Plants, unlike animals, possess a unique developmental plasticity, that allows them to adapt to changing environmental conditions. A fundamental aspect of this plasticity is their ability to undergo postembryonic de novo organogenesis. This requires the presence of regulators that trigger and mediate specific spatiotemporal changes in developmental programs. The phytohormone cytokinin has been known as a principal regulator of plant development for more than six decades. In de novo shoot organogenesis and in vitro shoot regeneration, cytokinins are the prime candidates for the signal that determines shoot identity. Both processes of de novo shoot apical meristem development are accompanied by changes in gene expression, cell fate reprogramming, and the switching-on of the shoot-specific homeodomain regulator, WUSCHEL. Current understanding about the role of cytokinins in the shoot regeneration will be discussed.

• Klíčová slova
• cytokinin, de novo organogenesis, plant stem cells, shoot apical meristem, shoot regeneration,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The At-Hook Motif Nuclear Localized Protein (AHL) gene family encodes embryophyte-specific nuclear proteins with DNA binding activity. They modulate gene expression and affect various developmental processes in plants. We identify AHL18 (At3G60870) as a developmental modulator of root system architecture and growth. AHL18 is involved in regulation of the length of the proliferation domain and number of dividing cells in the root apical meristem and thereby, cell production. Both primary root growth and lateral root development respond according to AHL18 transcription level. The ahl18 knock-out plants show reduced root systems due to a shorter primary root and a lower number of lateral roots. This change results from a higher number of arrested and non-developing lateral root primordia (LRP) rather than from a decreased LRP initiation. The over-expression of AHL18 results in a more extensive root system, longer primary roots, and increased density of lateral root initiation events. AHL18 is thus involved in the formation of lateral roots at both LRP initiation and their later development. We conclude that AHL18 participates in modulation of root system architecture through regulation of root apical meristem activity, lateral root initiation and emergence; these correspond well with expression pattern of AHL18.

• Klíčová slova
• AHL18, AT-hook motif nuclear protein 18, Arabidopsis, At3G60870, Cell proliferation, Lateral root development, Root apical meristem,
• MeSH
• Arabidopsis genetika   růst a vývoj   metabolismus   MeSH
• AT-hook motivy MeSH
• DNA vazebné proteiny chemie   genetika   metabolismus   MeSH
• kořeny rostlin genetika   růst a vývoj   metabolismus   MeSH
• mutace MeSH
• proteiny huseníčku chemie   genetika   metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• vývojová regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• proteiny huseníčku MeSH