Rapid and efficient plant regeneration from hypocotyl protoplasts of Brassica carinata

Protoplasts were isolated from hypocotyls of 7-d-old seedlings of three genotypes of Brassica carinata after enzymatic digestion in cellulase R-10 (0.5%) and pectolyase Y-23 (0.025%). The protoplasts were stabilized with 0.4 M mannitol used as osmoticum, and were cultured in darkness in Kao's liquid medium containing 0.4 M glucose and the growth regulators 2,4-D (1.0 mg/l), NAA (0.1 mg/l) and zeatin riboside (0.5 mg/l). Protoplasts were transferred to 16 h photoperiod conditions after 3 d of dark culture, and the medium was diluted to reduce the osmoticum on the seventh and tenth days of culture. Microcolonies were thus obtained which, upon transfer to MS agarose medium with 2,4-D (0.1 mg/l), BAP (1 mg/l) and 0.1 M sucrose, proliferated further to produce callus clumps. The plating efficiency of the three genotypes varied from 1 to 2%. Calli 2–3 mm in diameter were transferred to MS agarose plates with zeatin (2 mg/l) where they produced shoot buds and shoots with frequencies ranging from 22.5 to 74.2% for the three genotypes. The shoots were rooted in medium with IBA (1 mg/l) and were then established in soil. The time required for protoplast to plant development was 8 to 10 weeks.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - IAA Indole-3-acetic acid - IBA Indole-3-butyric acid - NAA -naphthalene acetic acid - BAP 6-Benzylaminopurine - KN Kinetin - 2IP 6-(Gamma, gamma-dimethylallyl-amino)purine     

A simple culture method for Brassica hypototyl protoplasts

Hypocotyl protoplasts from oil rape, Brassica napus L. cv. Isuzu were cultured in the dark at 25°C in a modified Nitsch and Nitsch medium containing 13% sucrose, 5 g/l Ficoll, 0.5 mg/l BAP, 1 mg/l NAA and 0.5 mg/l 2–4 D. Protoplasts floated on the surface of the medium and developed into microcolonies 0.5 mm in diameter in 4–6 weeks. The microcolonies also remained on the surface of the medium. Transfer to MS medium supplemented with 200 mg/l casein hydrolysate, 5mg/l BAP, 0.5 mg/l NAA and solidified with 0.6% agarose induced shoot regeneration in 3–4 weeks.Abbreviations BAP 6-benzylaminopurine - NAA 1-naphthaleneacetic acid - 2,4-D 2,4 — dichlorophenoxyacetic acid     

Protoplast culture and plant regeneration from Brassica carinata Braun

Protoplasts isolated from hypocotyls of three-day-old seedlings of Brassica carinata (Braun) cv R-2128 were cultured in a modified Nitsch and Nitsch liquid medium containing 13% sucrose, 0.4% Ficoll, 0.25 mg/l BA, 0.5 mg/l NAA and 0.5 mg/l 2,4-D. The density of medium caused the protoplasts and the developing microcalli to float on the surface of the liquid medium whereas all debris and lysed cells sank to the bottom of the culture plate. After 4–6 weeks developing microcalli were approximately 0.5 mm in diameter and were transferred onto MS medium containing 3% sucrose, 0.4% agarose, 200 mg/l casein hydrolysate, 5 mg/l BA and 0.5 mg/l NAA, pH 5.7. Approximately 20% of the calli transferred to this medium produced plantlets.Abbreviations BA 6-Benzylaminopurine - NAA 1-naphthaleneacetic acid - IAA indole-3-acetic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - MS Murashiqe-Skoog     

