We have recently discovered that brassinosteroids (BRs) can inhibit the growth of etiolated pea seedlings dose-dependently in a similar manner to the 'triple response' induced by ethylene. We demonstrate here that the growth inhibition of etiolated pea shoots strongly correlates with increases in ethylene production, which also responds dose-dependently to applied BRs. We assessed the biological activities of two natural BRs on pea seedlings, which are excellent material as they grow rapidly, and respond both linearly and uni-phasically to applied BRs. We then compared the BRs' inhibitory effects on growth, and induction of ethylene and ACC (1-aminocyclopropane-1-carboxylic acid) production, to those of representatives of other phytohormone classes (cytokinins, auxins, and gibberellins). Auxin induced ca. 50-fold weaker responses in etiolated pea seedlings than brassinolide, and the other phytohormones induced much weaker (or opposite) responses. Following the optimization of conditions for determining ethylene production after BR treatment, we found a positive correlation between BR bioactivity and ethylene production. Finally, we optimized conditions for pea growth responses and developed a new, highly sensitive, and convenient bioassay for BR activity.
- MeSH
- aminokyseliny cyklické metabolismus MeSH
- biotest metody MeSH
- brassinosteroidy farmakologie MeSH
- ethyleny metabolismus MeSH
- hrách setý účinky léků růst a vývoj metabolismus MeSH
- inhibitory růstu farmakologie MeSH
- kyseliny indoloctové farmakologie MeSH
- regulátory růstu rostlin farmakokinetika farmakologie MeSH
- semenáček účinky léků růst a vývoj metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A series of phenyl analogues of brassinosteroids was prepared via alkene cross-metathesis using commercially available styrenes and 24-nor-5α-chola-2,22-dien-6-one. All derivatives were successfully docked into the active site of BRI1 using AutoDock Vina. Plant growth promoting activity was measured using the pea inhibition biotest and Arabidopsis root sensitivity assay and then was compared with naturally occuring brassinosteroids. Differences in the production of plant hormone ethylene were also observed in etiolated pea seedlings after treatment with the new and also five known brassinosteroid phenyl analogues. Antiproliferative activity was also studied using normal human fibroblast and human cancer cell lines.
- MeSH
- alkeny chemie MeSH
- Arabidopsis účinky léků enzymologie růst a vývoj MeSH
- brassinosteroidy chemická syntéza chemie metabolismus farmakologie MeSH
- hrách setý účinky léků růst a vývoj MeSH
- katalytická doména MeSH
- proteinkinasy chemie metabolismus MeSH
- proteiny huseníčku chemie metabolismus MeSH
- simulace molekulového dockingu MeSH
- techniky syntetické chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Transporter genes and cytokinins are key targets for crop improvement. These genes are active during the development of the seed and its establishment as a strong sink. However, during germination, the seed transitions to being a source for the developing root and shoot. To determine if the sucrose transporter (SUT), amino acid permease (AAP), Sugar Will Eventually be Exported Transporter (SWEET), cell wall invertase (CWINV), cytokinin biosynthesis (IPT), activation (LOG) and degradation (CKX) gene family members are involved in both the sink and source activities of seeds, we used RT-qPCR to determine the expression of multiple gene family members, and LC-MS/MS to ascertain endogenous cytokinin levels in germinating Pisum sativum L. We show that genes that are actively expressed when the seed is a strong sink during its development, are also expressed when the seed is in the reverse role of being an active source during germination and early seedling growth. Cytokinins were detected in the imbibing seeds and were actively biosynthesised during germination. We conclude that, when the above gene family members are targeted for seed yield improvement, a downstream effect on subsequent seed germination or seedling vigour must be taken into consideration.
- MeSH
- buněčná stěna enzymologie MeSH
- cytokininy biosyntéza genetika MeSH
- hrách setý genetika růst a vývoj MeSH
- invertasa biosyntéza genetika MeSH
- klíčení genetika MeSH
- proteiny přenášející monosacharidy biosyntéza genetika MeSH
- regulace genové exprese u rostlin MeSH
- regulátory růstu rostlin genetika MeSH
- semena rostlinná genetika růst a vývoj MeSH
- semenáček genetika MeSH
- tandemová hmotnostní spektrometrie MeSH
- transportní systémy aminokyselin biosyntéza genetika MeSH
- Publikační typ
- časopisecké články MeSH
Apical dominance is one of the fundamental developmental phenomena in plant biology, which determines the overall architecture of aerial plant parts. Here we show apex decapitation activated competition for dominance in adjacent upper and lower axillary buds. A two-nodal-bud pea (Pisum sativum L.) was used as a model system to monitor and assess auxin flow, auxin transport channels, and dormancy and initiation status of axillary buds. Auxin flow was manipulated by lateral stem wounds or chemically by auxin efflux inhibitors 2,3,5-triiodobenzoic acid (TIBA), 1-N-naphtylphtalamic acid (NPA), or protein synthesis inhibitor cycloheximide (CHX) treatments, which served to interfere with axillary bud competition. Redirecting auxin flow to different points influenced which bud formed the outgrowing and dominant shoot. The obtained results proved that competition between upper and lower axillary buds as secondary auxin sources is based on the same auxin canalization principle that operates between the shoot apex and axillary bud.
- MeSH
- biologický transport MeSH
- hrách setý účinky léků genetika růst a vývoj MeSH
- kyseliny indoloctové farmakologie MeSH
- regulace genové exprese u rostlin účinky léků MeSH
- regulátory růstu rostlin farmakologie MeSH
- rostlinné proteiny genetika MeSH
- stonky rostlin účinky léků genetika růst a vývoj MeSH
- výhonky rostlin účinky léků genetika růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Shoot branching is one of the major determinants of plant architecture. Polar auxin transport in stems is necessary for the control of bud outgrowth by a dominant apex. Here, we show that following decapitation in pea (Pisum sativum L.), the axillary buds establish directional auxin export by subcellular polarization of PIN auxin transporters. Apical auxin application on the decapitated stem prevents this PIN polarization and canalization of laterally applied auxin. These results support a model in which the apical and lateral auxin sources compete for primary channels of auxin transport in the stem to control the outgrowth of axillary buds.
- MeSH
- hrách setý genetika růst a vývoj metabolismus MeSH
- kyseliny indoloctové metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- regulátory růstu rostlin metabolismus MeSH
- rostlinné proteiny genetika metabolismus MeSH
- stonky rostlin růst a vývoj metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
