Showing papers in "Plant Cell Tissue and Organ Culture in 2004"
TL;DR: It has been determined that at each stage salt tolerance is largely controlled by a few QTLs with major effects and several QTLS with smaller effects, suggesting the absence of genetic relationships among stages in tolerance to salinity.
Abstract: Salinity is an important environmental constraint to crop productivity in arid and semi-arid regions of the world. Most crop plants, including tomato, Lycopersicon esculentum Mill., are sensitive to salinity throughout the ontogeny of the plant. Despite considerable research on salinity in plants, there are only a few instances where salt-tolerant cultivars have been developed. This is due in part to the complexity of the trait. A plant's response to salt stress is modulated by many physiological and agronomical characteristics, which may be controlled by the actions of several to many genes whose expressions are influenced by various environmental factors. In addition, salinity tolerance is a developmentally regulated, stage-specific phenomenon; tolerance at one stage of plant development is often not correlated with tolerance at other stages. Specific ontogenic stages should be evaluated separately for the assessment of tolerance and the identification, characterization, and utilization of useful genetic components. In tomato, genetic resources for salt tolerance have been identified largely within the related wild species, and considerable efforts have been made to characterize the genetic controls of tolerance at various developmental stages. For example, the inheritance of several tolerance-related traits has been determined and quantitative trait loci (QTLs) associated with tolerance at individual developmental stages have been identified and characterized. It has been determined that at each stage salt tolerance is largely controlled by a few QTLs with major effects and several QTLs with smaller effects. Different QTLs have been identified at different developmental stages, suggesting the absence of genetic relationships among stages in tolerance to salinity. Furthermore, it has been determined that in addition to QTLs which are population specific, several QTLs for salt tolerance are conserved across populations and species. Research is currently underway to develop tomatoes with improved salt tolerance throughout the ontogeny of the plant by pyramiding QTLs through marker-assisted selection (MAS). Transgenic approaches also have been employed to gain a better understanding of the genetics of salt tolerance and to develop tomatoes with improved tolerance. For example, transgenic tomatoes with overexpression of a single-gene-controlled vacuolar Na+/H+ antiport protein, transferred from Arabidopsis thaliana, have exhibited a high level of salt tolerance under greenhouse conditions. Although transgenic plants are yet to be examined for field salt tolerance and salt-tolerant tomatoes are yet to be developed by MAS, the recent genetic advances suggest a good prospect for developing commercial cultivars of tomato with enhanced salt tolerance in near future.
297 citations
TL;DR: Progress in-depth of various aspects of biotechnological works such as micropropagation and alternative approaches, cell and organ culture techniques, genetic transformation, DNA markers as well as organelle genome and gene cloned from tea and related genera which will be valuable information for the workers working onVarious aspects of Camellia biotechnology are dealt with.
Abstract: Tea is one of the most important non-alcoholic beverage drinks worldwide and gaining further popularity as an important ‘health drink’. It is served as morning drink for 2/3rd of world population daily. Although conventional breeding and propagation contributed significantly for last several decades for varietal improvement, due to the limitations of conventional breeding coupled with the demand for increasing productivity with lower cost of production, application of biotechnology becomes an alternative approach. Therefore, apart from a dozen of tea research institutes globally, several other groups are working on tea and related genera that have registered many valuable information with several achievements. The present review deals with progress in-depth of various aspects of biotechnological works such as micropropagation and alternative approaches, cell and organ culture techniques, genetic transformation, DNA markers as well as organelle genome and gene cloned from tea and related genera which will be valuable information for the workers working on various aspects of Camellia biotechnology.
210 citations
TL;DR: Evidence in plant and animal cells supports the idea that, besides biophysical effects on membranes and nucleic acids, polyamines interact with protein kinases and transcription factors and are thus involved in signal transduction pathways, and suggests that polyamines may play a role in environmentally-induced plasticity of root development.
Abstract: Root development is under the control of hormonal, metabolic, and environmental cues that can act on genetically-controlled developmental programmes and thus affect the plasticity of root architecture. These processes involve not only the five `classical' plant hormones, but also other growth regulators, such as polyamines. The present review emphasises the importance of polyamines in the different aspects of root development: primary root growth and lateral and adventitious root formation. Free (agmatine, putrescine, spermidine, spermine), conjugated (such as hydroxycinnamate conjugates) and macromolecule-bound polyamines are reported to be present in root systems. Modifications of their endogenous levels by inhibitor treatment, by mutation, by gene manipulation, or by exogenous treatment can have drastic effects on root development and subsequent architecture. These effects may be related to the involvement of polyamines in the control of cell division and differentiation, which plays an important role in the root apex and during lateral and adventitious root formation. The exact mechanisms of action remain to be elucidated, but accumulating evidence in plant and animal cells supports the idea that, besides biophysical effects on membranes and nucleic acids, polyamines interact with protein kinases and transcription factors and are thus involved in signal transduction pathways. The high flexibility of polyamine metabolism in response to environmental stress and the metabolic link between polyamine and ethylene synthesis strongly suggest that polyamines may play a role in environmentally-induced plasticity of root development. Moreover, polyamines may be implicated in the establishment of biotic interactions between roots and rhizospheric micro-organisms.
