Immature Seeds and Embryos of Medicago truncatula Cultured In Vitro

Abstract

Legumes are an important source of proteins and lipids for food and feed. In addition, they are -environmentally friendly because of their capacity to fix nitrogen through a symbiosis with Rhizobium that permits them to produce abundant proteins even in the absence of nitrogen fertilization. Seed development in plants follows three chronological steps (1) seed coat differentiation, embryo morphogenesis and endosperm development; (2) embryo maturation with storage accumulation and (3) dehydration and the acquisition of desiccation tolerance. Finally, germination occurs when the environmental conditions become favourable. Working with the model legume Medicago truncatula, an in vitro protocol was developed for the culture of immature embryos that permits their development in a way comparable to that observed in plants.In this chapter, the usefulness of this system for investigating embryo development in legumes is outlined.

Protocols for Obtaining Zygotic and Somatic Embryos for Studying the Regulation of Early Embryo Development in the Model Legume <em>Medicago truncatula</em>

“…We recognize that there are advantages and disadvantages of both in vivo and in vitro approaches. Both allow more focus on early embryogenesis compared to culture of immature seeds 19 .…”

Agroecological impact of an in vitro biotechnology approach of embryo development and seed filling in legumes

“…The pods of M. truncatula are abundantly set in the absence of insect pollination and contain up to 12 seeds, where basal seeds develop faster than distal ones (Journet et al 2001;Gallardo et al 2006a, b;Ochatt 2011;Atif et al 2013a, b). Mature pods are compact spiky coils, which remain indehiscent (Garcia et al 2006;Gallardo et al 2006a, b;Ochatt 2011).…”

“…The pods of M. truncatula are abundantly set in the absence of insect pollination and contain up to 12 seeds, where basal seeds develop faster than distal ones (Journet et al 2001;Gallardo et al 2006a, b;Ochatt 2011;Atif et al 2013a, b). Mature pods are compact spiky coils, which remain indehiscent (Garcia et al 2006;Gallardo et al 2006a, b;Ochatt 2011). Besides its use as a forage crop, M. truncatula is phylogenetically close to the widely cultivated legumes pea and faba bean (Bataillon and Ronfort 2006), and closely related to alfalfa, Medicago sativa, which is a tetraploid, outcrossing species with low selffertility (Barker et al 1990).…”

“…Moreover, interactions of plants with symbionts, i.e. Sinorhizobium meliloti and Glomus spp., pests and pathogens can be investigated (Gallardo et al 2006a, b;Rose 2008;Parádi et al 2010;Ochatt 2011).…”

“…Seed development and storage protein accumulation follow a similar pattern as in the major grain legumes, and its use for genomic studies of seed development and for analysis of seed filling in grain legumes is fully adequate (Gallardo et al 2006a, b;Rose 2008;Ochatt 2011;Atif et al 2013a, b). Mature seeds of M. truncatula consist mainly of the embryo and of a persistent endosperm of up to 10 % of the final seed mass, whereas mature seeds of pea or faba bean comprise mainly the embryo (Ochatt 2011;Gallardo et al 2006a, b;Verdier et al 2013).…”