High Yields Of Protoplasts Research Articles

Establishment of transient and stable gene transformation systems in medicinal woody plant Acanthopanax senticosus

BackgroundTransient and stable gene transformation systems play a crucial role in elucidating gene functions and driving genetic improvement in plants. However, their application in medicinal woody plants has been hampered by inefficient procedures for isolating protoplasts and regenerating plants in vitro.ResultsEmbryogenic callus protoplast isolation and transient transformation system were successfully established. The highest yield of protoplasts was approximately 1.88 × 106 cells per gram with a viability of 90% under the combination of 1.5% cellulase and 0.2% macerozyme, with enzymatic digestion for 6 h in darkness followed by centrifugation at 400×g for 5 min. The transient transfection rate of protoplast reached 45.56% at a PEG 4000 concentration of 40%, a transfection time of 40 min, 16 h of dark incubation, a plasmid concentration of 1.5 ng μL−1, and 25 min heat shock at 45 °C. In addition, 15 Agrobacterium tumefaciens-mediated GUS-positive seedlings were obtained through the somatic embryogenetic pathway under the optimized conditions.ConclusionThis study successfully established both transient and stable genetic transformation systems, paving the way for future molecular biology research on A. senticosus.Graphical

Establishing Gene Expression and Knockout Methods in Esteya vermicola CBS115803.

Pine wilt disease, which is caused by the nematode Bursaphelenchus xylophilus, is one of the most destructive forest diseases worldwide. Esteya vermicola, a nematophagous fungus, has emerged as a promising biological control agent. However, the limited availability of gene function analysis techniques hinders further genetic modification of this fungus. In this study, we employed a combination of enzymes (driselase, snailase, and cellulase) to enzymatically degrade the cell wall of the fungus, resulting in a high yield of protoplasts. Furthermore, by utilizing 0.6M sucrose as an osmotic pressure stabilizer, we achieved a significant protoplast regeneration rate of approximately 31%. Subsequently, we employed the polyethylene glycol-mediated protoplast transformation method to successfully establish a genetic transformation technique for E. vermicola CBS115803. Additionally, through our investigation, we identified the Olic promoter from Aspergillus nidulans, which effectively enhanced the expression of the DsRed gene encoding a red fluorescent protein in E. vermicola CBS115803. Moreover, we successfully implemented a split-marker strategy to delete the EvIPMD gene in E. vermicola CBS115803. In summary, our findings present valuable experimental methodologies for gene function analysis in E. vermicola CBS115803.

Direct leaf-peeling method for areca protoplasts: a simple and efficient system for protoplast isolation and transformation in areca palm (Areca catechu)

BackgroundAreca palm (Areca catechu) is a woody perennial plant of both economical and medicinal importance grown in tropical and subtropical climates. Yet, the molecular biology study of areca palm is extremely impeded by its unavailability of a transformation method. An efficient protoplast isolation and transformation system could be highly desirable to overcome this barrier.ResultsHere, we described a simple and efficient method for protoplast isolation and transformation from the perennial plant areca palm. A high yield of protoplasts (2.5 × 107 protoplasts per gram of fresh leaf tissues) was obtained from the fresh light green leaflet from the newly-emerged leaf digested overnight in the enzyme solution [2% (w/v) cellulase R10, 0.5% (w/v) macerozyme R10, 0.7 M mannitol, 10 mM CaCl2, 20 mM KCl, 20 mM MES and 0.1% (w/v) BSA, pH 5.7] by the direct leaf-peeling method. The isolated areca protoplasts maintain viability of 86.6% and have been successfully transformed with a green fluorescent protein (GFP)-tagged plasmid (pGreen0029-GFP, 6.0 kb) via the polyethylene glycol (PEG)-mediated transformation. Moreover, the mannitol concentration (optimal: 0.7 M) was determined as a key factor affecting areca protoplast isolation. We also demonstrated that the optimal density of areca protoplast for efficient transformation was at 1.0–1.5 × 106 cells/ml. With the optimization of transformation parameters, we have achieved a relatively high transformation efficiency of nearly 50%.ConclusionWe have established the first efficient protocol for the high-yield isolation and transformation of areca palm protoplasts. This method shall be applied in various biological studies of areca palm, such as gene function analysis, genome editing, protein trafficking and localization and protein–protein interaction. In addition, the protoplast system offers a great genetic transformation approach for the woody perennial plant-areca palm. Moreover, the established platform may be applied in protoplast isolation and transformation for other important species in the palm family, including oil palm and coconut.