187 citations
TL;DR: An appraisal of the redox capacities of hyperhydrated shoots together with a study of some enzymic activities that catalyse pentose phosphate and glycolytic pathways has indeed shown that such shoots have evolved towards a temporary state of lower differentiation or a juvenile state with a sufficient activity to survive and to defend themselves.
Abstract: Hyperhydricity of micropropagated shoots, formerly called vitrification, undoubtedly results from growth and culture conditions, subjectively reputated as stressing factors: wounding, infiltration of soft culture medium, generally of a high ionic strength, rich in nitrogen and in growth regulators in a special balance, in a humid and gaseous confined atmosphere. Stress is (objectively) defined as a disruption of homeostasis resulting from a constraint escaping the usual flexibility of metabolism. It induces another temporary (reversible) or definitive (irreversible) thermodynamic physiological state. The state-change concept developed by Strasser (1988) and Strasser and Tsimilli-Michael (2001) is applicable to the phenomenon of hyperhydricity. An appraisal of the redox capacities of hyperhydrated shoots together with a study of some enzymic activities that catalyse pentose phosphate and glycolytic pathways has indeed shown that such shoots have evolved towards a temporary state of lower differentiation or a juvenile state with a sufficient activity to survive and to defend themselves.
185 citations
TL;DR: The advances made in various aspects of tissue culture in tomato are reviewed and the issues that still need to be addressed to utilise the full potential of plant tissue culture techniques in genetic improvement and mass propagation of tomato are discussed.
Abstract: Tomato is a major vegetable crop that has achieved tremendous popularity over the last century. It is grown in almost every country of the world. Development of protocols for in vitro selection can provide new advances for the production of stress tolerant cultivars. Techniques have been optimised for the production of haploids and somatic hybrids. Attempts have also been made to transfer the higher regenerative ability of wild varieties to cultivated tomatoes. Although, some information is available on the morphogenesis of tomato, the techniques have not been developed to a level at which they can be utilised in large-scale multiplication of commercially important cultivars. The morphogenesis response seems to be highly dependent PGRs used in the media, which is again cultivar and genotypic specific. Somatic embryogenesis in tomato is still at its infancy, and efficient procedures for large-scale production via somatic embryogenesis are yet to be developed. Genetic stability of the tissue culture raised tomato plants also needs to be addressed. The use of a combination of molecular and conventional breeding techniques could be the option for the development of cultivars resistant to biotic and abiotic stresses. This paper reviews the advances made in various aspects of tissue culture in tomato. It also discusses the issues that still need to be addressed to utilise the full potential of plant tissue culture techniques in genetic improvement and mass propagation of tomato.
130 citations
TL;DR: When the phenolic acetosyringone was present in the co-culture medium at 200 µM, confirmed transgenic lines reached 50% of antibiotic resistant shoots and the transformation efficiency reached 12.5%.
Abstract: Tomato transformation and regeneration were analysed and optimized. Cotyledon explants from Lycopersicon esculentum cv. UC82B, were infected by Agrobacterium tumefaciens strain LBA4404 harbouring the neomycin phosphotransferase (NPTII) reporter gene. The effects of phenolic compounds, vitamins and growth regulators on plant transformation and regeneration were studied. Increasing the vitamin thiamine concentration from 0.1 mg l−1 in standard medium to 0.4 mg l−1 decreased the chlorophyll lost that accompanied the expansion of necrotic areas in cotyledon explants. Optimal shoot regeneration rate was obtained with a balanced concentration of 0.5 mg l−1 auxin indolelacetic acid (IAA) and 0.5 mg l−1 cytokinin zeatin riboside. Finally, when the phenolic acetosyringone was present in the co-culture medium at 200 µM, confirmed transgenic lines reached 50% of antibiotic resistant shoots. Under the above conditions, the transformation efficiency reached 12.5%.
107 citations
TL;DR: Investigation of cell growth dynamics, intracellular levels of proteins, starch and polyamines in suspension cultures of Pinus taeda established in plant growth regulator-free medium and in medium supplemented with 2 μM 2,4-dichlorophenoxyacetic acid and 0.5 μM Kinetin finds highest putrescine levels occurred in cultures growing in BM0 medium and this was associated with the low cellular growth.
