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Eleonora Cominelli

Bio: Eleonora Cominelli is an academic researcher from University of Milan. The author has contributed to research in topics: Guard cell & Arabidopsis. The author has an hindex of 17, co-authored 23 publications receiving 2373 citations.

Papers
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Journal ArticleDOI
TL;DR: An Arabidopsis thaliana line that is mutant for the R2R3 MYB gene, AtMYB4, shows enhanced levels of sinapate esters in its leaves, indicating that derepression is an important mechanism for acclimation to UV‐B in A.thaliana.
Abstract: An Arabidopsis thaliana line that is mutant for the R2R3 MYB gene, AtMYB4, shows enhanced levels of sinapate esters in its leaves. The mutant line is more tolerant of UV-B irradiation than wild type. The increase in sinapate ester accumulation in the mutant is associated with an enhanced expression of the gene encoding cinnamate 4-hydroxylase, which appears to be the principal target of AtMYB4 and an effective rate limiting step in the synthesis of sinapate ester sunscreens. AtMYB4 expression is downregulated by exposure to UV-B light, indicating that derepression is an important mechanism for acclimation to UV-B in A.thaliana. The response of target genes to AtMYB4 repression is dose dependent, a feature that operates under physiological conditions to reinforce the silencing effect of AtMYB4 at high activity. AtMYB4 works as a repressor of target gene expression and includes a repression domain. It belongs to a novel group of plant R2R3 MYB proteins involved in transcriptional silencing. The balance between MYB activators and repressors on common target promoters may provide extra flexibility in transcriptional control.

794 citations

Journal ArticleDOI
TL;DR: The characterization of AtMYB60, a R2R3-MYB gene of Arabidopsis, is reported as the first transcription factor involved in the regulation of stomatal movements and opens new possibilities to engineeringStomatal activity to help plants survive desiccation.

470 citations

Journal ArticleDOI
TL;DR: It is concluded that specific members of the MYB and bHLH families play important roles in regulating anthocyanin biosynthesis in response to different light qualities in Arabidopsis.

247 citations

Journal ArticleDOI
TL;DR: The results suggest that AtMYB41 is part of a complex network of transcription factors controlling cell expansion and cuticle deposition in response to abiotic stress.
Abstract: The Arabidopsis AtMYB41 gene encodes an R2R3-MYB transcription factor whose expression is not detectable under normal growth conditions in any organ or at any developmental stage analysed. It is expressed at high levels in response to drought, ABA and salt treatments, suggesting a possible role in stress responses. Transgenic lines over-expressing this transcription factor showed a pleiotropic phenotype similar to that exhibited by some mutants that affect cuticle biosynthesis. This includes a dwarf appearance, dependent on smaller cells with abnormal morphology, enhanced sensitivity to desiccation, and enhanced permeability of leaf surfaces, suggesting discontinuity in the cuticle. The expression of genes involved in lipid metabolism and transport, in cell-wall modifications and cell expansion, genes coding for membrane-associated proteins and genes specifically involved in cuticle metabolism was differentially modulated between wild-type and transgenic plants, suggesting a direct or indirect role of AtMYB41 in the regulation of their transcription. Taken together, our results suggest that AtMYB41 is part of a complex network of transcription factors controlling cell expansion and cuticle deposition in response to abiotic stress.

202 citations

Journal ArticleDOI
TL;DR: The isolation of 47 insertions into 36 distinct MYB genes by screening a total of 73 genes is reported, providing the foundation for subsequent detailed functional analyses for the assignment of specific functions to individual members of the R2R3 MYB gene family.
Abstract: More than 92 genes encoding MYB transcription factors of the R2R3 class have been described in Arabidopsis. The functions of a few members of this large gene family have been described, indicating important roles for R2R3 MYB transcription factors in the regulation of secondary metabolism, cell shape, and disease resistance, and in responses to growth regulators and stresses. For the majority of the genes in this family, however, little functional information is available. As the first step to characterizing these genes functionally, the sequences of >90 family members, and the map positions and expression profiles of >60 members, have been determined previously. An important second step in the functional analysis of the MYB family, through a process of reverse genetics that entails the isolation of insertion mutants, is described here. For this purpose, a variety of gene disruption resources has been used, including T-DNA-insertion populations and three distinct populations that harbor transposon insertions. We report the isolation of 47 insertions into 36 distinct MYB genes by screening a total of 73 genes. These defined insertion lines will provide the foundation for subsequent detailed functional analyses for the assignment of specific functions to individual members of the R2R3 MYB gene family.

