Somatic embryogenesis and glucosinolate/myrosinase system in vulnerable Brassica repanda subsp. glabrescens (Poldini) Gómez-Campo

• Direct and indirect somatic embryogenesis of Brassica repanda subsp. glabrescens were developed.
• Leaves and whole plantlets are the better sources for in vitro responses.
• Sucrose controls the embryo development and shoot/root ratio.
• In the regenerated plantlets the glucosinolate/myrosinase system was operative.

The present study describes direct and indirect somatic embryogenesis of Brassica repanda subsp. glabrescens recognized as ‘vulnerable’ at the European level. Leaf and root explants, and whole seedlings have been subjected to plant growth regulator treatments. After 6 weeks of culture the same number of explants (leaves, roots, whole plantlets) was subcultured in part on the same medium and in part on hormone-free medium. Somatic embryogenesis via callus was obtained from leaf and root explants. The highest number of embryos was obtained in the calli developed in the medium with 1 mg l−1 6-benzylaminopurine (BAP) and 1 mg l−1 naphthaleneacetic acid (NAA), and subcultured in medium without hormones. The number of embryos per callus was significantly higher (52 vs. 20) in leaf derived calli. Direct somatic embryogenesis was obtained from whole plantlets cultured in 1 mg l−1 BAP with 1 or 2 mg l−1 NAA and subcultured both in medium with or without hormones. The number of embryos per plantlet was comparable to the highest number obtained in leaf derived calli. Mature embryos developed the characteristic rosette shoots and strong roots were obtained in low sucrose regime (2 g l−1), circa 63% of the plantlets survived to the acclimatization process. In leaves from in vivo and in vitro regenerated plantlets, and in seeds of native plants glucosinolates were present and the myrosinase system was operative. The regeneration protocols developed in this study provide a basis for germplasm conservation and for further investigation on the glucosinolate metabolism of this rare species.