Abstract: Somatic embryogenesis is the most important in vitro culture system for conifer propagation. However, Pinus taeda has been considered recalcitrant to somatic embryogenesis in commercial scale-up. The study of biochemical and physiological aspects of cell growth could lead to a better understanding of somatic embryogenesis in this species. In the present work, we investigated the cell growth dynamics, intracellular levels of proteins, starch and polyamines in suspension cultures of Pinus taeda established in plant growth regulator-free medium (BM0) and in medium supplemented with 2 μM 2,4-dichlorophenoxyacetic acid, 0.5 μM 6-benzylaminopurine and 0.5 μM Kinetin (BM2). Cell cultures growing in BM0 medium showed an increase in the sedimented cell volume from 3.77 to 17.73 ml after 24 days of culture. Those cultured in BM2 medium showed an increase in the sedimented cell volume from 4.23 to 25.17 ml after 20 days of culture. Intracellular proteins levels increased during the exponential growth phase and starch levels decreased until the exponential phase, followed by a synthesis up to the stationary phase, in both BM0 and BM2 media. Highest putrescine levels occurred in cultures growing in BM0 medium and this was associated with the low cellular growth.
102 citations
TL;DR: An attempt has been taken to establish an efficient plant regeneration system in vitro from 3, 5, 7 and 9-days-old root segments of four Indica (Bangladeshi) rice genotypes, withotypic effects observed in callus induction and subsequent plant regeneration.
Abstract: An attempt has been taken to establish an efficient plant regeneration system in vitro from 3, 5, 7 and 9-days-old root segments of four Indica (Bangladeshi) rice genotypes. Genotypic effects were observed in callus induction and subsequent plant regeneration. Moreover, the stage of development of the root explants also played a significant role in callus formation and subsequent plant regeneration. Younger explants were more efficient in both callus induction and plant regeneration. Plants regenerated in vitro were successfully established in soil and produced fertile seeds.
98 citations
TL;DR: High frequency of root induction was obtained due to pulse treatment with a NAA and IBA combination (1:1) at the concentration of 100 mg l−1 for 60 min.
Abstract: The effect of liquid pulse treatment of growth regulators on in vitro propagation of banana (Musa spp. AAA) was studied. Optimal shoot proliferation rates were achieved due to the pulse treatment of 6-benzylaminopurine (BA) and kinetin combination (1:1) at the concentration of 50 mg l −1 for 60 min. Similarly high frequency of root induction was obtained due to pulse treatment with a NAA and IBA combination (1:1) at the concentration of 100 mg l −1 for 60 min.
92 citations
TL;DR: Bamboo somatic embryos and in vitro regenerants and potted plants flowered, but no seeds were produced and the effects of sucrose and thidiazuron (TDZ) on callus proliferation were studied.
Abstract: Current research on somatic embryogenesis of bamboo uses reproductive tissue as explants. However, it was hard to obtain the explant. Shoots of a local accession (3–4 m high) were used for multiple shoot production. In order to obtain embryogenic callus, nodal and internodal tissues from in vitro plantlets were placed on Murashige and Skoog (MS) medium supplemented with 9.2 μM kinetin (KN), 13.6 μM 2,4-dichlorophenoxyacetic acid (2,4-D), 0.1% (v/v) coconut milk, and 6% (w/v) sucrose. We studied the effects of sucrose and thidiazuron (TDZ) on callus proliferation. Optimal additives to the MS medium for embryogenic callus proliferation were 0.046 μM TDZ, 13.6 μM 2,4-D and 3% (w/v) sucrose. TDZ also promoted the germination of bamboo somatic embryos. The germination rate of the somatic embryos exceeded 80% on MS-based medium supplemented with 0.455μM TDZ. Naphthaleneacetic acid (NAA) reduced germination. Well-developed plantlets were successfully transferred to soil. There was no albino mutant in subsequent culture. In vitro regenerants and potted plants flowered, but no seeds were produced.
91 citations
TL;DR: This review highlights the impact that biotechnology has had on the improvement of chrysanthemum in vitro cell, tissue and organ culture, micropropagation and transformation.
Abstract: The in vitro tissue culture and micropropagation of chrysanthemums, important floricultural (cut-flower) and ornamental (pot and garden) plants, have been well studied. An increase in genetic transformation studies aimed at improving aesthetic and growth characteristics of the plants has been hampered by low transformation efficiencies and genotype dependence of protocols. As a result chrysanthemum regeneration studies have once again emerged as an essential complement of transformation studies. This review highlights the impact that biotechnology has had on the improvement of chrysanthemum in vitro cell, tissue and organ culture, micropropagation and transformation.
