Plant steroid alcohols, plant sterols, are essential components of cell membranes that perform many functions. Their most prominent function is maintaining membrane semipermeability and regulating its fluidity through their specific interaction with phospholipids and membrane proteins. This work is focused on the study of the interaction of two groups of plant sterols, brassinosteroids (BRs) and phytoecdysteroids (PE). Steroid substances belonging to both groups are important signaling molecules essential for plant growth and development, but while the first group has all the known attributes of plant hormones, the second lacks hormonal function in plants. The aim of this preliminary study was to determine at what concentration level and to what extent substances of this type are able to interact with each other, and thus influence the early growth and development of a plant. It was found that exogenously applied PE 20-hydroxyecdysone (20E) significantly reduced the level of endogenous BRs in four-day-old garden cress (Lepidium sativum) seedlings. On the other hand, exogenously applied BRs, 24-epibrassinolide (epiBL), caused the opposite effect. Endogenous 20E was further detected at the picogram level in garden cress seedlings. Thus, this is the first report indicating that this plant species is PE-positive. The level of endogenous 20E in garden cress seedlings can be decreased by exogenous epiBL, but only at a relatively high concentration of 1·10-6 M in a culture medium. The image analysis of garden cress seedlings revealed that the length of shoot is affected neither by exogenous BRs nor PE, whereas the root length varies depending on the type and concentration of steroid applied.

• Klíčová slova
• Lepidium sativum, brassinosteroids, phytoecdysteroids, plant growth, triterpenoids,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Although many genetic manipulations of crops providing biofortified or safer food have been done, the acceptance of biotechnology crops still remains limited. We report on a transgenic barley expressing the multi-functional protein osmotin that improves plant defense under stress conditions. METHODS: An Agrobacterium-mediated technique was used to transform immature embryos of the spring barley cultivar Golden Promise. Transgenic barley plants of the T0 and T1 generation were evaluated by molecular methods. Transgenic barley tolerance to stress was determined by chlorophyll, total protein, malondialdehyde and ascorbate peroxidase content. Methanol extracts of i) Fusarium oxysporum infected or ii) salt-stressed plants, were characterized by their acute toxicity effect on human dermal fibroblasts (HDF), genotoxicity and affection of biodiversity interactions, which was tested through monitoring barley natural virus pathogen-host interactions-the BYDV and WDV viruses transmitted to the plants by aphids and leafhoppers. RESULTS: Transgenic plants maintained the same level of chlorophyll and protein, which significantly declined in wild-type barley under the same stressful conditions. Salt stress evoked higher ascorbate peroxidase level and correspondingly less malondialdehyde. Osmotin expressing barley extracts exhibited a lower cytotoxicity effect of statistical significance than that of wild-type plants under both types of stress tested on human dermal fibroblasts. Extract of Fusarium oxysporum infected transgenic barley was not able to damage DNA in the Comet assay, which is in opposite to control plants. Moreover, this particular barley did not affect the local biodiversity. CONCLUSION: Our findings provide a new perspective that could help to evaluate the safety of products from genetically modified crops.

• MeSH
• bezpečnost potravin * MeSH
• biologická adaptace MeSH
• ektopická exprese * MeSH
• fyziologický stres genetika   MeSH
• geneticky modifikované rostliny MeSH
• interakce hostitele a patogenu genetika   MeSH
• ječmen (rod) genetika   MeSH
• lidé MeSH
• rekombinantní proteiny * MeSH
• rostlinné proteiny genetika   MeSH
• tabák genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• rekombinantní proteiny * MeSH
• rostlinné proteiny MeSH

The contents of endogenous brassinosteroids (BRs) together with various aspects of plant morphology, water management, photosynthesis and protection against cell damage were assessed in two maize genotypes that differed in their drought sensitivity. The presence of 28-norbrassinolide in rather high quantities (1-2 pg mg-1 fresh mass) in the leaves of monocot plants is reported for the first time. The intraspecific variability in the presence/content of the individual BRs in drought-stressed plants is also described for the first time. The drought-resistant genotype was characterised by a significantly higher content of total endogenous BRs (particularly typhasterol and 28-norbrassinolide) compared with the drought-sensitive genotype. On the other hand, the drought-sensitive genotype showed higher levels of 28-norcastasterone. Both genotypes also differed in the drought-induced reduction/elevation of the levels of 28-norbrassinolide, 28-norcastasterone, 28-homocastasterone and 28-homodolichosterone. The differences observed between both genotypes in the endogenous BR content are probably correlated with their different degrees of drought sensitivity, which was demonstrated at various levels of plant morphology, physiology and biochemistry.

• MeSH
• brassinosteroidy farmakologie   MeSH
• fotosyntéza * MeSH
• fyziologický stres * MeSH
• genotyp MeSH
• kukuřice setá účinky léků   genetika   růst a vývoj   MeSH
• listy rostlin účinky léků   genetika   růst a vývoj   MeSH
• období sucha * MeSH
• regulátory růstu rostlin farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• brassinosteroidy MeSH
• regulátory růstu rostlin MeSH

The present review summarises current knowledge of phytoecdysteroids' biosynthesis, distribution within plants, biological importance and relations to plant hormones. Plant ecdysteroids (phytoecdysteroids) are natural polyhydroxylated compounds that have a four-ringed skeleton, usually composed of either 27 carbon atoms or 28-29 carbon atoms (biosynthetically derived from cholesterol or other plant sterols, respectively). Their physiological roles in plants have not yet been confirmed and their occurrence is not universal. Nevertheless, they are present at high concentrations in various plant species, including commonly consumed vegetables, and have a broad spectrum of pharmacological and medicinal properties in mammals, including hepatoprotective and hypoglycaemic effects, and anabolic effects on skeletal muscle, without androgenic side-effects. Furthermore, phytoecdysteroids can enhance stress resistance by promoting vitality and enhancing physical performance; thus, they are considered adaptogens. This review summarises current knowledge of phytoecdysteroids' biosynthesis, distribution within plants, biological importance and relations to plant hormones.

• Klíčová slova
• 20-Hydroxyecdysone, Ecdysteroids, Phytoecdysteroids, Plant hormones, Signalling molecules,
• MeSH
• ekdysteroidy biosyntéza   MeSH
• regulátory růstu rostlin metabolismus   MeSH
• rostliny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• ekdysteroidy MeSH
• regulátory růstu rostlin MeSH