Regeneration of banana (Musa spp. AAB cv. Dwarf Brazilian) via secondary somatic embryogenesis

Abstract

A method has been developed for the regeneration of the banana cultivar Dwarf Brazilian (Musa spp. AAB group). Primary somatic embryos were produced when explants of immature male flower buds were cultured on Murashige and Skoog (MS) medium plus 1 mg/l biotin, 100 mg/l malt extract, 100 mg/l glutamine, 4 mg/l 2,4-dichlorophenoxyacetic acid, 1 mg/l indole-3-acetic acid (IAA), 1 mg/l α-naphthaleneacetic acid, 30 g/l sucrose and 2.6 g/l Phytagel, pH 5.8 (M1 medium) and then transferred to M1 medium plus 200 mg/l casein hydrolysate and 2 mg/l proline. Subsequent transfer to MS supplemented with 10% coconut water produced rapidly proliferating embryogenic callus that developed into secondary somatic embryos (SE 2 ); these were subcultured on half-strength MS supplemented with 5 mg/l 6-benzylaminopurine (BA). Differentiated embryos were transferred to MS medium supplemented with 5 mg/l BA for development, and mature SE 2 were isolated and cultured on hormone-free MS for germination and development into plantlets. Approximately 90% of the SE 2 germinated and developed into plantlets, and these were subcultured onto MS medium plus 0.1% activated charcoal, 1 mg/l BA and 1 mg/l IAA where complete plantlets developed. Morphologically normal banana plants developed from all of the regenerated plantlets, the first of which were produced within 6 months of culture initiation.

Involvement of Plant Hormones and Plant Growth Regulators on in vitro Somatic Embryogenesis

“…Also, in some species, secondary SE occurs in absence of PGRs (e.g., das Neves et al 1999;Koh and Loh 2000;Puigderrajols et al 2000;Ć alic´et al 2005). Additionally, in the case of the banana cultivar Dwarf Brazilian, addition of coconut milk induced secondary SE (Khalil et al 2002). Coconut milk has been known for some decades now to be a natural source of CKs (Amasino 2005).…”

Direct and Indirect Somatic Embryogenesis in Mango Ginger (Curcuma amada Roxb.)

“…The initial features of somatic embryos obtained in C. amada were translucent globular in appearance, which were similar to somatic embryos of banana (Escalant et al 1994;Cote et al 1996;Grapin et al 1996Grapin et al , 2000Navarro et al 1997;Becker et al 2000;Ganapathi et al 2001;Khalil et al 2002). Translucent globular shape was an important visible stage during early somatic embryo development.…”

Somatic Embryogenesis in Banana, Musa ssp.

“…Either on semi-solid medium (calli) or in liquid medium (cell suspensions), the multiplication of embryogenic cells is a key step because it greatly and rapidly scales up the number of potential embryos that may be produced. Indirect SE with formation of a callus stage is a common experiential method use in bananas, while secondary somatic embryos/embryogenesis (SE 2 ) stimulated directly from the primary somatic embryo or through formation of a callus stage have been both reported (Khalil et al 2002). Whereas, direct SE from split shoot tips have been recently reported (Remakanthan et al 2014).…”

“…SE can be initiated directly from the explant of donor plant without callus formation (direct SE), or indirectly by means of a callus stage (indirect SE) (Quiroz-Figueroa et al 2006). In the latter case, SE usually follows a similar path, such as: (i) initiation of calli followed by selection of the embryogenic callus, (ii) proliferation of the embryogenic cells of the callus (undifferentiated phase), (iii) regeneration of numerous embryos from these phase (embryogenic phase), and (iv) conversion of somatic embryos into mature embryos with the ability to regenerate healthy plants (Khalil et al 2002;Gaj 2004;Ramírez-Villalobos and de García 2009). Either on semi-solid medium (calli) or in liquid medium (cell suspensions), the multiplication of embryogenic cells is a key step because it greatly and rapidly scales up the number of potential embryos that may be produced.…”