TL;DR: Immature embryos were superior explants in terms of plant regeneration, however, sufficient numbers of plants can be regenerated from mature embryos saving on growth facility resources and time required for the collection of immature embryos.
Abstract: This paper compared the behavior of a diverse set of wheat genotypes in their tissue culture response. Significant differences were detected in plant regeneration, culture efficiency, and regeneration capacity when mature embryos of 47 wheat cultivars, breeding lines, and the common wheat progenitors, Triticum monococcum, T.tauschii, and Aegilops speltoides were compared. Although not currently used in wheat tissue culture, mature embryo-derived callus of cv. ‘Zak’ (SWS), ‘Scarlet’ (HRS), ‘Tara’ (SWS), ‘Jagger’ (HRW), ‘UC 1036’ (HRS), and ‘Kyle’ durum showed better or comparable plant regeneration than commonly cultured cultivars ‘Fielder’ and ‘Bobwhite.’ Of the three diploid wheat progenitors tested, Ae. speltoides regenerated the most plants. In one replicated experiment, callus induction was correlated with culture efficiency (r = 0.42; p = 0.002) and regeneration capacity (r = 0.39; p = 0.002), and in a second larger screen, callus induction correlated with the total number of plants regenerated (r = 0.6; p = 0.001. Immature and mature embryos of ‘Bobwhite’ and ‘Crocus’ were compared for callus induction and plant regeneration. Immature embryos were superior explants in terms of plant regeneration. However, sufficient numbers of plants can be regenerated from mature embryos saving on growth facility resources and time required for the collection of immature embryos.
TL;DR: Leaf explants of Paphiopedilum phiIippinense hybrids directly formed adventitious shoots from wound regions within 1 month, when cultured on modified Murashige and Skoog medium free of plant growth regulator in darkness.
Abstract: Leaf explants of Paphiopedilum phiIippinense hybrids (hybrid PH59 and PH60) directly formed adventitious shoots from wound regions within 1 month, when cultured on modified Murashige and Skoog medium (1/2-strength macro- and full-strength micro-elements) free of plant growth regulator in darkness. The combinations of 2,4-dichlorophenoxyacetic acid ((2,4-D) acid (0, 4.52 and 45.25 μM) and 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea (TDZ) (0, 0.45, 4.54 and 22.71 μM) were used to test their effects on direct shoot bud formation from two types of explants (1.5-cm long intact leaf explants and 0.5-cm long leaf segment explants). In hybrid PH59, 4.54 μM TDZ increased mean numbers of shoots per explant with leaf segment explants. In hybrid PH60, 4.52 μM 2,4-D plus 0.45 μM TDZ promoted direct shoot bud formation from leaf segment explants. In addition, three treatments (4.52 μM 2,4-D, 22.71 μM TDZ, 4.52 μM 2,4-D plus 4.54 μM TDZ) gave a higher response than control on mean numbers of shoots per explant with intact leaf explants. Healthy plantlets each with one to three roots were obtained from leaf-derived shoots after transfer onto a hormone-free medium for 22 months. These plantlets were acclimatized in a greenhouse and grew well with 100% survival rate.
TL;DR: Electrolyte leakage and TTC-staining are efficient to predict viability and a mathematical model allows us to save time and plant material in order to develop an efficient encapsulation—dehydration protocol.
Abstract: Preservation of plant germplasm is important to safeguard biodiversity and to store elite plants. Cryopreservation is one of the possible preservation techniques. Research for a cryopreservation protocol is often inefficient because of slow or poor regrowth of plant material. Therefore, at least one technique, that allows a quick and accurate prognosis of viability after cryopreservation, is required. We evaluated five techniques: electrolyte leakage, triphe-nyltetrazoliumchloride (TTC) staining (visual and spectrophotometrical analysis), malondialdehyde concentrations in plant tissue and a mathematical model that relates ‘water content’ to the weight of encapsulated plant material. Electrolyte leakage and TTC-staining (if visually analysed) are efficient to predict viability. Our mathematical model allows us to save time and plant material in order to develop an efficient encapsulation—dehydration protocol. All other techniques were rejected because of the high variability of the results. This is due to the variability of biochemical activity in plant tissue and the small amount of tissue used in the experiments.
TL;DR: Initiation of embryogenic cell lines from all 20 open-pollinated families of maritime pine plus trees was possible only on DCR based medium, but the addition of L-glutamine and casein hydrolysate significantly increased the number of zygotic embryos producing SE.
