Recovery of plants from leaf protoplasts of hybrid-poplar and aspen clones

Leaf protoplasts were isolated from shoot cultures of two hybrid poplar clones (Populus alba × P. grandidentata Crandon, NC-5339 and P. nigra Betulifolia × P. trichocarpa, NC-5331) and the Upright European Aspen (P. tremula Erecta) and were cultured in contact with screen discs floated in liquid medium. Protoplast culture was influenced by the growth medium of the source shoot cultures, the protoplast purification procedure, the plating density, and the presence or absence of a coconut water and casein hydrolysate supplement added to the culture medium. The protoplast-derived cells divided more quickly and with higher incidence than previously reported for hybrid poplars. Shoots were regenerated from the protoplast-derived calli and were maintained as shoot cultures. Plants were developed from microcuttings rooted ex vitro and were grown-on in the greenhouse and field.Abbreviations BA benzyladenine - NAA 1-naphthaleneacetic acid - TDZ thidiazuron - WPM Woody Plant Medium, Lloyd and McCown (1980) - MS Murashige and Skoog Medium (1962) - NC-XXXX North Central Forest Experiment Station accession number assigned to hybrid poplar clones.     

Hyoscyamus muticus + Nicotiana tabacum fusion hybrids selected via auxotroph complementation

Protoplasts of the nicotinamide-deficient Hyoscyamus muticus cell line nic^– IVH2 and of the nitrate reductase-deficient Nicotiana tabacum cell line NR^– cnx 68 were induced to fuse. Selection for putative interspecific hybrid clones was via auxotroph complementation. Controls included tests for cross-feeding, cross inhibition, PEG-induced variation, culture-induced variation, reversion, viability, delayed selection. Protrotrophic cell lines were recovered exclusively from PEG-treated mixtures of both protoplast types. The putative hybrid clones grew independent of exogenously supplied auxins and cytokinins, and at a faster rate than either parent. The morphogenic potential of different clones varied from non-morphogenic to regeneration of fertile plants. Indirect evidence for the hybrid nature of the clones is provided from a) tight selection, b) hormone-independent growth, c) hybrid vigour, d) extreme morphological variation, e) isoenzyme bands from both parents, f) morphogenic potential. Definite proof for the hybrid nature was, however, provided from species-specific DNA hybridization. Chimerism could be excluded since only the large subunit of Hyoscyamus muticus ribulose bisphosphate carboxylase was found and since species-specific DNA hybridization identified clones which gave no Nicotiana tabacum signal.Abbreviations 2,4-D 2,4-Dichlorophenoxyacetic acid - NAA Naphthaleneacetic acid - BAP 6-Benzylaminopurine - PEG Polyethyleneglykol - MES (2[N-morpholino]ethane sulfonic acid - Tris-HCl Tris(hydroxymethyl)-aminoethane-HCl % is given throughout in w/v - FMI Friedrich Miescher-Institut     

Somatic hybrids between Solanum brevidens and Solanum tuberosum: Expression of a late blight resistance gene and potato leaf roll resistance

Hexaploid somatic hybrids resulting from mesophyll protoplast fusions between Solanum brevidens Phil., PI 218228, and Solanum tuberosum L., PI 203900 were tested for late blight resistance using two races of Phytophthora infestans Monte., de Bary. The S. tuberosum parent was a late blight differential possessing the R4 gene which confers resistance to race 0. The S. brevidens parent is resistant to potato leaf roll virus. Inoculations with both compatible (race 1.3.4.5) and incompatible (race 0) races of P. infestans clearly demonstrated the expression of the late blight resistance gene in all of the hybrid progeny tested. Most of the hybrids tested were also resistant to potato leaf roll virus (PLRV), indicating that the S. brevidens genes for PLRV resistance were present and expressed.     

Intergeneric somatic hybrid plants of Citrus sinensis cv. Hamlin and Poncirus trifoliata cv. Flying Dragon

