TIR1/AFB-Aux/IAA auxin perception mediates rapid cell wall acidification and growth of Arabidopsis hypocotyls
- Institute of Science and Technology Austria, Austria
- INRA - Centre de Versailles-Grignon, Saclay Plant Science, France
Figures
Figure 1
Auxin-triggered growth of hypocotyl segments correlates with nuclear auxin signaling.
(A) A brightfield image of a three-day old etiolated Arabidopsis hypocotyl and the corresponding decapitated hypocotyl segment used in the elongation assay. On the right, kymographs of growing …
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Figure 1—source data 1
Numerical data for the graphs.
- https://doi.org/10.7554/eLife.19048.003
Figure 2
Apoplast acidification visualized by the apo-pHusion marker line.
(A) Apoplast acidification and cell elongation follow approximately 20 min after auxin application (white arrowhead). A region of a hypocotyl segment of the apo-pHusion marker line is shown in time …
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Figure 2—source data 1
Numerical data for the graph 2A.
- https://doi.org/10.7554/eLife.19048.005
Figure 3 with 1 supplement
Nuclear auxin signaling is needed for growth and apoplast acidification.
(A) Mutations in the ABP1 gene do not influence auxin-induced hypocotyl elongation. (B) Inhibition of the TIR1/AFB Aux/IAA auxin receptor by the dominant-negative axr3-1 protein completely blocks …
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Figure 3—source data 1
Numerical data for the graphs.
- https://doi.org/10.7554/eLife.19048.009
Figure 3—figure supplement 1
Auxin induced growth of the tir1/afb2/afb3 mutant and the non-induced HS::axr3-1 line.
(A) The tir1-1/afb2/afb3 mutant reacts to auxin (10 µM NAA) and fusicoccin (1 µM) similarly to Col-0. Errorbars represent stdev.s. (B) The non-induced HS::axr3-1 hypocotyl segments also behave as a …
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Figure 3—figure supplement 1—source data 1
Numerical data for the graphs.
- https://doi.org/10.7554/eLife.19048.011
Figure 4
Activation of PM H+-ATPases triggers auxin-independent growth.
(A) The 35S::GFP-SAUR19 hypocotyls elongate in the absence of auxin, and the addition of auxin (10 µM NAA) does not further increase their growth. On the right, a kymograph of a decapitated …
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Figure 4—source data 1
Numerical data for the graphs.
- https://doi.org/10.7554/eLife.19048.013
Figure 5
An asymmetrical acidification of the apoplast is necessary for gravitropism.
(A) The lower epidermal side of a gravistimulated apo-pHusion marker line shows more acidic cell walls than the upper side. Hypocotyl was stimulated for 1 hr, the regions used for apoplastic pH …
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Figure 5—source data 1
Numerical data for the graphs.
- https://doi.org/10.7554/eLife.19048.015
Videos
Video 1
The movie shows an apo-pHusion marker line hypocotyl segment.
NAA (10 µM) is added at time 0, acidification follows in approximately 20 min. The pH-sensitive GFP is shown in green, the reference mRFP in magenta, therefore white color corresponds to higher pH, …
Video 2
Apoplastic pH drops rapidly after adding fusicoccin (5 µM at timepoint 0).
An apo-pHusion marker line hypocotyl segment. The pH-sensitive GFP is shown in green, the reference mRFP in magenta, therefore white color corresponds to higher pH, while magenta to lower pH values.
Video 3
Col-0 hypocotyls grown in darkness and imaged using an infrared imaging system.
At the beginning of the movie, the seedlings are stimulated by 90 degrees rotation. Seedlings bend up and continue growing upwards; note the waving of the tip of the growing seedlings. Roots are …
Additional files
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Supplementary file 1
The AreaKymo script.
- https://doi.org/10.7554/eLife.19048.017