Abstract: Immature zygotic embryos from 20 open-pollinated (OP) families of maritime pine (Pinus pinaster) plus trees were screened for their somatic embryogenic capacity. The best time for zygotic embryo collection was between 30th June and 16th July 1999 when most embryos were at a pre-cotyledonary stage of development. The somatic embryogenesis (SE) initiation frequency was highest on DCR basal medium with 13.6 µM 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.4 µM 6-benzylaminopurine (BAP) supplemented with L-glutamine and casein hydrolysate. On this medium, initiation frequencies among OP families ranged from 4.6 to 49.1%. Initiation of embryogenic cell lines from all 20 OP families was possible only on DCR based medium, but the addition of L-glutamine and casein hydrolysate significantly increased the number of zygotic embryos producing SE. Most families showed a similar behaviour on different initiation media; however, a few exceptions were observed. Further development of somatic embryos on maturation medium, consisting of DCR with 120 µM abscisic acid (ABA), 100 g l−1 polyethylene glycol (PEG) and 10 g l−1 gellan gum, occurred in 29% of 896 embryogenic lines representing all 20 OP families. However, development into cotyledonary somatic embryos was observed in only 11% of the cell lines, but this still represented 18 OP families.
TL;DR: A protocol is outlined for direct and indirect regeneration of a medicinally valuable Curcuma amada Roxb using rhizome and leaf sheath explants, which revealed most of the regenerated plantlets were similar to the mother plants.
Abstract: A protocol is outlined for direct and indirect regeneration of a medicinally valuable Curcuma amada Roxb. using rhizome and leaf sheath explants. Multiple shoots were obtained from rhizome explants on Murashige and Skoog (MS) medium fortified with 4.44 µM BA and 1.08 µM α-napthaleneacetic acid (NAA). For indirect regeneration, semi-friable callus obtained from leaf sheath explants on MS medium with 9.0 µM 2,4-D was used. Transfer to 8.88 µM BA and 2.7 µM NAA containing medium produced optimum shoot initiation and development. The regenerated plantlets were transferred to the field. Random amplified polymorphic DNA (RAPD) analysis of regenerated plantlets revealed 103 scorable bands from 10 primers, including nine polymorphic bands, which were absent in control. However, most of the regenerated plantlets were similar to the mother plants.
TL;DR: Randomly amplified polymorphic DNA (RAPD) was used as a tool to assess the clonal identity of four in vitro propagated chestnut rootstock hybrids, and polymorphism was detected between the material propagated in vitro and the donor plants they originated from.
Abstract: Randomly amplified polymorphic DNA (RAPD) was used as a tool to assess the clonal identity of four in vitro propagated chestnut rootstock hybrids (Castanea sativa × C. crenata) described as originally isolated from the same mother tree. To confirm genetic stability after in vitro multiplication for more than 4 years, RAPD patterns of in vitro and donor plants were compared. From 40 arbitrary 10-mer primers used to amplify DNA, 21 provided patterns and were chosen for comparisons. Although significant differences were found in growth parameters between in vitro material of the putative clones, RAPD profiling showed polymorphism in none but one. This accession may then be withdrawn from the same clonal origin as the other three. As expected, no polymorphism was detected between the material propagated in vitro and the donor plants they originated from.
TL;DR: Isolation of late torpedo/cotyledonary-stage embryos to lower carbenicillin/agar media reduced secondary embryogenesis and prevents hyperhydricity, improving embryo conversion and inheritance of the transgenes is shown to be stable in the T1 generation.
Abstract: A simple and efficient regeneration–transformation method was established to obtain transgenic plants of the model legume Medicago truncatula cv. Jemalong. This method takes advantage of a new highly embryogenic line (M9-10a) isolated in our laboratory. Leaflets of in vitro grown M9-10a plants were co-cultured with Agrobacterium tumefaciens EHA105. Plasmid constructs containing the oat arginine decarboxylase gene, Adc and the GUS reporter gene (p35SAdc–Gus) or ELIP-like drought stress protein 22 (DSP22) encoding gene from Craterostigma plantagineum (p35SDsp22) were used. Both constructs include the nptII gene as selection marker. Embryogenic calli (100–97%) were obtained on embryo induction medium containing 100 mg l −1 kanamycin and 500 mg l−1 carbenicillin. Using a two-fold increase in kanamycin concentration, instead of 50 mg l−1 usually used, we reduced the number of emerging false kanamycin-resistant (KanR) embryos, which is an important improvement to the method, making it less laborious and very efficient. Isolation of late torpedo/cotyledonary-stage embryos to lower carbenicillin/agar media reduced secondary embryogenesis and prevents hyperhydricity, improving embryo conversion. Primary transformants (T0) were regenerated within 3–4 months and those that were able to root in a 50 mg l−1 kanamycin medium were transferred to the greenhouse to produce seeds. Southern blot hybridisation analysis confirmed the integration of either the Adc or Dsp22 transgenes in the genome of the T0 transformants. Detection of β-glucuronidase (GUS) activity in Adc–Gus T0 plants demonstrated the expression of the inserted transgene. In average, 1–2 independent transgenic lines are obtained per KanR embryogenic callus, independently of the plasmid construct used for transformation. Inheritance of the transgenes is shown to be stable in the T1 generation.
