Epigenetics in plant tissue culture

Plants produced vegetatively in tissue culture may differ from the plants from which they have been derived. Two major classes of off-types occur: genetic ones and epigenetic ones. This review is about epigenetic aberrations. We discuss recent studies that have uncovered epigenetic modifications at the molecular level, viz., changes in DNA methylation and alterations of histone methylation or acetylation. Various studies have been carried out with animals, and with plant cells or tissues that have grown in tissue culture but only little work has been done with shoots generated by axillary branching. We present various molecular methods that are being used to measure epigenetic variation. In micropropagated plants mostly differences in DNA methylation have been examined. Epigenetic changes are thought to underlie various well-known tissue-culture phenomena including rejuvenation, habituation, and morphological changes such as flower abnormalities, bushiness, and tumorous outgrowths in, among others, oil palm, gerbera, Zantedeschia and rhododendron

Plant cell technologies in space: Background, strategies and prospects

An attempt is made to summarize work in plant cell technologies in space. The evolution of concepts and the general principles of plant tissue culture are discussed. The potential for production of high value secondary products by plant cells and differentiated tissue in automated, precisely controlled bioreactors is discussed. The general course of the development of the literature on plant tissue culture is highlighted

Effect of plant-based feed ingredients on osmoregulation in the Atlantic salmon lens

Lenses of adult Atlantic salmon fed with a plant oil and plant protein-based diet (plant diet) were compared to lenses of fish fed a diet based on traditional marine ingredients (marine diet) with respect to biochemical composition and functionality ex vivo. After 12 months of feeding, plant diet-fed fish had smaller lenses with higher water contents and lower concentrations of histidine (His) and N-acetylhistidine (NAH) than fish fed with the marine diet. Cataract development in both dietary groups was minimal and no differences between the groups were observed. Lens fatty acid and lipid class composition differed minimally, although a significant increase in linoleic acid was observed. The lenses were examined for their ability to withstand osmotic disturbances ex vivo. Culture in hypoosmotic and hyperosmotic media led to increase and decrease of lens volume, respectively. Lenses from plant diet-fed fish were less resistant to swelling and shrinking, released less NAH into the culture medium, and accumulated His and NAH at higher rates than lenses from marine diet-fed fish. Culture in hypoosmotic medium resulted in higher cataract scores than in control and hyperosmotic medium. mRNA expression of selected genes, including glutathione peroxidase 4 and SPARC (secreted protein acidic and rich in cysteine), was affected by diet and osmotic treatment. It can be concluded that lenses of farmed Atlantic salmon are affected by the diet composition, both in biochemical composition and physiological functionality in relation to osmoregulation

The growth of plant embryos in vitro. Preliminary experiments on the role of accessory substances

The aseptic culture of plant embryos isolated from the seed dates back to the work of Brown and Morris,(1) Hannig(2) and Dietrich.(3) More recent contributions to our knowledge concerning the culture in vitro of excised embryos have been made by Tukey,(4) Brunner(5) and LaRue,(6) among others. It has been recognized by, for example, Ray(7) that the embryo culture technique offers a useful tool for biochemical investigations, and it has also been recognized(4,8) that it may be used as a practical measure to circumvent the abortion of embryos. It has, however, been found that in general the growth of the excised embryo, even upon a medium containing essential inorganic materials and sugar, is far less than that of normal intact seedlings. This has led to the suggestion(5) that "accessory growth factors" which are needed in minute amounts, are required by the developing plant as they are by the developing animal organism. The present work, as well as that of Kogl and Haagen-Smit,(9) furnish final proof that this is the case; that these accessory substances, although normally furnished by the seed, may be replaced to some extent by pure compounds added in small amounts to the embryo culture medium. These investigations, taken up early in 1936, are concerned particularly with orienting experiments undertaken with an ultimate view toward the elucidation of the nature and mode of action of these accessory growth factors. The embryo culture technique is here to be used as a tool in the "hormonal" analysis of plant development

Modular plant culture systems for life support functions

The current state of knowledge with regard to culture of higher plants in the zero-G environment is assessed; and concepts for the empirical development of small plant growth chambers for the production of salad type vegetables on space shuttle or space station are evaluated. American and Soviet space flight experiences in gravitational biology are summarized

Micropropagation for the production of high quality phytochemicals

Plants area source of many valuable secondary metabolites that find a broad field of applications, ranging from the agrochemical to the pharmaceutical industries. Establishing a suitable source for extraction of phytochemicals is, however, not always straightforward. In many instances the production by chemical synthesis is not economically viable due to their complex structures and conservation issues may arise when they are harvested from natural sources. In vitro culture techniques offer an attractive alternative to these issues. Natural grown plants can be replaced by in vitro produced biomass with the advantage that several strategies can be implemented to increase production yields, such as genotype selection, altering growth conditions and use of elicitors, so that the higher investment costs are justified. Also, because plant tissue cultures can be generated on a continuous year-round basis without seasonal constraints, they can guarantee reliable and predictable production levels, which is of great importance for efficient process down-stream. Plant tissue culture techniques offer the possibility of establishing cultures from leaves, stems, roots and meristems, meaning that metabolites produced in specific plant organs can also be prospected. The successful production of a large number of phytochemicals from micropropagated biomass has been reported, and it seems that only in a few cases cultures fail to accumulate compounds of interest. The advantages and the range of possibilities offered by plant tissue culture techniques suggest that these might become a valuable and indispensable tool for the production of phytochemicals. In this work, the example of the prospection of plumbagin from micropropagated D. intermedia plants is described. Plumbagin is a naphthoquinone with potential pharmaceutical applications and results obtained by several hyphenated analytical techniques confirm that an end product with high purity and recoveries can be obtained from in vitro cultured plants. © ISHS 2013