Intergeneric somatic hybrid plants between Hamlin sweet orange [Citrus sinensis (L.) Osbeck] and Flying Dragon trifoliate orange (Poncirus trifoliata Raf.) were regenerated following protoplast fusion. Hamlin protoplasts, isolated from an habituated embryogenic suspension culture, were fused chemically with Flying Dragon protoplasts isolated from juvenile leaf tissue. The hybrid selection scheme was based on complementation of the regenerative ability of the Hamlin protoplasts with the subsequent expression of the trifoliate leaf character of Flying Dragon. Hybrid plants were regenerated via somatic embryogenesis and multiplied organogenically. Hybrid morphology was intermediate to that of the parents. Chromosome counts indicated that the hybrids were allotetraploids (2n=4x=36). Malate dehydrogenase (MDH) isozyme patterns confirmed the hybrid nature of the regenerated plants. These genetically unique somatic hybrid plants will be evaluated for citrus rootstock potential. The cell fusion, selection, and regeneration scheme developed herein should provide a general means to expand the germplasm base of cultivated Citrus by intergeneric hybridization with related sexually incompatible genera.Abbreviations MDH malate dehydrogenase - CTV citrus tristeza virus - MT Murashige and Tucker basal medium - BH3 protoplast culture medium, Grosser and Chandler, 1987 - PEG polyethylene glycol - GA3 giberellic acid - BA N-(phenylmethyl)-1 H-purin-6-amine - HCl hydrochloric acid Florida Agricultural Experiment Station Journal Series No. 7972     

The introduction of CMS mitochondria to triazine tolerant Brassica napus L., var. “Regent”, by micromanipulation of individual heterokaryons

Cytoplasmic triazine tolerance and cytoplasmic male sterility traits were combined in the nuclear genomic background of the Brassica napus variety Regent, following protoplast fusion, selection of fusion products by manual micro-manipulation, and culture in a Nicotiana tabacum nurse system. Whole plant cybrid regenerants were morphologically normal and produced seed on pollination, demonstrating their potential for incorporation into a breeding program.     

Selection of yeast hybrids by the sulfonylurea herbicide chlorsulfuron

Summary A new selection method based on the use of chlorsulfuron (CS) resistance as the selection marker for protoplast fusion in industrial yeast has been introduced using the system of protoplast fusion. A petite mutant of a spontaneously CS-resistant distiller's Saccharomyces cerevisiae strain and a wild-type CS-sensitive strain of the osmotolerant yeast Zygosaccharomyces mellis were fused in order to obtain a distiller's yeast suitable for fermentations on concentrated molasses. Fusion products were isolated as large colonies on minimal glycerol agar with 0.5 mg ml^–1 of the herbicide Glean (75% CS). Following prolonged cultivation on molasses, stable hybrid subxlones were obtained. Offprint requests to: F. Cvrková     

An assessment of the cultural capabilities of protoplasts of some wild species of linum

Protoplasts of several wildLinum species were isolated enzymatically from roots, hypocotyls and cotyledons of seedlings, and also from theirin vitro grown shoots and cell suspension cultures. When cultured all these protoplasts divided to produce callus but only good plant regeneration capability was evident in the case ofLinum lewissii and to a much lesser extent forL. strictum. Only rhizogenesis was observed withL. alpinum, L. narbonense, L. grandiflorum andL. altaicum. The high plant regeneration capacity ofL. lewissii from protoplast -derived tissues ofin vitro shoots and cell suspension cultures makes this species an attractive experimental system for somatic genetic manipulation.Abbreviations BAP benzylaminopurine - NAA -naphthaleneacetic acid - CPW cell and protoplast wash solution - gFW gram fresh weight On leave from Department of Crop Sciences University of Alexandria Egypt     

Isolation,culture and callus regeneration of protoplasts of wild and cultivated Helianthus species

Protoplasts were isolated from seedling roots, hypocotyls, and cotyledons of four cultivars of Helianthus annuus and from leaves of axenic shoot cultures of the wild species H. praecox, H. scaberimus and H. rigidus. Optimal culture conditions were established for the respective protoplast systems, using the agarose bead method of culture. Protoplast division was induced for all the species examined. In the case of the cultivars of H. annuus, hypocotyl and cotyledon protoplast division was sustained leading to callus formation, which in turn, could be induced to produce roots and organised meristematic regions in the presence of NAA and 6-BAP.Abbreviations 6-BAP 6-benzylaminopurine - NAA -naphthalene acetic acid - IAA indole-3-acetic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - MS Murashige and Skoog     

Improved efficiency of plant regeneration from protoplasts of eggplant Solanum melongena L.

Eggplant (Solanum melongena L.) mesophyll protoplasts were obtained from in vitro growing plants of line 410 and cv. Classic. Relatively high (15%) plating efficiency was achieved using petri dishes with alternate quadrants containing reservoir medium (R medium + 1% activated charcoal) and culture medium. Shoot regeneration occurred within 6 weeks following initiation of protoplast culture.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan Israel, No. 1164-E, 1984 Series.     