Plant regeneration from mesophyll protoplasts ofDianthus superbus

Leaf mesophyll protoplasts ofDianthus superbus were cultured at a density of 5 × 10⁴ protoplasts/ml and divided at about 18% plating efficiency in MS liquid medium supplemented with 0.5 mg/L BAP, 2.0 mg/L NAA and 9% mannitol after 2 weeks. Protocolonies formed after 3 to 4 weeks of culture in the dark at 27°C. These colonies were transferred to continuous illumination (21.5 E m^–2 sec^–1) for 2 weeks where most of the colonies divided to form microcalli, about 2 mm in diameter. Subsequently, green microcalli were transferred to MS solidified medium with 2.0 mg/L 2,4-D that induced shoot-forming calli after 4 weeks. These calli were transferred onto N₆-2 medium containing 0.1 mg/L 2,4-D, 0.1 mg/L NAA, 2.0 mg/L kinetin and 2.0 g/L casein hydrolysate and were cultured under light. After 5 weeks the calli gave rise to multiple shoots (10 to 15 per callus). Upon transfer to MS medium containing 2.0 mg/L NAA, individual shoots were rooted in 4 weeks. The regenerants were successfully transplanted into potting soil.Abbreviations MS Murashige and Skoog - BAP 6-benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA 1-naphthaleneacetic acid - N₆ Chu basal salt mixture - MES 2-N-morpholinoethanesulfonic acid     

Stable transformation of sugarbeet protoplasts by electroporation

Conditions were optimized for the culture, antibiotic selection and stable transformation by electroporation of suspension culture protoplasts of sugarbeet,Beta vulgaris L.. Highest plating efficiencies (up to 65% at day 21) were obtained if protoplasts were cultured in PGO salts (de Greef and Jacobs, 1979) supplemented with 0.1 mg/1 2,4-D, 0.01 mg/l BAP and 9% mannitol, and in 0.6% agarose rather than in liquid medium. Sensitivity to kanamycin also depended on whether protoplasts were cultured in liquid or agarose medium. Stable transformation of protoplast-derived colonies, as determined by resistance to kanamycin and Southern blot analysis, was achieved by electroporation using both rectangular and exponentially-decaying pulses.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - BAP 6-benzylaminopurine - npt-II neomycin phosphotransferase - EDTA ethylenediaminetetracetic acid - SDS sodium dodecyl sulphate     

Callus and embryoid formation from protoplasts of Helianthus annuus

Sunflower hypocotyl protoplasts have been isolated and cultured. Optimum plating density for cell division and colony formation was in the range of 5 to 7×10⁴ cells/mi in an agarose medium supplemented with BAP (1 mg/l) and NAA (1 mg/l). Plating efficiency was 60% after 21 days of culture. In the resultant culture a mixed population of calli and embryoids was observed. Thirty seven percent of the cell clusters exhibited a developmental pattern similar to an embryoid. Many stages of embryogenesis were observed in the same cultures.Abbreviations 2,4-D 2,4 dichlorophenoxyacetic acid - NAA 1-naphtaleneacetic acid - IAA Indole-3-acetic - BAP 6-benzylamino purine - GA₃ Gibberellic acid     

Somatic embryogenesis in protoplast derived calli of cultivated jute,Corchorus capsularis L.

Protoplasts were isolated from cotyledon, hypocotyl and mesophyll cells of Corchorus capsularis L., a major fibre crop, by one step enzyme digestion method. They were further cultured successfully on modified KM-8p (Kao and Michayluk, 1975) medium to form microcalli. The required cultural conditions could be used to achieve 34% to 78% plating efficiency, depending upon the source of protoplasts. Hypocotyl protoplasts gave the highest plating efficiency. On transfer to regeneration medium, somatic embryos developed at high frequency. The present success is a significant step forward in the development of meaningful plant cell culture methods for application in jute.Abbreviations B₅ Gamborg et al., 1968 - MS Murashige and Skoog, 1962 - SH Schenk and Hildebrandt, 1972 - Ad-SO₄ Adenine sulphate - BAP 6-benzylaminopurine - NAA 1-naphthalene acetic acid - GA₃ Gibberellic acid - 2,4-D 2,4-dichlorophenoxy acetic acid - Kn Kinetin - IBA Indole-3-butyric acid     

