RITA® Temporary Immersion System (TIS) for Biomass Growth Improvement and Ex Situ Conservation of Viola ucriana Erben & Raimondo

Viola ucriana Erben & Raimondo is a rare and endangered taxon, endemic to a limited area on Mount Pizzuta in northwestern Sicily, Italy. Its population is significantly threatened by anthropogenic activities, including fires, overgrazing, and habitat alterations. Temporary immersion systems (TISs) have proven effective for large-scale propagation in various protected species, offering potential for ex situ conservation and population reinforcement of V. ucriana. This study aimed to establish a bioreactor-based micropropagation protocol for shoot multiplication and compare the efficacy of a TIS with that of conventional solid culture medium (SCM). Three different plant growth regulators (PGRs) were also compared: 6-benzylaminopurine (BA), zeatin, and meta-topolin-9-riboside (mTR). The starting material originated from seeds collected from mother plants in their natural environment. The best growth outcomes (in terms of shoot multiplication, shoot length, and relative growth rate) were achieved using THE RITA® TIS, with BA (0.2 mg/L) and mTR (0.5 or 0.8 mg/L) outperforming SCM. Anomalous or hyperhydric shoots were observed with all zeatin treatments (especially with 0.8 mg/L) in both the TIS and SCM, suggesting that this cytokinin is unsuitable for V. ucriana biomass production. The rooting phase was significantly improved by transferring propagules onto rockwool cubes fertilized with Hoagland solution. This approach yielded more robust roots in terms of number and length compared to the conventional agar-based medium supplemented with indole-3-butyric acid (IBA). Flow cytometry analysis confirmed the genetic fidelity of the regenerants from the optimal PGR treatments, showing that all plantlets maintained the diploid ploidy level of their maternal plants. Over 90% of the in vitro derived plantlets were successfully acclimatized to greenhouse conditions. This paper represents the first report of V. ucriana biomass multiplication using a RITA® bioreactor. The stability of the regenerants, confirmed by nuclei quantification via cytofluorimetry, provides guidance in establishing a true-to-type ex situ population, supporting conservation and future reinforcement efforts.

Bioreactor configurations for adventitious root culture: recent advances toward the commercial production of specialized metabolites

In vitro plant cell and organ cultures are appealing alternatives to traditional methods of producing valuable specialized metabolites for use as: pharmaceuticals, food additives, cosmetics, perfumes, and agricultural chemicals. Cell cultures have been adopted for the production of specialized metabolites in certain plants. However, in certain other systems, adventitious roots are superior to cell suspension cultures as they are organized structures that accumulate high levels of specialized metabolites. The cultivation of adventitious roots has been investigated in various bioreactor systems, including: mechanically agitated, pneumatically agitated, and modified bioreactors. The main relevance and importance of this work are to develop a long-lasting industrial biotechnological technology as well as to improve the synthesis of these metabolites from the plant in vitro systems. These challenges are exacerbated by: the peculiarities of plant cell metabolism, the complexity of specialized metabolite pathways, the proper selection of bioreactor systems, and bioprocess optimization. This review's major objective is to analyze several bioreactor types for the development of adventitious roots, as well as the advantages and disadvantages of each type of bioreactor, and to describe the strategies used to increase the synthesis of specialized metabolites. This review also emphasizes current advancements in the field, and successful instances of scaled-up cultures and the generation of specialized metabolites for commercial purposes are also covered.

Types of Temporary Immersion Systems Used in Commercial Plant Micropropagation

Technological innovation in the design and manufacture of temporary immersion systems (TIS) has increased in the past decade. Innovations have involved the size, fitting, and replacement of components, as well as manufacturing materials. Air replacement by compressor has also been substituted by air replacement by preset tilting/rotation of culture bottles. This design modification aims to increase the biological yield (number of shoots) produced in these bottles and reduce manufacturing costs. However, the operative principle has remained unchanged through time: promote an environment where explant immersions in the culture medium are programmable. The changes in the TIS design involve advantages and disadvantages, generating the efficiency of one type over another. However, validation to identify the most effective type of TIS should be carried out for each plant species. This chapter lists the different types of temporary immersion available on the market, emphasizing the advantages and disadvantages of each when used for plant micropropagation.

Large-Scale Micropropagation of Vanilla (Vanilla planifolia Jacks.) in a Temporary Immersion Bioreactor (TIB)

The cultivation of vanilla (Vanilla planifolia) is of economic interest because vanillin is extracted from the fruits of this species. Vanillin is a natural flavoring highly valued in the food market. However, there is a short supply of propagules available for establishing commercial plantations and good-quality plants with phytosanitary certification. Plant tissue culture represents a viable option to supply large amounts of healthy plants to vanilla producers. In addition, the use of temporary immersion systems will allow commercial scale-up and the establishment of biofactories dedicated to in vitro vanilla propagation. This chapter describes a large-scale micropropagation protocol for vanilla using temporary immersion bioreactors (TIB).

Micropropagation of Encyclia cordigera (Kunth) Dressler in Ebb-and-Flow Bioreactor

The use of new technologies for micropropagation such as temporary immersion systems (TISs) is important, because it reduces costs by 40% lowering labor, agar and containers. TISs are containers designed for large-scale, semiautomatic production of plants in a liquid medium, which has been used in propagation of commercial orchids. This tool has high potential for application in micropropagation of medicinal and endangered orchids for conservation and commercial purposes. In this chapter, we describe a detailed protocol for propagation and development of Encyclia cordigera to be used in research projects for small-scale production. This protocol comprises all steps from explant preparation to the establishment orchids plantlets.

BioMINT: A Temporary Immersion System for Agave Micropropagation

Agaves are cultivated in Mexico as a source of industrial products such as fibers, nutritional supplements, and alcoholic beverages. Due to the demand for plant material, its long-life cycle, and the need to avoid predation on its natural populations, in vitro micropropagation represents a good option for agaves. Plant tissue culture has been successfully used to micropropagate selected elite individuals from plants of various Agave species of economic interest. However, it is necessary to implement systems that lower production costs without losing the quality of the plantlets obtained. This chapter describes the BioMINT™ bioreactor as an alternative for the micropropagation of agaves in the different stages of the micropropagation process.

Orchid Micropropagation Using Temporary Immersion Systems: A Review

Temporary immersion systems (TIS) have been used for orchid micropropagation. The main advantage of TIS use for micropropagation is that the explant is periodically immersed in nutrient media, and then, the nutrient solution is drained, which allows the explant tissue to stay in air. The current review resumes the application of TIS in orchid propagation. Fifty-three papers are discussed considering: explant, culture media, TIS bioreactor type, frequency and immersion time, and the TIS effects in acclimatization phase.

Conclusions and Perspectives on Plant Micropropagation in Temporary Immersion Systems

In vitro propagation protocols that include temporary immersion systems are available for the most economically important plant species. However, these have not been established yet for multiple species. Having protocols validated by the scientific community guarantees the success of the mass production of commercial propagules. Besides, adequate TIS parameters should be established for each plant species to improve the efficiency of micropropagation processes. This book compiles basic and applied aspects of temporal immersion systems used for in vitro plant micropropagation, along with several detailed protocols already established, which may be used as a guide by those interested in this technique, including laboratory technicians, scientists, and other professionals.