Improved sensitivity of genetic complementation of nitrate reductase deficient mutants via protoplast fusion

An improved rapid assay for complementation testing of mutants of Nicotiana tabacum deficient in nitrate reductase is described. The test is based on measurement of in vivo nitrate reductase activity in 7 to 10 day old cultures derived from fusion-treated protoplast mixtures of the respective mutants as a criterion for complementation. It allows to detect complementing hybrids induced by the conventional droplet fusion technique in small numbers of protoplasts per assay (8×10⁴).Abbreviations NR nitrate reductase - 2,4-D dichlorophenoxy-acetic acid - NAA -naphthaleneacetic acid - BAP 6-benzylaminopurine - PEG polyethylene glycol     

A new bioassay system for screening high berberine-producing cell colonies of Thalictrum minus

A new method of estimating the amount of berberine released from minute cell colonies of Thalictrum minus has been devised to facilitate the selection of high berberine-producing cell lines. In this system, cell aggregates obtained from a cell suspension culture are grown on small pieces of an agar culture medium and the concentration of berberine which has been released from the cells into the agar piece is assayed by the antibacterial activity against Bacillus cereus MT2026. Screening of 1000 cell colonies by the agar piece method has resulted in the isolation of four, high berberine-producing cell lines, although they have been found to be more or less unstable with respect to the biosynthetic capability during successive subcultures.     

The transfer of ‘Polima’ cytoplasmic male sterility from oilseed rape (Brassica napus) to broccoli (B. oleracea) by protoplast fusion

Protoplast fusion was utilised to transfer Polima type cytoplasmic male sterility (CMS) from Brassica napus, canola cv. Polima Karat (Pol-Karat) to B. oleracea, broccoli, var. Green Comet. Southern and RFLP analysis confirmed that four cybrids possessed nuclear genomes of broccoli with Polima mitochondria and chloroplasts. A fifth cybrid was a nuclear hybrid between broccoli and Pol-Karat, with Polima mitochondria and chloroplasts of broccoli. The broccoli type cybrids were morphologically similar to Green Comet, while the hybrid type was an intermediate of the two fusion parents. Flowers on the cybrids were distinctive in that although they possessed a morphology typical of Polima, they had very reduced petals. The broccoli type cybrids exhibited some female fertility, albeit low, establishing potential for F₁ hybrid production.     

Clonal propagation of Leptospermum spp. by tissue culture

Propagation by axillary and multiple axillary bud development was achieved in three native Leptospermum spp. when axillary buds derived from nodal tissues ex mature plants were placed in benzylaminopurine media (0.04–1.0 M) containing macro- and micro-nutrients, sucrose (0.06 M) and a vitamin/amino acid supplement. Reduction of agar concentration from 0.8 to 0.2% greatly stimulated axillary bud development and growth in L. flavescens and L. brachyandrum. Rooting of axillary shoots was stimulated by 2,4-dichlorophenoxyacetic acid and p-chlorophenoxy acetic acid in L. flavescens at concentrations of 5 and 1 M respectively. In L. petersonii ssp. root initiation and development was favoured by -naphthoxyacetic acid (1 M) and in L. brachyandrum indole butyric acid and -naphthalene acetic acid (1 M) were almost equally effective.     

Transfer of DNA coding for cellulases from Cellulomonas species to Bacillus subtilis by protoplast fusion

Summary Cellulose utilising hybrids between Cellulomonas spp. and Bacillus subtilis were isolated after PEG mediated protoplast fusion. These stable hybrids selected using genomic markers harboured DNA from both the parents. Higher CMCase and -glucosidase activities were detected extracellularly in case of one of the hybrids unlike only CMCase in case of Cellulomonas.NCL Communication No. 3542     

Polymerization of amino acids containing nucleotide bases

Summary We have prepared the nucleoamino acids 1-(3-amino, 3-carboxypropyl)uracil (3) and 9-(3-amino, 3-carboxypropyl)adenine (4) as (l)-enantiomers and as racemic mixtures. When3 or4 is suspended in water and treated with N,N-carbonyldiimidazole, peptides are formed in good yield. The products formed from the (l)-enantiomers are hydrolyzed to the monomeric amino acids by pronase.Attempts to improve the efficiency of these oligomerizations by including a polyuridylate template in the reaction mixture were not successful. Similarly, oligomers derived from the (l)-enantiomer of3 did not act as templates to facilitate the oligomerization of4.     

