Publications by authors named "Andréa Dias Koehler"

5 Publications

  • Page 1 of 1

Transcriptome Analysis of (Cactaceae) Reveals Metabolic Changes During Shoot Organogenesis Induction.

Front Plant Sci 2021 20;12:697556. Epub 2021 Aug 20.

Plant Biology Department/Laboratory of Plant Tissue Culture II-BIOAGRO, Federal University of Viçosa (UFV), Viçosa, Brazil.

is an endangered cactus highly valued for its ornamental properties. shoot production of this species provides a sustainable alternative to overharvesting from the wild; however, its propagation could be improved if the genetic regulation underlying its developmental processes were known. The present study generated transcriptome data, describing shoot organogenesis induction in . Total RNA was extracted from explants before (control) and after shoot organogenesis induction (treated). A total of 14,478 unigenes (average length, 520 bases) were obtained using Illumina HiSeq 3000 (Illumina Inc., San Diego, CA, USA) sequencing and transcriptome assembly. Filtering for differential expression yielded 2,058 unigenes. Pairwise comparison of treated vs. control genes revealed that 1,241 (60.3%) unigenes exhibited no significant change, 226 (11%) were downregulated, and 591 (28.7%) were upregulated. Based on database analysis, more transcription factor families and unigenes appeared to be upregulated in the treated samples than in controls. Expression of () and () genes, both of which were upregulated in treated samples, was further validated by real-time quantitative PCR (RT-qPCR). Differences in gene expression patterns between control and treated samples indicate substantial changes in the primary and secondary metabolism of after the induction of shoot organogenesis. These results help to clarify the molecular genetics and functional genomic aspects underlying propagation in the Cactaceae family.
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http://dx.doi.org/10.3389/fpls.2021.697556DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8417902PMC
August 2021

Anatomy, Flow Cytometry, and X-Ray Tomography Reveal Tissue Organization and Ploidy Distribution in Long-Term Cultures of Species.

Front Plant Sci 2020 31;11:1314. Epub 2020 Aug 31.

Laboratory of Plant Tissue Culture II-BIOAGRO, Plant Biology Department, Federal University of Viçosa (UFV), Viçosa, Brazil.

Cacti have a highly specialized stem that enables survival during extended dry periods. Despite the ornamental value of cacti and the fact that stems represent the main source of explants in tissue culture, there are no studies on their morpho-anatomical and cytological characteristics in . The present study seeks to address the occurrence of cells with mixed ploidy level in cacti tissues. Specifically, we aim to understand how stem tissue is organized, how mixoploidy is distributed when present, and whether detected patterns of ploidy change after long periods of culture. To analyze tissue organization, and plants that had been germinated and cultivated were analyzed for stem structure using toluidine blue, Xylidine Ponceau, Periodic Acid Schiff, ruthenium red, and acid floroglucin. To investigate patterns of ploidy, apical, medial, and basal zones of the stem, as well as, periphery, cortex, and stele (vascular tissue and pith) regions of the stem and root apexes from four- and ten-year old cultured were analyzed by flow cytometry. X-ray micro-computed tomography (XRµCT) was performed with fragments of stems from both species. The scarcity of support elements (, sclereids and fibers) indicates that epidermis, hypodermis, and wide-band tracheids present in cortical vascular bundles and stele, as well as water stored in aquifer parenchyma cells along the cortex, provide mechanical support to the stem. Parenchyma cells increase in volume with a four-fold increase in ploidy. and exhibit the same pattern of cell ploidy irrespective of topophysical region or age, but there is a marked difference in ploidy between the stem periphery (epidermis and hypodermis), cortex, stele, and roots. Mixoploidy in is not related to the age of the culture, but is a developmental trait, whereby endocycles promote cell differentiation to accumulate valuable water.
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http://dx.doi.org/10.3389/fpls.2020.01314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7488924PMC
August 2020

De novo assembly and transcriptome of Pfaffia glomerata uncovers the role of photoautotrophy and the P450 family genes in 20-hydroxyecdysone production.

Protoplasma 2019 May 25;256(3):601-614. Epub 2018 Oct 25.

Departamento de Biologia Vegetal/BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG, Brazil.