Temporary Immersion Systems in Plant Micropropagation

Temporary immersion systems (TIS) are technological tools that support plant micropropagation. Given their high efficiency in the in vitro propagation of shoots, a current goal is to update the protocols addressing micropropagation in semisolid culture systems to protocols involving TIS. To this end, different parameters have been evaluated, including TIS types and designs, immersion times, immersion frequencies, and volume of medium per explant, among other characteristics. This has resulted in the improved production of propagules of plants of economic interest and the production of physiologically upgraded plants with high percent survival during acclimatization. TIS are specialized culture flasks that provide countless advantages during the commercial micropropagation of plants.

Micropropagation of Chayote (Sechium edule L.) var. virens levis in RITA®

Chayote (Sechium edule) belongs to the Cucurbitaceae family, an important family at the nutritional and medicinal levels, that has been covering international markets. Having vigorous and healthy plants is important for producers, who are very interested in cultivating chayote plants obtained from in vitro tissue culture in their orchards. Bioreactors have become an alternative with high potential for plant propagation, showing significant advantages over micropropagation in semisolid medium, by generating more plant material, larger, and more vigorous. In this chapter, a micropropagation protocol of S. edule in RITA® bioreactors is reported.

Disposable Bioreactors Used in Process Development and Production Processes with Plant Cell and Tissue Cultures

The bioreactor is the centerpiece of the upstream processing in any biotechnological production process. Its design, the cultivation parameters, the production cell line, and the culture medium all have a major influence on the efficiency of the process and the result of the cultivation. Disposable bioreactors have been used for the past 20 years, playing a major role in process development and commercial production of high-value substances at medium scales.Our review deals with scalable, disposable bioreactors that have proven to be useful for the cultivation of plant cell and tissue cultures. Based on the definitions of terms and a categorization approach, the most commonly used, commercially available, disposable bioreactor types are presented below. The focus is on wave-mixed, stirred, and orbitally shaken bioreactors. In addition to their instrumentation and bioengineering characteristics, cultivation results are discussed, and emerging trends for the development of disposable bioreactors for plant cell and tissue cultures are also addressed.

Biochemical and Molecular Characterization of Musa sp. Cultured in Temporary Immersion Bioreactor

The genus Musa sp. contains commercially important fleshy fruit-producing plants, including plantains and bananas, with a strong potential for providing food security and sources of revenue to farmers. Concerns with the quality of vegetative tissues along with the possibility of the transmission of phytopathogens makes the availability of healthy plantlets limited for farmers. Micropropagation of plantains offers an alternative to producing large numbers of plantlets. However, conventional methods of micropropagation have high production costs and are labor-intensive. Recently, the temporary immersion bioreactor (TIB) has emerged as an alternative to conventional micropropagation (CM) methods. Our work utilized SEM microscopy (scanning electron microscope) and molecular and biochemical tools (qRT-PCR and ICP-OES) to characterize and compare the morphological properties, elemental composition, and photosynthetic gene expression of plantains cultured on TIB. Additionally, morphological features of growth and propagation rates were analyzed to compare outputs obtained from TIB and CM. Results showed higher growth and multiplication rates for plantlets cultivated in TIB. Gene expression analysis of selected photosynthetic genes demonstrated high transcript abundance of phosphoenolpyruvate carboxylase (PEPC) in plantain tissues obtained by TIB. Elemental composition analysis showed higher content of iron in plantains grown in TIB, suggesting a potential correlation with PEPC expression. These results demonstrate that micropropagation of Musa sp. via the liquid medium in TIB is an efficient and low-cost approach in comparison with solid media in CM.

In vitro and ex vitro propagation of Turkish myrtles through conventional and plantform bioreactor systems

The myrtle (Myrtus communis) plant naturally grows in the temperate Mediterranean and subtropical regions and is used for various purposes; thus, it is among the promising species of horticultural crops. This study aimed to evaluate and compare the performance of different propagation systems, including rooting, solid media propagation, rooting, and with the Plantform bioreactor system, in achieving healthy and rapid growth of four myrtle genotypes with diverse genetic origins and well-regional adaptation. The selection of myrtle genotypes with distinct genetic backgrounds and proven adaptability to specific regions allowed for a comprehensive assessment of the propagation systems under investigation. Present findings proved that the Plantform system, the new-generation tissue culture system, was quite successful in micropropagation and rooting myrtle genotypes. We succeeded in vitro micropropagation and rooting of diverse wild myrtle genotypes, enabling year-round propagation without reliance on specific seasons or environmental conditions. The process involved initiating cultures from explants and multiplying them through shoot proliferation in a controlled environment. This contributes to sustainable plant propagation, preserving and utilizing genetic resources for conservation and agriculture.

Dittrichia viscosa Selection Strategy Based on Stress Produces Stable Clonal Lines for Phytoremediation Applications

Dittrichia viscosa uptake and translocation of the metalloid As is not fully understood and some data are contradictory, but its adaptability to this pollutant is known and is dependent on its genetic variability. D. viscosa is not a hyperaccumulator plant, but it can grow in high-drought conditions while still producing large biomass, even tolerating significant concentrations of As3+ and As5+. In spite of these remarkable characteristics, adaptive modification of performances is not predictable in wild populations. In previous work, we established experimental clonal populations to perform a functional study on the aquaporin NIP1.1. Here, we propose a strategy to select a clonal population of D. viscosa with a defined phenotype related to As tolerance and to reduced NIP1.1 expression levels for phytoremediation applications. From the previous work, we selected four independent clones, two of them belonging to the weak population (W8 and W9) and the other two belonging to the strong population (S1 and S3). The weak and strong populations differ for a different expression ratio root/shoot of DvNip1;1 that brings a different tolerance to As presence. The stress response of the populations, revealed by the CAT enzymatic test, was statistically correlated to the clones, but not to As uptake. Performance of the selected plants on a second unrelated metallic pollutant, Cd, was evaluated, showing that Cd uptake is also independent from the tolerant phenotype. In vitro culture methods using solid media and temporary immersion bioreactors were compared to propose an optimized combined protocol. The procedure yielded propagation of genetically stable tolerant clonal lines with good uptake of As and Cd. The plants, mass-produced with the developed in vitro protocol, were able to maintain their acquired abilities and are potentially able be later applied in phytoremediation or contaminated areas' re-naturalization.