171 citations


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Journal ArticleDOI
TL;DR: The elucidation ofMYB protein function and regulation that is possible in Arabidopsis will provide the foundation for predicting the contributions of MYB proteins to the biology of plants in general.

3,542 citations

Journal ArticleDOI
TL;DR: Lignin is the generic term for a large group of aromatic polymers resulting from the oxidative combinatorial coupling of 4-hydroxyphenylpropanoids, deposited predominantly in the walls of secondarily thickened cells, making them lignin-like polymers.
Abstract: Lignin is the generic term for a large group of aromatic polymers resulting from the oxidative combinatorial coupling of 4-hydroxyphenylpropanoids ([Boerjan et al., 2003][1]; [Ralph et al., 2004][2]). These polymers are deposited predominantly in the walls of secondarily thickened cells, making them

1,956 citations

Journal ArticleDOI
TL;DR: Improved understanding of the molecular and biochemical mechanisms by which plants respond to elevated [CO2], and the feedback of environmental factors upon them, will improve the ability to predict ecosystem responses to rising [ CO2] and increase the potential to adapt crops and managed ecosystems to future atmospheric [CO 2].
Abstract: This review summarizes current understanding of the mechanisms that underlie the response of photosynthesis and stomatal conductance to elevated carbon dioxide concentration ([CO2]), and examines how downstream processes and environmental constraints modulate these two fundamental responses. The results from free-air CO2 enrichment (FACE) experiments were summarized via meta-analysis to quantify the mean responses of stomatal and photosynthetic parameters to elevated [CO2]. Elevation of [CO2] in FACE experiments reduced stomatal conductance by 22%, yet, this reduction was not associated with a similar change in stomatal density. Elevated [CO2] stimulated light-saturated photosynthesis (Asat) in C3 plants grown in FACE by an average of 31%. However, the magnitude of the increase in Asat varied with functional group and environment. Functional groups with ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco)-limited photosynthesis at elevated [CO2] had greater potential for increases in Asat than those where photosynthesis became ribulose-1,5-bisphosphate (RubP)-limited at elevated [CO2]. Both nitrogen supply and sink capacity modulated the response of photosynthesis to elevated [CO2] through their impact on the acclimation of carboxylation capacity. Increased understanding of the molecular and biochemical mechanisms by which plants respond to elevated [CO2], and the feedback of environmental factors upon them, will improve our ability to predict ecosystem responses to rising [CO2] and increase our potential to adapt crops and managed ecosystems to future atmospheric [CO2].

1,836 citations

Journal ArticleDOI
TL;DR: Systematic screens for knockout mutations in MYB genes, followed by phenotypic analyses and the dissection of mutants with interesting phenotypes, have started to unravel the functions of the 125 R2R3-MYB genes in Arabidopsis thaliana.

1,779 citations

Journal ArticleDOI
TL;DR: The results achieved so far indicate that various plant organs, in a definite hierarchy and in interaction with each other, are involved in determining crop yield under stress.
Abstract: As the result of intensive research and breeding efforts over the last 20 years, the yield potential and yield quality of cereals have been greatly improved. Nowadays, yield safety has gained more importance because of the forecasted climatic changes. Drought and high temperature are especially considered as key stress factors with high potential impact on crop yield. Yield safety can only be improved if future breeding attempts will be based on the valuable new knowledge acquired on the processes determining plant development and its responses to stress. Plant stress responses are very complex. Interactions between plant structure, function and the environment need to be investigated at various phases of plant development at the organismal, cellular as well as molecular levels in order to obtain a full picture. The results achieved so far in this field indicate that various plant organs, in a definite hierarchy and in interaction with each other, are involved in determining crop yield under stress. Here we attempt to summarize the currently available information on cereal reproduction under drought and heat stress and to give an outlook towards potential strategies to improve yield safety in cereals.

1,547 citations