Plant regeneration from cotyledonary node explants of mungbean (Vigna radiata (L.) Wilczek)

Abstract

Sexually-mature mungbean (Vigna radiata (L.) Wilczek) plants were efficiently regenerated from cotyledonary node explants. The explants were capable of directly developing multiple shoots on basal media devoid of any growth regulators. The shoot multiplication was influenced by media composition, growth regulators, age of donor seedling and explant type. The explants with both the cotyledons attached to the embryonic axis excised from 4-d-old seedlings, produced the highest number of shoots (5 or 6) in 100% of the cultures within 2 weeks on B5 basal medium (BBM) containing BAP or 2-iP, respectively, (at 5x10(-7)M) and 3% sucrose. Shoots elongated and developed better using BAP. Increasing micronutrients, carbohydrate and nitrogen levels in the medium above the original formulation of B5 basal medium appeared to be of no benefit for increasing the number of shoots. The shoots were rooted on basal MS medium or MS containing 10(-6) of NAA, IAA or IBA. This protocol was found applicable to six other cultivars of mungbean. One hundred rooted shoots were successfully established in soil in the glasshouse, where 90% of them survived. The regenerated plants flowered precociously, but produced normal pods and viable seeds.

In vitro plant regeneration from the petioles of primary leaves of mungbean Vigna radiata L.

“…The present regeneration protocol developed from preexisting meristem of petiole of primary leaf supports and confirms earlier reports (Gulati and Jaiwal 1992;Gulati and Jaiwal 1994;) that the BA could induce highly efficient multiple shoot development in mungbean followed by successful rooting, transplantation and survival. The concentration of BA at 1.0 mg 1 Ϫ1 was found to be the most responsive in the production of multiple shoot-buds (Table 1).…”

“…Earlier reports on direct multiple shoot regeneration from various explants (Gulati and Jaiwal 1992;Gulati and Jaiwal 1994;) have claimed a moderate regeneration frequency and a lesser number of shoots per explant compared to the present report. Previous studies on plant regeneration from various explants of mungbean obtained through callus also reported very low frequency of regeneration with low survival (Mathews 1987;Patel et al 1991;Mendoza et al 1992;Gulati and Jaiwal 1994).…”

“…Previous studies on plant regeneration from various explants of mungbean obtained through callus also reported very low frequency of regeneration with low survival (Mathews 1987;Patel et al 1991;Mendoza et al 1992;Gulati and Jaiwal 1994). Plant regeneration from somatic embryos has also been reported albeit with a lower frequency (Devi et al 2004).…”

“…Hence, direct plant regeneration from meristems is the most ideal for genetic transformation. Previous reports on multiple shoot regeneration of mungbean have utilized shoot apices (Gulati and Jaiwal 1992) or cotyledonary node explants (Gulati and Jaiwal 1994;. The regenerated plantlets produced presently from leaf explants were healthy and produced normal flowers and pods and set viable seeds.…”

“…Techniques making use of multiple shoot formation around pre-existing meristems may provide an ideal system for in vitro culture and transformation of grain legumes (Ramsay 1993;Olhoft and Somers 2001). There are a few reports on plant regeneration in mungbean from cotyledon explants (Gulati and Jaiwal 1990), shoot tip explants (Mathew 1987;Gulati and Jaiwal 1992) and cotyledonary node explants (Gulati and Jaiwal 1994;. Leaves obtained from in vitro grown seedlings eliminate the risk of contamination.…”