Successful In Vitro Shoot Multiplication of Quercus robur L. Trees Aged up to 800 Years

The conservation of the genetic resources of old trees is crucial to their ecological role but is extremely difficult, especially for oak species (Quercus spp.) displaying recalcitrance in seed and vegetative propagation methods. Our study aimed to assess the regenerative potential of Quercus robur trees of different ages (up to 800 years) during micropropagation. We also aimed to determine how in vitro conditions can influence in vitro regeneration responses. Lignified branches collected from 67 selected trees were cultivated ex vitro in culture pots at 25 °C to obtain epicormic shoots (explant sources). The explants were cultivated on an agar medium supplemented with 0.8 mg L^-1 6-benzylaminopurine (BAP) for at least 21 months. In a second experiment, two different shoot multiplication conditions (temporary immersion-RITA^® bioreactor and agar medium) and two culture medium formulations (Woody Plant Medium and modified Quoirin and Lepoivre medium) were tested. The results showed that the mean length of the epicormic shoots obtained in a pot culture was a function of donor age and was similar among the group of younger trees (ca. 20-200 years), and varied between older trees (ca. 300-800 years). The efficiency of in vitro shoot multiplication strictly depended on the genotype. A sustainable in vitro culture (defined as survival after 6 months) was only possible for half of the tested old donor trees, even when they survived the first month of in vitro growth. A continuous monthly increase in the number of in vitro cultured shoots was reported in younger oaks and in some old oaks. We found a significant effect of the culture system and the macro- and micronutrient composition on in vitro shoot growth. This is the first report demonstrating that the in vitro culture can be successfully applied to the propagation of even 800-year-old pedunculate oak trees.

The Effect of Silver Nanoparticle Addition on Micropropagation of Apricot Cultivars (Prunus armeniaca L.) in Semisolid and Liquid Media

Silver nanoparticles (AgNPs) are novel compounds used as antimicrobial and antiviral agents. In addition, AgNPs have been used to improve the growth of different plants, as well as the in vitro multiplication of plant material. In this work the effect of AgNPs on in vitro growth of 'Canino' and 'Mirlo Rojo' cultivars, as well as the leaf ion composition, are studied. Different concentrations of AgNPs (0, 25, 50, 75 and 100 mg L^-1) were added to two culture systems: semisolid medium with agar (SSM) in jars and liquid medium in temporary immersion system (TIS). Proliferation (number of shoots), shoot length, productivity (number of shoot × average length), leaf surface, fresh and dry weight were measured. Additionally, the silver and other ion accumulation in the leaves were evaluated by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. The productivity of 'Canino' and 'Mirlo Rojo' decreased when increasing the concentration of AgNPs in the semisolid medium. However, the use of AgNPs in the TIS improved the proliferation and productivity of 'Canino' and Mirlo Rojo', increasing biomass production, and the concentration of nutrients in the plants, although these effects are genotype-dependent. TISs are the best system for introducing silver into shoots, the optimum concentration being 50 mg L^-1 for 'Canino' and 75 mg L^-1 for 'Mirlo Rojo'. Principal component analysis, considering all the analyzed ions along the treatments, separates samples in two clear groups related to the culture system used. The use of bioreactors with a liquid medium has improved the productivity of 'Canino' and 'Mirlo Rojo' in the proliferation stage, avoiding hyperhydration and other disorders. The amount of metallic silver that penetrates apricot plant tissues depends on the culture system, cultivar and concentration of AgNPs added to the culture medium. Silver ion accumulation measured in the shoots grown in the TIS was higher than in shoots micropropagated in a semisolid medium, where it is barely detectable. Furthermore, AgNPs had a beneficial effect on plants grown in TIS. However, AgNPs had a detrimental effect when added to a semisolid medium.

Orchid Micropropagation Using Conventional Semi-Solid and Temporary Immersion Systems: A Review

Orchids, with their astonishingly stunning flowers, dominate the international floricultural market. They are considered prized assets for commercial applications in pharmaceutical and floricultural industries as they possess high therapeutic properties and superior ornamental values. The alarming depletion of orchid resources due to excessive unregulated commercial collection and mass habitat destruction makes orchid conservation measures an extreme priority. Conventional propagation methods cannot produce adequate number of orchids, which would meet the requirement of these ornamental plants for commercial and conservational purposes. In vitro orchid propagation using semi-solid media offers an outstanding prospect of rapidly producing quality plants on a large scale. However, the semi-solid (SS) system has shortcomings with low multiplication rates and high production costs. Orchid micropropagation using a temporary immersion system (TIS) overcomes the limitations of the SS system by reducing production costs and making scaleup and full automation possible for mass plant production. The current review highlights different aspects of in vitro orchid propagation using SS and TIS and their benefits and drawbacks on rapid plant generation.

Bioreactor systems for micropropagation of plants: present scenario and future prospects

Plant micropropagation has been adapted in the fields of agriculture, horticulture, forestry, and other related fields for large-scale production of elite plants. The use of liquid media and adoption of bioreactors have escalated the production of healthy plants. Several liquid-phase, gas-phase, temporary immersion, and other modified bioreactors have been used for plant propagation. The design, principle, operational mode, merits, and demerits of various bioreactors used for the regeneration of propagules, such as bulblets, cormlets, rhizomes, microtubers, shoots (subsequent rooting), and somatic embryos, are discussed here. In addition, various parameters that affect plant regeneration are discussed with suitable examples.

Effect of Soil Type and In Vitro Proliferation Conditions on Acclimation and Growth of Willow Shoots Micropropagated in Continuous Immersion Bioreactors

Salix viminalis L. is a species with high capacity for micropropagation and acclimation and could therefore be used to evaluate emergent techniques in the field of plant propagation. The aims of this study were to propagate willow in liquid medium with a continuous immersion system, to explore the application of photoautotrophic conditions and to investigate the adaptation of willow plantlets to different soils that could be used as alternatives to commercial peat. For proliferation, we used 3% sucrose or sugar-free medium, and as substrates, we used commercial peat, a soil from an oak forest with high organic matter content and a crop soil with low organic matter content. The effect of sugar supplementation during proliferation and the soil characteristics during acclimation and growth were evaluated on the basis of aerial and root growth and the hydrolytic and dehydrogenase enzymatic activities of the soils. The results indicate that under photoautotrophic conditions, the supplementation of sucrose during micropropagation did not affect the subsequent growth of the plantlets. All plants acclimated without loss, but the type of soil influenced the height and vigor. Plants produced the highest shoots in peat, whereas the most root development occurred in crop soil. Soil enzyme activities were more influenced by the type of soil than by the presence of plants.

