants obtained approximately 73.7 ± 2.0% of their total carbon from their mycorrhizal fungi when the sprouting individuals were used as the 100% carbon gain standard. CONCLUSIONS: Our results indicated that despite its leafless status, fruiting plants of C. macrorhizon were capable of fixing significant quantities of carbon. Considering the autotrophic carbon gain increases during the fruiting season, its photosynthetic ability may contribute to fruit and seed production. These results indicate that C. macrorhizon should, therefore, be considered a partially mycoheterotrophic species rather than fully mycoheterotrophic, at least during the fruiting stage.


Assuntos
Orchidaceae/microbiologia , Clorofila/metabolismo , Micorrizas , Orchidaceae/metabolismo , Orchidaceae/fisiologia , Simbiose
12.
J Exp Bot ; 69(18): 4363-4377, 2018 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-29982590

RESUMO

Floral scent is an important factor in attracting pollinators and repelling florivores. In Phalaenopsis bellina (Orchidaceae), the major floral scent components are monoterpenoids. Previously, we determined that expression of GERANYL DIPHOSPHATE SYNTHASE (PbGDPS) is highly correlated with monoterpene biosynthesis in Phalaenosis orchids. Here, we found that both cis- and trans-regulation were present on the GDPS promoters, with trans-regulation playing a key role. To investigate the regulation of biosynthesis of floral scent, we compared the transcriptomic data of two Phalaenopsis orchids with contrasting scent phenotypes. Eight transcription factors (TFs) that exhibited sequential elevation in abundance through floral development in P. bellina were identified, and their transcript levels were higher in the scented orchid than the scentless one. Five of these TFs transactivated several structural genes involved in monoterpene biosynthesis including PbbHLH4, PbbHLH6, PbbZIP4, PbERF1, and PbNAC1. Ectopic transient expression of each of these TFs in scentless orchids resulted in stimulation of terpenoid biosynthesis. PbbHLH4 most profoundly induced monoterpene biosynthesis, with a 950-fold increase of monoterpenoid production in the scentless orchid. In conclusion, we determined that biosynthesis of orchid floral monoterpenes was sequentially regulated, with PbbHLH4 playing a crucial role for monoterpene biosynthesis.


Assuntos
Regulação da Expressão Gênica de Plantas , Monoterpenos/metabolismo , Orchidaceae/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Transcriptoma , Flores/metabolismo , Odorantes/análise , Orchidaceae/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo
13.
Int J Mol Sci ; 19(5)2018 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-29710804

RESUMO

Phalaenopsis flowers are some of the most popular ornamental flowers in the world. For most ornamental plants, petal longevity determines postharvest quality and garden performance. Therefore, it is important to have insight into the senescence mechanism of Phalaenopsis. In the present study, a proteomic approach combined with ultrastructural observation and activity analysis of antioxidant enzymes was used to profile the molecular and biochemical changes during pollination-induced petal senescence in Phalaenopsis “Red Dragon”. Petals appeared to be visibly wilting at 24 h after pollination, accompanied by the mass degradation of macromolecules and organelles during senescence. In addition, 48 protein spots with significant differences in abundance were found by two-dimensional electrophoresis (2-DE) and subjected to matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/TOF-MS). There were 42 protein spots successfully identified and homologous to known functional protein species involved in key biological processes, including antioxidant pathways, stress response, protein metabolism, cell wall component metabolism, energy metabolism, cell structure, and signal transduction. The activity of all reactive oxygen species (ROS)-scavenging enzymes was increased, keeping the content of ROS at a low level at the early stage of senescence. These results suggest that two processes, a counteraction against increased levels of ROS and the degradation of cellular constituents for maintaining nutrient recycling, are activated during pollination-induced petal senescence in Phalaenopsis. The information provides a basis for understanding the mechanism regulating petal senescence and prolonging the florescence of Phalaenopsis.