Evaluation and Improvement of Protocols for Ganoderma boninense Protoplast Isolation and Regeneration

Ganoderma boninense is the causal agent of basal stem rot (BSR) disease of oil palm. The BSR disease reduces oil palm yield by up to 80% of the average oil yield. Attempts to control the disease caused by this fungus in the field showed varying levels of success and cases of infection increased from year to year. Hence, the development of new efficient methods to control the spread of this fungus should be commenced promptly. To ensure a better strategy is created, more thorough research on the method deploy by this fungus to infect the host at the molecular level need to be carried out first. However, the major limitation in endeavoring into the functional analysis of virulence genes related to the pathogenicity of this fungus was hampered by the unavailability of established methods for protoplast isolation with a high regeneration rate to be used in the genetic manipulation analysis. Thus, in this paper, we report an efficient protocol for protoplast isolation and regeneration in G. boninense and successfully used the isolated protoplasts in PEG-mediated transformation analysis. A large quantity of protoplast was obtained using the protocol that utilizes the following parameters: 3 to 4-day-old mycelia, treated with 1% lysing enzyme and 0.02% Driselase, incubated at 30 °C in an osmotic medium containing 0.6 M mannitol at pH 5.8 for 2 h. The highest protoplast yield was in the range of 8.95 × 109 to 3.12 × 1010 cells/mL per 5 g of mycelia used. The regeneration rate ranged from 9.03% to 22.55%, depending on the regeneration media used. By using 5 µg of vector to transform into 1.0 × 107 protoplast/mL, around 3 – 10 mitotically stable putative transformants were successfully obtained and verified via PCR. This protocol will find useful applications in genetic studies to enhance insight into this poorly characterized and understood phytopathogen.

Development of a petal protoplast transfection system for Sinningia speciosa.

PremiseTransient gene expression systems are powerful tools for studying gene interactions in plant species without available or stable genetic transformation protocols. We optimized a petal protoplast transformation protocol for Sinningia speciosa, a model plant, to study the development of floral symmetry.Methods and ResultsA high yield of petal protoplasts was obtained using a 6‐h enzyme digestion in a solution of 1.5% cellulase and 0.4% macerozyme. Modest transfection efficiency (average 41.4%) was achieved. The viability of the transfected protoplasts remained at more than 90%. A fusion of green fluorescent protein and CYCLOIDEA (SsCYC), the Teosinte branched 1/Cincinnata/Proliferating cell factor transcription factor responsible for floral symmetry, was subcellularly localized inside the nuclei of the protoplasts. Transiently overexpressing SsCYC indicates the success of this system, which resulted in the predicted increased (but nonsignificant) expression of its known target RADIALIS (SsRAD1), consistent with gene network expectations.ConclusionsThe transient transfection system presented herein can be effectively used to study gene‐regulatory interactions in Gesneriaceae species.

Application of Protoplast Regeneration to CRISPR/Cas9 Mutagenesis in Nicotiana tabacum.

Protoplast transfection is widely used in plant research to rapidly evaluate RNA degradation, reporter assay, gene expression, subcellular localization, and protein-protein interactions. In order to successfully use protoplast transfection with the newly emerging clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) protein editing platform, high yield of protoplasts, stable transfection efficiency, and reliable regeneration protocols are necessary. The Nicotiana tabacum transient protoplast transfection and regeneration system can effectively obtain target gene mutations in regenerated plants without transgenes and is thus a very attractive technique for evaluating gene editing reagents using CRISPR/Cas-based systems. Here, we describe in detail sterilized seed germination, culture conditions, isolation of Nicotiana tabacum protoplasts from tissue culture explants, construction of a vector containing the Cas protein and sgRNA cassette, highly efficient polyethylene glycol-calcium transient transfection of plasmids delivered into protoplasts, evaluation of mutagenesis efficiency and genotype analysis from protoplasts and regenerated plants, and the regeneration conditions to obtain CRISPR-edited plants from single protoplasts.

