Purple: H + -ATPase; blue: AUX1; dashed arrow: diffusion Yellow: PIN proteins ; red: PGPs
description
Transcript of Purple: H + -ATPase; blue: AUX1; dashed arrow: diffusion Yellow: PIN proteins ; red: PGPs
Purple: H+-ATPase; blue: AUX1; dashed arrow: diffusion
Yellow: PIN proteins; red: PGPs
PINs/PGP proteins:
Tissue-specific distribution of PIN efflux facilitator proteins
br2 mutant:
Normal tassels and ear, but compact lower stalks
Auxin transport inhibitors
efflux inhibitor
influx inhibitor
Aglycone flavonoids
displace NPA
isoflavones
Actin-dependent PIN complex cycling
Auxin transport inhibitors may act by interfering with PIN1 complex cycling
Web Essay 19.1
PLoS ONE (January 2008)
In dark: PIN2, in vacuole;
In light: predominantly in PM
Physiological effects of auxin – cell elongation
Endogenous vs. Exogenous auxin
Oat coleoptile sections
Suc maintain turgor pressure; can be substituted by KCl; 15 min lag time
The optimal auxin concentration– pea stem or oat coleoptile sections
ppm (ethylene induction)
For roots: opt. 10-10 to 10-9 M; 10-6 M inhibition
Not only for IAA level but also for auxin types for different cells
10 M IAA, 2% sucrose
The characteristics of auxin induce stem growth: acquire energy is inhibited when the presence of inhibitor of metabolic, protein synthesis
(cycloheximide), or RNA synthesis the limiting time of lag phase could not be shortened some biochemical machinery involved
0.5 h
Auxin-induced elongation vs. cell wall acidification
Maize coleoptile
lag time
Current models for IAA-induced H+ extrusion
(cell wall loosening proteins)
ABP1: track H+-ATPase to membrane
(auxin-binding protein)
Receptor (?)
p. 503 polyubiquitin