The aim of this study was to show whether/how the application of exogenous 24-epibrassinolide can affect the content of ecdysteroids in spinach leaves. Brassinosteroids and ecdysteroids, structurally related phytosterols, show effect on a range of processes in plants. Brassinosteroids increase biomass yield in some species, photosynthesis and resistance to stress, and ecdysteroids show effect on proteins responsible for binding of CO2 or water cleavage. The mutual interaction of these sterols in plants is unclear. The UPLC-(+)ESI-MS/MS analyses of extracts of treated and untreated spinach (Spinacia oleracea L.) leaves show that the application of exogenous 24-epibrassinolide does influence the ecdysteroid content in plant tissues. The response differs for the major ecdysteroids and also differs from that for the minor ones and is dependent on the developmental stage of the leaves within the same plant or the 24-epibrassinolide concentration applied.

• Klíčová slova
• 20-Hydroxyecdysone, 24-Epibrassinolide, Ecdysteroids, Spinach,
• MeSH
• brassinosteroidy farmakologie   MeSH
• ekdysteroidy metabolismus   MeSH
• listy rostlin účinky léků   metabolismus   MeSH
• molekulární konformace MeSH
• Spinacia oleracea chemie   účinky léků   MeSH
• steroidy heterocyklické farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• brassinolide MeSH Prohlížeč
• brassinosteroidy MeSH
• ekdysteroidy MeSH
• steroidy heterocyklické MeSH

The aim of the work was to examine the effect of brassinosteroid (24-epibrassinolide; 24E) and ecdysteroid (20-hydroxyecdysone; 20E) on various parts of primary photosynthetic processes in maize and spinach. Additionally, the effect of steroids on gaseous exchange, pigment content and biomass accumulation was studied. The efficiency of the photosynthetic whole electron-transport chain responded negatively to the 24E or 20E treatment in both species, but there were interspecific differences regarding Photosystem (PS) II response. A positive effect on its oxygen-evolving complex and a slightly better energetical connectivity between PSII units were observed in maize whereas the opposite was true for spinach. The size of the pool of the PSI end electron acceptors was usually diminished due to 24E or 20E treatment. The treatment of plants with 24E or 20E applied individually positively influenced the content of photosynthetic pigments in maize (not in spinach). On the other hand, it did not affect gaseous exchange in maize but resulted in its reduction in spinach. Plants treated with combination of both steroids mostly did not significantly differ from the control plants. We have demonstrated for the first time that 20E applied in low (10nM) concentration can affect various parts of photosynthetic processes similarly to 24E and that brassinosteroids regulate not only PSII but also other parts of the photosynthetic electron transport chain - but not necessarily in the same way.

• Klíčová slova
• Brassinosteroids, Chlorophyll, Ecdysteroids, Gas exchange, OJIP analysis, Photosynthetic electron transport,
• MeSH
• brassinosteroidy aplikace a dávkování   MeSH
• ekdysteron aplikace a dávkování   MeSH
• fotosyntéza účinky léků   genetika   MeSH
• fotosystém II - proteinový komplex účinky léků   genetika   MeSH
• kukuřice setá účinky léků   růst a vývoj   MeSH
• listy rostlin účinky léků   metabolismus   MeSH
• oxidace-redukce MeSH
• rostlinné proteiny biosyntéza   MeSH
• Spinacia oleracea účinky léků   růst a vývoj   MeSH
• steroidy heterocyklické aplikace a dávkování   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• brassinolide MeSH Prohlížeč
• brassinosteroidy MeSH
• ekdysteron MeSH
• fotosystém II - proteinový komplex MeSH
• rostlinné proteiny MeSH
• steroidy heterocyklické MeSH

The aim of this work was to isolate plant ecdysteroid-binding proteins using affinity chromatography. Ecdysteroids as insect hormones have been investigated thoroughly but their function and the mechanism of action in plants and other organisms is still unknown although ecdysteroids occur in some plants in a relatively large amount. Therefore, 20-hydroxyecdysone was immobilized on a polymeric carrier as a ligand for affinity chromatography in order to isolate plant ecdysteroid-binding proteins from the cytosolic extract of New Zealand spinach (Tetragonia tetragonoides). Non-specifically bound proteins were eluted with a rising gradient of concentration of sodium chloride, and 3% (v/v) acetic acid was used for the elution of the specifically bound proteins. Using this method, ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) was isolated. The influence of ecdysteroids on RuBisCO was further studied. Our results show that ecdysteroids are able to increase the yield of RuBisCO-mediated reaction in which CO(2) is fixed into organic matter by more than 10%.

• MeSH
• chromatografie afinitní * MeSH
• cytosol enzymologie   MeSH
• ekdysteron metabolismus   MeSH
• enzymy imobilizované MeSH
• ribulosa-1,5-bisfosfát-karboxylasa izolace a purifikace   metabolismus   MeSH
• Spinacia oleracea enzymologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ekdysteron MeSH
• enzymy imobilizované MeSH
• ribulosa-1,5-bisfosfát-karboxylasa MeSH