Size control is a fundamental question in biology, showing incremental complexity in plants, whose cells possess a rigid cell wall. The phytohormone auxin is a vital growth regulator with central importance for differential growth control. Our results indicate that auxin-reliant growth programs affect the molecular complexity of xyloglucans, the major type of cell wall hemicellulose in eudicots. Auxin-dependent induction and repression of growth coincide with reduced and enhanced molecular complexity of xyloglucans, respectively. In agreement with a proposed function in growth control, genetic interference with xyloglucan side decorations distinctly modulates auxin-dependent differential growth rates. Our work proposes that auxin-dependent growth programs have a spatially defined effect on xyloglucan's molecular structure, which in turn affects cell wall mechanics and specifies differential, gravitropic hypocotyl growth.
- Klíčová slova
- auxin, cell wall, gravitropism, growth, hypocotyls, xyloglucans,
- MeSH
- Arabidopsis fyziologie MeSH
- buněčná stěna metabolismus MeSH
- fluorescenční protilátková technika MeSH
- fyziologie rostlin * MeSH
- glukany chemie metabolismus MeSH
- hrách setý fyziologie MeSH
- kyseliny indoloctové metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné buňky metabolismus MeSH
- signální transdukce MeSH
- vývoj rostlin * MeSH
- xylany chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- glukany MeSH
- kyseliny indoloctové MeSH
- xylany MeSH
- xyloglucan MeSH Prohlížeč
Auxin is a key plant regulatory molecule, which acts upon a plethora of cellular processes, including those related to cell differentiation and elongation. Despite the stunning progress in all disciplines of auxin research, the mechanisms of auxin-mediated rapid promotion of cell expansion and underlying rearrangement of cell wall components are poorly understood. This is partly due to the limitations of current methodologies for probing auxin. Here we describe a click chemistry-based approach, using an azido derivative of indole-3-propionic acid. This compound is as an active auxin analogue, which can be tagged in situ. Using this new tool, we demonstrate the existence of putative auxin binding sites in the cell walls of expanding/elongating cells. These binding sites are of protein nature but are distinct from those provided by the extensively studied AUXIN BINDING PROTEIN 1 (ABP1). Using immunohistochemistry, we have shown the apoplastic presence of endogenous auxin epitopes recognised by an anti-IAA antibody. Our results are intriguingly in line with previous observations suggesting some transcription-independent (non-genomic) activity of auxin in cell elongation.
Intercellular flow of the phytohormone auxin underpins multiple developmental processes in plants. Plant-specific pin-formed (PIN) proteins and several phosphoglycoprotein (PGP) transporters are crucial factors in auxin transport-related development, yet the molecular function of PINs remains unknown. Here, we show that PINs mediate auxin efflux from mammalian and yeast cells without needing additional plant-specific factors. Conditional gain-of-function alleles and quantitative measurements of auxin accumulation in Arabidopsis and tobacco cultured cells revealed that the action of PINs in auxin efflux is distinct from PGP, rate-limiting, specific to auxins, and sensitive to auxin transport inhibitors. This suggests a direct involvement of PINs in catalyzing cellular auxin efflux.
- MeSH
- ABC transportéry genetika metabolismus MeSH
- Arabidopsis cytologie růst a vývoj metabolismus fyziologie MeSH
- biologický transport MeSH
- buněčná membrána metabolismus MeSH
- ftalimidy farmakologie MeSH
- gravitropismus MeSH
- HeLa buňky MeSH
- kinetika MeSH
- kořeny rostlin fyziologie MeSH
- kultivované buňky MeSH
- kyseliny indoloctové metabolismus MeSH
- kyseliny naftalenoctové metabolismus MeSH
- lidé MeSH
- membránové transportní proteiny genetika metabolismus MeSH
- mutace MeSH
- proteiny huseníčku genetika metabolismus MeSH
- Saccharomyces cerevisiae genetika MeSH
- tabák MeSH
- transfekce MeSH
- transformace genetická MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Názvy látek
- 1-naphthaleneacetic acid MeSH Prohlížeč
- ABC transportéry MeSH
- alpha-naphthylphthalamic acid MeSH Prohlížeč
- ATPGP1 protein, Arabidopsis MeSH Prohlížeč
- ftalimidy MeSH
- kyseliny indoloctové MeSH
- kyseliny naftalenoctové MeSH
- membránové transportní proteiny MeSH
- PIN1 protein, Arabidopsis MeSH Prohlížeč
- PIN2 protein, Arabidopsis MeSH Prohlížeč
- PIN4 protein, Arabidopsis MeSH Prohlížeč
- PIN7 protein, Arabidopsis MeSH Prohlížeč
- proteiny huseníčku MeSH
