INRA-URLEG,BP 86510,21065 Dijon cedex,FranceMini-biographySergio OCHATT, agronomist, PhD, HDR. Heads the Cell Physiology, Morphogenesis and Validation team (PCMV) at URLEG from INRA Research Center of Dijon (France) since 1998. Chairman of COST Action 843 (
www.cost843.org, 1999-2005) and FAO expert on development of biotechnological plant breeding. Over 100 publications and several book chapters, has attended as many congresses and been an invited speaker 20 times. Associate Editor of Plant Cell Tissue Organ Culture, Referee of several journals, has co-edited two books. Having worked on fruit tree biotechnology until 1995 and on protein legumes since then, some landmark results include:
- plant regeneration from protoplasts,
- somatic hybridisation (fruit trees, legumes)
- demonstration of role of electricity on DNA synthesis and regeneration competence of cells
- production of drought/salt resistant genotypes,
- acceleration of generation cycles in vitro,
- haplo-diploidisation (mustard, asparagus, onion, pea),
- elucidation of genetic basis of hyperhydricity in vitro
- flow cytometry characterization of a range of species
- gene mapping of brown mustard
- identification of markers of embryogenesis in vitro (legumes, Arabidopsis)
Towards the efficient doubled haploidy of peaSergio Ochatt
URLEG, C.R. Dijon, INRA, 21110 Bretenière, France
ochatt@epoisses.inra.frHaploids have the same chromosome complement as the gametes of the species. Following chromosome doubling, doubled haploids (DHs), being homozygous in all their loci, can be useful as parental genotypes for breeding but also per se. DH research in plants is not new but, even if many species have been studied so far, haploid plants have not been obtained for all of them. With legumes (described as recalcitrant to this approach), despite an early encouraging report (never reproduced to date) for pea, recent communications underline a lack of success in this domain. The process, called androgenesis, is based on culture of male organs (anthers) or gametes (microspores). Under certain conditions, microspores can shift development from gametophytic to sporophytic to form embryos. Inducing divisions and cell differentiation to produce such embryos is modulated by several factors including genotype, growth conditions of donor plants, developmental stage of microspores, pre-treatment of flower buds, culture medium, etc. Thus, the positive effects of modifying the osmotic pressure on androgenesis responses have already been observed, and electroporation of isolated cells and microspores has already induced a significant improvement in regeneration competence of many species. Against this background, we studied the induction of embryogenesis from isolated microspores and anthers of various pea, grass pea and Medicago truncatula genotypes. Only three other groups carry out research in this domain (SARDI and CLIMA in Australia, and the University of Saskatoon in Canada), with pea, chickpea and vetch, all concentrating mainly on isolated microspore culture, having found the culture of anthers unresponsive. In our microspore culture studies, a combination of osmotic and electric shocks significantly improved responses and 10-15% microspores reproducibly yielded microcalluses and calluses, but only a few underwent morphogenesis. When a similar strategy was applied to anthers, calluses were for the first time obtained from them. Upon culture, some gave somatic embryos and buds, confirmed as haploid by flow cytometry and chromosome counts, but only a few DH plants survived colchicine chromosome doubling and only for pea and grass pea. Although meagre, this result represents to our knowledge the first success in DH plant production for these species. Having worked with homozygous genotypes as starting material, it needs further genetic confirmation of the true DH nature of regenerants. Further studies are under way to improve responses and to extend them to other genotypes.
