Temporary immersion systems (TISs): A comprehensive review

Innovative aspects of micropropagation in olive

The olive tree is one of the most iconic species within the Mediterranean Sea Basin. Countries bordering this sea enjoy a favourable climate that contributes to high-quality agricultural production for numerous horticultural species. The quality of the propagation material is one of the most important factors in determining the value of the final product, regardless of the cultivation-model, climate, and soil characteristics. Therefore, it is crucial to ensure genetic and sanitary certainty of vegetal/propagation material, which can be achieved through nursery productions. These goals are based on efficient propagation systems and methods to obtain high-biological quality plants. Over the last four decades, the application of biotechnology has introduced significant changes in the sector of nursery production. The Authors in this chapter aimed to present through their personal experimental experiences the latest advances in in vitro techniques and technologies that are revolutionizing the field of olive tree nurseries. While some of these methods are currently being employed, others are still undergoing research and development. Experts in this field firmly believe that all these techniques hold great practical value and have immense potential for high-quality nursery production.

The Enhancement of Biomass Accumulation, Caffeoylquinic Acid Derivative Production, and Antioxidant Activity of Rhaponticum carthamoides Transformed Roots Cultured in a Nutrient Sprinkle Bioreactor

Rhaponticum carthamoides (Willd.) Iljin. is an endemic plant species found in Siberia, Mongolia, and Kazakhstan. Its roots and rhizomes are used to treat physical fatigue and weakness following illness. The present study examines the scaling up of caffeoylquinic acid (CQA) derivative and flavonoid production in R. carthamoides transformed roots. The transformed roots were grown in shaken Erlenmeyer flasks of varying volumes (0.5-2 L), a temporary immersion system (TIS) (Rita® and PlantForm bioreactors), and a nutrient sprinkle bioreactor (NSB) in Woody Plant medium for 35 days. The highest dry biomass production was achieved in the 0.5 L and 1 L flasks and in the NSB bioreactor, yielding 22.2 to 20.4 g/L-approximately 14 to 23 times the weight of the inoculum. The accumulation of individual specialized metabolites varied depending on the culture system used. The peak amount of CQAs (544.5 mg/L), in terms of the increase in dry weight and metabolite levels, was obtained in the NSB bioreactor. The primary CQAs were chlorogenic acid (5-CQA) and a tri-CQA 1. The highest concentration of 5-CQA (7.38 mg/g DW) was found in the roots cultivated in the NSB bioreactor. In contrast, the tri-CQA 1 dominated in the roots from 2 L shaken Erlenmeyer flasks (8.44 mg/g DW). Our findings demonstrate that transformed roots growing in an NSB bioreactor are an effective system for increasing CQA production, potentially serving as an alternative source. This biotechnological approach could help reduce the overexploitation of field-grown R. carthamoides, a currently threatened species.

Bulbil initiation: a comprehensive review on resources, development, and utilisation, with emphasis on molecular mechanisms, advanced technologies, and future prospects

Bulbil is an important asexual reproductive structure of bulbil plants. It mainly grows in leaf axils, leaf forks, tubers and the upper and near ground ends of flower stems of plants. They play a significant role in the reproduction of numerous herbaceous plant species by serving as agents of plant propagation, energy reserves, and survival mechanisms in adverse environmental conditions. Despite extensive research on bulbil-plants regarding their resources, development mechanisms, and utilisation, a comprehensive review of bulbil is lacking, hindering progress in exploiting bulbil resources. This paper provides a systematic overview of bulbil research, including bulbil-plant resources, identification of development stages and maturity of bulbils, cellular and molecular mechanisms of bulbil development, factors influencing bulbil development, gene research related to bulbil development, multi-bulbil phenomenon and its significance, medicinal value of bulbils, breeding value of bulbils, and the application of plant tissue culture technology in bulbil production. The application value of the Temporary Immersion Bioreactor System (TIBS) and Terahertz (THz) in bulbil breeding is also discussed, offering a comprehensive blueprint for further bulbil resource development. Additionally, additive, seven areas that require attention are proposed: (1) Utilization of modern network technologies, such as plant recognition apps or websites, to collect and identify bulbous plant resources efficiently and extensively; (2) Further research on cell and tissue structures that influence bulb cell development; (3) Investigation of the network regulatory relationship between genes, proteins, metabolites, and epigenetics in bulbil development; (4) Exploration of the potential utilization value of multiple sprouts, including medicinal, ecological, and horticultural applications; (5) Innovation and optimization of the plant tissue culture system for bulbils; (6) Comprehensive application research of TIBS for large-scale expansion of bulbil production; (7) To find out the common share genetics between bulbils and flowers.