Callus formation from protoplasts of a sugarbeet cell suspension culture

Protoplasts of sugarbeet (Beta vulgaris L.) were isolated from cell suspension cultures and cultured in modified PGo medium. Conditions required for the efficient division of the protoplasts were investigated.The optimal combination of phytohormones was found to be 1 mg/l NAA, 0.2 mg/l 2,4-D, 0.5 mg/l zeatin. Protoplast division was also considerably stimulated by the addition of 250 mg/l casein hydrolysate, 200 mg/l yeast extract, and 20% v/v conditioned culture medium to the protoplast culture medium. The highest division rate (up to 35% of the protoplasts) was achieved at a density of 4×10⁴- 1×10⁵ protoplasts/ml. From the colonies callus and suspension cultures were readily obtained.Abbreviations BAP 6-Benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA Indole-3-acetic acid - Kin 6-Furfurylaminopurine (kinetin) - NAA -Naphtalenacetic acid - Zea Zeatin     

Isolation,culture and division of olive (Olea europaea L.) protoplasts

Protoplasts from Olea europaea L. have been compared in terms of their yield, viability, cell division and callus differentiation. Viable protoplasts were isolated from in vitro cultured leaves and cotyledons by an overnight incubation in an enzyme solution containing 1–1.5% driselase and 0.5M sucrose. This method allowed high yield of purified protoplasts, which floated and formed a dark green band at the meniscus, after centrifugation. Purified protoplasts were diluted to 3×10⁴ protoplasts·ml^–1 in culture medium. After cell wall regeneration, protoplasts gradually increased their volumes under appropriate conditions. The first divisions occurred during the second week in culture. Division efficiency ranged from 5.2 to 9.8% after 20 days in culture. Two weeks later visible microcolonies developed only from cotyledon protoplasts. After 6 weeks in culture, the microcalli were transferred to a solidified culture medium with 0.6% agarose, which induced active callus growth.Abbreviations OM olive proliferation medium, Rugini 1984 - Omg OM for the germination of olive embryos - OMr=OM for root induction - OMp=OM for protoplasts - OMc=OM for callus - BN Bourgin and Nitsch medium 1967 - IBA indol-3-butyric acid - NAA naphthalene acetic acid - 2,4-D dichlorophenoxyacetic acid.     

Regeneration of leaf mesophyll protoplasts of tomato cultivars (L. esculentum): factors important for efficient protoplast culture and plant regeneration

Conditions were established for efficient plant regeneration from four freshmarket cultivars of Lycopersicon esculentum. In order to increase the yield of viable protoplasts which are able to sustain cell divisions, the donor plants are preconditioned by incubation at 25°C in the dark for 18 hours, followed by a cold treatment at 4°C in the dark for the last 6 hours, prior to protoplast isolation. Browning of the dividing cell colonies can be prevented by culturing protoplasts in 100 l droplets of low-melting agarose, surrounded by liquid medium. Alternatively, protoplasts can be cultured in liquid medium. In both procedures the plating efficiencies and percentage of shoot regeneration are increased, only when dilutions were performed with auxin-free culture medium. Shoot regeneration is obtained by using a two step procedure: initiation of greening of microcalli on a medium containing 0.2 M mannitol and 7.3 mM sucrose, which is followed by shoot development on a mannitol-free medium containing 0.5 M sucrose. In this way, plants can be regenerated within 3 months from the hybrid cultivars Bellina, Abunda, Sonatine and also from the true seedline Moneymaker. The latter one showed the highest regeneration frequency (30%).Abbreviations BAP 6-Benzylamino purine - 2,4-D 2,4-dichlorophenoxy acetic acid - IAA indole acetic acid - MES 2-(N-morpholino)- ethane sulfonic acid - NAA naphthalene acetic acid - PE plating efficiency     

Isolation and culture of protoplasts from embryogenic suspension cultures of red fescue (Festuca rubva L.)

