Large-scale phylogeography of the disjunct Neotropical tree species Schizolobium parahyba (Fabaceae-Caesalpinioideae).

Neotropical rainforests exhibit high levels of endemism and diversity. Although the evolutionary genetics of plant diversification has garnered increased interest, phylogeographic studies of widely distributed species remain scarce. Here we describe chloroplast and nuclear variation patterns in Schizolobium parahyba (Fabaceae), a widespread tree in Neotropical rainforests that harbor two varieties with a disjunct distribution. Chloroplast and nuclear sequence analyses yielded 21 and 4 haplotypes, respectively. Two genetic diversity centers that correlate with the two known varieties were identified: the Southeastern Atlantic forest and the Amazonian basin. In contrast, the populations from southern and northeastern Atlantic forests and Andean-Central American forests exhibited low levels of genetic diversity and divergent haplotypes, likely related to historical processes that impact the flora and fauna in these regions, such as a founder's effect after dispersion and demographic expansion. Phylogeographic and demographic patterns suggest that episodes of genetic isolation and dispersal events have shaped the evolutionary history for this species, and different patterns have guided the evolution of S. parahyba. Moreover, the results of this study suggest that the dry corridor formed by Cerrado and Caatinga ecoregions and the Andean uplift acted as barriers to this species' gene flow, a picture that may be generalized to most of the plant biodiversity tropical woodlands and forests. These results also reinforce the importance of evaluating multiple genetic markers for a more comprehensive understanding of population structure and history. Our results provide insight into the conservation efforts and ongoing work on the genetics of population divergence and speciation in these Neotropical rainforests. (C) 2012 Elsevier Inc. All rights reserved

Avaliação da expressão e identificação de genes diferencialmente regulados durante o desenvolvimento do fruto das cultivares de uva Isabel e Isabel Precoce.

A maturação precoce é uma caracteristica agronômica desejada nos programas de melhoramento genético de uvas, pois permite a ampliação do periodo de processamento na vitivinicultura tradicional, e também a obtenção de duas safras por ano em regiões tropicais. Portanto, a compreensão da regulação da expressão gênica associada à maturação do fruto toma-se um pré-requisito essencial ao desenvolvimento de ferramentas aplicadas ao melhoramento genético que possibilitem, por exemplo, a seleção assistida e modificação do amadurecimento.Resumo

Differential transcriptional profiles of dormancy-related genes in apple buds

The production of temperate fruit crops depends on plant developmental processes, primarily the shift from the juvenile phase to the reproductive phase, dormancy transitions and flowering. Apple tree (Malus ×domestica Borkh.) development is regulated by chilling temperatures, which are required for bud dormancy progression. The apple cultivar Castel Gala is a spontaneous mutation of "Gala Standard". "Castel Gala" is characterized by a 50 % decrease in the chilling requirement (CR) for dormancy release, which results in an earlier budbreak. This work explores the contrasting phenotypes of these cultivars using suppression subtractive hybridization (SSH). From 1,019 unigenes identified by SSH, we selected 28 candidate genes putatively associated with dormancy cycling. Reverse transcription-quantitative polymerase chain reaction was used to validate the differential expression profiles and to transcriptionally characterize these genes in three distinct apple cultivars ("Castel Gala", "Royal Gala" and "Fuji Standard") during a cycle comprising growth to dormancy. Of the 28 candidate genes analyzed, 17 confirmed the differences in expression predicted by SSH. Seasonal transcript accumulation during the winter was observed for several genes, with higher steady-state mRNA levels maintained longer in cultivars with a high CR. The transcription profiles suggest that these genes may be associated with dormancy establishment and maintenance. Of the 17 candidate genes, transcripts coding for dormancy-associated MADS-box (DAM), dehydrins, GAST1, LTI65, NAC, HTA8, HTA12 and RAP2.12-like proteins displayed major differences in gene expression between cultivars through the winter. These genes were therefore considered good candidates for key roles in the dormancy process in apple trees.DOI 10.1007/s11105-013-0690-

Seleção de genes-referência para estudos de expressão gênica utilizando PCR quantitativa em macieiras.

A macieira (Malus x domestica) é uma das mais importantes frutíferas do mundo, e sua produção tem destaque na região sul do Brasil.Resumo publicado também no ENCONTRO DE INICIAÇÃO CIENTÍFICA, 8.; ENCONTRO DE PÓS-GRADUANDOS DA EMBRAPA UVA E VINHO, 4., 2010, Bento Gonçalves. Resumos. Bento Gonçalves: Embrapa Uva e Vinho, 2010; e REUNIÃO ANUAL DO PROGRAMA DE PÓS-GRADUAÇÃO EM BIOLOGIA CELULAR E MOLECULAR DO CENTRO DE BIOTECNOLOGIA DA UFRGS, 12., 2010, Porto Alegre. Livro de resumos. Porto Alegre: UFRGS, 2010

Perfil transcricional comparativo de genes associados ao desenvolvimento do fruto das cultivares de uva Isabel e Isabel Precoce (Vitis labrusca L.).

A cultivar de uva Isabel Precoce é resultante de uma mutação somática espontânea da cultivar Isabel (Vitis labrusca) caracterizada pela antecipação da colheita em cerca de trinta dias. As cultivares precoces permitem aos produtores, a possibilidade de programar o período de colheita para janelas de mercado com preços mais atrativos, podendo com isso, agregar valor ao produto.Resumo