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Marcelo Carnier Dornelas

Bio: Marcelo Carnier Dornelas is an academic researcher from State University of Campinas. The author has contributed to research in topics: Arabidopsis & Meristem. The author has an hindex of 27, co-authored 90 publications receiving 2607 citations. Previous affiliations of Marcelo Carnier Dornelas include University of Paris & University of São Paulo.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a review focuses on recent literature reporting on the main types of abiotic and biotic stresses that alter the biosynthesis of lignin in plants and how a stressor modulates expression of the genes related with ligninsynthesis.
Abstract: Lignin is a polymer of phenylpropanoid compounds formed through a complex biosynthesis route, represented by a metabolic grid for which most of the genes involved have been sequenced in several plants, mainly in the model-plants Arabidopsis thaliana and Populus. Plants are exposed to different stresses, which may change lignin content and composition. In many cases, particularly for plant-microbe interactions, this has been suggested as defence responses of plants to the stress. Thus, understanding how a stressor modulates expression of the genes related with lignin biosynthesis may allow us to develop study-models to increase our knowledge on the metabolic control of lignin deposition in the cell wall. This review focuses on recent literature reporting on the main types of abiotic and biotic stresses that alter the biosynthesis of lignin in plants.

761 citations

Journal ArticleDOI
TL;DR: Results point to an antagonistic function of class I and class II TCP proteins in the control of leaf development via the jasmonate signaling pathway in JAW plants.
Abstract: TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR1 (TCP) transcription factors control developmental processes in plants. The 24 TCP transcription factors encoded in the Arabidopsis (Arabidopsis thaliana) genome are divided into two classes, class I and class II TCPs, which are proposed to act antagonistically. We performed a detailed phenotypic analysis of the class I tcp20 mutant, showing an increase in leaf pavement cell sizes in 10-d-old seedlings. Subsequently, a glucocorticoid receptor induction assay was performed, aiming to identify potential target genes of the TCP20 protein during leaf development. The LIPOXYGENASE2 (LOX2) and class I TCP9 genes were identified as TCP20 targets, and binding of TCP20 to their regulatory sequences could be confirmed by chromatin immunoprecipitation analyses. LOX2 encodes for a jasmonate biosynthesis gene, which is also targeted by class II TCP proteins that are under the control of the microRNA JAGGED AND WAVY (JAW), although in an antagonistic manner. Mutation of TCP9, the second identified TCP20 target, resulted in increased pavement cell sizes during early leaf developmental stages. Analysis of senescence in the single tcp9 and tcp20 mutants and the tcp9tcp20 double mutants showed an earlier onset of this process in comparison with wild-type control plants in the double mutant only. Both the cell size and senescence phenotypes are opposite to the known class II TCP mutant phenotype in JAW plants. Altogether, these results point to an antagonistic function of class I and class II TCP proteins in the control of leaf development via the jasmonate signaling pathway.

258 citations

Journal ArticleDOI
TL;DR: Recent progress in quantitative imaging and computational modelling will facilitate analysis of the multiple interconnections between plant cell growth and cell cycle and ultimately will be required for the predictive manipulation of plant growth.
Abstract: The growth of organs and whole plants depends on both cell growth and cell-cycle progression, but the interaction between both processes is poorly understood In plants, the balance between growth and cell-cycle progression requires coordinated regulation of four different processes: macromolecular synthesis (cytoplasmic growth), turgor-driven cell-wall extension, mitotic cycle, and endocycle Potential feedbacks between these processes include a cell-size checkpoint operating before DNA synthesis and a link between DNA contents and maximum cell size In addition, key intercellular signals and growth regulatory genes appear to target at the same time cell-cycle and cell-growth functions For example, auxin, gibberellin, and brassinosteroid all have parallel links to cell-cycle progression (through S-phase Cyclin D-CDK and the anaphase-promoting complex) and cell-wall functions (through cell-wall extensibility or microtubule dynamics) Another intercellular signal mediated by microtubule dynamics is the mechanical stress caused by growth of interconnected cells Superimposed on developmental controls, sugar signalling through the TOR pathway has recently emerged as a central control point linking cytoplasmic growth, cell-cycle and cell-wall functions Recent progress in quantitative imaging and computational modelling will facilitate analysis of the multiple interconnections between plant cell growth and cell cycle and ultimately will be required for the predictive manipulation of plant growth