TL;DR: Efficient shoot regeneration of Vanda coerulea was achieved using thin shoot tip sections and thidiazuron and the highest percentage of protocorm-like bodies (95%) survived and ultimately produced healthy shoots with 2 – 3 leaves when subjected to a 4 week thid Diazuron treatment.
Abstract: Efficient shoot regeneration of Vanda coerulea was achieved using thin shoot tip sections and thidiazuron Protocorm-like bodies or proliferating shoot buds was observed when thin shoot tip sections were cultured on Vacin and Went's (VW) (1949) basal medium supplemented with 1135 µM thidiazuron The highest percentage of protocorm-like bodies (95%) survived and ultimately produced healthy shoots with 2 – 3 leaves when subjected to a 4 week thidiazuron treatment A culture period longer than 8 weeks with thidiazuron resulted in the formation of fasciated or distorted shoots Shoots produced roots when cultured on half strength VW basal medium supplemented with 1142 µM IAA The well rooted shoots were transferred to pots containing charcoal chips, coconut husk and broken tiles (2:2:1) and a 98% survival rate was achieved
TL;DR: Shoot regeneration was achieved from leaves of in vitro cultures of Prunus avium L. cv.
Abstract: Shoot regeneration was achieved from leaves of in vitro cultures of Prunus avium L. cv. 'Lapins' and 'Sweetheart' using woody plant medium (WPM) supplemented with 1-naphthalene-acetic acid (NAA) and thidiazuron (TDZ) or benzyladenine (BA). Percent regeneration was influenced by plant growth regulators and by explant type, orientation and wounding. Optimal regeneration was observed with whole-leaf explants wounded by transverse cuts along the midrib and incubated abaxial surfaces uppermost, on media supplemented with 2.27 or 4.54 µM TDZ plus 0.27 µM NAA. The percent regeneration of the two cultivars was not significantly different. Optimum conditions for regeneration resulted in 71.4% of 'Lapins' and 54% of 'Sweetheart' explants producing one or more shoots per explant.
TL;DR: The results indicate that the easiest and most successful method for grafting was slit micrografting and shoot tips from mature trees of pistachio micrografted onto in vitro juvenile rootstocks, resulted in the restoration of shoot-bud proliferation.
Abstract: The success of various in vitro micrografting methods of shoot tips of pistachio (Pistacia vera L. var. Siirt) have been examined. Excised zygotic embryos that germinated in vitro were used as rootstocks. Current year shoot tips from mature trees of pistachio micrografted onto in vitro juvenile rootstocks, resulted in the restoration of shoot-bud proliferation. Variables tested include a size of microscion, grafting method, effects of culture medium and effects of time of the year at which shoot tips were used. The results indicate that the easiest and most successful method for grafting was slit micrografting. High levels of micrograft take were achieved with 2–4 mm (56.75%) and 4–6 mm (79.25%) long scions obtained from the regenerated shoot tips. The survival rate of the shoot tips was directly related to time of the year. The best growth of microscion was obtained with the in vitro forced shoot tips rather than with shoot tips excised from tree. Slow growth and lack of axillary shoot development on the micrografts was noticeable when the micrografts were cultured on hormone-free and germination medium. In vitro micrografted plantlets were successfully weaned and no problems were encountered with the establishment of micrografted plants in vivo.
TL;DR: The protocol developed in this study suggests a universal and highly efficient cryopreservation system suitable for several genetically diversed Vitis species.
Abstract: Embryogenic cell suspensions of two grapevine rootstocks: 110 Ritcher (V. berlandieri × V. rupestris), 41B (V. vinifera × V. berlandieri) and several table grape and wine cultivars (Vitis vinifera) were successfully cryopreserved by the encapsulation–vitrification method. Embryogenic cell suspensions were precultured for 3 days in liquid MGN medium supplemented with daily increasing sucrose concentrations of 0.25, 0.5, 0.75 M. Precultured cells were encapsulated and directly dehydrated with a highly concentrated vitrification solution prior to immersion in liquid nitrogen for 1 h. After rewarming at 40 °C for 3 min, cryopreserved cells were post-cultured on solid MGN medium supplemented with 2.5 g l−1 activated charcoal. Surviving cells were transferred to solid MGN medium for regrowth or solid MG medium for embryo development and then to solid WPM for plant regeneration. Optimal viability was 42–76% of cryopreserved cells when cell suspensions were precultured with a final sucrose concentration of 0.75 M and dehydrated with PVS2 at 0 °C for 270 min. Biochemical analysis showed that sucrose preculture caused changes in levels of total soluble protein and sugars in cell suspensions. Although the increase in fresh weight was significantly lower in cryopreserved cells than in control cells, the growth pattern of the cryopreserved cells and control cells was the same after two subcultures, following re-establishment in cell suspensions. Protocol developed in this study suggests a universal and highly efficient cryopreservation system suitable for several genetically diversed Vitis species.