Efficient isolation and purification of tissue-specific protoplasts from tea plants (Camellia sinensis (L.) O. Kuntze)

BackgroundPlant protoplasts constitute unique single-cell systems that can be subjected to genomic, proteomic, and metabolomic analysis. An effective and sustainable method for preparing protoplasts from tea plants has yet to be established. The protoplasts were osmotically isolated, and the isolation and purification procedures were optimized. Various potential factors affecting protoplast preparation, including enzymatic composition and type, enzymatic hydrolysis duration, mannitol concentration in the enzyme solution, and iodixanol concentration, were evaluated.ResultsThe optimal conditions were 1.5% (w/v) cellulase and 0.4–0.6% (w/v) macerozyme in a solution containing 0.4 M mannitol, enzymatic hydrolysis over 10 h, and an iodixanol concentration of 65%. The highest protoplast yield was 3.27 × 106 protoplasts g−1 fresh weight. As determined through fluorescein diacetate staining, maximal cell viability was 92.94%. The isolated protoplasts were round and regularly shaped without agglomeration, and they were less than 20 μm in diameter. Differences in preparation, with regard to yield and viability in the tissues (roots, branches, and leaves), cultivars, and cultivation method, were also observed.ConclusionsIn summary, we reported on a simple, efficient method for preparing protoplasts of whole-organ tissue from tea plant. The findings are expected to contribute to the rapid development of tea plant biology.

Protoplast isolation and culture from Kalancho\xeb species: optimization of plant growth regulator concentration for efficient callus production

A high yield of isolated protoplasts and efficient regeneration protocols are prerequisites for successful development of somatic hybrids. In the present study, protoplast isolation and regeneration were evaluated in 12 Kalanchoë accessions belonging to nine species. The highest protoplast yield was obtained from K. blossfeldiana ‘Charming Red Meadow’ with 10.78 ± 0.51 × 105 protoplasts per gram fresh weight. We observed significant differences of protoplast yield while there was no distinct difference in viability among the accessions. Seven accessions reached the microcolony stage and four developed microcalli in medium supplemented with 1.0 mg/l 1-naphthaleneacetic acid (NAA), 0.5 mg/l 6-benzylaminopurine (BAP) and 0.5 mg/l 2,4-dichlorophenoxy acetic acid (2,4-D). Using five selected accessions we optimized the PGR (plant growth regulators) concentrations using combinations of NAA, BAP and 2,4-D. K. blossfeldiana cultivars ‘Charming Red Meadow’ and ‘Paris’ produced significantly different numbers of calli depending on the PGR concentrations. For plant regeneration, the medium was supplemented with 1 mg/l NAA and 2 mg/l BAP or 2 mg/l zeatin. Shoots were regenerated on medium supplemented with NAA and BAP for K. blossfeldiana ‘Charming Red Meadow’ and K. blossfeldiana ‘Paris’. The plants successfully developed roots on the medium supplemented with IAA. The medium containing zeatin induced root formation directly from callus in K. blossfeldiana ‘Charming Red Meadow’. Our findings have the potential to facilitate the use of Kalanchoë species in somatic hybridization breeding programs.

A high-throughput transient expression system for rice.

