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Search Results: 1 - 10 of 17685 matches for " Marcelo Carnier;Rodriguez "
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A Floricaula/Leafy gene homolog is preferentially expressed in developing female cones of the tropical pine Pinus caribaea var. caribaea
Dornelas, Marcelo Carnier;Rodriguez, Adriana Pinheiro Martinelli;
Genetics and Molecular Biology , 2005, DOI: 10.1590/S1415-47572005000200021
Abstract: in angiosperms, flower formation is controlled by meristem identity genes, one of which, floricaula (flo)/leafy (lfy), plays a central role. it is not known if the formation of reproductive organs of pre-angiosperm species is similarly regulated. here, we report the cloning of a conifer (pinus caribaea var. caribaea) flo/lfy homolog, named pclfy. this gene has a large c-terminal region of high similarity to angiosperm flo/lfy orthologs and shorter regions of local similarity. in contrast to angiosperms, conifers have two divergent genes resembling lfy. gymnosperm flo/lfy proteins constitute a separate clade, that can be divided into two divergent groups. phylogenetic analysis of deduced protein sequences has shown that pclfy belongs to the lfy-like clade. northern hybridization analysis has revealed that pclfy is preferentially expressed in developing female cones but not in developing male cones. this expression pattern was confirmed by in situ hybridization and is consistent with the hypothesis of pclfy being involved in the determination of the female cone identity. additionally, mutant complementation experiments have shown that the expression of the pclfy coding region, driven by the arabidopsis lfy promoter, can confer the wild-type phenotype to lfy-26 transgenic mutants, suggesting that both gymnosperm and angiosperm lfy homologs share the same biological role.
Identifying Eucalyptus expressed sequence tags related to Arabidopsis flowering-time pathway genes
Dornelas, Marcelo Carnier;Rodriguez, Adriana Pinheiro Martinelli;
Brazilian Journal of Plant Physiology , 2005, DOI: 10.1590/S1677-04202005000200009
Abstract: flowering initiation depends on the balanced expression of a complex network of genes that is regulated by both endogenous and environmental factors. the timing of the initiation of flowering is crucial for the reproductive success of plants; therefore, they have developed conserved molecular mechanisms to integrate both environmental and endogenous cues to regulate flowering time precisely. extensive advances in plant biology are possible now that the complete genome sequences of flowering plants is available and plant genomes can be comprehensively compared. thus, association studies are emerging as powerful tools for the functional identification of genes involved on the regulation of flowering pathways. in this paper we report the results of our search in the eucalyptus genome sequencing project consortium (forests) database for expressed sequence tags (ests) showing sequence homology with known elements of flowering-time pathways. we have searched the 33,080 sequence clusters in the forests database and identified eucalyptus sequences that codify putative conserved elements of the autonomous, vernalization-, photoperiod response- and gibberellic acid-controlled flowering-time pathways. additionally, we have characterized in silico ten putative members of the eucalyptus homologs to the arabidopsis constans family of transcription factors.
EgLFY, the Eucalyptus grandis homolog of the Arabidopsis gene LEAFY is expressed in reproductive and vegetative tissues
Dornelas, Marcelo Carnier;Amaral, Weber A. Neves do;Rodriguez, Adriana Pinheiro Martinelli;
Brazilian Journal of Plant Physiology , 2004, DOI: 10.1590/S1677-04202004000200006
Abstract: the eglfy gene cloned from eucalyptus grandis has sequence homology to the floral meristem identity gene leafy (lfy) from arabidopsis and floricaula (flo) from antirrhinum. eglfy is preferentially expressed in the developing eucalypt floral organs in a pattern similar to that described previously for the arabidopsis lfy. in situ hybridization experiments have shown that eglfy is strongly expressed in the early floral meristem and then successively in the primordia of sepals, petals, stamens and carpels. it is also expressed in the leaf primordia of adult trees. the expression of the eglfy coding region under control of the arabidopsis lfy promoter could complement strong lfy mutations in transgenic arabidopsis plants. these data suggest that eglfy plays a similar role to lfy in flower development and that the basic mechanisms involved in flower initiation and development in eucalyptus may be similar to those occurring in arabidopsis.
Signal transduction, cell division, differentiation and development: towards unifying mechanisms for pattern formation in plants
Dornelas, Marcelo Carnier;
Brazilian Journal of Plant Physiology , 2003, DOI: 10.1590/S1677-04202003000100001
Abstract: the elaboration of plant form and function depends on the ability of a plant cell to divide and differentiate. the decisions of individual cells to enter the cell cycle, maintain proliferation competence, become quiescent, expand, differentiate, or die depend on cell-to-cell communication and on the perception of various signals. these signals can include hormones, nutrients, light, temperature, and internal positional and developmental cues. in recent years, progress has been made in understanding the molecular control of plant pattern formation, especially in the model plant arabidopsis thaliana. furthermore, specific genes have been found that are necessary for normal pattern formation and the control of the rates of cell division and differentiation. cloning of these genes is revealing the molecular basis of plant pattern formation and the key players on plant signal transduction systems.
