Characterization of transmembrane auxin transport in Arabidopsis suspension-cultured cells

Seifertová, Daniela; Skůpa, Petr; Rychtář, Jan; Laňková, Martina; Pařezová, Markéta; Dobrev, Petre I.; Hoyerová, Klára; Petrášek, Jan; Zažímalová, Eva

doi:10.1016/j.jplph.2013.09.026

Cited by 17 publications

(16 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S11A). This result is consistent with evidence showing that auxin efflux transporters effectively transport IAA and NAA but not 2,4-D (29). These findings suggest that auxin transport and local biosynthesis coordinately determine the position of auxin maxima in the root apex.…”

Section: Auxin Transport System Regulates the Distribution Of Fluoressupporting

confidence: 91%

Auxin transport sites are visualized in planta using fluorescent auxin analogs

Hayashi

Nakamura

Fukunaga

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The plant hormone auxin is a key morphogenetic signal that controls many aspects of plant growth and development. Cellular auxin levels are coordinately regulated by multiple processes, including auxin biosynthesis and the polar transport and metabolic pathways. The auxin concentration gradient determines plant organ positioning and growth responses to environmental cues. Auxin transport systems play crucial roles in the spatiotemporal regulation of the auxin gradient. This auxin gradient has been analyzed using SCF-type E3 ubiquitin-ligase complex-based auxin biosensors in synthetic auxin-responsive reporter lines. However, the contributions of auxin biosynthesis and metabolism to the auxin gradient have been largely elusive. Additionally, the available information on subcellular auxin localization is still limited. Here we designed fluorescently labeled auxin analogs that remain active for auxin transport but are inactive for auxin signaling and metabolism. Fluorescent auxin analogs enable the selective visualization of the distribution of auxin by the auxin transport system. Together with auxin biosynthesis inhibitors and an auxin biosensor, these analogs indicated a substantial contribution of local auxin biosynthesis to the formation of auxin maxima at the root apex. Moreover, fluorescent auxin analogs mainly localized to the endoplasmic reticulum in cultured cells and roots, implying the presence of a subcellular auxin gradient in the cells. Our work not only provides a useful tool for the plant chemical biology field but also demonstrates a new strategy for imaging the distribution of smallmolecule hormones.auxin transporter | subcellular localization

show abstract

Section: Auxin Transport System Regulates the Distribution Of Fluoressupporting

confidence: 91%

Auxin transport sites are visualized in planta using fluorescent auxin analogs

Hayashi

Nakamura

Fukunaga

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…AUX1 is the dominant route for uptake of IAA into plant cells, accounting for 75% of accumulation activity (Delbarre et al ., ; Rutschow et al ., ), a situation common to Arabidopsis and tobacco BY‐2 cells (Seifertová et al ., ). In common with the current debates on drug permeation into cells (Kell & Oliver, ; Mendes et al ., ), it remains unclear exactly how the auxin herbicides which are not AUX1 substrates enter plant cells.…”

Section: Discussionmentioning

confidence: 68%

Auxin molecular field maps define AUX1 selectivity: many auxin herbicides are not substrates

et al. 2017

View full text Add to dashboard Cite

Developmental responses to auxin are regulated by facilitated uptake and efflux, but detailed molecular understanding of the carrier proteins is incomplete. We have used pharmacological tools to explore the chemical space that defines substrate preferences for the auxin uptake carrier AUX1. Total and partial loss-of-function aux1 mutants were assessed against wild-type for dose-dependent resistance to a range of auxins and analogues. We then developed an auxin accumulation assay with associated mathematical modelling to enumerate accurate IC values for a small library of auxin analogues. The structure activity relationship data were analysed using molecular field analyses to create a pharmacophoric atlas of AUX1 substrates. The uptake carrier exhibits a very high level of selectivity towards small substrates including the natural indole-3-acetic acid, and the synthetic auxin 2,4-dichlorophenoxyacetic acid. No AUX1 activity was observed for herbicides based on benzoic acid (dicamba), pyridinyloxyacetic acid (triclopyr) or the 6-arylpicolinates (halauxifen), and very low affinity was found for picolinic acid-based auxins (picloram) and quinolinecarboxylic acids (quinclorac). The atlas demonstrates why some widely used auxin herbicides are not, or are very poor substrates. We list molecular descriptors for AUX1 substrates and discuss our findings in terms of herbicide resistance management.

show abstract

“…When added to BY-2 cell cultures 2,4-D rapidly accumulated in the cells, and MDCA had a mild, but positive effect on this profile; however, the mild accumulation likely reflects the partial inhibition of the active cellular efflux of 2,4-D under these conditions as a similar profile was described for the auxin efflux blocker NPA as well (Hosek et al, 2012). In Arabidopsis cell cultures, 2,4-D seems to be a good substrate for both influx and efflux auxin carriers (Seifertová et al, 2014) and, accordingly, the positive effect of MDCA on the accumulation of 2,4-D is more pronounced here than in BY-2 cells (Supplemental Fig. S10).…”

Section: Mdca Affects Auxin Transportmentioning

confidence: 64%

The allelochemical MDCA inhibits lignification and affects auxin homeostasis

et al. 2016

Self Cite

View full text Add to dashboard Cite

The phenylpropanoid 3,4-(methylenedioxy)cinnamic acid (MDCA) is a plant-derived compound first extracted from roots of Asparagus officinalis and further characterized as an allelochemical. Later on, MDCA was identified as an efficient inhibitor of 4-COUMARATE-CoA LIGASE (4CL), a key enzyme of the general phenylpropanoid pathway. By blocking 4CL, MDCA affects the biosynthesis of many important metabolites, which might explain its phytotoxicity. To decipher the molecular basis of the allelochemical activity of MDCA, we evaluated the effect of this compound on Arabidopsis thaliana seedlings. Metabolic profiling revealed that MDCA is converted in planta into piperonylic acid (PA), an inhibitor of CINNAMATE-4-HYDROXYLASE (C4H), the enzyme directly upstream of 4CL. The inhibition of C4H was also reflected in the phenolic profile of MDCA-treated plants. Treatment of in vitro grown plants resulted in an inhibition of primary root growth and a proliferation of lateral and adventitious roots. These observed growth defects were not the consequence of lignin perturbation, but rather the result of disturbing auxin homeostasis. Based on DII-VENUS quantification and direct measurement of cellular auxin transport, we concluded that MDCA disturbs auxin gradients by interfering with auxin efflux. In addition, mass spectrometry was used to show that MDCA triggers auxin biosynthesis, conjugation, and catabolism. A similar shift in auxin homeostasis was found in the c4h mutant ref3-2, indicating that MDCA triggers a cross talk between the phenylpropanoid and auxin biosynthetic pathways independent from the observed auxin efflux inhibition. Altogether, our data provide, to our knowledge, a novel molecular explanation for the phytotoxic properties of MDCA.

show abstract

Characterization of transmembrane auxin transport in Arabidopsis suspension-cultured cells

Cited by 17 publications

References 51 publications

Auxin transport sites are visualized in planta using fluorescent auxin analogs

Auxin transport sites are visualized in planta using fluorescent auxin analogs

Auxin molecular field maps define AUX1 selectivity: many auxin herbicides are not substrates

The allelochemical MDCA inhibits lignification and affects auxin homeostasis

Contact Info

Product

Resources

About