Somatic embryogenesis of Arabica coffee in temporary immersion culture: Advances, limitations, and perspectives for mass propagation of selected genotypes

Culture in temporary immersion systems (TIS) is a valuable tool for the semi-automation of high frequency somatic embryogenesis of coffee. This system allows the intermittent exposure of explants to liquid medium in cycles of specific frequency and duration of immersion with renewal of the culture atmosphere in each cycle. TIS have revolutionized somatic embryogenesis of coffee plants as an alternative for scaling up and reducing costs associated with labor-intensive solid media culture. In Central America, somatic embryogenesis is employed on a commercial scale to produce F1 Coffea arabica hybrids. In Asia and Africa, somatic embryogenesis is used for the multiplication of selected genotypes of C. arabica and C.canephora. Somatic embryogenesis of coffee plants is considered a model system for woody species due to its biological versatility and low frequency of somaclonal variation. Nevertheless, the success of somatic embryogenesis for mass propagation of coffee plants depends on the development, optimization, and transfer of complementary technologies. Temporary immersion using the RITA^® bioreactor is, so far, the best complementary tool for somatic embryogenesis of Arabica coffee for a single recipient with simple changes in liquid media. Likewise, high volume bioreactors, such as 10-L glass BIT^® and 10-L flexible disposable plastic bags, have been successfully used for somatic embryogenesis of other coffee species. These bioreactors allow the manipulation of thousands of embryos under semi-automated conditions. The protocols, advantages, and benefits of this technology have been well documented for organogenesis and somatic embryogenesis pathways. However, adaptation in commercial laboratories requires technical and logistical adjustments based on the biological response of the cultures as well as the costs of implementation and production. This review presents the historical and present background of TIS and its commercial application and, in particular, pertinent information regarding temporary immersion culture for C. arabica somatic embryogenesis. The main limitations of this technology, such as hyperhydricity, asynchrony, and developmental abnormalities, are examined, and a critical analysis of current knowledge regarding physiological, biochemical, and molecular aspects of the plant response to temporary immersion is offered. Further, perspectives are provided for understanding and solving the morpho-physiological problems associated with temporary immersion culture of coffee plants. Systematic Review Registration.

Temporary immersion systems (TISs): A comprehensive review

The temporary immersion systems (TISs) have been widely used in plant biotechnology. TISs have different advantages from the point of micropropagation and production of secondary metabolites over other continuous liquid-phase bioreactors. The current work presents the structure, operation mode, configuration type, and micropropagation or secondary metabolite production in TISs. This review deals with the advantages and disadvantages of TISs and the factors affecting their performance. Future research could focus on new designs based on CFD simulation, facilitating sterilization, and combining TISs with other bioreactors (e.g., mist bioreactors) to make a hybrid bioreactor.

Micropropagation of Plum (Prunus domestica L.) in Bioreactors Using Photomixotrophic and Photoautotrophic Conditions

In this study, we propagated two old Galician plum varieties in liquid medium using a temporary immersion system with RITA© bioreactors. Environmental variables including culture system, light intensity, CO2 enrichment, immersion frequency and sucrose supplementation were evaluated in relation to in vitro proliferation, physiological status and ex vitro performance. Bioreactors were superior to jars for culturing shoots in photomixotrophic conditions, producing up to 2 times more shoot numbers and up to 1.7 times more shoot length (depending on the genotype) using shoot clusters. The number and quality of shoots were positively influenced by the sucrose concentration in the medium, plus by the light and gaseous environment. For individual apical sections the best response occurred with 3% sucrose, 150 µmol m−2 s−1 photosynthetic photon flux density and 2000 ppm CO2, averaging 2.5 shoots per explant, 26 mm shoot length and 240 mm2 leaf area, while with 50 µmol m−2 s−1 light and ambient CO2 (400 ppm) values decreased to 1.2 shoots per explant, 14 mm of shoot length and 160 mm2 of leaf area. Shoots cultured photoautotrophically (without sucrose) were successfully rooted and acclimated despite of showing limited growth, low photosynthetic pigments, carbohydrate, phenolic and antioxidant contents during the multiplication phase.

In Vitro Technologies for American Chestnut (Castanea dentata (Marshall) Borkh) Conservation

American chestnut (Castanea dentata), a native species of eastern North America, is an economically important deciduous hardwood tree that has been designated as endangered in Canada. The population of American chestnut trees has dwindled significantly across Southern Ontario due to chestnut blight and many of the surviving trees continue to show blight disease symptoms. American chestnut requires efficient strategies for propagation and preservation for species recovery. The objective of this study was to develop a long-term plant conservation program using micropropagation and cryopreservation protocols. An in vitro technology using a liquid-based temporary immersion system (TIS) was developed for micropropagation of American chestnut. The highest rate of shoot multiplication was observed in cultures grown in the DKW (Driver and Kuniyuki 1984) basal medium supplemented with 2.2 µM 6-benzylaminopurine and 1.0 µM gibberellic acid. More than 95% of proliferated microshoots, about 40-50 mm in size, developed roots after 30 days of culture within bioreactor vessels containing DKW basal medium supplemented with 15 µM 3-Indolebutyric acid. Rooted plantlets transplanted to the greenhouse had a survival efficiency of 82% after one month of growth. The cryopreservation protocol for germplasm preservation was developed through droplet vitrification of shoots. Optimal regeneration of shoot tips occurred from explants precultured on stepwise concentrations of sucrose and subsequent dehydration in PVS3 for 30 min. Cryopreserved shoot tips were regenerated to whole plants using pre-optimized conditions of micropropagation. This study confirms the potential of TIS for micropropagation in ex situ conservation and reintroduction of endangered American chestnuts and possibly other woody plant species.

Genetic Manipulation and Bioreactor Culture of Plants as a Tool for Industry and Its Applications

In recent years, there has been a considerable increase in interest in the use of transgenic plants as sources of valuable secondary metabolites or recombinant proteins. This has been facilitated by the advent of genetic engineering technology with the possibility for direct modification of the expression of genes related to the biosynthesis of biologically active compounds. A wide range of research projects have yielded a number of efficient plant systems that produce specific secondary metabolites or recombinant proteins. Furthermore, the use of bioreactors allows production to be increased to industrial scales, which can quickly and cheaply deliver large amounts of material in a short time. The resulting plant production systems can function as small factories, and many of them that are targeted at a specific operation have been patented. This review paper summarizes the key research in the last ten years regarding the use of transgenic plants as small, green biofactories for the bioreactor-based production of secondary metabolites and recombinant proteins; it simultaneously examines the production of metabolites and recombinant proteins on an industrial scale and presents the current state of available patents in the field.

A Temporary Immersion System to Improve Cannabis sativa Micropropagation

The aim of this study was to propagate axillary shoots of Cannabis sativa L. using liquid medium in temporary immersion bioreactors. The effect of immersion frequency (3 or 6 immersions per day), explant type (apical or basal sections), explant number (8, 10, and 16 explants), mineral medium (Murashige and Skoog half-strength nitrates, β-A and β-H, all supplemented with 2-μM metatopoline), sucrose supplementation (2, 0.5, and 0% sucrose), culture duration (4 and 6 weeks), and bioreactor type (RITA® and Plantform™) were investigated. As a result, we propose a protocol for the proliferation of cannabis apical segments in RITA® or Plantform™ bioreactors. The explants (8 per RITA® and 24 per Plantform™) are immersed for 1 min, 3 times per day in β-A medium supplemented with 2-μM metatopoline and 0.5% of sucrose and subcultured every 4 weeks. This is the first study using temporary immersion systems in C. sativa production, and our results provide new opportunities for the mass propagation of this species.

