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Marc Behr

Bio: Marc Behr is an academic researcher from Université libre de Bruxelles. The author has contributed to research in topics: Bast fibre & Secondary cell wall. The author has an hindex of 13, co-authored 34 publications receiving 538 citations. Previous affiliations of Marc Behr include Université catholique de Louvain & Behr.

Papers
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TL;DR: This work sheds light on how, in the growing hemp hypocotyl, the provision of the precursors needed to synthesize the aromatic biomolecules lignin and lignans is regulated at the transcriptional and proteomic level.
Abstract: Lignin and lignans are both derived from the monolignol pathway. Despite the similarity of their building blocks, they fulfil different functions in planta. Lignin strengthens the tissues of the plant, while lignans are involved in plant defence and growth regulation. Their biosyntheses are tuned both spatially and temporally to suit the development of the plant (water conduction, reaction to stresses). We propose to study the general molecular events related to monolignol-derived product biosynthesis, especially lignin. It was previously shown that the growing hemp hypocotyl (between 6 and 20 days after sowing) is a valid system to study secondary growth and the molecular events accompanying lignification. The present work confirms the validity of this system, by using it to study the regulation of lignin and lignan biosynthesis. Microscopic observations, lignin analysis, proteomics, together with in situ laccase and peroxidase activity assays were carried out to understand the dynamics of lignin synthesis during the development of the hemp hypocotyl. Based on phylogenetic analysis and targeted gene expression, we suggest a role for the hemp dirigent and dirigent-like proteins in lignan biosynthesis. The transdisciplinary approach adopted resulted in the gene- and protein-level quantification of the main enzymes involved in the biosynthesis of monolignols and their oxidative coupling (laccases and class III peroxidases), in lignin deposition (dirigent-like proteins) and in the determination of the stereoconformation of lignans (dirigent proteins). Our work sheds light on how, in the growing hemp hypocotyl, the provision of the precursors needed to synthesize the aromatic biomolecules lignin and lignans is regulated at the transcriptional and proteomic level.

138 citations

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TL;DR: A transcriptomic close-up of the key events accompanying bast fibre development in textile hemp, a fibre crop of great importance, shows that the fibres sampled at each stem region are characterized by a specific transcriptomic signature and that the major changes in cell wall-related processes take place at the internode containing the snap point.
Abstract: Bast fibres are long extraxylary cells which mechanically support the phloem and they are divided into xylan- and gelatinous-type, depending on the composition of their secondary cell walls. The former, typical of jute/kenaf bast fibres, are characterized by the presence of xylan and a high degree of lignification, while the latter, found in tension wood, as well as flax, ramie and hemp bast fibres, have a high abundance of crystalline cellulose. During their differentiation, bast fibres undergo specific developmental stages: the cells initially elongate rapidly by intrusive growth, subsequently they cease elongation and start to thicken. The goal of the present study is to provide a transcriptomic close-up of the key events accompanying bast fibre development in textile hemp (Cannabis sativa L.), a fibre crop of great importance. Bast fibres have been sampled from different stem regions. The developmental stages corresponding to active elongation and cell wall thickening have been studied using RNA-Seq. The results show that the fibres sampled at each stem region are characterized by a specific transcriptomic signature and that the major changes in cell wall-related processes take place at the internode containing the snap point. The data generated also identify several interesting candidates for future functional analysis.

55 citations

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TL;DR: Postbloom horizontal cluster division can be recommended as an efficient crop cultural tool for premium wine production under cool-climate conditions and is able to loosen the cluster structure and reduce the bunch rot disease severity.
Abstract: Manual horizontal cluster division may constitute an efficient tool to optimize wine composition. To test this hypothesis and to determine the optimal timing of this viticultural practice, the impact of cluster division on cluster morphology, bunch rot disease severity, and harvest parameters such as yield and total soluble solids was examined on the white Vitis vinifera L. cultivars Pinot gris and Riesling in the Luxembourgish winegrowing region in 2010 and 2011. Treatments were applied at five different times between prebloom (BBCH 57) and veraison (BBCH 81). In both varieties, all postbloom cluster division treatments were able to loosen the cluster structure and reduce the bunch rot disease severity. The later cluster division took place, the more pronounced were the effects on cluster structure. The density index was a suitable measure of the cluster structure and the predisposition to bunch rot infestation. Cluster division resulted in yield reductions (up to 30%), which increased with time after flowering. Postbloom cluster division may help to optimize wine quality by improving grape maturity due to crop load reduction, reducing fungal contamination, and improving grape composition through the possibility of elongating the ripening period. Postbloom horizontal cluster division can be recommended as an efficient crop cultural tool for premium wine production under cool-climate conditions.