132 citations

Journal ArticleDOI
TL;DR: The AtSK genes are homologues of the Drosophila shaggy (SGG) gene and the mammalian Glycogen-Synthase Kinase-3 (GSK-3).
Abstract: Summary In higher plants, the correct patterning of the floral meristem in terms of organ type, number and form is the result of a concerted expression of a network of genes. We describe phenotypes of flower patterning, resulting from a reduction of transcript levels of the Arabidopsis SHAGGY-related protein kinase genes AtSK11(ASKα) and AtSK12(ASKγ). The AtSK genes are plant homologues of the Drosophila shaggy (SGG) gene and the mammalian Glycogen-Synthase Kinase-3 (GSK-3). The SGG protein kinase is a key component of the wingless signalling pathway and is required for the establishment of tissue patterning and cell fate determination. The expression patterns of the AtSK11(ASKα) and AtSK12(ASKγ) genes during wild-type Arabidopsis inflorescence development, detected by in situ hybridisation, have been shown to be consistent with a possible role in floral meristem patterning. AtSK11(ASKα) and AtSK12(ASKγ) transcripts were detected at the periphery of the inflorescence meristem and in the floral meristem. At later stages the expression of the AtSK genes became localised in specific regions of developing flower organ primordia. Furthermore, we have obtained and analysed transgenic plants containing AtSK11(ASKα) and AtSK12(ASKγ) gene specific antisense constructs. These plants developed flowers showing a higher number of perianth organs and an alteration of the apical-basal patterning of the gynoecium.

112 citations

Journal ArticleDOI
TL;DR: The results show a role for AlaAT in the catabolism of alanine during the initial period of re-oxygenation following hypoxia, and indicates that AlaAT might not only be important during hypoxic stress, but also during the recovery phase after waterlogging, when oxygen is available to the tissue again.
Abstract: Alanine aminotransferase (AlaAT) catalyses the reversible conversion of pyruvate and glutamate into alanine and oxoglutarate. In soybean, two subclasses were identified, each represented by two highly similar members. To investigate the role of AlaAT during hypoxic stress in soybean, changes in transcript level of both subclasses were analysed together with the enzyme activity and alanine content of the tissue. Moreover, the dependency of AlaAT activity and gene expression was investigated in relation to the source of nitrogen supplied to the plants. Using semi-quantitative PCR, GmAlaAT genes were determined to be highest expressed in roots and nodules. Under normal growth conditions, enzyme activity of AlaAT was detected in all organs tested, with lowest activity in the roots. Upon waterlogging-induced hypoxia, AlaAT activity increased strongly. Concomitantly, alanine accumulated. During re-oxygenation, AlaAT activity remained high, but the transcript level and the alanine content decreased. Our results show a role for AlaAT in the catabolism of alanine during the initial period of re-oxygenation following hypoxia. GmAlaAT also responded to nitrogen availability in the solution during waterlogging. Ammonium as nitrogen source induced both gene expression and enzyme activity of AlaAT more than when nitrate was supplied in the nutrient solution. The work presented here indicates that AlaAT might not only be important during hypoxia, but also during the recovery phase after waterlogging, when oxygen is available to the tissue again.

83 citations


Cited by
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Journal ArticleDOI
TL;DR: Important new components of jasmonate signalling including its receptor were identified, providing deeper insight into the role ofJASMONATE signalling pathways in stress responses and development.

1,868 citations

10 Dec 2007
TL;DR: The experiments on both rice and human genome sequences demonstrate that EVM produces automated gene structure annotation approaching the quality of manual curation.
Abstract: EVidenceModeler (EVM) is presented as an automated eukaryotic gene structure annotation tool that reports eukaryotic gene structures as a weighted consensus of all available evidence. EVM, when combined with the Program to Assemble Spliced Alignments (PASA), yields a comprehensive, configurable annotation system that predicts protein-coding genes and alternatively spliced isoforms. Our experiments on both rice and human genome sequences demonstrate that EVM produces automated gene structure annotation approaching the quality of manual curation.

1,528 citations

Journal ArticleDOI
TL;DR: This review provides a “beginning‐to‐end” analysis of the recent advances reported in lignin valorisation, with particular emphasis on the improved understanding of lign in's biosynthesis and structure.
Abstract: Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine-tuning of multiple "upstream" (i.e., lignin bioengineering, lignin isolation and "early-stage catalytic conversion of lignin") and "downstream" (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a "beginning-to-end" analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding of lignin's biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.

1,390 citations

Journal ArticleDOI
TL;DR: Different strategies and achievements through the genetic engineering of flavonoid biosynthesis with implication in the industry and the combinatorial biosynthesis in microorganisms by the reconstruction of the pathway to obtain high amounts of specific compounds are discussed.
Abstract: Flavonoids are widely distributed secondary metabolites with different metabolic functions in plants. The elucidation of the biosynthetic pathways, as well as their regulation by MYB, basic helix-loop-helix (bHLH), and WD40-type transcription factors, has allowed metabolic engineering of plants through the manipulation of the different final products with valuable applications. The present review describes the regulation of flavonoid biosynthesis, as well as the biological functions of flavonoids in plants, such as in defense against UV-B radiation and pathogen infection, nodulation, and pollen fertility. In addition, we discuss different strategies and achievements through the genetic engineering of flavonoid biosynthesis with implication in the industry and the combinatorial biosynthesis in microorganisms by the reconstruction of the pathway to obtain high amounts of specific compounds.

1,260 citations

Journal ArticleDOI
19 Apr 2002-Cell
TL;DR: BES1, a semidominant suppressor of bri1, is identified, which exhibits constitutive BR response phenotypes including long and bending petioles, curly leaves, accelerated senescence, and constitutive expression of BR-response genes.

1,064 citations