Protoplasts were isolated from fast-growing embryogenic suspension cultures of red fescue cv. Dawson (Festuca rubra L.) without agitation. The enzyme isolation solution was highly efficient at releasing protoplasts of greater than 95% viability (5×10⁶–10⁷ protoplasts per ml of packed cell volume). A three step procedure was followed for washing and transferring protoplasts from a solution high in inorganic salts to a medium containing glucose and sucrose. The addition of 30 mM sodium thiosulfate to the wash and culture media was found to be helpful in reducing the number of lysed protoplasts. Isolated protoplasts began to divide within 48–72 h when protoplasts were plated in agarose squares and surrounded by nurse cells (mixed nurse plating technique). Maximum colony formation (plating efficiency) was approximately 1%. Many of the colonies continued to grow and produced embryos when transferred to a medium consisting of half-strength MS salts, 4 mg/l 2,4-D, 3 g/l casein hydrolysate and 30 g/l sucrose. Upon transfer to hormone-free medium and exposure to light 16 h/day, many of the embryos germinated to produce green leaves and roots.Abbreviations BA Benzylaminopurine - 2,4-D 2,4-dicholorophenoxyacetic acid - DMSO dimethyl sulfoxide - MES 2-(N-morpholino)-ethanesulfonicn acid - MS Murashige and Skoog medium (1962) - UGC Ultraclone Growth Chamber - KM Kao and Michayluk medium (1975) - NAA Naphthalene acetic acid     

Fertile indica and japonica rice plants regenerated from protoplasts isolated from embryogenic haploid suspension cultures

Summary A system to regenerate fertile rice (Oryza sativa L.) plants (both indica and japonica varieties) from protoplasts isolated from anther-derived embryogenic haploid suspension cultures has been established. Green plants were regenerated from protoplast-derived cell clusters five months after suspension culture initiation. Protoplast yields and subsequent growth of the protoplast-derived microcalli were enhanced by transferring suspension cells into AA medium (Muller et al. 1978) three to four days prior to protoplast isolation. Protoplasts were cultured initially in Kao medium (Kao et al. 1977) and in association with nurse cells for four weeks. Protoplast-derived microcalli were transferred onto N6 (Chu et al. 1975) or MS (Murashige and Skoog 1962) media for callus proliferation. Callus growth was more rapid and the calli were more enbryogenic when grown on N6 medium. The 2,4-D concentration used to develop the suspension culture was important. Cell cultures grown in medium containing 0.5 mg/l 2,4-D released protoplasts whose plating efficiency was higher than for protoplasts obtained from suspension cultures grown in 2.0 mg/l 2,4-D. However, suspension cells grown in 2.0 mg/l 2,4-D were superior with regard to the ability of protoplast-derived calli to regenerate green plants. Amongst several hormone treatments evaluated, a combination of 0.5 mg/l NAA + 5.0 mg/l BAP resulted in the largest number of green plants regenerated. There were no significant differences between BAP or kinetin regarding total number of plants regenerated. More than 200 green plants have been produced form six independently initiated suspension cell lines. The number of regenerated plants per 10⁶ protoplats plated anged from 0.4 to 20.0, and the average seed fertility of single panicles of these R_O plants was about 40%.     

Regeneration of plantlets from the callus of stem segments of adult plants of Ficus religiosa L.

Stem segments of adult plants of Ficus religiosa L. cultured on MS medium containing 1.0 mg/l 2,4-D produced callus. Shoots were regenerated when the induced calli were transferred to medium supplemented with 0.05 to 2.0 mg/l BAP. Callus derived shoots produced roots and developed into plantlets when transferred to medium supplemented with 1.0 mg/l NAA.Abbreviations MS Murashige and Skoog (1962) - BAP 6-benzylaminopurine - NAA naphthaleneacetic acid - 2,4-D 2,4-dichlorophenoxyacetic acid     

Tissue,cell culture and micropropagation of Mandevilla velutina,a natural source of a bradykinin antagonist

Leaf, stem and root explants of Mandevilla velutina were cultured in vitro and produced vigorous callus in LS basal medium containing one auxin (2,4-D or NAA) plus BAP. Calli can be subcultured indefinitely with vigorous growth. Subculture of calli to NAA (1.0 mg/l) plus BAP (5.0 mg/l) caused profuse regeneration of shoots. Isolated shoots were rooted in basal medium plus NAA (5.0 mg/l) or IBA (8.0 mg/l). Rapidly growing cell suspensions can be easily obtained from friable callus cultured in liquid medium.Abbreviations LS Linsmaier & Skoog - 2,4-D 2,4 dichlorophenoxi-acetic acid - NAA -naphthalene-acetic acid - GA₃ gibberellic acid - IAA indole-3-acetic acid - BAP 6-benzylaminopurine - IBA indole-3-butyric acid     