Rice is an important global crop and represents a vital source of calories for many food insecure regions. Efforts to improve this crop by improving yield, nutritional content, stress tolerance, or resilience to climate change are certain to include biotechnological approaches, which rely on the expression of transgenes in planta. The throughput and cost of currently available transgenic expression systems is frequently incompatible with modern, high‐throughput molecular cloning methods. Here, we present a protocol for isolating high yields of green rice protoplasts and for PEG‐mediated transformation of isolated protoplasts. Factors affecting transformation efficiency were investigated, and the resulting protocol is fast, cheap, robust, high‐throughput, and does not require specialist equipment. When coupled to a high‐throughput modular cloning system such as Golden Gate, this transient expression system provides a valuable resource to help break the “design‐build‐test” bottleneck by permitting the rapid screening of large numbers of transgenic expression cassettes prior to stable plant transformation. We used this system to rapidly assess the expression level, subcellular localisation, and protein aggregation pattern of nine single‐gene expression cassettes, which represent the essential component parts of the β‐cyanobacterial carboxysome.

Preparation and Regeneration of Protoplasts from the Ethyl Vincamine Producing Fungus CH1 (Geomyces sp.)

Vinpocetine, a semi-synthetic compound derived from the alkaloid vincamine, exhibits effective pharmacological activities for the treatment and prevention of cerebrovascular circulation and vascular cognitive disorders. Vinpocetine can be produced through a one-step chemical reaction beginning with ethyl vincamine, and a two-step chemical reaction beginning with vincamine. In our previous study, the endophytic fungus CH1, Geomyces sp., was isolated and identified as a producer of ethyl vincamine, which was first obtained by endophytic fungal fermentation. However, the production was largely limited. Fungal protoplasts are a valuable experimental tool for physiological and genetic research such as protoplast fusion, gene transfer and metabolite production. In this paper, we optimized some key factors for the preparation and regeneration of protoplasts from strain CH1. Using an enzymes mixture consisting of cellulase (2.0%, w/v), glusulase (3.0%, w/v) and driselase (1.0%, w/v) in osmotic stabilizer (0.7 mol/L NaCl), the highest yield of protoplasts (6.78×107/mL) was obtained with mycelia after 72 h at pH 5.0-6.0 by digesting for 1.5 h at 30°C. After purification of the prepared protoplasts, they were regenerated in the regeneration medium using a bilayer plate culture method.

Efficient isolation of Magnolia protoplasts and the application to subcellular localization of MdeHSF1

BackgroundMagnolia is a woody ornamental plant, which is widely used in urban landscaping. However, its lengthy juvenile period and recalcitrance to regeneration impedes functional characterization of its genes.ResultsWe developed an efficient protoplast isolation and transient expression system for Magnolia denudata × Magnolia acuminata ‘Yellow River’. The highest yield of protoplasts was obtained from young leaves digested in 3% Cellulase R10, 0.8% Macerozyme R10, 0.04% pectinase and 0.4 M mannitol enzymolysis solution for 6 h. For transfection of protoplasts, 20% PEG4000 for 5 min was optimal. To verify the protoplast system and begin to understand heat tolerance in Magnolia, a heat shock transcription factor MdeHSF1 was cloned from ‘Yellow River’, which belongs to the HSF subfamily A and has significant homology with AtHSFA1A. Subcellular localization analysis indicated that MdeHSF1 was expressed in the cell nucleus. Furthermore, qPCR analysis of the MdeHSF1 transcript level in response to high temperature stress suggested that MdeHSF1 might be involved in regulating heat stress tolerance in ‘Yellow River’.ConclusionThe described protocol provides a simple and straightforward method for isolating protoplast and exploring gene subcellular localization of MdeHSF1 in Magnolia. This expands the new research of protoplast isolation and transfection in Magnolia.

