Journal
NEW PHYTOLOGIST
Volume 212, Issue 2, Pages 497-509Publisher
WILEY-BLACKWELL
DOI: 10.1111/nph.14049
Keywords
Arabidopsis; AUX1; auxin; cytokinins; PIN-FORMED (PIN); root gravitropism
Categories
Funding
- Ministry of Education, Youth and Sports Czech Republic [CEITEC 2020 (LQ1601), LO1204, LH14104]
- European Research Council [ERC-2011-StG-20101109-PSDP]
- Czech Science Foundation [GAP501/11/1150, GA13-40637S, GP14-30004P]
Ask authors/readers for more resources
Redirection of intercellular auxin fluxes via relocalization of the PIN-FORMED 3 (PIN3) and PIN7 auxin efflux carriers has been suggested to be necessary for the root gravitropic response. Cytokinins have also been proposed to play a role in controlling root gravitropism, but conclusive evidence is lacking. We present a detailed study of the dynamics of root bending early after gravistimulation, which revealed a delayed gravitropic response in transgenic lines with depleted endogenous cytokinins (Pro35S:AtCKX) and cytokinin signaling mutants. Pro35S:AtCKX lines, as well as a cytokinin receptor mutant ahk3, showed aberrations in the auxin response distribution in columella cells consistent with defects in the auxin transport machinery. Using invivo real-time imaging of PIN3-GFP and PIN7-GFP in AtCKX3 overexpression and ahk3 backgrounds, we observed wild-type-like relocalization of PIN proteins in the columella early after gravistimulation, with gravity-induced relocalization of PIN7 faster than that of PIN3. Nonetheless, the cellular distribution of PIN3 and PIN7 and expression of PIN7 and the auxin influx carrier AUX1 was affected in AtCKX overexpression lines. Based on the retained cytokinin sensitivity in pin3 pin4 pin7 mutant, we propose the AUX1-mediated auxin transport rather than columella-located PIN proteins as a target of endogenous cytokinins in the control of root gravitropism.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available