The Effect of Sucrose Supplementation on the Micropropagation of Salix viminalis L. Shoots in Semisolid Medium and Temporary Immersion Bioreactors

The effect of sucrose concentration on the micropropagation of axillary shoots of willow was investigated. The following factors were examined: the culture system (semisolid medium in glass jars versus liquid medium in temporary immersion bioreactors), the type of explant (apical and basal sections), the frequency of immersion, and CO2 enrichment. Shoots and leaf growth were significantly higher in RITA® bioreactors than in the jars for all the sucrose treatments. Apical or basal sections of willow cultured in bioreactors under high light intensity (150 µmol m−2 s−1) and ventilated six times a day with CO2-enriched air were successfully proliferated without sucrose, whereas shoots cultured in jars did not proliferate well if sucrose concentration was 0.5% or lower. More roots were formed when sucrose was added to the medium. Shoots cultured in bioreactors were successfully acclimatized irrespective of the sucrose treatment and the root biomass when transferred to ex vitro conditions. This is the first report of photoautotrophic willow micropropagation, our results confirm the importance of proper gaseous exchange to attain autotrophy during in vitro propagation.

A novel temporary immersion bioreactor system for large scale multiplication of banana (Rasthali AAB-Silk)

Musa sp. cultivar Rasthali (Silk AAB) is a choice variety of the Asian sub-continent. Its production and sustenance are threatened by Fusarium wilt, which affects the livelihoods of small and marginal farmers. The use of quality planting material is one of the strategies to manage the disease. Availability of quality planting material for varieties other than Grand Naine is limited. Large-scale micropropagation using existing technologies is laborious and expensive. Temporary immersion bioreactor system is emerging as a potential advancement in the micropropagation industry. In this study, a cost-effective temporary immersion bioreactor (TIB) system has been developed and an efficient micropropagation method has been standardized. Explants cultured in TIB with 250 ml of culture medium in a 2-min immersion frequency of 6 h were found to be efficient for shoot proliferation and rooting. Its efficacy has been compared with the semisolid culture method. At the end of the 6th subculture, 1496 ± 110 shoots per explant were obtained in TIB. Chlorophyll, carotenoid, stomatal index, and the number of closed stomata were examined to determine the physiological functions of the plants grown in TIB and compared with semisolid grown plantlets. Plantlets grown in TIB were genetically stable and were confirmed using inter-simple sequence repeat (ISSR) markers. The multiplication of shoots in TIB was 2.7-fold higher than the semisolid culture method, which is suitable for large-scale production of planting material for commercial applications.

A temporary immersion system for mass micropropagation of pitahaya (Hylocereus undatus)

Scaling-up techniques in temporary immersion systems are an alternative for commercial micropropagation. In vitro propagation of pitahaya (Hylocereus undatus) using temporary immersion with liquid culture medium improves micropropagation efficiency compared to the conventional method in semisolid medium. The objective of this work was to evaluate the efficiency of traditional culture and temporary immersion during micropropagation of pitahaya to facilitate the rapid establishment of new commercial plantations of high genetic and phytosanitary quality. Semisolid culture, liquid media in partial immersion and temporary immersion in an Ebb-and-Flow bioreactor were evaluated. Also, in temporary immersion, different immersion frequencies (every 4, 8, 12, and 16 h) and culture densities (5, 10, 15 and 20 explants per bioreactor) were evaluated. For the multiplication stage, new shoots and length were recorded per explant at 45 d of in vitro culture and in the acclimatization stage, the survival percentage was determined at 30 d of greenhouse cultivation. A temporary immersion of 2 min every 4 h and 15 explants per bioreactor was the best culture system, obtaining on average 10.7 shoots per explant with a length of 1.9 cm. No significant differences were observed among treatments during acclimatization, obtaining survival percentages of 98%-100%. This study reports for the first time a protocol for scaling-up techniques in temporary immersion for commercial micropropagation of pitahaya (and for any species of the Cactaceae family) and its establishment in a productive plantation.

Recent applications of plant cell culture technology in cosmetics and foods

Plants have been used as the main source of phytochemicals with nutritional, medicinal, cultural and cosmetic applications since times immemorial. Nowadays, achieving sustainable development, global climate change, restricted access to fresh water, limited food supply and growing energy demands are among the critical global challenges faced by humanity. Plant cell culture technology has the potential to address some of these challenges by providing effective tools for sustainable supply of phyto-ingredients with reduced energy, carbon and water footprints. The main aim of this review is to discuss the recent trends in the development of plant cell culture technologies for production of plant-derived substances with application in food products and cosmetic formulations. The specific technological steps and requirements for the final products are discussed in the light of the advances in cultivation technologies used for growing differentiated and undifferentiated plant in vitro systems. Future prospects and existing challenges of the commercialization of plant cell culture-derived products have been outlined through the prism of the authors' point of view. We expect this review will encourage scientists, policymakers and business enterprises to join efforts for speeding-up the mass commercialization and popularization of plant cell culture technology as an eco-friendly alternative method for sustainable production of plant-derived additives with application in food and cosmetic products.

Large-Scale Plant Production of Lycium barbarum L. by Liquid Culture in Temporary Immersion System and Possible Application to the Synthesis of Bioactive Substance

Goji (Lycium barbarum L.) has recognized nutritive and antioxidant properties and many products are commercialized for health in food market. Besides its food use, goji has been the subject of more than 2000 years of traditional Chinese medicine, using berries, root bark, and leaves. Here, the potential of the liquid culture in temporary immersion system (TIS) by using the bioreactor Plantform^TM was tested for the large-scale production of high-quality goji shoots and the subsequent production of total phenols and flavonoids. The three tested immersion cycles differently influenced the shoot quality in terms of proliferation and hyperhydricity. The best immersion cycle (time and frequency) was proven to have the shortest daily immersion time (6 min every 24 h) which ensured good levels of relative growth and multiplication rate, very limited onset of hyperydricity, and the longest shoots, promoting direct rooting after only 30 days of culture. In comparison with the semisolid culture, the TIS culture resulted in an increase of the total phenolic content (TPC) and in a lower value of the total flavonoid content (TFC). However, considering the higher quantity of biomass produced in the Plantform^TM bioreactor, the difference in terms of TFC productivity between semisolid medium and TIS liquid culture was proven to be statistically equivalent.

Micropropagation of Guarianthe skinneri (Bateman) Dressler et W. E. Higging in Temporary Immersion Systems

This study's aim was to establish a protocol for the micropropagation of G. skinneri using temporary immersion system (TIS). Different concentrations of 6-Benzylaminopurine (0, 1, 2, and 3 mg L^-1), three different systems of cultivate semi-solid (SS) and liquid media under partial (PI) and temporary immersion systems (TIS), different compositions of the inorganic salts, and the number of subcultures were evaluated. The results showed a maximum of 16.56 shoots per explant obtained through TIS, adjusting all the parameters evaluated in our study. One higher number of shoots per explant was observed in the micropropagation of G. skinneri TIS compared to SS and PI. While the use of 3 mg L^-1 of BAP + MS (Murashige and Skoog) media was better than 3 mg L^-1 of BAP VW (Vacint and Went) for the generation of a greater number of shoots per explant, 6.33 and 2.72, respectively. The immersion frequency of 2 min every 4 h allowed the production to be scaled to 8.54 shoots per explant. While it was necessary to perform three subcultures every 30 days, to obtain 16.56 shoots per explant, a rooting phase was not required due to the generation of adventitious roots during the different subcultures. However, a phase of elongation of the regenerated plants with ½ MS + GA3 (gibberellic acid) was needed to guarantee 100% survival in the process of acclimatization. In conclusion, this plant production system can be applied for the commercial micropropagation of this species for ornamental purposes, as well as for its reintroduction in protected natural areas.

