Estelle Goulas - Academia.edu (original) (raw)

Papers by Estelle Goulas

Molecular & cellular proteomics : MCP, Jan 13, 2017

Experimentally-generated (nanoLC-MS/MS) proteomic analyses of four different flax organs/tissues ... more Experimentally-generated (nanoLC-MS/MS) proteomic analyses of four different flax organs/tissues (inner-stem, outer-stem, leaves and roots) enriched in proteins from 3 different sub-compartments (soluble-, membrane-, and cell wall-proteins) was combined with publically available data on flax seed and whole-stem proteins to generate a flax protein database containing 2996 non-redundant total proteins. Subsequent multiple analyses (MapMan, CAZy, WallProtDB and expert curation) of this database were then used to identify a flax cell wall proteome consisting of 456 non-redundant proteins localized in the cell wall and/or associated with cell wall biosynthesis, remodeling and other cell wall related processes. Examination of the proteins present in different flax organs/tissues provided a detailed overview of cell wall metabolism and highlighted the importance of hemicellulose and pectin remodeling in stem tissues. Phylogenetic analyses of proteins in the cell wall proteome revealed an i...

Annals of Botany, 2001

The kinetic pattern of protein mobilization in roots, stolons and nodules of white clover (Trifol... more The kinetic pattern of protein mobilization in roots, stolons and nodules of white clover (Trifolium repens cv. Grasslands Huia) was studied over a regrowth period following complete defoliation. Defoliation led to a significant decrease in soluble protein in stolons and roots during the first days of regrowth as compared with uncut plants. Protein degradation was also observed in nodules of both uncut and defoliated plants. Two of the proteins characterized (15 and 17.3 kDa), which accumulate mainly in perennial tissues, have previously been referred to as Vegetative Storage Proteins (VSPs). Using plants inoculated with either efficient (potentially functional) or inefficient Rhizobium strains, the 15 kDa VSP appeared to be located exclusively in the nodules, and it cross-reacted positively with antibodies raised against soybean leghaemoglobin. Nevertheless, the kinetics of its hydrolysis-accumulation following defoliation clearly supported the view that it may play a role in nitrogen storage. The 17-3 kDa protein was shown to accumulate in response to exposure to low temperature, and exhibited a seasonal pattern of relative accumulation under field conditions. Results are discussed in terms of the putative role that this VSP may play in overwintering of clover.

The Plant Journal, 2006

† The first two authors contributed equally to this paper, and this work is the result of an equa... more † The first two authors contributed equally to this paper, and this work is the result of an equal collaboration between the laboratories of the last two authors.

Plant Science, 2011

Two pea lines (Pisum sativum L.) with contrasted behaviours towards chilling and subsequent frost... more Two pea lines (Pisum sativum L.) with contrasted behaviours towards chilling and subsequent frost were studied by a proteomic approach to better understand cold acclimation. Following a chilling period, the Champagne line becomes tolerant to frost whereas Terese remains sensitive. Variance analysis allowed to select 260 statistically variable spots with 68 identified proteins (35 in leaves, 18 in stems, and 15 in roots). These proteins were shared out in proteins related to chilling response or cold acclimation. The better adaptation of Champagne to chilling might be related to a higher content in proteins involved in photosynthesis and in defence mechanisms. Moreover Champagne might prevent freezing damage particularly thanks to a higher constitutive expression of housekeeping proteins related to Terese. After three days of subsequent frost, proteomes of previously chilled plants also showed significant differences compared to unchilled plants. Out of 112 statistically variable spots (44 in leaves, 38 in stems, and 30 in roots), 32 proteins were identified. These proteins were related to frost response or frost resistance. It seems that Champagne could resist to frost with the reorientation of the energy metabolism.

Physiologia Plantarum, 2007

The stolons of white clover (Trifolium repens L.) contain a predominant 17.3-kDa protein, previou... more The stolons of white clover (Trifolium repens L.) contain a predominant 17.3-kDa protein, previously characterized as a vegetative storage protein (VSP), which accumulates under autumn and winter conditions. Its full-length complementary DNA, TrVsp, was obtained and its 157 amino acid sequence deduced. This VSP has common characteristics to stress-responsive proteins (high neutral amino acid content and potential alpha helices in its secondary structure) and shows high homologies to abscisic acid-responsive and pathogenesis-related-10 proteins. The lack of any common amino acid sequence domains with known dehydrins or late embryogenesis abundant proteins suggests that clover VSP is not related to these proteins. Antibodies raised against the protein were produced and used in light and electron microscopic studies to show that it is localized to the cytosol of cortical parenchyma cells. This is in agreement with the VSP sequence, which does not contain any transit peptide signal. The accumulation of the transcript and the protein in roots is quickly induced by root chilling, suggesting a direct transcriptional regulation of TrVsp in response to low temperatures. Altogether, these results suggest that the 17.3-kDa protein may have an additional or alternative function to its role in nitrogen storage and may confer putative tolerance to chilling in white clover.