Assuntos
Orchidaceae/genética , Proteoma/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Flores/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/metabolismo , Desenvolvimento Vegetal , Proteoma/genética
14.
PLoS One ; 13(4): e0195642, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29649288

RESUMO

Anoectochilus sp. and Ludisia discolor are known as Jewel orchids. Both species are terrestrial wild orchids that grow in shaded areas of forests. The Jewel orchids are renowned for the beauty of their leaves, which are dark-green laced with silvery or golden veins. The orchids are used as a cure in various parts of Asia. Overharvesting and anthropogenic disturbances threaten the existence of the Jewel orchids in the wild, necessitating human intervention in their survival. An understanding of the structure and adaptations of a plant may assist in its survival when propagated outside of its habitat. In this study, ex vitro leaves of Anoectochilus sp. and L. discolor were subjected to freehand sectioning, and then inspected through brightfield and fluorescence microscopy. The study indicated that all parts of both plants presented typical monocotyledonous characteristics except the leaves. The leaves displayed dorsiventrality with distinct palisade and spongy mesophyll layers. The spongy mesophyll layer contained cells which fluoresced a bright red when exposed to ultraviolet, blue, and green light wavelengths, hinting at the presence of anthocyanins for photoprotection. Cyanidin was detected in the leaves of L. discolor, as enumerated through high performance liquid chromatography (HPLC). The observations indicated that Anoectochilus sp. and L. discolor are well-adapted to live under shaded conditions with minimal exposure to light.


Assuntos
Antocianinas/análise , Fluorescência , Orchidaceae/química , Antocianinas/química , Cromatografia Líquida de Alta Pressão , Orchidaceae/metabolismo , Fotossíntese , Folhas de Planta/química , Folhas de Planta/metabolismo
15.
Curr Biol ; 28(6): 980-986.e3, 2018 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-29526587

RESUMO

Nursery pollination involves pollinators that lay eggs on the flowers they pollinate and have their brood fed on flower parts or developing ovules [1-4]. Active pollination, a ritualistic behavioral sequence shown by nursery pollinators when transferring pollen from anthers to stigmas, is known in only four plant lineages [5-8], including the classical examples of fig trees-fig wasps and yuccas-yucca moths [5, 6]. We report in detail a system in which weevils actively pollinate orchids prior to having their larvae fed on the developing fruits. Sampling over five years revealed that although weevils trigger fruit set, this interaction is negative for the plant as weevil larvae often consume all contents of infested fruits. However, part of weevil-infested fruits is often "rescued" by parasitoid wasps, which kill the weevil larvae before all fruit content is consumed (Figure 1). "Rescued" fruits present high seed viability and biomass similar to that of non-infested fruits, much higher than that of fruits with weevils only. Hence, parasitoids mediate the fitness consequences of the interaction between the plant and its parasitic pollinator. Weevils constitute a megadiverse group of herbivores commonly reported as florivores [9] but are also appreciated as flower-ovipositing pollinators of cycads and palms [4, 10-13] and were previously recorded carrying orchid pollinaria [14-16]. The orchid-weevil system presented here shows that plant-floral visitor interaction outcome can be mediated by a third party (parasitoids) and illustrates a way by which the biological context may allow the emergence and persistence of active nursery pollination behavior in nature.


Assuntos
Vespas/parasitologia , Gorgulhos/metabolismo , Animais , Feminino , Flores , Frutas , Herbivoria/fisiologia , Larva , Orchidaceae/metabolismo , Parasitos , Pólen , Polinização/fisiologia , Reprodução , Sementes , Simbiose/fisiologia , Vespas/metabolismo , Gorgulhos/parasitologia
16.
Mol Ecol ; 27(5): 1324-1337, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29419910

