Efficient in vitro direct shoot organogenesis and regeneration of fertile plants from embryo explants of Bambara groundnut ( Vigna subterranea L. Verdc.)

Abstract

An efficient protocol has been developed for direct shoot organogenesis from embryo axes derived from mature seeds of two different landraces of Bambara groundnut. Multiple shoots were initiated on several media containing different concentrations and combinations of benzylaminopurine (BAP) or thidiazuron (TDZ). Efficient regeneration occurred when the embryo axes were first plated for 6 days on a medium containing high concentrations of BAP (1 mg/l) and alpha-naphthaleneacetic acid (NAA, 1 mg/l) and then cut transversely and transferred onto a medium containing 1.5 mg/l BAP. Shoot regeneration frequency was 100% and from five to eight shoots per explant were obtained. The importance of using embryo explants and cytokinins in the culture media, with respect to controlling the development of a highly organogenic system, was demonstrated. Histological studies revealed that proliferating buds originated directly from the superficial layers of the explants without an intermediate callus phase. The regenerated shoots were rooted on a medium containing 1 mg/l NAA and then transferred to the greenhouse. Flow cytometric analyses and chloroplast counts of guard cells suggested that the regenerants were diploid. All were morphologically normal and fertile. The short duration, high efficiency and low frequency of somaclonal variation of this system make it well suited for wider biotechnological applications of Bambara groundnut-a neglected and under-utilized crop.

In vitro culture of Bambara groundnut [<i>Vigna subrerranea</i> (L.) Verdc., Favaceae ]: Effect of plant growth regulators, explant type and genotype on callus induction and differentiation

“…They noticed that leaves, petioles, hypocotyls and epicotyls were unable to regenerate shoots. On the other hand, this also confirms data for Bambara groundnut reported by Lacroix et al (2003), where stems, roots, leaves and cotyledons failed to regenerate shoots with BAP, TDZ, TIBA and NAA media. This underlines the importance of the explant in the regeneration ability with this species.…”

“…The results also indicated that all the 3 explants tested were recalcitrant to direct shoot organogenesis. As for prev ious observations, both auxin and cytokinin hormones were necessary to produce callus from explants of Vigna subterranea L. (Koné et al, 2007 ;Lacroix et al, 2003). BAP alone induced small amount of calli, as in many other leguminous species (Amutha et al, 2003 ;Dhar and Joshi, 2005).…”

“…Biotechnological tools have been used for various minor legumes including Vigna mungo, Lathyrus sativus, Vigna angularis and Vigna sesquipedalis (Popelka et al, 2004 ;Ochatt and Jain, 2007), but literature data in this domain for Vigna subterranea L. is scanty, with just a few formal reports so far. Lacroix et al (2003) have succeded on the regeneration of whole plants from embryo axes containing pre-existing meristems, but callusing from leaves, stems or roots was limited and without any differentiation. More recently, Koné et al (2007) succeeded in inducing de novo plant regeneration from cotyledons and epicotyls.…”

Multiple shoots induction in wild cotton (Gossypium bickii) through organogenesis and the analysis of genetic homogeneity of the regenerated plants

“…Flow cytometric, cytological analysis and molecular markers such as RAPD, RFLP (restriction fragment length polymorphism), and SSR (simple sequence repeat) were ideal approaches to evaluate somaclonal variation. Most reports on organogenesis in cotton have not referred to identifying the inheritance of the regenerants (Agrawal et al 1997;Hazra et al 2000), while some just mentioned cytological approaches for confirming the regenerants in other plants (Lacroix et al 2003). In this study, we combined cytological and molecular methods to identify the genetic homogeneity of the regenerant and their offsprings as the seed-derived diploid parents.…”

In vitro morphogenesis from cotyledon and epicotyl explants and flow cytometry distinction between landraces of Bambara groundnut [Vigna subterranea (L.) Verdc], an under-utilised grain legume

“…Nutritionally, it contains 17.4% protein, 53.1% carbohydrate, 6.1% fat, 6.1% fibre, 3.4% ash, 0.098% calcium, 0.007% iron, 1.2% potassium and 0.003% sodium (Rowland 1993;Amarteifio et al 1997). The gross energy value of Bambara groundnut seed is greater than that of several pulses (Amarteifio et al 2002;Lacroix et al 2003). Bambara groundnut fixes atmospheric nitrogen in symbiosis with Bradyrhizobium strains through a nodulation process and so it is useful in crop rotation (Dakora and Muofhe 1996;Gueye et al 1998).…”