Rhizogenesis in callus from Conference pear (Pyrus communis L.) protoplasts

Large numbers (ca 6×10⁶ protoplasts/g f.wt) of viable (80%) protoplasts were isolated from embryo-callus tissues of Conference pear using an enzyme mixture which contained 2.0% (w/v) Meicelase, 2.0% (w/v) Rhozyme HP-150 and 0.03% (w/v) Macerozyme R-10. A medium based on ammonium-free MS salts and supplemented with 2.0 mg/l NAA, 0.5 mg/l BAP and 9% (w/v) mannitol supported protoplast division and the proliferation of multicellular colonies. Colonies were taken to the callus stage on a medium which contained MS salts plus 0.1 mg/l 2,4-D and 0.1 mg/l BAP. Roots were regenerated from these protoplastderived calli on MS medium with 0.1 mg/l NAA, 5.0 mg/l BAP and 50 mg/l casein hydrolysate.Abbreviations BAP 6-benzylaminopurine - CPW13M CPW salts medium [15] with 13% (w/v) mannitol - FDA fluorescein diacetate, f. wt-fresh weight - MS Murashige and Skoog [14] - NAA -naphthaleneacetic acid - PE plating efficiency (%) - 2,4-D 2,4-dichlorophenoxyacetic acid     

Intergeneric protoplast fusion between Brassica carinata and Camelina sativa

Camelina sativa is a wild crucifer that is reported to be resistant to Alternaria blight. Polyethylene glycol mediated fusion was attempted between protoplasts from etiolated hypocotyls of Brassica carinata and mesophyll protoplasts of Camelina sativa. The mean frequency of heterokaryons was 6.8%. Three hybrid shoots were regenerated, each from a single fusionderived callus. These shoots failed to produce roots capable of withstanding transplantation. Confirmation of hybridity was obtained from the morphology of in vitro produced leaves, somatic chromosome number in leaf tips, and restriction fragment length polymorphism for a nuclear rDNA probe. Analysis for organelle constitution using RFLPs indicated that the hybrid contained chrloroplasts derived from the wild species and mitochondria from the cultivated Brassica species.Abbreviations 2,4-D 2,4-dichlorophenoxy-acetic acid - IAA Indole-3-acetic acid - NAA -Naphthaleneacetic acid - IBA Indole-3-butyric acid - GA₃ gibberellic acid - BAP 6-Benzylaminopurine - MS Murashige and Skoog (1962) basal medium     

Plant regeneration from protoplasts isolated from callus ofGentiana crassicaulis

Fast growing calli induced from hypocotyl segments ofGentiana crassicaulis were used for preparation of protoplasts. High yields of viable protoplasts were produced in an enzyme solution containing 1–2% cellulase, I% pecfinase, and 0.5% Hemicellulase. Protoplasts were cultured in KM8P medium containing 1 mg/l 2,4-D, 0.5 mg/l 6BA, 500 mg/l LH, 0.5 M glucose and 0.1 M mannitol by the solid-liquid dual layer culture method. First division occurred within 4–5 days of culture at a frequency of 17.8%. Sustained divisions led to callus formation. Periodically diluting the cultures with freshly prepared liquid medium containing 1% glucose was critical for colony formation. Protocolonies about 2 mm in size were transferred onto MS medium supplemented with 3 mg/l ZT, 2 mg/l 6BA, 1 mg/l GA₃, 1 mg/l NAA and 6% sucrose to obtain embryogenic calli. Plantlets were regenerated via somatic embryogenesis at high frequency on hormone-free MS Medium.Abbreviations 6BA 6-benzylaminopurine - NAA naphthaleneacetic acid - 2,4-D 2,4 - dichlorophenoxyacetic acid - ZT zeatin - GA₃ gibberellic acid - LH lactalbumin hydrolysate - MES 2-(N-morpholino)-ethane sulfonic acid - MS Murashige & Skoog's medium(1962)     