52 citations

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TL;DR: A targeted approach has been used here to study the expression of cell wall-related genes in different organs of alfalfa plants subjected for four days to three different abiotic stress treatments, namely salt, cold and heat stress.
Abstract: Abiotic constraints are a source of concern in agriculture, because they can have a strong impact on plant growth and development, thereby affecting crop yield. The response of plants to abiotic constraints varies depending on the type of stress, on the species and on the organs. Although many studies have addressed different aspects of the plant response to abiotic stresses, only a handful has focused on the role of the cell wall. A targeted approach has been used here to study the expression of cell wall-related genes in different organs of alfalfa plants subjected for four days to three different abiotic stress treatments, namely salt, cold and heat stress. Genes involved in different steps of cell wall formation (cellulose biosynthesis, monolignol biosynthesis and polymerization) have been analyzed in different organs of Medicago sativa L. Prior to this analysis, an in silico classification of dirigent/dirigent-like proteins and class III peroxidases has been performed in Medicago truncatula and M. sativa. The final goal of this study is to infer and compare the expression patterns of cell wall-related genes in response to different abiotic stressors in the organs of an important legume crop.

44 citations

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TL;DR: This study focuses on the mechanisms marking the transition from primary to secondary growth in the hemp hypocotyl by analysing the suite of events accompanying vascular tissue and bast fiber development by transcriptomics, imaging and quantification of phytohormones.
Abstract: Cannabis sativa L. is an annual herbaceous crop grown for the production of long extraxylary fibers, the bast fibers, rich in cellulose and used both in the textile and biocomposite sectors. Despite being herbaceous, hemp undergoes secondary growth and this is well exemplified by the hypocotyl. The hypocotyl was already shown to be a suitable model to study secondary growth in other herbaceous species, namely Arabidopsis thaliana and it shows an important practical advantage, i.e. elongation and radial thickening are temporally separated. This study focuses on the mechanisms marking the transition from primary to secondary growth in the hemp hypocotyl by analysing the suite of events accompanying vascular tissue and bast fiber development. Transcriptomics, imaging and quantification of phytohormones were carried out on four representative developmental stages (i.e. 6-9-15-20 days after sowing) to provide a comprehensive overview of the events associated with primary and secondary growth in hemp. This multidisciplinary approach provides cell wall-related snapshots of the growing hemp hypocotyl and identifies marker genes associated with the young (expansins, β-galactosidases and transcription factors involved in light-related processes) and the older hypocotyl (secondary cell wall biosynthetic genes and transcription factors).

43 citations


Cited by
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Wilhelm Rademacher1
TL;DR: Plant growth regulators are widely used in modern agriculture, horticulture and viticulture and the achieved benefits range from facilitating crop management to increasing and securing yield and quality of the harvested produce and improving its storage and shelf life.
Abstract: Plant growth regulators are widely used in modern agriculture, horticulture and viticulture. “True” plant growth regulators interfere directly with the plant’s hormonal status. They are represented by plant hormones or their synthetic analogs, by inhibitors of hormone biosynthesis or translocation and by hormone receptor blockers. “Atypical” plant growth regulators act by displaying a local and/or transient phytotoxic effect. Approximately 40 active ingredients are in use, applied either as a single component or as combinations. Many plant developmental processes can be actively regulated in cultivated plants, for example, acceleration or delay of seed germination, dormancy breaking in woody perennials, stimulation or reduction of shoot elongation, induction of flowering and fruiting, reduction or increase of fruit set, acceleration or delay of senescence processes including fruit ripening and defoliation. The achieved benefits range from facilitating crop management to increasing and securing yield and quality of the harvested produce and improving its storage and shelf life. Systematic use of plant growth regulators started in the 1930s. Current global annual sales are in the range of US$ 1.2 billion.

303 citations

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TL;DR: In this paper, the effects of heavy metal-induced reactive oxygen species (ROS) on plant cell wall-related processes and the stimulatory/inhibitory effects of ROS on plant secondary metabolism were investigated.

254 citations

Journal ArticleDOI
TL;DR: In this article, the authors predicted that climate change is anticipated to exacerbate these recent trends on suitability for wine production, while wine typicity may also be threatened in most cases.
Abstract: Viticulture and winemaking are important socioeconomic sectors in many European regions. Climate plays a vital role in the terroir of a given wine region, as it strongly controls canopy microclimate, vine growth, vine physiology, yield, and berry composition, which together determine wine attributes and typicity. New challenges are, however, predicted to arise from climate change, as grapevine cultivation is deeply dependent on weather and climate conditions. Changes in viticultural suitability over the last decades, for viticulture in general or the use of specific varieties, have already been reported for many wine regions. Despite spatially heterogeneous impacts, climate change is anticipated to exacerbate these recent trends on suitability for wine production. These shifts may reshape the geographical distribution of wine regions, while wine typicity may also be threatened in most cases. Changing climates will thereby urge for the implementation of timely, suitable, and cost-effective adaptation strategies, which should also be thoroughly planned and tuned to local conditions for an effective risk reduction. Although the potential of the different adaptation options is not yet fully investigated, deserving further research activities, their adoption will be of utmost relevance to maintain the socioeconomic and environmental sustainability of the highly valued viticulture and winemaking sector in Europe.

210 citations

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TL;DR: How addressing limitations in plant biology will help advance the knowledge of plant biology and enable us to fully domesticate and maximize the agronomic potential of this promising crop is reviewed.

184 citations