Nejvíce citovaný článek - PubMed ID 16297075
Directional transport of the phytohormone auxin is a versatile, plant-specific mechanism regulating many aspects of plant development. The recently identified plant hormones, strigolactones (SLs), are implicated in many plant traits; among others, they modify the phenotypic output of PIN-FORMED (PIN) auxin transporters for fine-tuning of growth and developmental responses. Here, we show in pea and Arabidopsis that SLs target processes dependent on the canalization of auxin flow, which involves auxin feedback on PIN subcellular distribution. D14 receptor- and MAX2 F-box-mediated SL signaling inhibits the formation of auxin-conducting channels after wounding or from artificial auxin sources, during vasculature de novo formation and regeneration. At the cellular level, SLs interfere with auxin effects on PIN polar targeting, constitutive PIN trafficking as well as clathrin-mediated endocytosis. Our results identify a non-transcriptional mechanism of SL action, uncoupling auxin feedback on PIN polarity and trafficking, thereby regulating vascular tissue formation and regeneration.
- MeSH
- Arabidopsis genetika metabolismus MeSH
- heterocyklické sloučeniny tricyklické metabolismus MeSH
- hrách setý genetika metabolismus MeSH
- kyseliny indoloctové metabolismus MeSH
- laktony metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin genetika fyziologie MeSH
- regulátory růstu rostlin metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- GR24 strigolactone MeSH Prohlížeč
- heterocyklické sloučeniny tricyklické MeSH
- kyseliny indoloctové MeSH
- laktony MeSH
- proteiny huseníčku MeSH
- regulátory růstu rostlin MeSH
Auxin is unique among plant hormones due to its directional transport that is mediated by the polarly distributed PIN auxin transporters at the plasma membrane. The canalization hypothesis proposes that the auxin feedback on its polar flow is a crucial, plant-specific mechanism mediating multiple self-organizing developmental processes. Here, we used the auxin effect on the PIN polar localization in Arabidopsis thaliana roots as a proxy for the auxin feedback on the PIN polarity during canalization. We performed microarray experiments to find regulators of this process that act downstream of auxin. We identified genes that were transcriptionally regulated by auxin in an AXR3/IAA17- and ARF7/ARF19-dependent manner. Besides the known components of the PIN polarity, such as PID and PIP5K kinases, a number of potential new regulators were detected, among which the WRKY23 transcription factor, which was characterized in more detail. Gain- and loss-of-function mutants confirmed a role for WRKY23 in mediating the auxin effect on the PIN polarity. Accordingly, processes requiring auxin-mediated PIN polarity rearrangements, such as vascular tissue development during leaf venation, showed a higher WRKY23 expression and required the WRKY23 activity. Our results provide initial insights into the auxin transcriptional network acting upstream of PIN polarization and, potentially, canalization-mediated plant development.
- MeSH
- Arabidopsis genetika růst a vývoj MeSH
- geneticky modifikované rostliny MeSH
- genové regulační sítě * účinky léků MeSH
- kořeny rostlin účinky léků genetika růst a vývoj metabolismus MeSH
- kyseliny indoloctové metabolismus farmakologie MeSH
- membránové transportní proteiny genetika metabolismus MeSH
- mikročipová analýza MeSH
- polarita buněk * genetika MeSH
- proteiny huseníčku genetika metabolismus fyziologie MeSH
- regulace genové exprese u rostlin účinky léků MeSH
- stanovení celkové genové exprese MeSH
- transkripční faktory fyziologie MeSH
- zpětná vazba fyziologická účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- kyseliny indoloctové MeSH
- membránové transportní proteiny MeSH
- PIN1 protein, Arabidopsis MeSH Prohlížeč
- proteiny huseníčku MeSH
- transkripční faktory MeSH
- WRKY23 protein, Arabidopsis MeSH Prohlížeč
Synchronized tissue polarization during regeneration or de novo vascular tissue formation is a plant-specific example of intercellular communication and coordinated development. According to the canalization hypothesis, the plant hormone auxin serves as polarizing signal that mediates directional channel formation underlying the spatio-temporal vasculature patterning. A necessary part of canalization is a positive feedback between auxin signaling and polarity of the intercellular auxin flow. The cellular and molecular mechanisms of this process are still poorly understood, not the least, because of a lack of a suitable model system. We show that the main genetic model plant, Arabidopsis (Arabidopsis thaliana) can be used to study the canalization during vascular cambium regeneration and new vasculature formation. We monitored localized auxin responses, directional auxin-transport channels formation, and establishment of new vascular cambium polarity during regenerative processes after stem wounding. The increased auxin response above and around the wound preceded the formation of PIN1 auxin transporter-marked channels from the primarily homogenous tissue and the transient, gradual changes in PIN1 localization preceded the polarity of newly formed vascular tissue. Thus, Arabidopsis is a useful model for studies of coordinated tissue polarization and vasculature formation after wounding allowing for genetic and mechanistic dissection of the canalization hypothesis.
- MeSH
- Arabidopsis fyziologie MeSH
- kambium fyziologie MeSH
- kyseliny indoloctové metabolismus MeSH
- regenerace MeSH
- stonky rostlin fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- kyseliny indoloctové MeSH
The concept of plant intelligence, as proposed by Anthony Trewavas, has raised considerable discussion. However, plant intelligence remains loosely defined; often it is either perceived as practically synonymous to Darwinian fitness, or reduced to a mere decorative metaphor. A more strict view can be taken, emphasizing necessary prerequisites such as memory and learning, which requires clarifying the definition of memory itself. To qualify as memories, traces of past events have to be not only stored, but also actively accessed. We propose a criterion for eliminating false candidates of possible plant intelligence phenomena in this stricter sense: an "intelligent" behavior must involve a component that can be approximated by a plausible algorithmic model involving recourse to stored information about past states of the individual or its environment. Re-evaluation of previously presented examples of plant intelligence shows that only some of them pass our test.