Signal transduction, cell division, differentiation and development: towards unifying mechanisms for pattern formation in plants
Dornelas Marcelo Carnier
Brazilian Journal of Plant Physiology , 2003,
Abstract: The elaboration of plant form and function depends on the ability of a plant cell to divide and differentiate. The decisions of individual cells to enter the cell cycle, maintain proliferation competence, become quiescent, expand, differentiate, or die depend on cell-to-cell communication and on the perception of various signals. These signals can include hormones, nutrients, light, temperature, and internal positional and developmental cues. In recent years, progress has been made in understanding the molecular control of plant pattern formation, especially in the model plant Arabidopsis thaliana. Furthermore, specific genes have been found that are necessary for normal pattern formation and the control of the rates of cell division and differentiation. Cloning of these genes is revealing the molecular basis of plant pattern formation and the key players on plant signal transduction systems.
PASSIOMA: Exploring Expressed Sequence Tags during Flower Development in Passiflora spp.
Lucas Cutri,Marcelo Carnier Dornelas
Comparative and Functional Genomics , 2012, DOI: 10.1155/2012/510549
Abstract: The genus Passiflora provides a remarkable example of floral complexity and diversity. The extreme variation of Passiflora flower morphologies allowed a wide range of interactions with pollinators to evolve. We used the analysis of expressed sequence tags (ESTs) as an approach for the characterization of genes expressed during Passiflora reproductive development. Analyzing the Passiflora floral EST database (named PASSIOMA), we found sequences showing significant sequence similarity to genes known to be involved in reproductive development such as MADS-box genes. Some of these sequences were studied using RT-PCR and in situ hybridization confirming their expression during Passiflora flower development. The detection of these novel sequences can contribute to the development of EST-based markers for important agronomic traits as well as to the establishment of genomic tools to study the naturally occurring floral diversity among Passiflora species.
A genomic approach to characterization of the Citrus terpene synthase gene family
Dornelas, Marcelo Carnier;Mazzafera, Paulo;
Genetics and Molecular Biology , 2007, DOI: 10.1590/S1415-47572007000500011
Abstract: terpenes are a very large and structurally diverse group of secondary metabolites which are abundant in many essential oils, resins and floral scents. additionally, some terpenes have roles as phytoalexins in plant-pathogen relationships, allelopathic inhibitors in plant-plant interactions, or as airborne molecules of plant-herbivore multitrophic signaling. thus the elucidation of the biochemistry and molecular genetics of terpenoid biosynthesis has paramount importance in any crop species. with this aim, we searched the citest database for clusters of expressed sequence tags (ests) coding for terpene synthases. herein is a report on the identification and in silico characterization of 49 putative members of the terpene synthase family in diverse citrus species. the expression patterns and the possible physiological roles of the identified sequences are also discussed.
From leaf to flower: revisiting Goethe's concepts on the ¨metamorphosis¨ of plants
Dornelas, Marcelo Carnier;Dornelas, Odair;
Brazilian Journal of Plant Physiology , 2005, DOI: 10.1590/S1677-04202005000400001
Abstract: goethe?s seminal scientific work, versuch die metamorphose der pflanzen zu erklaren (an attempt to interpret the metamorphosis of plants) dated from 1790, has created the foundations for many domains of modern plant biology. the archetypal leaf concept, which considers floral organs as modified leaves, besides being the best known has been proven true, following the description of the abc molecular model of floral organ identity determination during the last decade. here we analyze the whole theoretical frame of goethe?s 1790 publication and present two previously misconsidered aspects of this work: the "refinement of the sap" concept as a directional principle and the "cycles of contractions and expansions" as cycles of differential determination of the shoot apical meristem. the reinterpretation of these concepts are in line with the modern view that molecular networks integrate both environmental and endogenous cues and regulate plant development. this reassessment also helps to elaborate a theoretical frame that considers the evolutionary conservation of the molecular mechanisms that regulate plant development.
PASSIOMA: Exploring Expressed Sequence Tags during Flower Development in Passiflora spp.