Comparative Assessment of Lignan Profiling and Biological Activities of Schisandra henryi Leaf and In Vitro PlantForm Bioreactor-Grown Culture Extracts

This research's scope encompassed biotechnological, phytochemical, and biological studies of Schisandra henryi, including investigations into its in vitro microshoot culture grown in PlantForm bioreactors (temporary immersion systems, TISs), as well as extracts from leaves of the parent plant, focusing on anti-inflammatory, antioxidant, anticancer, and antimicrobial activities. The phytochemical analysis included the isolation and quantification of 17 compounds from dibenzocyclooctadiene, aryltetralin lignans, and neolignans using centrifugal partition chromatography (CPC), HPLC-DAD, and UHPLC-MS/MS tandem mass spectrometry with triple quadrupole mass filter methods. Higher contents of compounds were found in microshoots extracts (max. 543.99 mg/100 g DW). The major compound was schisantherin B both in the extracts from microshoots and the leaves (390.16 and 361.24 mg/100 g DW, respectively). The results of the anti-inflammatory activity in terms of the inhibition of COX-1, COX-2, sPLA2, and LOX-15 enzymes indicated that PlantForm microshoot extracts showed strong activity against COX-1 and COX-2 (for 177 mg/mL the inhibition percentage was 76% and 66%, respectively). The antioxidant potential assessed using FRAP, CUPRAC, and DPPH assays showed that extracts from microshoot cultures had 5.6, 3.8, and 3.3 times higher power compared to extracts from the leaves of the parent plant, respectively. The total polyphenol content (TPC) was 4.1 times higher in extracts from the in vitro culture compared to the leaves. The antiproliferative activity against T-cell lymphoblast line Jurkat, breast adenocarcinoma cultures (MCF-7), colon adenocarcinoma (HT-29), and cervical adenocarcinoma (HeLa), showed that both extracts have considerable effects on the tested cell lines. The antimicrobial activity tested against strains of Gram-positive and Gram-negative bacteria and fungi showed the highest activity towards H. pylori (MIC and MBC 0.625 mg/mL).

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.

Temporary Immersion Bioreactors for Sugarcane Multiplication and Rooting

Sugarcane is used to produce sugar, ethanol, and other by-products, so it is considered one of the most important crops worldwide. Using temporary immersion systems for sugarcane micropropagation represents an alternative to reduce the labor force, increase plant development, and improve plant quality. Temporary immersion systems are semi-automated bioreactors designed for the large-scale propagation of tissues, embryos, and organs. These are temporarily exposed in a liquid culture medium under a specific time and immersion frequency. Using this protocol and a temporary immersion bioreactor, it is possible to achieve multiplication and rooting. The use of temporary immersion bioreactors improves the multiplication rate and the rooting of sugarcane, reducing the culture time, labor force, and reagents needed while maintaining high survival rates during acclimatization.

Micropropagation of Guarianthe skinneri (Bateman) Dressler & W. E. Higging in Temporary Immersion Bioreactors

Guarianthe skinneri (Bateman) Dressler & W. E. Higgins is an orchid valued for its ornamental characteristics. However, it is an orchid classified as threatened with extinction due to the illegal extraction from its natural habitat. In addition, its propagation through seed germination is very low, as is the case with most members of the family Orchidaceae. Its asexual propagation through pseudobulb separation is slow and produces a few propagules. For this reason, in vitro propagation techniques are an alternative to increase the number of plants obtained and thus be able to recover this valuable plant genetic resource. Temporary immersion systems (TIS) offer the advantage of mass-propagating plants for different purposes. This chapter describes a large-scale micropropagation protocol for Guarianthe skinneri using temporary immersion bioreactors (TIB).

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).

Scale-Up of Coffea canephora Somatic Embryogenesis in Temporary Immersion System

Somatic embryogenesis (SE) is a clear example of cellular totipotency. The SE of the genus Coffea has become a model for in vitro propagation for woody species and for the large-scale production of disease-free plants that provide an advantage for modern agriculture. Temporary immersion systems (TIS) are in high demand for the propagation of plants. The success of this type of bioreactor is based on the alternating cycles of immersion of the plant material in the culture medium, usually a few minutes, and the permanence outside the medium of the tissues for several hours. Some bioreactors are very efficient for propagating one species but not another. The efficiency of bioreactors depends on the species, the tissue used to propagate, the species' nutritional needs, the amount of ethylene produced by the tissue, and many more. In this protocol, we show how we produce C. canephora plants that are being taken to the field.

Micropropagation of Stevia (Stevia rebaudiana Bert.) in RITA®

Stevia rebaudiana Bert. is a plant that contains noncaloric sweeteners highly appreciated in the food industry. However, there is a high demand for propagules to establish commercial plantations, and the conventional reproduction types for this species are inefficient. Micropropagation is a technique that allows obtaining a large number of plants and can be used to meet the demand in the field. However, it requires in vitro propagation techniques such as temporary immersion systems (SIT) to increase yield and reduce production costs. This chapter describes an effective protocol for the large-scale micropropagation of S. rebaudiana using a TIS.