RESUMO

The climbing orchid Erythrorchis altissima is the largest mycoheterotroph in the world. Although previous in vitro work suggests that E. altissima has a unique symbiosis with wood-decaying fungi, little is known about how this giant orchid meets its carbon and nutrient demands exclusively via mycorrhizal fungi. In this study, the mycorrhizal fungi of E. altissima were molecularly identified using root samples from 26 individuals. Furthermore, in vitro symbiotic germination with five fungi and stable isotope compositions in five E. altissima at one site were examined. In total, 37 fungal operational taxonomic units (OTUs) belonging to nine orders in Basidiomycota were identified from the orchid roots. Most of the fungal OTUs were wood-decaying fungi, but underground roots had ectomycorrhizal Russula. Two fungal isolates from mycorrhizal roots induced seed germination and subsequent seedling development in vitro. Measurement of carbon and nitrogen stable isotope abundances revealed that E. altissima is a full mycoheterotroph whose carbon originates mainly from wood-decaying fungi. All of the results show that E. altissima is associated with a wide range of wood- and soil-inhabiting fungi, the majority of which are wood-decaying taxa. This generalist association enables E. altissima to access a large carbon pool in woody debris and has been key to the evolution of such a large mycoheterotroph.


Assuntos
Micorrizas/fisiologia , Orchidaceae/microbiologia , Carbono/metabolismo , Isótopos de Carbono/análise , Micorrizas/metabolismo , Nitrogênio/metabolismo , Isótopos de Nitrogênio/análise , Orchidaceae/classificação , Orchidaceae/metabolismo , Raízes de Plantas/classificação , Raízes de Plantas/genética
17.
Protoplasma ; 255(2): 565-574, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28944415

RESUMO

Although many Orchidaceae have deceit flowers that produce no reward, the most common reward, when present, is nectar. Bulbophyllum, however, is unusual in that the labellar secretions of most species investigated to date lack sugars, and, therefore, cannot be considered true nectar. The African species Bulbophyllum saltatorium is an exception in that it produces not only nectar but also possesses specialized, capitate oleiferous trichomes. The nectary of B. saltatorium is borne on the labellum and is represented by a deep, narrow, median longitudinal groove, having a small aperture, and flanked by trichomes. Isodiametric epidermal cells lining this groove secrete nectar which collects both in the groove and on the surface of the labellum. As well as a nectary, the labellum of B. saltatorium also bears three types of unicellular trichomes: the longest trichomes are borne distally and abaxially; the marginal ones form a rim around the entire labellum, and finally, massive, capitate trichomes occur proximally and adaxially. These are oleiferous, containing large quantities of oil which might function as precursors of volatile components of fragrance or provide a food-reward. To the best of our knowledge, this is the first time for such oleiferous trichomes to be described for Bulbophyllum. Therefore, apart from their color and markings, flowers of this species are able to attract pollinators in at least two, possibly three ways: food-reward in the form of nectar; fragrance; and possibly food-rewards in the form of food-hairs.


Assuntos
Flores/fisiologia , Orchidaceae/metabolismo , Néctar de Plantas/metabolismo , Óleos Vegetais/metabolismo , Tricomas/metabolismo , Flores/anatomia & histologia , Flores/ultraestrutura , Orchidaceae/ultraestrutura , Tricomas/ultraestrutura
18.
Physiol Plant ; 162(3): 353-369, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28967227