TL;DR: Polyploid Spathiphyllum wallisii Regel 'Speedy' plants were obtained from somatic embryos induced on anther filaments exposed to mitosis inhibitors, and flow cytometry was applied as an unambiguous screening tool.
Abstract: Polyploid Spathiphyllum wallisii Regel 'Speedy' plants were obtained from somatic embryos induced on anther filaments exposed to mitosis inhibitors. Primary embryos yielded less polyploid plantlets than secondary embryos. Colchicine could be efficiently replaced by oryzalin or trifluralin (10 µM), resulting in an average yield of 5% polyploids. The mitosis inhibitors were directly added to the induction medium. Morphological differences between diploid and tetraploid S. wallisii hybrids were observed. Throughout our experiments flow cytometry was applied as an unambiguous screening tool. Ploidy breeding within the genus Spathiphyllum holds promises towards the development of tetraploid hybrids with an altered morphology, or triploids with a reduced fertility.
TL;DR: In vitro propagation can be a useful tool in the conservation of this endangered medicinal species and among the three factors, sucrose was the most important for bud initiation followed by BA, and NAA had the weakest effect.
Abstract: A rapid micropropagation protocol was established for Aloe vera L. var. chinensis (Haw.) Berger, Chinese Aloe. The effects of three factors, namely BA, NAA and sucrose, on bud initiation were evaluated by L9 (34) orthogonal design. The variance analysis of the experimental results showed that the actions of the three factors were all considerable. Among the three factors, sucrose was the most important for bud initiation followed by BA, and NAA had the weakest effect. The best medium for bud initiation was semi-solid MS supplemented with 2.0 mg l−1 BA, 0.3 mg l−1 NAA, 30 g l−1 sucrose and 0.6 g l−1 PVP (pH 5.8), on which Chinese aloe could multiply 15 times in 4 weeks. Some shoots rooted spontaneously on 1/2 strength MS medium, but the rooting percentage was improved in the presence of 0.2 mg l−1 NAA. Rooted plantlets were acclimatized to greenhouse conditions. The young plantlets from tissue culture were transplanted successfully. In vitro propagation can be a useful tool in the conservation of this endangered medicinal species.
TL;DR: Pepper was characterized by a strong asynchrony of pollen development within a single anther, and associations were found among the percentage of early-binucleate pollen, the frequency of embryogenic multinucleates pollen, and the yield of pollen embryos.
Abstract: Anthers of Capsicum annuum L. were cultured on Murashige and Skoog (MS) medium containing 0.1 mg l−1 NAA and 0.1 mg l−1 kinetin. Inoculated anthers were subjected to 31 °C and development of microspores in anthers of varying stages was observed cytologically using 4′-6-diamidino-2-phenylindol-2HCl (DAPI). Pepper was characterized by a strong asynchrony of pollen development within a single anther. Percentage of pollen at different stages changed with the culture period, and the proportion of dead pollen increased drastically from day 2 after culture. Microspores that were cultured at the late-uninucleate stage followed one of two developmental pathways. In the more common route, the first sporophytic division was asymmetric and produced what appeared to be a typical bicellular pollen. Embryogenic pollen was formed by repeated divisions of the vegetative nucleus. In the second pathway, which occurred in fewer microspores, the first division was symmetric and both nuclei divided repeatedly to form embryogenic pollen. In early-bicellular pollen, sporophytic pollen was produced through division of the vegetative nucleus. In mid-bicellular pollen, the generative nucleus may undergo division to produce two or more sperm-like nuclei. However, division of the generative nucleus alone to form the embryo was never observed. The anther stage optimal for embryo production contained a large proportion (>75%) of early-binucleate pollen. Associations were found among the percentage of early-binucleate pollen, the frequency of embryogenic multinucleate pollen, and the yield of pollen embryos.
TL;DR: Somatic embryo induction and plant regeneration have been obtained in tissues from mature Quercus robur L. trees by forcing Epicormic shoots to flush in branch segments collected from the crown of trees growing in selected stands on different collection dates.