Highly efficient mesophyll protoplast isolation and PEG-mediated transient gene expression for rapid and large-scale gene characterization in cassava (Manihot esculenta Crantz)

BackgroundCassava (Manihot esculenta Crantz) is a major crop extensively cultivated in the tropics as both an important source of calories and a promising source for biofuel production. Although stable gene expression have been used for transgenic breeding and gene function study, a quick, easy and large-scale transformation platform has been in urgent need for gene functional characterization, especially after the cassava full genome was sequenced.MethodsFully expanded leaves from in vitro plantlets of Manihot esculenta were used to optimize the concentrations of cellulase R-10 and macerozyme R-10 for obtaining protoplasts with the highest yield and viability. Then, the optimum conditions (PEG4000 concentration and transfection time) were determined for cassava protoplast transient gene expression. In addition, the reliability of the established protocol was confirmed for subcellular protein localization.ResultsIn this work we optimized the main influencing factors and developed an efficient mesophyll protoplast isolation and PEG-mediated transient gene expression in cassava. The suitable enzyme digestion system was established with the combination of 1.6% cellulase R-10 and 0.8% macerozyme R-10 for 16 h of digestion in the dark at 25 °C, resulting in the high yield (4.4 × 107 protoplasts/g FW) and vitality (92.6%) of mesophyll protoplasts. The maximum transfection efficiency (70.8%) was obtained with the incubation of the protoplasts/vector DNA mixture with 25% PEG4000 for 10 min. We validated the applicability of the system for studying the subcellular localization of MeSTP7 (an H+/monosaccharide cotransporter) with our transient expression protocol and a heterologous Arabidopsis transient gene expression system.ConclusionWe optimized the main influencing factors and developed an efficient mesophyll protoplast isolation and transient gene expression in cassava, which will facilitate large-scale characterization of genes and pathways in cassava.

Influence of culture vessels on mesophyll protoplast yield ofPelargoniumssp.

Somatic hybridization is a multistage process with many factors of influence. It requires a high yield of stable protoplasts. Plant protoplasts can be isolated from different plant tissues. Leaves of in vitro cultivated plants are one of the preferential sources. Using the same isolation protocol for four Pelargonium genotypes (Pelargonium ‘Pink Capitatum’, P. graveolens, P. × hortorum ‘Antik Violet’, wild type 585) the yield of leaf protoplasts from in vitro plants was very inconstant between the experiments, from high yield up to no protoplasts. To investigate the influence of culture conditions of the starting plants on the protoplast yield, plants were cultivated in Magenta vessels®, baby jars and 300 mL flasks. After 15 weeks, apex necrosis was observed in all vessels but with different strength: in Magenta® vessels it was lower, whereas plants cultivated in 300 mL flasks showed stronger symptoms. At the same time, these plants had a number of adventitious shoots with small leaves. Independently of the kind of culture vessel, ‘Pink Capitatum’ protoplasts could be isolated and they developed further in protoplast culture medium (PPM 1). The protoplast yield ranged between 1.6-5.0 × 105 protoplasts g-1 fresh weight (both from Magenta® vessel). Wild type 585 protoplasts were received also from all three plant culture conditions. However, getting protoplasts from Magenta® vessel plants involved some problems, the protoplast viability was low and a further development, at least a cell wall formation was not observed. Protoplasts of P. × hortorum could be isolated from all three variants. High number of protoplasts (1.8 × 106 g-1 fresh weight) was received from 300 mL flasks plants. Despite the high yield these protoplasts did not develop further. P. × hortorum protoplasts from Magenta® vessels showed cell divisions. A strong influence of culture vessels was found for P. graveolens protoplasts. Plants from 300 mL vessels gave stable protoplasts. These protoplasts showed a striking cell division activity. Plants from other vessels gave only once (from baby jar) viable protoplasts. The results show a considerable effect of plant culture conditions on Pelargonium protoplasts. Unfortunately, there is no vessel which would be optimal for all.

Efficient production of Aschersonia placenta protoplasts for transformation using optimization algorithms.