Root exudates: from plant to rhizosphere and beyond

This article describes the composition of root exudates, how these metabolites are released to the rhizosphere and their importance in the recruitment of beneficial microbiota that alleviate plant stress. Metabolites secreted to the rhizosphere by roots are involved in several processes. By modulating the composition of the root exudates, plants can modify soil properties to adapt and ensure their survival under adverse conditions. They use several strategies such as (1) changing soil pH to solubilize nutrients into assimilable forms, (2) chelating toxic compounds, (3) attracting beneficial microbiota, or (4) releasing toxic substances for pathogens, etc. In this work, the composition of root exudates as well as the different mechanisms of root exudation have been reviewed. Existing methodologies to collect root exudates, indicating their advantages and disadvantages, are also described. Factors affecting root exudation have been exposed, including physical, chemical, and biological agents which can produce qualitative and quantitative changes in exudate composition. Finally, since root exudates play an important role in the recruitment of mycorrhizal fungi and plant growth-promoting rhizobacteria (PGPR), the mechanisms of interaction between plants and the beneficial microbiota have been highlighted.

Use of bioreactor systems in the propagation of forest trees

Plant biotechnology can be used to conserve the germplasm of natural forests, and to increase the productivity and sustainability of plantations. Both goals imply working with mature trees, which are often recalcitrant to micropropagation. Conventional in vitro culture uses closed containers and gelled medium with sugar supplementation. Bioreactor culture uses liquid medium and usually incorporates aeration. The increased absorption of nutrients via the liquid medium together with the renewal of the air inside the bioreactors may improve the physiological state of the explants. In this review, we will explore the feasibility of using bioreactors to overcome the recalcitrance of many trees to micropropagation and/or to decrease the cost of large-scale propagation. We will focus on the recent use of bioreactors during the multiplication, rooting (plant conversion in the case of somatic embryos), and acclimation stages of the micropropagation of axillary shoots and somatic embryos of forest trees (including some shrubs of commercial interest), in both temporary and continuous immersion systems. We will discuss the advantages and the main obstacles limiting the widespread implementation of bioreactor systems in woody plant culture, considering published scientific reports and contributions from the business sector.

In Vitro Propagation of Rheophytic Orchid, Epipactis flava Seidenf.-A Comparison of Semi-Solid, Continuous Immersion and Temporary Immersion Systems

Epipactis flava Seidenf. is an endangered Thai rheophytic orchid that has recently shown a rapid decrease in its natural habitat, prompting an urgent need for conservation using ex situ reintroduction methods. Temporary immersion system (TIS) has been successfully applied for large-scale propagation in various plants species. Propagation efficiency of E. flava using TIS was investigated and compared with conventional semi-solid system (SSS) and liquid continuous immersion system (CIS). The highest percentage of new shoot and shoot bud formation was obtained from TIS, followed by CIS and SSS, respectively. Growth parameters as indicated by number of new shoots, shoot buds, shoot height and leaves per explant were significantly higher using TIS than with SSS and CIS. Moreover, the maximum number of new shoots and shoot buds per replication were reliably obtained from TIS higher than SSS and CIS. After acclimatization, the highest survival percentage of plantlets was observed in TIS (76.7%), with 60% surviving after eight weeks of transplantation in artificial stream. TIS was determined as the most suitable culture system for in vitro mass propagation of E. flava compared to CIS and SSS.

Elicitation with methyl jasmonate combined with cultivation in the Plantform™ temporary immersion bioreactor highly increases the accumulation of selected centellosides and phenolics in Centella asiatica (L.) Urban shoot culture

Centella asiatica (L.) Urban is an important pharmacopoeial plant used not only in medicine but also in cosmetology. C. asiatica agitated shoot cultures were established to study the influence of ethephon, methyl jasmonate, l-phenylalanine (Eth 50 µM, MeJa 50 µM, L-Phe 2.4 g/L of medium, respectively; seven variants of the supplementation) on the accumulation of secondary metabolites: the main centellosides (asiaticoside and madecassoside) and selected phenolic acids, and flavonoids in the biomass. Microshoots were harvested two and six days after the supplementation. Secondary metabolites were analyzed in methanolic extracts by UPLC-MS/MS (centellosides) and by HPLC-DAD (phenolics). In comparison with the reference cultures, the concentrations of individual secondary metabolites increased as follows: centellosides up to 5.6-fold (asiaticoside), phenolic acids up to 122-fold (p-coumaric acid) and flavonoids up to 22.4-fold (kaempherol). The highest production increase of individual compounds was observed for different variants of supplementation. Variant C (50 µM MeJa), the most optimal for centellosides and flavonoid accumulation, was selected for the experiment with bioreactors. Bioreactor Plantform™, compared to RITA^® system and agitated cultures, appeared to be the most advantageous for secondary metabolites production in C. asiatica shoot cultures. The phenolic acid, flavonoid, centelloside, and total secondary metabolite productivity in Plantform™ system is 1.8-fold, 1.7-fold, 2.8-fold, 2.1-fold, respectively, higher than in MeJa elicitated agitated cultures, and 4.3-fold, 7.3-fold, 12.2-fold, 7.2-fold, respectively, higher than in control agitated cultures.

Assessment of different temporary immersion systems in the micropropagation of anthurium (Anthurium andreanum)

Anthurium has been micropropagated mainly through conventional techniques in semisolid culture medium. However, this culture system involves constraints due to the low number of shoots produced and the high costs of the gelling agent and labor. Temporary immersion systems (TIS) are an alternative for increasing biological performance, reducing costs, and facilitating a semi-automated micropropagation process. The objective of this study was to compare the efficiency of different types of TIS during the in vitro propagation of anthurium. We used 2-cm-long nodal segments from in vitro plants. Explants were cultured in different TIS: temporary immersion bioreactors (TIB^®), Ebb-and-Flow bioreactor, and recipient for automated temporary immersion (RITA^®), with a 2-min immersion frequency at 12-h intervals. We used Murashige and Skoog (MS) medium supplemented with 3% (w/v) of sucrose and 8.88 µM benzylaminopurine. After 60 days of culture, we evaluated various physiological variables and the percent survival in the different TIS. The largest numbers of shoots per explant were observed in TIB^® and Ebb-and-Flow, with 50.83 and 43.16 shoots per explant, respectively; the lowest number of shoots per explant was observed in RITA^®, with 30.66. TIB^® yielded the highest content of photosynthetic pigments (chlorophyll a, b, and total chlorophyll), stomatal index, and percentage of closed stomata relative to both Ebb-and-Flow and RITA^®. The TIB^® and RITA^® systems showed a 99% shoot survival, while Ebb-and-Flow yielded 86% survival. In conclusion, TIS design and type affect a number of physiological processes and in vitro development, with TIB^® as a feasible option for the commercial micropropagation of anthurium.

