SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Dornelas,Marcelo Carnier; Rodriguez,Adriana Pinheiro Martinelli.

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....

A genetic framework for flowering-time pathways in Citrus spp.

Palavras-chave: LEAFY; Plant reproduction; Development; Gene expression; Flowering.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000200021

Dornelas,Marcelo Carnier; Camargo,Raquel Luciana Boscariol; Figueiredo,Luciana Harumi Morimoto; Takita,Marco Aurélio.

Floral transition is one the most drastic changes occurring during the life cycle of a plant. The shoot apical meristem switches from the production of leaves with associated secondary shoot meristems to the production of flower meristems. This transition is abrupt and generally irreversible, suggesting it is regulated by a robust gene regulatory network capable of driving sharp transitions. The moment at which this transition occurs is precisely determined by environmental and endogenous signals. A large number of genes acting within these pathways have been cloned in model herbaceous plants such as Arabidopsis thaliana. In this paper, we report the results of our search in the Citrus expressed sequence tag (CitEST) database for expressed sequence tags...

A genomic approach to characterization of the Citrus terpene synthase gene family

Palavras-chave: Reproductive development; Flowering-time genes; Reproduction; Photoperiod; CONSTANS.

Ano: 2007

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000500006

Dornelas,Marcelo Carnier; Mazzafera,Paulo.

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...

EgLFY, the Eucalyptus grandis homolog of the Arabidopsis gene LEAFY is expressed in reproductive and vegetative tissues

Palavras-chave: Secondary metabolism; Flavor; Aroma; Plant protection; Terpene synthesis.

Ano: 2007

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000500011

Dornelas,Marcelo Carnier; Amaral,Weber A. Neves do; Rodriguez,Adriana Pinheiro Martinelli.

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...

Exploring the role of auxin in the androgynophore movement in Passiflora

Palavras-chave: Eucalyptus; Flowering; LEAFY; Reproductive development.

Ano: 2004

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202004000200006

Scorza,Livia C.T.; Dornelas,Marcelo Carnier.

The flowers of the species belonging to the genus Passiflorashow a range of features that are thought to have arisen as adaptations to different pollinators. Some Passiflora species belonging to the subgenus Decaloba sect. Xerogona, show touch-sensitive motile androgynophores. We tested the role of auxin polar transport in the modulation of the androgynophore movement by applying auxin (IAA) or an inhibitor of auxin polar transport (NPA) in the flowers. We recorded the movement of the androgynophore during mechano-stimulation and analyzed the duration, speed, and the angle formed by the androgynophore before and after the movement, and found that both IAA and NPA increase the amplitude of the movement in P. sanguinolenta. We hypothesize that auxin might...

From leaf to flower: revisiting Goethe's concepts on the ¨metamorphosis¨ of plants

Palavras-chave: Passiflora; Androgynophore; IAA; NPA; Thigmotropism.

Ano: 2015

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572015000300301

Dornelas,Marcelo Carnier; Dornelas,Odair.

Goethes 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 Goethes 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...

Identifying Eucalyptus expressed sequence tags related to Arabidopsis flowering-time pathway genes

Palavras-chave: Flower development; Gene expression; Meristem behavior; Theory of plant development.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000400001

Dornelas,Marcelo Carnier; Rodriguez,Adriana Pinheiro Martinelli.

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...

Signal transduction, cell division, differentiation and development: towards unifying mechanisms for pattern formation in plants

Palavras-chave: CONSTANS; Data mining; EST; Photoperiod; Vernalization.

Ano: 2005

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000200009

Dornelas,Marcelo Carnier.

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....

Towards the identification of flower-specific genes in Citrus spp

Palavras-chave: Cell differentiation; Developmental genetics; Transduction pathways.

Ano: 2003

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202003000100001

Dornelas,Marcelo Carnier; Camargo,Raquel Luciana Boscariol; Berger,Irving Joseph; Takita,Marco Aurélio.

Citrus sinensis is a perennial woody species, for which genetic approaches to the study of reproductive development are not readily amenable. Here, the usefulness of the CitEST Expressed Sequence Tag (EST) database is demonstrated as a reliable new resource for identifying novel genes exclusively related to Citrus reproductive biology. We performed the analysis of an EST dataset of the CitEST Project containing 4,330 flower-derived cDNA sequences. Relying on bioinformatics tools, sequences exclusively present in this flower-derived sequence collection were selected and used for the identification of Citrus putative flower-specific genes. Our analysis revealed several Citrus sequences showing significant similarity to conserved genes known to have...