The insect pathogenic fungus Aschersonia placenta is a highly effective pathogen of whiteflies and scale insects. However, few genetic tools are currently available for studying this organism. Here we report on the conditions for the production of transformable A. placenta protoplasts using an optimized protocol based on the response surface method (RSM). Critical parameters for protoplast production were modelled by using a Box-Behnken design (BBD) involving 3 levels of 3 variables that was subsequently tested to verify its ability to predict protoplast production (R(2) = 0.9465). The optimized conditions resulted in the highest yield of protoplasts ((4.41 ± 0.02) × 10(7) cells/mL of culture, mean ± SE) when fungal cells were treated with 26.1 mg/mL of lywallzyme for 4 h of digestion, and subsequently allowed to recover for 64.6 h in 0.7 mol/L NaCl-Tris buffer. The latter was used as an osmotic stabilizer. The yield of protoplasts was approximately 10-fold higher than that of the nonoptimized conditions. Generated protoplasts were transformed with vector PbarGPE containing the bar gene as the selection marker. Transformation efficiency was 300 colonies/(μg DNA·10(7) protoplasts), and integration of the vector DNA was confirmed by PCR. The results show that rational design strategies (RSM and BBD methods) are useful to increase the production of fungal protoplasts for a variety of downstream applications.

A Simplified and Rapid Method for the Isolation and Transfection of Arabidopsis Leaf Mesophyll Protoplasts for Large-Scale Applications.

Arabidopsis leaf mesophyll protoplasts constitute an important and versatile tool for conducting cell-based experiments to analyze the functions of distinct signaling pathways and cellular machineries using proteomic, biochemical, cellular, genetic, and genomic approaches. Thus, the methods for protoplast isolation and transfection have been gradually improved to achieve efficient expression of genes of interest. Although many well-established protocols have been extensively tested, their successful application is sometimes limited to researchers with a high degree of skill and experience in protoplasts handling. Here we present a detailed method for the isolation and transfection of Arabidopsis mesophyll protoplasts, in which many of the time-consuming and critical steps present in the current protocols have been simplified. The method described is fast, simple, and leads to high yields of competent protoplasts allowing large-scale applications.

A transient gene expression system in Populus euphratica Oliv. protoplasts prepared from suspension cultured cells

Populus euphratica Oliv., a species of the model woody plant genus Populus, is well known for its tolerance to salinity stress, the underlying mechanism of which is a research hotspot. Transient expression of fluorescent fusion proteins is commonly used for rapid assessment of gene functions and interactions, and thus would be useful to study the genes involved in salt tolerance in this species. Our transient gene expression protocol for P. euphratica included a simple protoplast preparation and transformation procedure from suspension cultured cells. The highest protoplast yield (8 × 107 g−1 fresh weight) with high viability (above 90 %) was obtained using an optimized enzyme mix of 4 % (w/v) cellulase R10, 0.5 % (w/v) pectinase, and 0.2 % (w/v) hemicellulase. Factors affecting protoplast transformation efficiency were also optimized: 20 μg plasmid DNA versus 105 protoplasts, and a transformation time of 20 min using PEG, which resulted in a transformation efficiency greater than 50 %. A pair of known markers was simultaneously and correctly expressed in the same P. euphratica protoplasts by co-transformation. The isolation and transformation protocol took 5 h, and results could be obtained within 24 h. This protoplast transient expression system is suitable for studying gene expression, protein localization, and protein–protein interactions in woody plants. In addition, it would be particularly useful for studying the signaling pathway involved in the salt tolerance of P. euphratica in a homologous system, which may not even be possible using protoplasts prepared from other species.

A comparison of different Gracilariopsis lemaneiformis (Rhodophyta) parts in biochemical characteristics, protoplast formation and regeneration

Gracilariopsis lemaneiformis is a commercially exploited alga. Its filaceous thallus can be divided into three parts, holdfast, middle segment and tip. The growth and branch forming trend and agar content of these three parts were analyzed, respectively, in this study. The results showed that the tip had the highest growth rate and branched most, although it was the last part with branch forming ability. The holdfast formed branches earliest but slowly. Holdfast had the highest agar content. We also assessed the difference in protoplast formation and regeneration among three parts. The middle segment displayed the shortest enzymolysis time and the highest protoplast yield; whereas the tip had the strongest vitality of protoplasts formation. Juvenile plants were only obtained from the protoplasts generated from the tip. These results suggested that the differentiation and function of G. lemaneiformis was different.