Echinacea biotechnology: advances, commercialization and future considerations

CONTEXT

Plants of the genus Echinacea (Asteraceae) are among the most popular herbal supplements on the market today. Recent studies indicate there are potential new applications and emerging markets for this natural health product (NHP).

OBJECTIVE

This review aims to synthesize recent developments in Echinacea biotechnology and to identify promising applications for these advances in the industry.

METHODS

A comprehensive survey of peer-reviewed publications was carried out, focusing on Echinacea biotechnology and impacts on phytochemistry. This article primarily covers research findings since 2007 and builds on earlier reviews on the biotechnology of Echinacea.

RESULTS

Bioreactors, genetic engineering and controlled biotic or abiotic elicitation have the potential to significantly improve the yield, consistency and overall quality of Echinacea products. Using these technologies, a variety of new applications for Echinacea can be realized, such as the use of seed oil and antimicrobial and immune boosting feed additives for livestock.

CONCLUSIONS

New applications can take advantage of the well-established popularity of Echinacea as a NHP. Echinacea presents a myriad of potential health benefits, including anti-inflammatory, anxiolytic and antibiotic activities that have yet to be fully translated into new applications. The distinct chemistry and bioactivity of different Echinacea species and organs, moreover, can lead to interesting and diverse commercial opportunities.

Bioreactor-based advances in plant tissue and cell culture: challenges and prospects

Bioreactors are engineered systems capable of supporting a biologically active situation for conducting aerobic or anaerobic biochemical processes. Stability, operational ease, improved nutrient uptake capacity, time- and cost-effectiveness, and large quantities of biomass production, make bioreactors suitable alternatives to conventional plant tissue and cell culture (PTCC) methods. Bioreactors are employed in a wide range of plant research, and have evolved over time. Such technological progress, has led to remarkable achievements in the field of PTCC. Since the classification of bioreactors has been extensively reviewed in numerous reviews, the current article avoids repeating the same material. Alternatively, it aims to highlight the principal advances in the bioreactor hardware s used in PTCC rather than classical categorization. Furthermore, our review summarizes the most significant steps as well as current state-of-the-art of PTCC carried out in various types of bioreactor.

Food additives and bioactive substances from in vitro systems of edible plants from the Balkan peninsula

During the last few years there is an increasing demand to the natural biologically active compounds. According to the World Health Organization (WHO) about 11% of the conventional medicines are of plant origin. Nowadays, plant biotechnologies are modern and reliable tool for producing valuable bioactive compounds. Recently, the potential of plant cells as foods also was confirmed. The advantages of plant in vitro systems over the intact plants are well known: growing under controlled and optimized laboratory conditions; independence of climatic and soil differences; preservation of rare and endangered plant species; cultivation in diverse bioreactor systems for increasing production yields of target metabolites. There have been developed many in vitro systems for production of various plant bioactive compounds with potential application in food industries. But potential for industrial implementation of this technology depends on solving problems with the scale-up of bioreactor cultivation, development of additional approaches for improving/modification of bioactivities of the target plant secondary metabolites, and to find way to exclude or replace in the culture media the carcinogenic plant growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D) with its safety analogs, such as α-naphtaleneacetic acid (NAA) and/or indole-3-butyric acid (IBA). The aim of the current mini review is to summarize information about different in vitro systems of edible plants from the Balkan Peninsula with potential for producing food additives and biologically active substances and to describe prospects for successful industrial implementation of this technology.

Plant cell culture technology in the cosmetics and food industries: current state and future trends

The production of drugs, cosmetics, and food which are derived from plant cell and tissue cultures has a long tradition. The emerging trend of manufacturing cosmetics and food products in a natural and sustainable manner has brought a new wave in plant cell culture technology over the past 10 years. More than 50 products based on extracts from plant cell cultures have made their way into the cosmetics industry during this time, whereby the majority is produced with plant cell suspension cultures. In addition, the first plant cell culture-based food supplement ingredients, such as Echigena Plus and Teoside 10, are now produced at production scale. In this mini review, we discuss the reasons for and the characteristics as well as the challenges of plant cell culture-based productions for the cosmetics and food industries. It focuses on the current state of the art in this field. In addition, two examples of the latest developments in plant cell culture-based food production are presented, that is, superfood which boosts health and food that can be produced in the lab or at home.

In vitro multiplication and growth improvement of Olea europaea L. cv Canino with temporary immersion system (Plantform™)

Olea europaea L. cv Canino shoots were micropropagated to test two different culture systems: (1) on conventional semi-solid medium in glass jars and (2) in liquid culture in a Plantform™ bioreactor. The temporary immersion system, Plantform™, is a new propagation approach that uses liquid culture, where shoots undergo periodic immersion in liquid medium alternated with dry periods, avoiding gas accumulation through forced ventilation. This study proposes a protocol to improve in vitro propagation of olive reducing production costs. Our findings revealed that olive shoots propagated in Plantform™, with an immersion frequency of 8 min every 16 h and additional ventilation, showed good adaptability and better growth rates than those cultured in conventional system. Overall, the Plantform™ improves in vitro culture of 'Canino', showing higher proliferation, shoot length and better vigour of shoots. Moreover, the study found no significant differences in shoot length when 5 or 10 µM zeatin was applied in Plantform™ (3.04 and 3.13 cm, respectively); it is, therefore, possible to achieve efficient olive proliferation also with half hormone concentration. The positive performance of the bioreactor approach was also confirmed by Relative Growth Rate index. This is the first documented study of the Plantform™ technique for olive propagation.

Enhanced production of the pharmaceutically important polyphenolic compounds in Vitex agnus castus L. shoot cultures by precursor feeding strategy

Agitated Vitex agnus castus L. shoot cultures were established to analyse the content of selected pharmaceutically important flavonoids and phenolic acids. Two variants (selected from nine ones) of MS medium were prepared: A (BAP 1 mg/L; NAA 0.5 mg/L; GA₃ 0.25 mg/L) and B (BAP 2 mg/L; NAA 0.5 mg/L). The biomass was harvested after 1, 2, 3,4, 5 and 6 weeks. Four-week cultures (variant A) were selected to perform the precursor feeding experiment. The L-phenylalanine dose of 1.6 g/L appears to be the most advantageous. Compared to the control cultures, the content of the individual compounds increased in a range from 1.4 to 17.3-fold (e.g. p-coumaric acid - 17.3 fold; casticin - 4.8-fold). The biomass from in vitro cultures is richer in neochlorogenic acid (16-fold), p-coumaric acid (5.3-fold), rutin (2.8-fold), caffeic acid (1.5-fold) and cinaroside (1.5-fold) than the leaves of its parent greenhouse-cultivated plants. Extracts contained 30 mg/100 g DW of casticin, but after the hydrolysis its amount increased up to 200 mg/100 g DW and twice exceeded the content in the greenhouse leaves. The results indicate that V. agnus castus agitated shoot cultures might be considered as a potential biotechnological source of some pharmaceutically important compounds, especially casticin, rutin, neochlorogenic and p-coumaric acids.