Sand to Root Transfer of PAHs and PCBs by Carrots Grown on Sand with Pure Substances and Biosolids Amended Sand

A study on behaviour of trace organic compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Polychlorinated Biphenyls, PCB) in a sand-plant system has been carried out, with the reclamation of wastewater treatment plant biosolids for agriculture in mind. Carrot plants (Daucus carota) were grown on soilless culture (sand), to provide optimal transfer conditions, in plant containers inside a temperature regulated greenhouse. There were two types of experiment. The trace organic compounds have initially been introduced as pure substances. A second experiment has been carried out under the same conditions, but using biosolids. Plant development has been unaffected by the presence of the pure substances and the biosolids. The transfer of the trace organic compounds has been followed in the peel, the core and the leaves of the carrot plants. Results obtained are expressed as fluxes of the trace organic compounds into the plant. The results clearly show that trace organic compounds accumulate in the carrot peel

The sensitivity of plant tissue culture and plant cell of citrullus lanatus cv. round dragon against basta®

Current study provides an efficient screening system for transformed plant of Citrullus lanatus cv. Round Dragon harboring bar gene. The untransformed 5-day-old cotyledon explants were cultured on the shoot-inducing media supplemented with Basta® (0.2, 0.5, 1.0, 2.0 and 3.0 mg L-1) and without Basta® for 3 weeks and subcultured on fresh shoot-inducing media with the same media composition for another 3 weeks. The shoot growth on the cotyledon decreased, as the Basta® concentration increased. A complete inhibition of shoot growth was observed on growth medium supplemented with 2.0 and 3.0 mg L-1 of Basta®, respectively. For ex vitro condition, untransformed healthy plant leaves (derived from acclimatized in vitro plantlets) were leaf painted with an aqueous solution of Basta® at the concentration of 0.001, 0.01 and 0.1% (v/v) using writing brush. The sensitivity of untransformed plant tissues were evaluated based on tissue browning and necrosis due to herbicidal damage. Healthy plant leaves subjected to leaf painting assay showed serious necrotic within 3 days at the concentration of 0.1% (v/v) of Basta®. An efficient herbicide Basta® selection mode has been established via in vitro and ex vitro conditions of untransformed Citrullus lanatus cv. Round Dragon

A heterologous expression system for bovine lens transmembrane main intrinsic protein (MIP) in Nicotiana tabacum plants

We have developed a heterologous expression system for transmembrane lens main intrinsic protein (MIP) in Nicotiana tabacum plant tissue. A native bovine MIP26 amplicon was subcloned into an expression cassette under the control of a constitutive Cauliflower Mosaic Virus promoter, also containing a neomycin phosphotransferase operon. This cassette was transformed into Agrobacterium tumefaciens by triparental mating and used to infect plant tissue grown in culture. Recombinant plants were selected by their ability to grow and root on kanamycin-containing media. The presence of MIP in the plant tissues was confirmed by PCR, RT-PCR and immunohistochemistry. A number of benefits of this system for the study of MIP will be discussed, and also its application as a tool for the study of heterologously expressed proteins in general

Selectivity and functional diversity in arbuscular mycorrhizas of co-occurring fungi and plants from a temperate deciduous woodland

1 The arbuscular mycorrhizal (AM) fungi colonizing plants at a woodland site in North Yorkshire (UK) have been characterized from the roots of five plant species (Rubus fruticosus agg. L., Epilobium angustifolium L., Acer pseudoplatanus L., Ajuga reptans L. and Glechoma hederacea L.), and identified using small-subunit rRNA (SSUrRNA) gene amplification and sequencing. 2 Interactions between five plant species from the site and four co-occurring glomalean fungi were investigated in artificial one-to-one AM symbioses. Three of the fungi were isolated from the site; the fourth was a culture genetically similar to a taxon found at the site. Phosphorus uptake and growth responses were compared with non-mycorrhizal controls. 3 Individual fungi colonized each plant with different spatial distribution and intensity. Some did not colonize at all, indicating incompatibility under the conditions used in the experiments. 4 Glomus hoi consistently occupied a large proportion of root systems and outperformed the other fungi, improving P uptake and enhancing the growth of four out of the five plant species. Only G. hoi colonized and increased P uptake in Acer pseudoplatanus, the host plant with which it associates almost exclusively under field conditions. Colonization of all plant species by Scutellospora dipurpurescens was sparse, and beneficial to only one of the host plants (Teucrium scorodonia). Archaeospora trappei and Glomus sp. UY1225 had variable effects on the host plants, conferring a range of P uptake and growth benefits on Lysimachia nummularia and T. scorodonia, increasing P uptake whilst not affecting biomass in Ajuga reptans and Glechoma hederacea, and failing to form mycorrhizas with A. pseudoplatanus. 5 These experimental mycorrhizas show that root colonization, symbiont compatibility and plant performance vary with each fungus-plant combination, even when the plants and fungi naturally co-exist. 6 We provide evidence of physical and functional selectivity in AM. The small number of described AM fungal species (154) has been ascribed to their supposed lack of host specificity, but if the selectivity we have observed is the general rule, then we may predict that many more, probably hard-to-culture glomalean species await discovery, or that members of species as currently perceived may be physiologically or functionally distinct