Pfaffia glomerata is a medically important species because it produces the phytoecdysteroid 20-hydroxyecdysone (20-E). However, there has been no ready-to-use transcriptome data available in the literature for this plant. Here, we present de novo transcriptome sequencing of RNA from P. glomerata in order to investigate the 20-E production as well as to understand the biochemical pathway of secondary metabolites in this non-model species. We then analyze the effect of photoautotrophy on the production of 20-E genes phylogenetically identified followed by expression analysis. For this, total messenger RNA (mRNA) from leaves, stems, roots, and flowers was used to construct indexed mRNA libraries. Based on the similarity searches against plant non-redundant protein database, gene ontology, and eukaryotic orthologous groups, 164,439 transcripts were annotated. In addition, the effect of photoautotrophy in two genes putatively involved in the 20-E synthesis pathway was analyzed. The Phantom gene (CYP76C), a precursor of the route, showed increased expression in P. glomerata plants cultured under photoautotrophic conditions. This was accompanied by increased production of this metabolite indicating a putative involvement in 20-E synthesis. This work reveals that several genes in the P. glomerata transcriptome are related to secondary metabolism and stresses, that genes of the P450 family participate in the 20-E biosynthesis route, and that plants cultured under photoautotrophic conditions promote an upregulated Phantom gene and enhance the productivity of 20-E. The data will be used for future investigations of the 20-E synthesis pathway in P. glomerata while offering a better understanding of the metabolism of the species.
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http://dx.doi.org/10.1007/s00709-018-1322-1DOI Listing
May 2019

Cellular and Morpho-histological Foundations of In Vitro Plant Regeneration.

Methods Mol Biol 2018 ;1815:47-68

Laboratório de Cultura de Tecidos-LCT, Instituto de Biotecnologia Aplicada à Agropecuária-BIOAGRO/Departamento de Biologia Vegetal, Campus Universitário, Universidade Federal de Viçosa, Viçosa, MG, Brazil.

In vitro plant regeneration systems have turned into invaluable tools to plant biotechnology. Despite being poorly understood, the molecular mechanisms underlying the control of both morphogenetic pathways, de novo organogenesis and somatic embryogenesis, have been supported by recent findings involving proteome-, metabolome-, and transcriptome-based profiles. Notwithstanding, the integration of molecular data with structural aspects has been an important strategy of study attempting to elucidate the basis of the cell competence acquisition to further follow commitment and determination to specific a particular in vitro regeneration pathway. In that sense, morpho-histological tools have allowed to recognize cellular markers and patterns of gene expression at cellular level and this way have collaborated in the identification of the cell types with high regenerative capacity. This chapter ties together up those fundamental and important microscopy techniques that help to elucidate that regeneration occurs, most of the time, from epidermis or subepidermal cells and from the procambial cells (pericycle and vascular parenchyma). Important findings are discussed toward ultrastructural differences observed in the nuclear organization among pluripotent and totipotent cells, implying that regeneration occurs from two cellular mechanisms based on cellular reprogramming or reactivation.
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http://dx.doi.org/10.1007/978-1-4939-8594-4_3DOI Listing
March 2019

Morpho-histological, histochemical, and molecular evidences related to cellular reprogramming during somatic embryogenesis of the model grass Brachypodium distachyon.

Protoplasma 2017 Sep 13;254(5):2017-2034. Epub 2017 Mar 13.

Laboratório de Cultura de Tecidos/BIOAGRO, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Avenida P. H. Rolfs s/n, 36570-900, Viçosa, MG, Brazil.

The wild grass species Brachypodium distachyon (L.) has been proposed as a new model for temperate grasses. Among the biotechnological tools already developed for the species, an efficient induction protocol of somatic embryogenesis (SE) using immature zygotic embryos has provided the basis for genetic transformation studies. However, a systematic work to better understanding the basic cellular and molecular mechanisms that underlie the SE process of this grass species is still missing. Here, we present new insights at the morpho-histological, histochemical, and molecular aspects of B. distachyon SE pathway. Somatic embryos arose from embryogenic callus formed by cells derived from the protodermal-dividing cells of the scutellum. These protodermal cells showed typical meristematic features and high protein accumulation which were interpreted as the first observable steps towards the acquisition of a competent state. Starch content decreased along embryogenic callus differentiation supporting the idea that carbohydrate reserves are essential to morphogenetic processes. Interestingly, starch accumulation was also observed at late stages of SE process. Searches in databanks revealed three sequences available annotated as BdSERK, being two copies corresponding to SERK1 and one showing greater identity to SERK2. In silico analysis confirmed the presence of characteristic domains in a B. distachyon Somatic Embryogenesis Receptor Kinase genes candidates (BdSERKs), which suggests SERK functions are conserved in B. distachyon. In situ hybridization demonstrated the presence of transcripts of BdSERK1 in all development since globular until scutellar stages. The results reported in this study convey important information about the morphogenetic events in the embryogenic pathway which has been lacking in B. distachyon. This study also demonstrates that B. distachyon provides a useful model system for investigating the genetic regulation of SE in grass species.
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http://dx.doi.org/10.1007/s00709-017-1089-9DOI Listing
September 2017
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