Lucas Cutri,Marcelo Carnier Dornelas
International Journal of Genomics , 2012, DOI: 10.1155/2012/510549
Abstract: The genus Passiflora provides a remarkable example of floral complexity and diversity. The extreme variation of Passiflora flower morphologies allowed a wide range of interactions with pollinators to evolve. We used the analysis of expressed sequence tags (ESTs) as an approach for the characterization of genes expressed during Passiflora reproductive development. Analyzing the Passiflora floral EST database (named PASSIOMA), we found sequences showing significant sequence similarity to genes known to be involved in reproductive development such as MADS-box genes. Some of these sequences were studied using RT-PCR and in situ hybridization confirming their expression during Passiflora flower development. The detection of these novel sequences can contribute to the development of EST-based markers for important agronomic traits as well as to the establishment of genomic tools to study the naturally occurring floral diversity among Passiflora species. 1. Introduction The genus Passiflora comprises almost 600 species of vines, lianas, and small trees, and its diversity reaches a maximum in Central and South America [1, 2]. To the genus Passiflora belongs the passionfruit (Passiflora edulis Deg.) and other species producing ornamental flowers known collectively as “passionflowers.” Passionflowers are appreciated exactly due to a remarkable range of floral complexity and diversity. The flowers of Passiflora exhibits several unique floral features, including multiple series of brightly colored coronal filaments, diverse operculum morphology, an androgynophore, and elaborate floral nectary structures (Figure 1). The evolution of this extreme variation of flower morphologies is believed to be the result of interactions with a wide range of pollinators [2, 3]. Therefore, this genus is specially suited to any study on the evolution of pollination syndromes, especially those aiming to elucidate the molecular mechanisms underlying these adaptative steps. Figure 1: Longitudinal sections of Passiflora spp. flowers. (a) a large insect- (bumblebee) pollinated flower ( P. edulis); (b) a small insect- (wasp) pollinated flower ( P. suberosa); (c) a hummingbird-pollinated flower ( P. tulae); (d) a bat-pollinated flower ( P. setacea). co: corona; an: androgynophore; li: limen; op: operculum. Bars: (a), (c), and (d): 1?cm; (b): 0.2?cm. Accordingly, one of the major challenges of current plant biology is to understand the genetic basis and molecular mechanisms of all naturally occurring developmental variation. This analysis has begun to benefit from the ever growing number of
A Genomic Approach to Study Anthocyanin Synthesis and Flower Pigmentation in Passionflowers
Lilian Cristina Baldon Aizza,Marcelo Carnier Dornelas
Journal of Nucleic Acids , 2011, DOI: 10.4061/2011/371517
Abstract: Most of the plant pigments ranging from red to purple colors belong to the anthocyanin group of flavonoids. The flowers of plants belonging to the genus Passiflora (passionflowers) show a wide range of floral adaptations to diverse pollinating agents, including variation in the pigmentation of floral parts ranging from white to red and purple colors. Exploring a database of expressed sequence tags obtained from flower buds of two divergent Passiflora species, we obtained assembled sequences potentially corresponding to 15 different genes of the anthocyanin biosynthesis pathway in these species. The obtained sequences code for putative enzymes are involved in the production of flavonoid precursors, as well as those involved in the formation of particular (“decorated”) anthocyanin molecules. We also obtained sequences encoding regulatory factors that control the expression of structural genes and regulate the spatial and temporal accumulation of pigments. The identification of some of the putative Passiflora anthocyanin biosynthesis pathway genes provides novel resources for research on secondary metabolism in passionflowers, especially on the elucidation of the processes involved in floral pigmentation, which will allow future studies on the role of pigmentation in pollinator preferences in a molecular level. 1. Introduction Anthocyanins belong to a diverse group of secondary metabolites of the phenylpropanoid class, the flavonoids, which are found in different plant species. They represent some of the most important natural pigments, which are responsible for the wide range of red to purple colors present in many flowers, fruits, seeds, leaves, and stems. Besides having great economical relevance, flower and fruit pigments play an important ecological role in the animal attraction for pollination and seed dispersal, wich is a spectacular example of coevolution between plants and animals [1–3]. The biosynthetic pathway of anthocyanins has been well characterized biochemically and genetically in species with different floral morphology, pigmentation pattern, and pollination syndromes such as Petunia hybrida [4, 5], Matthiola [6], Dianthus [7], Eustoma [8], Gerbera [9], Zea mays [10, 11], Antirrhinum majus [12], and Ipomoea [13, 14]. A representation of a general anthocyanin biosynthetic pathway is shown in Figure 1. Figure 1: Schematic representation of the anthocyanin biosynthetic pathway (adapted from [ 16]). Enzymes are indicated in red, and classes of compounds are in green. Anthocyanidin is further modified with glycosyl, acyl, or methyl groups,
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