RESUMO

Cymbidium goeringii Rchb.f. is an important ornamental plant with a striking well-differentiated lip. Its complex floral architecture presents an exciting opportunity to examine perianth development. In flowering plants, class A, B and E floral homeotic genes play key roles in the specification of perianth identity. In this study, we used a cDNA library of wild-type C. goeringii flower buds for transcriptome sequencing. Eighteen candidate class A, B and E genes (including AP1/FUL-, AP2-, DEF-, GLO-, SEP- and AGL6-like genes) were identified. Quantitative real time polymerase chain reaction (qRT-PCR) results showed that CgDEF1, CgSEP2 and CgAGL6-1 were strongly detected only in the sepals and petals and were significantly downregulated in the lips. CgDEF3, CgDEF4 and CgAGL6-3 were highly expressed in the lips and lip-like petals but were only minimally detected in the sepals. Yeast two-hybrid analysis indicated that CgDEF1 and CgGLO formed a heterodimer. CgAGL6-1/CgSEP2 and CgDEF1 formed higher-order protein complexes with the assistance of the CgGLO protein, and both CgAGL6-1 and CgSEP2 formed a heterodimer. CgDEF3/CgDEF4 could interact independently with CgGLO and CgAGL6-3, respectively, while CgDEF3 and CgDEF4 also formed heterodimers with the assistance of the CgGLO. Based on a comprehensive analysis relating these gene expression patterns to protein interaction profiles, the mechanism of sepal/petal/lip determination was studied in C. goeringii. Furthermore, a hypothesis explaining the sepal/petal/lip determination of C. goeringii is proposed. The lip-quartet (CgDEF3/CgDEF4/CgAGL6-3/CgGLO) promoted lip formation, whereas the sepal/petal-quartet (CgDEF1/CgAGL6-1/CgSEP2/CgGLO) promoted sepal/petal formation. These results enrich the current knowledge regarding the mechanism and pathways of perianth formation in orchids.


Assuntos
Flores/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Domínio MADS/genética , Orchidaceae/genética , Proteínas de Plantas/genética , Flores/metabolismo , Perfilação da Expressão Gênica/métodos , Biblioteca Gênica , Proteínas de Domínio MADS/classificação , Proteínas de Domínio MADS/metabolismo , Modelos Genéticos , Orchidaceae/metabolismo , Filogenia , Proteínas de Plantas/metabolismo , Ligação Proteica
19.
Molecules ; 22(9)2017 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-28869565

RESUMO

Oncidium is an important ornamental crop worldwide, and in recent years, the characteristics of the flower aroma have become a concern for breeders. This study used headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC-MS) analysis of the volatile compounds to study the aroma characteristics of Onc. Rosy Sunset. A total of 45 compounds were identified, with the major compound being linalool. Onc. Rosy Sunset had the highest odor concentration from 10:00 to 12:00 and lowest from 20:00 to 24:00. The inflorescence emitted the highest quantities of volatile compounds during stages 3-6, which then decreased with the aging of the flowers. In Onc. Rosy Sunset, the sepals and petals were the major parts for the floral fragrance emission, in which linalool content was the highest, whereas the lip and column had a different composition of major volatile compounds, of which benzaldehyde, ß-myrcene, and ß-caryophyllene dominated.


Assuntos
Flores/química , Odorantes/análise , Orchidaceae/química , Rosa/química , Compostos Orgânicos Voláteis/química , Benzaldeídos/química , Ritmo Circadiano , Flores/metabolismo , Humanos , Monoterpenos/química , Orchidaceae/metabolismo , Componentes Aéreos da Planta/química , Rosa/metabolismo , Sesquiterpenos/química , Fatores de Tempo
20.
Chem Biodivers ; 14(11)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28771984

RESUMO

The Orchidaceae family is the largest group of flowering plants in the Angiosperm monocotyledons spread on our planet. Its members, called orchids, are herbs or epiphytes with showy flowers distributed mainly in tropical regions. Several classes of phytoconstituents have been so far isolated from therapeutically-used orchids showing a great chemical diversity. Among them, phenolic derivatives have been studied for their biological activities, especially in the field of cancer, inflammation, and neurodegeneration. On the other hand, limited information has been so far obtained on the numerous alkaloids and terpenoids isolated from several orchid species. Recent articles revealed pronounced effects of some alkaloids on the CNS. Published literature on orchids that are used in traditional medicine has been reviewed in this work indicating a great potential of such organisms as source of chemical entities for the development of new drugs.


Assuntos
Orchidaceae/química , Orchidaceae/metabolismo , Extratos Vegetais/química , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/toxicidade , Descoberta de Drogas/tendências , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Extratos Vegetais/farmacologia
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