Conservation and Reproduction of Forest Trees Team (CORE) - "Study of the physiological and molecular determinism of the somatic embryogenesis of conifers in a changing environment".
Tel : +33 (0)2.38.41.78.00
Email : marie-anne.lelu-walter@inrae.fr
Current Position
- Research Director at INRAE (Institute for Agriculture, Food, and Environment)
- Unit: UMR BioForA, INRAE-ONF (Integrated Biology for the valorisation of trees and forest diversity)
- Department ECODIV (Ecology and Biodiversity of forest, grassland and freshwater ecosystems)
- In charge of lecture/teaching at University of Orléans.
Education and Work Experience
- 1995: HDR (Habilitation to Direct scientific Research), University of Orléans.
- 1988-1989: Post-Doctoral position at Hilleshög Laboratory, Sweden, Prof C Bornman: “induction of somatic embryogenesis in Picea sp. (P. mariana, P. glauca, P. abies) from excised cotyledons of young plants”
- 1985-1987: PhD AFOCEL Nangis France, Drs A Franclet, M Boulay: “Somatic embryogenesis in Picea abies from excised cotyledons of young plants”,
- 1984: DEA/ Master II Establishments Clause France: “Androgenesis in Brassica sps.”
Research Topics
Reproduction, Conservation of forest genetic resources in climate change
- Physiology of conifer embryo development (somatic vs zygotic)
- Aptitude to somatic embryogenesis
- Cryopreservation of conifer embryonal masses
- Integration of conifer somatic embryogenesis into breeding program
Functions, Animations, Previous missions
- Research Missions to Canada (7.5 months/ Ontario1991-1992, Québec 1995-1996); New Zealand (1 month, 2012)
- Involved in cooperation network and people exchange with Canada, Czech Republic, Poland and New Zealand; PI in 7 EU projects, 11 international projects (coordinator in 6), in 15 national projects (coordinator in 7).
- Organization of Cost Eurosilva meeting E6 Working Group1 "Advances on somatic embryogenesis in forest trees" (1998, 45 participants from 17 countries)
- Associate Editor of In Vitro Cell Dev. Biol.Plant, Propagation of Ornamental Plants. Reviewer of many other International Journals.
- Invited speaker: 1995 Montréal Canada; 1996 Malmö Sweden; 1998 Prague Czech Rep.; 1999 Univ. Laval Canada; 2015 Suwon South Chorea; 2016 La Plata Argentine (Key note speaker); 2017 Univ. Harbin China
Supervision
27 students including 7phD
Recent phD students:
- Florian Gautier (2017): Capacity of Douglas (Pseudostuga menziesii) to embryogenesis: cellular and molecular physiology approaches through proteome and transcriptome analysis, Univ. Limoges.
- Alexandre Morel (2014): Molecular physiology of somatic embryo development of maritime pine (Pinus pinaster Ait.): transcriptomic and protéomic approaches, Univ Orléans.
Expertise/Activities
Dr Lelu-Walter has expertise in the biotechnologies of forest trees, in particular conifer species. Clonal propagation method such as somatic embryogenesis has been developed for the production of a large number of genetically improved plants (Lelu-Walter et al 2013*; Klimaszewska et al 2016). Dr Lelu-Walter contributed to pioneering work on induction of somatic embryogenesis from older material than immature zygotic embryos of Picea sp. (phD 1987, Lelu et al 1987*; Lelu and Bornman 1990*, Lelu et al 1990*) and Larix sp. (Lelu et al 1994*). Over the past 30 years Dr Lelu-Walter has been developed somatic embryogenesis of Picea, Larix species especially hybrid larch, becoming a model system for conifer species (Lelu-Walter and Pâques 2009*, Lelu-Walter et al 2016a). Anatomical studies (von Aderkas et al. 2015), proteomic and methylation analyses (Teyssier et al 2011*, 2014) have been carried out allowing a better understanding of the process. Since 1998, Dr Lelu-Walter’s somatic embryogenesis research has been on Pinus pinaster and P. sylvestris, both economically important to forest industry in France and Europe (Lelu-Walter et al 2016b). In maritime pine, early physiological, cellular and molecular mechanisms (transcriptomic, proteomic levels) controlling somatic embryo differentiation have been studied (Morel et al 2014a). Finally, cotyledonay somatic embryo appeared very similar to fresh cotyledonary zygotic embryo, proteome profiling further confirmed high similarity (94.5%) between them (Morel et al 2014b). Recently, Dr Lelu-Walter successfully improved somatic embryogenesis of Pseudotsuga menziesii an important conifer species in Europe (Lelu-Walter et al 2018, Reeves et al 2018). Repetitive somatic embryogenesis dramatically improved the proliferating lines’ cellular organization (Gautier et al 2018). Integrated multi-scale transcriptomic, proteomic, biochemical, histological and anatomical analyses have been carried out to obtain insights into molecular events associated with embryogenesis and more specifically to the embryogenic state of cell in Douglas-fir. Sub-Network Enrichment Analyses highlighted functions and interactions between transcripts and proteins (Gautier et al 2019).
