Somatic embryogenesis in Crambe abyssinica Hochst. ex R.E. Fries using seedling explants

Abstract

Somatic embryogenesis in Crambe abyssinica, an important industrial oilseed species, was investigated. Cotyledon, hypocotyl and root explants from 8-day-old seedlings of C. abyssinica cv. Prophet were cultured with levels of 1-naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) ranging from 2.2 to 39.0 lM, combined with 6-benzyladenine (BA) to achieve an auxin:cytokinin ratio of 20:1, and callus formation assessed. Callus formation frequency for cotyledon and hypocotyl explants was 100% for levels of 2,4-D from 4.5 to 33.9 lM. The response was similar with NAA levels of 13.0 to 39.0 lM. Root explants were less responsive. When calluses were transferred to a medium containing 0.56 lM each of thidiazuron and BA with 1.0 lM indole-3-butyric acid (IBA), somatic embryos were induced. Moreover, embryos were induced from calluses grown on media containing either 11.3 lM 2,4-D or 13.0 lM NAA, or higher. On a medium without plant growth regulators, embryos were induced but at a much lower frequency. For all three explants, 22.6 lM 2,4-D and 26.0 lM NAA was optimal for embryogenic callus induction. Hypocotylderived calluses were superior to cotyledon-and rootderived calluses for embryo induction. The best embryo formation response was with medium containing 5.0-6.0% sucrose. The highest average number of embryos per callus (36) was obtained from hypocotyl calluses from medium with 22.6 lM 2,4-D. Somatic embryos germinated best on half-strength B5 or MS medium with 3% sucrose, and plantlets were successfully established under greenhouse conditions. The results indicate that high levels of auxins are required for the induction of embryogenic calluses from explants of C. abyssinicia, while cytokinins are critical for somatic embryo formation.

Micropropagation of Crambe Abyssinica Hochst. Ex R.E. Fr.

“…With regards to the micropropagation, different parts of the plant have been used as explant, for instance hypocotyls (Li et al, 2010(Li et al, , 2011Palmer and Keller, 2011;Chhikara et al, 2012), cotyledons (Palmer and Keller, 2011;Chhikara et al, 2012), root (Palmer and Keller, 2011;Chhikara et al, 2012) and cells in culture (protoplasts) (Gao et al, 1998), with only the protocol developed by Li et al (2011) obtaining a satisfactory rate of shoot regeneration, of 95%. Although a great number of genetically identical plants can be regenerated by means of micropropagation, some somaclonal variations can be detected (Miguel and Marum, 2011;Pathak and Dhawan, 2012), which in turn depend on various factors, among which the type of explant used should be considered (Leela et al, 2011).…”

Leaf anatomy of Crambe abyssinica Hochst. during in vitro shoot induction

“…Its seeds contain 45 to 50% of crude protein and up to 35% of oil, which consists of up to 55 to 60% of erucic acid (Palmer and Keller, 2011). Such characteristics make it highly valuable for animal feed, industrial and pharmaceutical applications, biodiesel production, as well as fabrication of coatings, detergents, gliding products, cosmetics, lubricants and nylon (Vargas-Lopez et al, 1999;Capelle and Tittonel, 1999;Palmer and Keller, 2011).…”

Genetic stability of micropropagated plants of Crambe abyssinica Hochst using ISSR markers

“…In this context, in vitro cell and tissue culturing techniques are important both for mass propagation Li et al, 2011;Palmer and Keller, 2011;Chhikara et al, 2012) and as a tool for genetic improvement (Wang et al, 2004;Wang et al, 2006).…”

“…Micropropagation studies have documented crambe regeneration in vitro via direct Li et al, 2011) and indirect organogenesis (Chhikara et al, 2012), using hypocotyls as explants for both, and via indirect somatic embryogenesis (Palmer and Keller, 2011) with cotyledons, hypocotyls, and roots as explants. However, no published data describe crambe regeneration using apical segments via multiplication by axillary bud proliferation.…”

“…Crambe tissue culturing has been used to propagate (Li et al, 2011;Palmer and Keller, 2011), genetically improve Chhikara et al, 2012;Li et al, 2013), and to identify and use some of its genes to improve other species (Wang et al, 2004;Wang et al, 2006). The use of molecular markers in crambe reported in the literature is limited to the study of genetic diversity (Lara-Fioreze et al, 2013), identification and characterization of genetic transformants (Wang et al, 2004;Wang et al, 2006;Li et al, 2010;Xu et al, 2010;Chhikara et al, 2012;Li et al, 2013), and identification of genes of interest (Paulose et al, 2010;Cheng et al, 2013).…”