Use of Temporary Immersion Systems in the Establishment of Biofactories

Companies dedicated to the large-scale propagation of plant species are known as biofactories or agricultural biotechnology companies. Globally, there are a large number of biofactories (large-scale production) or plant tissue culture laboratories (small-scale production) in charge of supplying commercial propagules of plants of economic interest. Each biofactory implements technological developments such as temporary immersion (TIS) systems that allow them to reduce costs. This chapter analyzes some of the biofactories established globally, the main plant species propagated, and whether or not they implement the use of TIS.

Temporary Immersion System for Biomass Production of Salvia spp.: A Mini-Review

Salvia is a very valuable medicinal plant for the pharmaceutical industry. Tissue culture techniques can be used to increase the number of plants in a shorter time. Although protocols for in vitro propagation of more than 15 plant species have been developed, they are not yet efficient enough to increase mass propagation of plants. Therefore, the use of temporary immersion systems is necessary to increase the morphological quality of plants as well as their biomass in several Salvia species. In this chapter, progress in in vitro propagation in several Salvia species using liquid medium and automation is described.

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.

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.

In Vitro Conversion of Coffea spp. Somatic Embryos in SETIS™ Bioreactor System

Somatic embryogenesis (SE) is an excellent example of mass plant propagation. Due to its genetic variability and low somaclonal variation, coffee SE has become a model for in vitro propagation of woody species, as well as for large-scale production of vigorous plants that are advantageous to modern agriculture. The success of the large-scale propagation of an embryogenic system is dependent on the development, optimization, and transfer of complementary system technologies. In this study, two successful SE systems were combined with a SETIS™ bioreactor immersion system to develop an efficient and cost-effective approach for the in vitro development of somatic embryos of Coffea spp. This study used an efficient protocol for obtaining somatic embryos, utilizing direct and indirect SE for both C. canephora and C. arabica. Embryos in the cotyledonary stage were deposited in a bioreactor to complete their stage of development from embryo to plant with minimal manipulation. Following ten weeks of cultivation in the bioreactor, complete and vigorous plants were obtained. Different parameters such as fresh weight, length, number of leaves, and root length, as well as stomatal index and relative water content, were recorded. In addition, the survival rate and ex vitro development of plantlets during acclimatization was assessed. The best substrate combination was garden soil (GS), peat moss (PM), and agrolite (A) in a 1:1:0.5 ratio, in which the bioreactor-regenerated plants showed an acclimatization rate greater than 90%. This is the first report on the use of SETIS™ bioreactors for the in vitro development of somatic embryos in Coffea spp., providing a technology that could be utilized for the commercial in vitro propagation of coffee plants. A link between research and innovation is necessary to establish means of communication that facilitate technology transfer. This protocol can serve as a basis for the generation and scaling of different species of agroeconomic importance. However, other bottlenecks in the production chains and the field must be addressed.

Different Types of Hypericum perforatum cvs. (Elixir, Helos, Topas) In Vitro Cultures: A Rich Source of Bioactive Metabolites and Biological Activities of Biomass Extracts

Microshoot agitated and bioreactor cultures (PlantForm bioreactors) of three Hypericum perforatum cultivars (Elixir, Helos, Topas) were maintained in four variants of Murashige and Skoog medium (MS) supplemented with 6-benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) (in the range of 0.1-3.0 mg/L). In both types of in vitro cultures, the accumulation dynamics of phenolic acids, flavonoids, and catechins were investigated during 5- and 4-week growth cycles, respectively. The contents of metabolites in methanolic extracts from biomasses collected in 1-week intervals were estimated by HPLC. The highest total contents of phenolic acids, flavonoids, and catechins were 505, 2386, and 712 mg/100 g DW, respectively (agitated cultures of cv. Helos). The extracts from biomass grown under the best in vitro culture conditions were examined for antioxidant and antimicrobial activities. The extracts showed high or moderate antioxidant activity (DPPH, reducing power, and chelating activity assays), high activity against Gram-positive bacteria, and strong antifungal activity. Additionally, experiments with phenylalanine feeding (1 g/L) in agitated cultures were performed reaching the highest enhancement of the total contents of flavonoids, phenolic acids, and catechins on day 7 after the addition of the biogenetic precursor (2.33-, 1.73- and 1.33-fold, respectively). After feeding, the highest accumulation of polyphenols was detected in the agitated culture of cv. Elixir (4.48 g/100 g DW). The high contents of metabolites and the promising biological properties of the biomass extracts are interesting from a practical point of view.

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.