Isolation and cell regeneration of protoplasts from sugar pine (Pinus lambertiana)

Protoplasts were isolated at high yields from actively growing callus and cell suspensions of cotyledons and needles of mature trees. The best protoplast growth response was obtained from cell suspensions of cotyledon and needle callus. Lower protoplast yields were obtained directly from young needles of flushing buds on explants from mature shoots (30-year-old trees) growing in vitro. In all cases, the first divisions, promoted by dimethyl sulfoxide, were observed in 10–45% of the protoplasts by 7–10 days. After 25–30 days, colonies of 8–10 cells were established. Browning of protoplast-derived cell cultures was observed within 40–45 days (cotyledons) and 20–25 days (mature tree sources).Abbreviations BA N⁶-Benzyladenine - DCR Douglas-fir cotyledon revised medium - 2,4-D 2,4-dichlorophenoxyacetic acid - DMSO dimethyl sulfoxide - FDA Fluorescein diacetate - Mes 2-(N-morpholino) ethanesulfonic acid - NAA -naphthaleneacetic acid     

Plant regeneration from Carica protoplasts

Summary Rapidly proliferating and highly regenerable suspension cultures of somatic embryos of Carica papaya x C. cauliflora were used for protoplast isolation. On average, protoplast yield was 1.5×10⁶/g fresh weight of somatic embryos. Protoplasts were first cultured in liquid KM8P-S medium for 2 weeks and then plated in the same medium solidified with 1% agarose. About 1.4% of the protoplasts developed directly into somatic embryos. Protoplast-derived somatic embryos proliferated rapidly through direct embryogenesis on modified MS medium supplemented with 1 mg/1 ABA, and developed into plantlets upon transfer to MS medium devoid of plant growth regulators. The plantlets were successfully transplanted to soil.Abbreviations MS Murashige and Skoog medium (1962) - KM8P Kao and Michayluk medium (1975) - NAA -naphthaleneacetic acid - BAP 6-benzylaminopurine - ABA abscisic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - FDA fluorescein diacetate - CPW Frearson et al. medium (1973)     

Sandalwood plantlets from ‘Synthetic seeds’

Somatic embryos of sandalwood (Santalum album) were encapsulated in an alginate matrix to prepare Synthetic seeds. Encapsulated single embryos germinated to form plants with roots and shoots. Embryogenic cell suspensions encapsulated and stored at 4°C for 45 days produced embryos when recultured as suspensions.Abbreviations BAP benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - GA gibberellic acid - IAA indole acetic acid - IBA indole butyric acid - MS Murashige and Skoog (1962) - TW tap water - WM White's medium     

Secondary product formation by cultures of Beta vulgaris and Nicotiana rustica transformed with Agrobacterium rhizogenes

Hairy root cultures of Beta vulgaris and Nicotiana rustica were established after roots were induced on plants following infection with Agrobacterium rhizogenes. The transformed cultures of B. vulgaris and N. rustica synthesised their characteristic secondary products, the betalain pigments and nicotine alkaloids respectively, at levels comparable with those of in vivo roots from the same variety. Betalains were entirely retained inside the root tissue. In contrast, a proportion of the nicotine alkaloids was secreted into the medium. The potential of this type of in vitro plant tissue culture for the production of valuable plant secondary products is identified and confirmed.     

Micropropagation of Uniola paniculata L.

Uniola paniculata L. is a major sand-dune stabilizing grass which is being utilized to prevent shoreline erosion. In vitro cultured caryopses of U. paniculata produced callus on MS medium supplemented with 22.5 M 2,4-D, 4.4 M BA and 87.6 mM sucrose. Shoot induction occurred after these calli were inoculated onto the same medium without 2,4-D. Rooting of in vitro-derived shoots occurred when transferred to a one-half strength MS medium containing 43.8 mM sucrose and 14.7 M IBA. Plantlets were planted after the roots reached a length greater than 20 mm.Abbreviations BA N-(phenyl-methyl)-lH-purine-6-amine - IBA lH-indole-3-butanoic acid - MS Murashige and Skoog (1962) - 2,4-D (2,4-dichlorophenoxy) acetic acid - TC agar tissue culture agar, (K.C. Biologicals, Lenexa, KS) - Subdue methaxyl:N-(2,6-dimethylphenyl)-N-(methyoxyacetyl) alanine methyl ester (CIBA- GEIGY)