Selection and Clonal Propagation of High Artemisinin Genotypes of Artemisia annua

Artemisinin, produced in the glandular trichomes of Artemisia annua L. is a vital antimalarial drug effective against Plasmodium falciparum resistant to quinine-derived medicines. Although work has progressed on the semi-synthetic production of artemisinin, field production of A. annua remains the principal commercial source of the compound. Crop production of artemisia must be increased to meet the growing worldwide demand for artemisinin combination therapies (ACTs) to treat malaria. Grower artemisinin yields rely on plants generated from seeds from open-pollinated parents. Although selection has considerably increased plant artemisinin concentration in the past 15 years, seed-generated plants have highly variable artemisinin content that lowers artemisinin yield per hectare. Breeding efforts to produce improved F₁ hybrids have been hampered by the inability to produce inbred lines due to self-incompatibility. An approach combining conventional hybridization and selection with clonal propagation of superior genotypes is proposed as a means to enhance crop yield and artemisinin production. Typical seed-propagated artemisia plants produce less than 1% (dry weight) artemisinin with yields below 25 kg/ha. Genotypes were identified producing high artemisinin levels of over 2% and possessing improved agronomic characteristics such as high leaf area and shoot biomass production. Field studies of clonally-propagated high-artemisinin plants verified enhanced plant uniformity and an estimated gross primary productivity of up to 70 kg/ha artemisinin, with a crop density of one plant m^-2. Tissue culture and cutting protocols for the mass clonal propagation of A. annua were developed for shoot regeneration, rooting, acclimatization, and field cultivation. Proof of concept studies showed that both tissue culture-regenerated plants and rooted cutting performed better than plants derived from seed in terms of uniformity, yield, and consistently high artemisinin content. Use of this technology to produce plants with homogeneously-high artemisinin can help farmers markedly increase the artemisinin yield per cultivated area. This would lead to increased profit to farmers and decreased prices of ACT.

Improved production of dibenzocyclooctadiene lignans in the elicited microshoot cultures of Schisandra chinensis (Chinese magnolia vine)

Dibenzocyclooctadiene lignans are a specific group of secondary metabolites that occur solely in Schisandra chinensis. The aim of the presented work was to boost the accumulation of lignans in the agitated microshoot cultures of S. chinensis, using different elicitation schemes. The experiments included testing of various concentrations and supplementation times of cadmium chloride (CdCl₂), chitosan (Ch), yeast extract (YeE), methyl jasmonate (MeJa), and permeabilizing agent—dimethylsulfoxide (DMSO). After 30 days, the microshoots were harvested and evaluated for growth parameters and lignan content by LC-DAD method. The analyses showed enhanced production of lignans in the elicited S. chinensis microshoots, whereas the respective media samples contained only trace amounts of the examined compounds (< 5 mg/l). Elicitation with CdCl₂ caused up to 2-fold increase in the total lignan content (max. ca. 730 mg/100 g DW after the addition of 1000 μM CdCl₂ on the tenth day). Experiments with chitosan resulted in up to 1.35-fold increase in lignan concentration (max. ca. 500 mg/100 g DW) after the supplementation with 50 mg/l on the first day and 200 mg/l on the tenth day. High improvement of lignan production was also recorded after YeE elicitation. After the elicitation with 5000 mg/l of YeE on the first day of the growth period, and with 1000 and 3000 mg/l on the 20th day, the lignan production increased to the same degree—about 1.8-fold. The supplementation with 1000 mg/l YeE on the 20th day of the growth cycle was chosen as the optimal elicitation scheme, for the microshoot cultures maintained in Plantform temporary immersion system—the total content of the estimated lignans was equal to 831.6 mg/100 g DW.

Pneumatic hydrodynamics influence transplastomic protein yields and biological responses during in vitro shoot regeneration of Nicotiana tabacum callus: Implications for bioprocess routes to plant-made biopharmaceuticals

Transplastomic plants are capable of high-yield production of recombinant biopharmaceutical proteins. Plant tissue culture combines advantages of agricultural cultivation with the bioprocess consistency associated with suspension culture. Overexpression of recombinant proteins through regeneration of transplastomic Nicotiana tabacum shoots from callus tissue in RITA^® temporary immersion bioreactors has been previously demonstrated. In this study we investigated the hydrodynamics of periodic pneumatic suspension of liquid medium during temporary immersion culture (4 min aeration every 8 h), and the impact on biological responses and transplastomic expression of fragment C of tetanus toxin (TetC). Biomass was grown under a range of aeration rates for 3, 20 and 40-day durations. Growth, mitochondrial activity (a viability indicator) and TetC protein yields were correlated against the hydrodynamic parameters, shear rate and energy dissipation rate (per kg of medium). A critical aeration rate of 440 ml min^-1 was identified, corresponding to a shear rate of 96.7 s^-1, pneumatic power input of 8.8 mW kg^-1 and initial 20-day pneumatic energy dissipation of 127 J kg^-1, at which significant reductions in biomass accumulation and mitochondrial activity were observed. There was an exponential decline in TetC yields with increasing aeration rates at 40 days, across the entire range of conditions tested. These observations have important implications for the optimisation and scale-up of transplastomic plant tissue culture bioprocesses for biopharmaceutical production.

Temporary Immersion System for Date Palm Micropropagation

The temporary immersion system (TIS) is being used with tremendous success for automation of micropropagation of many plant species. TIS usually consists of a culture vessel comprising two compartments, an upper one with the plant material and a lower one with the liquid culture medium and an automated air pump. The latter enables contact between all parts of the explants and the liquid medium by setting overpressure to the lower part of the container. These systems are providing the most satisfactory conditions for date palm regeneration via shoot organogenesis and allow a significant increase of multiplication rate (5.5-fold in comparison with that regenerated on agar-solidified medium) and plant material quality, thereby reducing production cost.

In Vitro Mass Propagation of Cymbopogon citratus Stapf., a Medicinal Gramineae

Cymbopogon citratus (D.C.) Stapf. is a medicinal plant source of lemon grass oils with multiple uses in the pharmaceutical and food industry. Conventional propagation in semisolid culture medium has become a fast tool for mass propagation of lemon grass, but the production cost must be lower. A solution could be the application of in vitro propagation methods based on liquid culture advantages and automation. This chapter provides two efficient protocols for in vitro propagation via organogenesis and somatic embryogenesis of this medicinal plant. Firstly, we report the production of shoots using a temporary immersion system (TIS). Secondly, a protocol for somatic embryogenesis using semisolid culture for callus formation and multiplication, and liquid culture in a rotatory shaker and conventional bioreactors for the maintenance of embryogenic culture, is described. Well-developed plants can be achieved from both protocols. Here we provide a fast and efficient technology for mass propagation of this medicinal plant taking the advantage of liquid culture and automation.