A new species of Metrodorea (Rutaceae) from Brazil: Morphology, molecular phylogenetics, and distribution

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morfoanatomia e ontogênese de frutos e sementes de três espécies de Chamaecrista moench (Fabaceae, Caesalpinioideae) de cerrado do Estado de São Paulo

Pós-graduação em Ciências Biológicas (Botânica) - IBB

Anatomia floral e aspectos reprodutivos de espécies de Poales (Monocotiledôneas)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morfoanatomia de órgãos reprodutivos de cinco espécies de malpighiaceae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estrututra e ontogênese de órgãos reprodutivos de Connarus suberosus Planch. (Connaraceae) e Oxalis cytisoides Cucc. (Oxalidaceae)

Pós-graduação em Ciências Biológicas (Botânica) - IBB

Anatomia floral de espécies de Cyperaceae (Poales)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization of the procera Tomato Mutant Shows Novel Functions of the SlDELLA Protein in the Control of Flower Morphology, Cell Division and Expansion, and the Auxin-Signaling Pathway during Fruit-Set and Development

procera (pro) is a tall tomato (Solanum lycopersicum) mutant carrying a point mutation in the GRAS region of the gene encoding SlDELLA, a repressor in the gibberellin (GA) signaling pathway. Consistent with the SlDELLA loss of function, pro plants display a GA-constitutive response phenotype, mimicking wild-type plants treated with GA(3). The ovaries from both nonemasculated and emasculated pro flowers had very strong parthenocarpic capacity, associated with enhanced growth of preanthesis ovaries due to more and larger cells. pro parthenocarpy is facultative because seeded fruits were obtained by manual pollination. Most pro pistils had exserted stigmas, thus preventing self-pollination, similar to wild-type pistils treated with GA(3) or auxins. However, Style2.1, a gene responsible for long styles in noncultivated tomato, may not control the enhanced style elongation of pro pistils, because its expression was not higher in pro styles and did not increase upon GA(3) application. Interestingly, a high percentage of pro flowers had meristic alterations, with one additional petal, sepal, stamen, and carpel at each of the four whorls, respectively, thus unveiling a role of SlDELLA in flower organ development. Microarray analysis showed significant changes in the transcriptome of preanthesis pro ovaries compared with the wild type, indicating that the molecular mechanism underlying the parthenocarpic capacity of pro is complex and that it is mainly associated with changes in the expression of genes involved in GA and auxin pathways. Interestingly, it was found that GA activity modulates the expression of cell division and expansion genes and an auxin signaling gene (tomato AUXIN RESPONSE FACTOR7) during fruit-set.

Morfología y anatomía floral de Schinopsis balansae (Anacardiaceae)

Se realizó el análisis morfo-anatómico de Schinopsis balansae Engl. con microscopía óptica y electrónica de barrido a fin de obtener datos de las flores de esta especie, definida como polígamo-dioica. Los resultados muestran que las flores estructuralmente perfectas son funcionalmente pistiladas, si bien presentan cinco estaminodios, los mismos carecen de tejido esporógeno; mientras que en las flores estaminadas la estructura denominada pistilo vestigial no es más que la excrecencia del ápice del receptáculo, cubierta por tejido nectarífero. De este modo, lo correcto es describir S. balansae como especie dioica. El estudio de la vascularización de las flores estaminadas muestra que el proceso de reducción es completo, ya que ni siquiera persisten los haces vasculares del pistilo. El gineceo de las flores pistiladas es pseudomonómero, con un carpelo funcional, un estilo/estigma dorsal y un óvulo; además posee dos carpelos vestigiales representados por sendos estilo/estigma laterales. Ambos tipos de flores presentan un disco nectarífero intraestaminal, con nectarostomatas para la salida del néctar. El análisis de la estructura anatómica de S. balansae brinda datos que concuerdan con los encontrados en otros géneros estudiados de la subfamila Anacardioideae de la familia Anacardiaceae.

Toward a new synthesis: Major evolutionary trends in the angiosperm fossil record

Angiosperm paleobotany has widened its horizons, incorporated new techniques, developed new databases, and accepted new questions that can now focus on the evolution of the group. The fossil record of early flowering plants is now playing an active role in addressing questions of angiosperm phylogeny, angiosperm origins, and angiosperm radiations. Three basic nodes of angiosperm radiations are identified: (i) the closed carpel and showy radially symmetrical flower, (ii) the bilateral flower, and (iii) fleshy fruits and nutritious nuts and seeds. These are all coevolutionary events and spread out through time during angiosperm evolution. The proposal is made that the genetics of the angiosperms pressured the evolution of the group toward reproductive systems that favored outcrossing. This resulted in the strongest selection in the angiosperms being directed toward the flower, fruits, and seeds. That is why these organs often provide the best systematic characters for the group.

Shaping the Dicot Fruit: Molecular and Genomic Approaches to Fruit Development

The fruit is one of the most complex and important structures produced by flowering plants, and understanding the development and maturation process of fruits in different angiosperm species with diverse fruit structures is of immense interest. In the work presented here, molecular genetics and genomic analysis are used to explore the processes that form the fruit in two species: The model organism Arabidopsis and the diploid strawberry Fragaria vesca. One important basic question concerns the molecular genetic basis of fruit patterning. A long-standing model of Arabidopsis fruit (the gynoecium) patterning holds that auxin produced at the apex diffuses downward, forming a gradient that provides apical-basal positional information to specify different tissue types along the gynoecium’s length. The proposed gradient, however, has never been observed and the model appears inconsistent with a number of observations. I present a new, alternative model, wherein auxin acts to establish the adaxial-abaxial domains of the carpel primordia, which then ensures proper development of the final gynoecium. A second project utilizes genomics to identify genes that regulate fruit color by analyzing the genome sequences of Fragaria vesca, a species of wild strawberry. Shared and distinct SNPs among three F. vesca accessions were identified, providing a foundation for locating candidate mutations underlying phenotypic variations among different F. vesca accessions. Through systematic analysis of relevant SNP variants, a candidate SNP in FveMYB10 was identified that may underlie the fruit color in the yellow-fruited accessions, which was subsequently confirmed by functional assays. Our lab has previously generated extensive RNA-sequencing data that depict genome-scale gene expression profiles in F. vesca fruit and flower tissues at different developmental stages. To enhance the accessibility of this dataset, the web-based eFP software was adapted for this dataset, allowing visualization of gene expression in any tissues by user-initiated queries. Together, this thesis work proposes a well-supported new model of fruit patterning in Arabidopsis and provides further resources for F. vesca, including genome-wide variant lists and the ability to visualize gene expression. This work will facilitate future work linking traits of economic importance to specific genes and gaining novel insights into fruit patterning and development.