Callus formation and plant regeneration from protoplasts of sunflower calli and hypocotyls

Sunflower (cv. Girapac SH222) protoplasts were obtained from 4-7 day-old hypocotyls and cotyledons and from two-month old calli. Higher yields of protoplasts were achieved with medium El (KCl 25g dm<sup>-3</sup>, CaCl<sub>2</sub> 2g dm<sup>-3</sup>, MES 0.7 g• dm<sup>-3</sup>, pH 5.5) and the combination of Driselase Fluka 0.2%, Macerozyme Onozuka 0.2% and Cellulase Onozuka R10 0.2%. Hypocotyls gave the highest yields of protoplasts, followed by cotyledons and calli. Protoplasts were cultivated in liquid and on solid media using both L4M (Burrus et al., 1991) and V-KM (Bokelman and Roest, 1983) media. Culture on solid M1 medium (L4M medium supplemented with NAA 3.0 mg•dm<sup>- 3</sup>, 2,4-D 0.1 mg•dm<sup>-3</sup> and BA 1.0 mg•dm <sup>-3</sup>) gave a good planting efficiency with the development of many white-green colonies. These colonies gave rise to small calli which were transferred to MSmod medium (MS medium supplemented with KCI 5 g•dm<sup>-'</sup>, and polyvinylpyrrolidone (PVP, 4 g• dm<sup>-3</sup>) containing benziladenine (BA, 0.5 mg•dm<sup>-3</sup>), naphtaleneacetic acid (NAA, 0.5 mg•dm<sup>-3</sup>) and giberelic acid (GA3 0.1 mg•dm<sup>-3</sup>). After two weeks, calli were transferred to MSmod medium containing BA 1.0 mg•dm<sup>-3</sup>, NAA 0.1 mg•dm<sup>-3</sup>, and GA3 0.1 mg•dm<sup>-3</sup> for shoot formation. Shoots were excised and induced to root in MSmod supplemented with BA 0.1 mg•dm<sup>-3</sup>, NAA 1.0 mg•dm<sup>-3</sup>, and GA3 0.1 mg•dm<sup>-3</sup>. Plantlets were then transferred to sterilised vermiculite for greenhouse acclimation.

Methods for Cercospora coffeicola protoplast isolation and genetic transformation with the green fluorescent protein

Cercospora coffeicola is the causal agent of brown eye spot on coffee leaves. Although the disease has significant importance, few molecular studies have been done with C. coffeicola. Here we report a protocol for isolating protoplasts as well as development of a genetic transformation system using Green Fluorescent Protein. High yields of protoplasts (≈108/ml) were obtained from mycelial cultures from five isolates of C. coffeicola. One isolate was transformed with a vector encoding hygromycin resistance and Green Fluorescent Protein. Out of 43 hygromycin-resistant transformants obtained, Green Fluorescent Protein was highly expressed in one (2.3 %).

ПОЛУЧЕНИЕ ПРОТОПЛАСТОВ ОБЛЕПИХИ ( HIPPOPHAE RHAMNOIDES L.)

The aim of research was to study the effect of a method of protoplast isolation on Hippophae rhamnoides cell viability. The main objectives were the release of protoplasts H. rhamnoides from callus tissue by a combination of mechanical and enzymatic effects, as well as evaluation of the general state of isolated cells after isolation and purification. The objects of studies were mesophyll cells and leaf mesophyll explants introduced in culture in vitro. It is assumed that considerable damage of cells in the process of mechanical-enzymatic treatment is not only a result of mechanical impact, but also an effect of the release of metabolic products (polyphenolic components) of cells and their decay. Also protoplasts are dedifferentiated and simplify the process of differentiation in various breeding and biotechnological experiments. As a result of the work, an optimized method of H. rhamnoides protoplast isolation with decreased levels of cell damage is set up. It is revealed that important factors for high yield of viable protoplasts are: proper concentration of D-mannite as an osmoticum; proper concentration of cellulase R10 and macerozime R10; use of sodium tiosulfate as an antioxidante; proper time of incubation of leaf explants in medium with enzymes.