Biology subjects

Costa, M. M. R.

Publications and source records attributed to Costa, M. M. R..

4 recordsLinked to original sources

bioRxiv2020

RNA editing in inflorescences of wild grapevine unveils association to sex and development

RNA editing challenges the central dogma of molecular biology, by modifying the genetic information at the transcription level. Recent reports, suggesting increased levels of RNA editing in plants, raised questions on the nature and dynamics of such events during development. We here report the occurrence of distinct RNA editing patterns in wild Vitis flowers during development, with twelve possible RNA editing modifications observed for the first time in plants. RNA editing events are gender and developmental stage specific, identical in subsequent years of this perennial species and with distinct nucleotide frequencies neighboring editing sites on the 5 and 3 flanks. The transcriptome dynamics unveils a new regulatory layer responsible for gender plasticity enhancement or underling dioecy evolution in Vitis.

plant biology↗

bioRxiv2020

Portuguese wild grapevine genome re-sequencing (Vitis vinifera sylvestris)

Vitis is a relevant genus worldwide. The genome of a Vitis vinifera representative (PN40024) published in 2007 boosted grapevine related studies. While this reference genome is a suitable tool for the overall studies in the field, it lacks the ability to unveil changes accumulated during V. vinifera domestication. Considering that grapevines for wine production (V. v. vinifera, hereafter vinifera) have evolved from V. v. sylvestris (hereafter sylvestris), or from a shared no-longer existing ancestor, both subspecies are quite close, but sylvestris has not been domesticated and still exist nowadays, preserving wild characteristics, making it a good material to provide insights into vinifera domestication. The difference in the reproductive strategy between both subspecies is one of the characteristics that sets them apart. While vinifera flowers are hermaphrodite with functional male and female organs, sylvestris is mostly dioecious. Male plants present flowers lacking functional carpels unable to produce grapes and female individuals have flowers with reflexed stamens producing infertile pollen but able to exhibit small and acidic grapes. In this paper, we describe the re-sequencing of the genomes from a male and a female individual of the wild sylvestris and its comparison against the reference vinifera genome.

plant biology↗

bioRxiv2020

Genome-Wide Identification of Epigenetic Regulators in Quercus suber

Modifications of DNA and histones, including methylation and acetylation, are critical for the epigenetic regulation of gene expression during plant development, particularly during environmental adaptation processes. However, information on the enzymes catalyzing all these modifications in perennial trees, such as Quercus suber, is still not available. In this study, several epigenetic modifier proteins, including eight DNA methyltransferases (DNA Mtases), three DNA demethylases (DDMEs) and ninety-one histone modifiers including thirty-five histone methyltransferases (HMTs), twenty-six histone demethylases (HDMTs), eight histone acetyltransferases (HATs) and twenty-two histone acetylases (HDACs) were identified in Q. suber. Phylogenetic analyses of the DNA and histone modifier proteins were performed using several plant species homologs, enabling the classification of the Q. suber proteins. Additional in silico analysis showed that some Q. suber DNA Mtases, DMEs and histone modifiers have the typical domains found in the plant model Arabidopsis, which might suggest a conserved functional role. A link between the expression levels of each gene in different Q. suber tissues (buds, flowers, acorns, embryos, cork and roots) with the functions already known for their closest homologs in other species was also established. Therefore, the data generated here are important for future studies exploring the role of epigenetic regulators in this economically important species.

genomics↗

bioRxiv2020

Unisexual flower initiation in the monoecious Quercus suber L., a molecular approach

Several plant species display a temporal separation of the male and female flower organ development to enhance outbreeding, however, little is known regarding the genetic mechanisms controlling this temporal separation. Quercus suber is a monoecious oak tree with accentuated protandry: in late winter, unisexual male flowers emerge adjacent to the swollen buds, whereas unisexual female flowers emerge in the axils of newly formed leaves formed during spring (4 to 8 weeks after male flowering). Here, phylogenetic profiling lead to the identification of cork oak homologs of key floral regulatory genes. The role of these cork oak homologs during flower development was identified with functional studies in Arabidopsis thaliana. The expression profile of flower regulators (inducers and repressors) throughout the year, in leaves and buds, suggests that the development of male and female flowers may be preceded by separated induction events. Female flowers are most likely induced during the vegetative flush occurring in spring, whereas male flowers may be induced in early summer, staying enclosed within the pre-dormant buds, but complete their development before the vegetative flush of the following year, displaying a long period of anthesis that spans the dormant period. Results portray a genetic mechanism that may explain similar reproductive habits in other tree species.

plant biology↗