Dr Lelu-Walter has also been developed a simplified method for the cryopreservation of embryogenic cultures of both Larix and Pinus species.
Genetic engineering constitutes a powerful tool for breeding and research (to study tree physiology via gene regulation, Trontin et al 2016a). Since 1994, Dr Lelu-Walter contributed to pioneering work on genetic transformation of Larix via Agrobacterium tumefaciens (Levée et al 1997*, Lelu and Pilate 2000*) resulting for the first time in the establishment of an optimised transformation procedure for a conifer species that has been successfully transferred to Picea sp. (Klimaszewska et al. 2001*) and applied for physiological studies (Gleeson et al. 2005*, Rincon et al. 2005*, Mathieu et al. 2006*, Guillaumot et al. 2008*).
* Gleeson D, Lelu-Walter MA, Parkinson M (2005) Overproduction of proline in transgenic hybrid larch (Larix x leptoeuropaea (Dengler)) cultures renders them tolerant to cold, salt and frost. Mol Breeding, 15, 21-29.
* Guillaumot D, Lelu-Walter MA, Germot A, Meytraud F, Gastinel L, Riou-Khamlichi C (2008) Expression patterns of LmAP2L1 and LmAP2L2 encoding two-APETALA2 domain proteins during somatic embryogenesis and germination of hybrid larch (Larix x marschlinsii). J. Plant Physiol., 165, 1003-1010.
*Klimaszewska K, Lachance D, Pelletier G, Lelu MA, Séguin A (2001) Regeneration of transgenic Picea glauca, P. mariana, and P. abies after cocultivation of embryogenic tissue with Agrobacterium tumefaciens. In Vitro Cell Dev Biol. 748-755.
*Lelu MA (1987) Somatic embryogenesis of Picea abies L. Karst. from excised cotyledons of young plants. PhD University Pierre, Marie Curie, Paris VI, 126p.
* Lelu MA, Pilate G (2000) Transgenic in Larix. Dans Molecular Biology of Woody Plant, Vol. 2, S.M. Jain et S.C. Minocha éditeurs, Kluwer Academic Publishers, the Netherlands, 119-134.
Lelu-Walter MA, Pâques L (2009) Simplified and improved somatic embryogenesis of hybrid larches (Larix x eurolepis and Larix x marschlinsii). Perspectives for breeding. Annals of For Sci, 66, 104p1-104p10.
*Lelu MA, Boulay M Arnaud Y (1987) Obtention de cals embryogènes à partir de cotylédons de Picea abies (L.) Karst. prélevés sur de jeunes plantes âgées de 3 à 7 jours après germination. C.R.Acad. Sci. Paris, t.305, Série III, 105-109.
*Lelu MA, Bornman CH (1990) Induction of somatic embryogenesis in excised cotyledons of Picea glauca and Picea mariana. Plant Physiol. Biochem., 28, 785-791.
*Lelu MA, Boulay M, Bornman CH (1990) Somatic embryogenesis in cotyledons of Picea abies is enhanced by an adventitious bud-inducing treatment. New Forest, 4, 125-135.
*Lelu M.A., Klimaszewska K, Charest P (1994) Somatic embryogenesis from immature and mature zygotic embryos and from cotyledons and needles of somatic plantlets of Larix. Can. J. For. Res. 24, 100-106.
*Levée V, Lelu MA, Jouanin L, Cornu D, Pilate G (1997) Agrobacterium tumefaciens-mediated transformation of hybrid larch (Larix kaempferi x L. decidua) and transgenic plant regeneration. Plant Cell Reports, 16, 680-685.
* Lelu-Walter MA, Thompson D, Harvengt L, Sanchez L, Toribio M, Pâques LE (2013) Somatic embryogenesis in forestry with a focus on Europe: state-of-the-art, benefits, challenges and future direction. Tree Genet Genomes, 9, 883-899.
* Mathieu M, Lelu-Walter MA, Blervacq AS, David H, Hawkins S, Neutelings G (2006) Germin-like genes are expressed during somatic embryogenesis and early development of conifers. Plant Mol Biol 61:4-5:615-627.
* Rincon A, Priha O, Lelu-Walter MA, Sotta B, Le Tacon F (2005) Shoot water status and ABA responses of transgenic hybrid larch Larix kaempferi x L. decidua to ectomycorrhizal fungi and osmotic stress. Tree Physiology, 25, 1101-1108.
* Teyssier C, Grondin C, Bonhomme L, Lomenech A-M, Vallance M, Morabito D, Label P, Lelu-Walter MA (2011) Increased gelling agent concentration promotes somatic embryo maturation in hybrid larch (Larix x eurolepis): a 2- DE proteomic analysis. Physiol Plant 141, 152-165.
Publications