In vitro propagation of guayule (Parthenium argentatum) — a rubber yielding shrub

Nodal explants (0.5 to 0.8 cm long) isolated from 2-year old shrubs of guayule, Parthenium argentatum Gray, when cultured on MS medium supplemented with different concentrations of KN, BAP, 2,4-D, 2,4-D + BAP, NAA and NAA + BAP produced callus tissues and shoots simultaneously with varying frequencies. Shoots were regenerated with a high frequency (80–88%) from callus on MS medium containing NAA + BAP with or without glutamine. Addition of glutamine to these media improved considerably the number of shoots formed from a known amount of callus. Shoots could be regenerated from 200 day old callus cultures with a very high frequency but the organogenetic capacity declined thereafter. Increase in the concentration of sucrose (upto 4%) significantly enhanced the shoot forming ability of callus, but higher concentrations (6%) suppressed it. Rooting was induced only in dark when IAA, IBA and NAA were used, but 2,4-D could induce them both in light and dark. The system is suitable for the mass propagation of this important rubber yielding plant.Abbreviations MS Murashige and Skoog (1962) - IAA Indole-3-acetic acid - IBA Indole-3-butyric acid - NAA -Naphthaleneacetic acid - 2,4-D 2,4-Dichlorophenoxyacetic acid - KN Kinetin - BAP 6-Benzylaminopurine     

High frequency plant regeneration of Cymbopogon martinii (Roxb.) Wats by somatic embryogenesis and organogenesis

Embryogenic callus cultures were obtained upon repeated sub-culture of non-embryogenic callus from nodal segments of Cymbopogon martinii (Roxb.) Wats. Murashige and Skoog's medium supplemented with 1mg/l 2,4-dichlorophenoxyacetic acid and 0.5 mg/l kinetin and Linsmaier and Skoog's medium supplemented with 2mg/l 2,4-dichlorophenoxyacetic acid and 0.4 mg/l kinetin were used as maintenance media for non-embryogenic and embryogenic cultures, respectively. Plant regeneration occurred through organogenesis in MS basal media containing 2 mg/l kinetin, 1 mg/l 6-benzylaminopurine, 0.2 mg/l biotin, 0.2 mg/l Ca-pantothonate and 0.1 mg/l napthalene acetic acid. Embryogenesis was induced in LS medium supplemented with 1 mg/l kinetin, 0.5 mg/l 6-benzylaminopurine and 0.1 mg/l 3-indole acetic acid. Plant regeneration at high frequency was recorded both through organogenesis and embryogenesis in different passages of long term callus cultures.Abbreviation MS Murashige and Skoog medium - LS Linsmair and Skoog medium - BAP 6-benzylaminopurine - kin kinetin - 2,4-D 2,4-Dichlorophenoxyacetic acid - IAA Indole-3-acetic acid - CH Casein hydrolysate - CaP calcium pantothonate - NAA napthalene acetic acid     

Morphogenesis and plant regeneration from cultured endosperm of Emblica officinalis Gaertn

Mature endosperm of Emblica Officinalis (Euphorbiaceae) formed a continously growing callus on MS medium supplemented with an auxin (2,4-D or IAA) and a cytokinin (K or BAP). Subculture of callus on MS with BAP (0.2 mg/l) and IAA (0.1 mg/l) resulted in formation of shoots and embryo-like structures in 50 and 8 per cent cultures, respectively. Regeneration of shoots was more frequent when both BAP (0.2 mg/l) and IAA (0.1 mg/l) were present than on BAP (0.2 mg/l) alone. The embryo-like structures produced plantlets.Abbreviations BAP benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - GA₃ gibberellic acid - IAA indoleacetic acid - K kinetin - NAA naphthaleneacetic acid - PDB para-dichlorobenzene (née Arora)