Abstract: Somatic embryo induction and plant regeneration have been obtained in tissues from mature Quercus robur L. trees. Epicormic shoots were forced to flush in branch segments collected from the crown of trees growing in selected stands on different collection dates. Expanding leaves from five genotypes, cultured following a multistage treatment procedure, produced somatic embryos at frequencies ranging from 0.3 to 3.6% of leaf explants, depending on genotype and collection date. After being induced, somatic embryos started a recurrent process by secondary embryogenesis which amplified the 15 embryogenic lines established. Plant recovery was achieved in 60% and 17% of matured embryos from two genotypes.
TL;DR: The most intriguing aspects of past and current research on rolB and rolD genes are highlighted and discussed.
Abstract: Rol genes belong to the T-DNA which is transferred by Agrobacterium rhizogenes into plant cells Each of these genes affects plant development and is regulated by the host In this review, after a brief historical background, the most intriguing aspects of past and current research on rolB and rolD genes are highlighted and discussed
TL;DR: The results suggest that sucrose is a better carbon source than glucose for organogenesis of ‘Wegierka Zwykła’, even though at lower concentrations the efficiency of the sugars was comparable, and at 2–5% concentrations glucose uptake was higher than sucrose uptake.
Abstract: Leaf explants of plum ‘Wegierka Zwykla’ were cultured on modified MS medium supplemented with 7.5 µM TDZ (thidiazuron) and 0.9 µM 2,4-D (2,4-dichlorophenoxyacetic acid), with the addition of either sucrose or glucose at a concentration of 2%, 3%, 4%, 5% or 6% (w/v). Regeneration was carried out in two steps: the first in darkness, the second in photoperiod conditions after subculture onto fresh medium. The study assessed the influence of the kind of sugar used and its concentration in the medium on organogenesis efficiency, and on sugar uptake from the medium. The results suggest that sucrose is a better carbon source than glucose for organogenesis of ‘Wegierka Zwykla’, even though at lower concentrations the efficiency of the sugars was comparable. With increasing concentration of sugars, the efficiency of organogenesis decreased, a relation more evident for media with glucose. In the first (dark) step of regeneration, the explants utilised less carbohydrates from the media than in the second step, when the main increase of explant weight took place. In the second phase, at 2–5% concentrations glucose uptake was higher than sucrose uptake.
TL;DR: Together, these experiments have established optimized parameters for propagation and growth of C. cujete plantlets in a sterile controlled environment for biochemical characterization and production of high-quality medicinal products.
Abstract: Crescentia cujete L. is a widely distributed medicinal tree with a diverse range of phytochemicals used as medicinal compounds. Seedlings of wild-harvested C. cujete were established in vitro and used as the starting material for the establishment of axenic cultures. Shoots were proliferated from nodal segments and were maintained over a period of more than 2 years by sequential subculture on a medium containing 1.0 µmol l−1 kinetin. De novo regeneration was induced on petiole sections cultured onto a medium containing thidiazuron in combination with 2,4-dichlorophenoxyacetic acid. Axenic cultures were also used to test the efficiency of three different cultivation systems for production of biomass of C. cujete. Growth of plantlets in a temporary immersion bioreactor resulted in significant increases in biomass, leaf number, shoot height and transplant efficiency. Plantlets grown in the bioreactors were acclimatized under greenhouse conditions. Together, these experiments have established optimized parameters for propagation and growth of C. cujete plantlets in a sterile controlled environment for biochemical characterization and production of high-quality medicinal products.
TL;DR: The recent advances made in the use of transgenic plants and plant cell cultures as biological factories for the production of human therapeutics and biopharmaceuticals are summarized and the long-term potential of `molecular farming' as a low-cost, efficient method for theProduction of biological materials with demonstrated utility to the pharmaceutical industry or medical community is discussed.
Abstract: In recent years there has been a dramatic increase in the application of plant biotechnology for the production of a variety of commercially valuable simple and complex biological molecules (biologics) for use in human and animal healthcare. Transgenic whole plants and plant cell culture systems have been developed that have the capacity to economically produce large-scale quantities of antibodies and antibody fragments, antigens and/or vaccine epitopes, metabolic enzymes, hormones, (neuro)peptides and a variety of biologically active complexes and secondary metabolites for direct use as therapeutic agents or diagnostic tools in the medical healthcare industry. As the products of genetically modified plants make their way from concept to commercialization the associated risks and acceptance by the public has been become a focal point. In this paper, we summarize the recent advances made in the use of transgenic plants and plant cell cultures as biological factories for the production of human therapeutics and biopharmaceuticals and discuss the long-term potential of `molecular farming' as a low-cost, efficient method for the production of biological materials with demonstrated utility to the pharmaceutical industry or medical community.