Efficient somatic embryogenesis in sugar beet (Beta vulgaris L.) breeding lines

Abstract

Efficient regeneration via somatic embryogenesis (SE) would be a valuable system for the micropropagation and genetic transformation of sugar beet. This study evaluated the effects of basic culture media (MS and PGo), plant growth regulators, sugars and the starting plant material on somatic embryogenesis in nine sugar beet breeding lines. Somatic embryos were induced from seedlings of several genotypes via an intervening callus phase on PGo medium containing N 6 -benzylaminopurine (BAP). Calli were mainly induced from cotyledons. Maltose was more effective for the induction of somatic embryogenesis than was sucrose. There were significant differences between genotypes. HB 526 and SDM 3, which produced embryogenic calli at frequencies of 25-50%, performed better than SDM 2, 8, 9 and 11. The embryogenic calli and embryos produced by this method were multiplied by repeated subculture. Histological analysis of embryogenic callus cultures indicated that somatic embryos were derived from single-or a small number of cells. 2,4-dichlorophenoxyacetic acid (2,4-D) was ineffective for the induction of somatic embryogenesis from seedlings but induced direct somatic embryogenesis from immature zygotic embryos (IEs). Somatic embryos were mainly initiated from hypocotyls derived from the cultured IEs in line HB 526. Rapid and efficient regeneration of plants via somatic embryogenesis may provide a system for studying the molecular mechanism of SE and a route for the genetic transformation of sugar beet.

Evaluation of the potential for somatic embryogenesis in sugar beet (Beta vulgaris L.) breeding lines and improvement of regeneration efficiency

“…The frequencies of somatic embryo formation were previously shown to vary among genotypes in sugar beet cultivars and breeding lines (Abe et al 1991;Doley and Saunders 1989;Saunders and Shin 1986;Zhang et al 2008), so these results may reflect genetic differences, as we hypothesized for the callus formation. There was no significant correlation between PEC and PSE (r=0.15; Figure 4).…”

“…We found that PEC varied widely, ranging from 0 to 88.9%, with relatively continuous variation (Table 1). It was previously recognized that the frequencies of embryogenic callus formation in sugar beet cultivars and breeding lines depended on the kinds of explants that were used (Roussy et al 1996;Zhang et al 2004) or their genotypes (Abe et al 1991;Doley and Saunders 1989;Saunders and Shin 1986;Yu 1989;Zhang et al 2004Zhang et al , 2008. These results may reflect differences in the levels of endogenous plant hormones in the explants or in various genetic factors that control callus formation in the breeding lines.…”

“…The development of an efficient plant regeneration system that can be applied to a wide range of sugar beet genotypes is a prerequisite for utilizing such genetic transformation techniques. Many researchers have reported procedures for the induction of adventitious shoot regeneration and somatic embryogenesis in sugar beet cultivars and breeding lines (Abe et al 1991;Dovzhenko and Koop 2003;Freytag et al 1988;Jacq et al 1992; Krens and Jamar 1989;Roussy et al 1996;Saunders and Daub 1984;Saunders and Shin 1986;Saunders and Tsai 1999;Tétu et al 1987;Tsai and Saunders 1995;Zhang et al 2001Zhang et al , 2004Zhang et al , 2008. Regeneration via somatic embryogenesis is regarded as a promising pathway for Agrobacterium-mediated transformation to avoid the production of genetic chimeras, because a somatic embryo is assumed to be derived from a single callus cell (Zhang et al 2008).…”

Advances in Somatic Embryogenesis Research of Horticultural Plants

“…For example, the immature embryos and cotyledons of peach (Prunus persica L.) [4], the young embryos of cherry (Prunus avium L.) [5], the leaves of apple (Malus pumila Mill.) [6], the embryos of sugar beet (Beta vulgaris L.) [7], the young leaves of Bartlett (Pyrus communis L.) [8], the flowers of chrysanthemum (Dendranthema morifolium) [9], the leaves of carnation (Dianthus caryophyllus L.) [10] (Yantcheva A. et al, 1998), the scale leaves of lily (Lilium brownii var. viridulum) [11], the tender leaf of Kalanchoe blossfeldiana [12], and the leaves of Alaenopsis orchid [13] could all induce the somatic embryos to form regeneration plants.…”

Establishment of a tissue culture system for somatic embryogenesis from germinating embryos of Arabidopsis thaliana

“…Furthermore, natural variations in Arabidopsis have been used extensively for molecular genetic studies of developmental and physiological processes (Alonso-Blanco et al 2009;Koornneef et al 2004 collection and used for quantitative trait loci analysis of seed germinability (Meng et al 2008), flowering time (Werner et al 2005), light sensitivity (Maloof et al 2001), and leaf architecture (Pérez-Pérez et al 2002). Because somatic embryogenesis is strongly influenced by genotype in many plant species (Brown and Atanassov 1985;Hiraga et al 2007;Sharma and Rajam 1995;Zhang et al 2008), characterization of Arabidopsis accessions with differing capacities for somatic embryos is helpful for investigating molecular mechanisms of somatic embryogenesis. RIKEN BioResource Center preserves over 340 natural accessions collected worldwide and is characterizing morphological and physiological properties of all individual accessions.…”