Journal of Plant Physiology, 2003

The ability of white clover (Trifolium repens L.) to undergo cold acclimation is an important det... more The ability of white clover (Trifolium repens L.) to undergo cold acclimation is an important determinant of its persistence in mixed swards since growth rate at low temperatures sustains higher clover contents at the start of spring. During a re-growth period following defoliation, a gradual exposure of the root system (cv. Grasslands Huia) led to some physiological and morphological changes of cold-adaptive significance, similar to those developed by clover ecotypes originating in northern areas of Europe. Thus, cold exposure of the root system resulted in small-leaved prostrate forms of white clover after one month of re-growth. Similarly, cold exposure increased the ability of plants to store nitrogen since the application of low temperatures to the root system enhanced soluble protein accumulation in roots and in stolons. More specifically, cold exposure of the roots induced gene expression of a vegetative storage protein (17.3 kDa VSP) in both organs. These results demonstrate that the root system of clover plants should be a site of perception of the low-temperature stimulus, and gave rise to the question of the transduction of the cold signal from the roots to the aerial parts. On the basis of this study and taking into account molecular aspects concerning the clover VSP, it is suggested that this protein could participate in cold acclimation in addition to its role in nitrogen storage.

Journal of Experimental Botany, 2002

The contribution of nitrogen reserves to regrowth following defoliation was studied in white clov... more The contribution of nitrogen reserves to regrowth following defoliation was studied in white clover plants (Trifolium repens cv. Huia). This was found to be closely linked to the morphological pattern of development of the aerial parts during the same period. Low temperature (6°C) and short day exposure (8 h photoperiod) were used to induce dwarf development, i.e. to increase branching rate and to enhance new sites of leaf production during a period of regrowth. Treated plants exhibited a large reduction in leaf area and a large increase in leaf pool size for the ®rst 10 d of a subsequent regrowth under standard culture conditions (16 h daylight; 22/18°C day/ night). The contribution of nitrogen from storage compounds in organs remaining after defoliation (sources) to regrowing tissues (sinks) was assessed by 15 N pulse±chase labelling during regrowth following shoot removal. The mobilization of nitrogen reserves from storage tissues of regrowing clover was closely linked to the pattern of differentiation of the newly developed organs. It appeared that regrowth was supported less by endogenous N for the ®rst 10 d after defoliation in treated plants, compared with control plants grown continuously in standard conditions. It is assumed that dwarf plants exhibit a lower dependence upon the mobilization of soluble proteins previously accumulated in roots and uncut stolons. The relationship between leaf development rate and N-uptake recovery following defoliation is discussed.

European Journal of Agronomy, 2004

The influence of cutting frequency was studied on white clover (Trifolium repens L.) cultivars (g... more The influence of cutting frequency was studied on white clover (Trifolium repens L.) cultivars (giant-Aran and dwarf-Rivendel) during two experiments set up under field conditions. Clover morphological and biochemical characteristics were measured prior to regrowth in response to various cutting interval treatments (1, 2, 3, 6 and 8 weeks of regrowth between two successive defoliations). The morphology of the aerial

Canadian Journal of Botany, 2003

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Frontiers in Plant Science, 2015

The primary objective of crop breeding is to improve yield and/or harvest quality while minimizin... more The primary objective of crop breeding is to improve yield and/or harvest quality while minimizing inputs. Global climate change and the increase in world population are significant challenges for agriculture and call for further improvements to crops and the development of new tools for research. Significant progress has been made in the molecular and genetic analysis of model plants. However, is science generating false expectations? Are &amp;amp;amp;#39;omic techniques generating valuable information that can be translated into the field? The exploration of crop biodiversity and the correlation of cellular responses to stress tolerance at the plant level is currently a challenge. This viewpoint reviews concisely the problems one encounters when working on a crop and provides an outline of possible workflows when initiating cellular phenotyping via &amp;amp;amp;quot;-omic&amp;amp;amp;quot; techniques (transcriptomics, proteomics, metabolomics).