Auxin Transport

Lomax, Terri L.; Muday, Gloria K.; Rubery, P. H.

doi:10.1007/978-94-011-0473-9_24

Cited by 252 publications

(251 citation statements)

References 57 publications

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“…Preliminary experiments carried out with this species have also shown significant promotive effect of light on callus fresh mass in the explants oriented horizontally (Catapan 1999). Endogenous and applied auxins can move in the plant vascular system both in the phloem and in the xylem (Lomax et al 1995), therefore it may possibly be that higher kinetics of NAA uptake and transport to receiver cells in the stem, probably located in the vascular cambium, were facilitated when the explants were oriented in the vertical position.…”

Section: Resultsmentioning

confidence: 99%

In vitro culture of Phyllanthus stipulatus (Euphorbiaceae)

Catapan¹,

Otuki²,

Viana³

2001

Rev. bras. Bot.

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-(In vitro culture of Phyllanthus stipulatus (Euphorbiaceae)). An efficient micropropagation protocol was developed for the medicinal plant Phyllanthus stipulatus (Euphorbiaceae) using nodal segments for axillary shoot proliferation. Maximum multiplication rates (8-9 shoots per explant) was achieved on MS media supplemented with either 2.5-5.0 µM IBA. The best basal media for axillary shoot proliferation when 0.62 µM BA was supplemented were MS, MS/2 and AR (4-5 shoots per explant). Rooting was achieved with 100% of the microshoots on MS medium without growth regulators. Regenerated plants were successfully acclimatized and about 88% of plantlets survived under ex vitro conditions. Flowering was observed in 81% of the ex vitro grown plantlets after 12 weeks of acclimatization. High frequency callus initiation and growth was achieved when nodal segment explants were inoculated either in the vertical position, in the light on MS medium supplemented with 5.0 µM NAA or horizontally oriented, in the dark on MS supplemented with 5.0 µM NAA or 1.25-5.0 µM BA or 2iP. Root cultures were successfully established on MS medium containing 1.1 µM NAA. The optimized micropropagation, callus and root culture protocols offer the possibility to use cell/organ culture techniques for vegetative propagation and secondary metabolism studies.RESUMO -(Cultura in vitro de Phyllanthus stipulatus (Euphorbiaceae)). Um eficiente protocolo de micropropagação foi desenvolvido para a espécie medicinal Phyllanthus stipulatus (Euphorbiaceae) através da utilização de segmentos nodais para a proliferação de ramos. Taxas máximas de multiplicação (8-9 ramos por explante) foram obtidas em meio MS suplementado com 2,5-5,0 µM de IBA. As melhores formulações de meios de cultura quando 0,62 µM de BA foi suplementado foram MS, MS/2 e AR (4-5 ramos por explante). O enraizamento foi obtido em 100% das microestacas em meio MS sem reguladores de crescimento. As microplantas regeneradas foram aclimatadas com successo e ao redor de 88% delas sobreviveram às condições ex vitro. A floração foi observada em 81% das microplantas crescidas ex vitro 12 semanas após a aclimatação. Altas freqüências de iniciação e crescimento de calos foram obtidas quando os segmentos nodais foram inoculados na posição vertical, na luz, no meio MS suplementado com 5,0 µM NAA ou na posição horizontal, no escuro em meio MS suplementado com 5,0 µM NAA or 1,25-5,0 µM de BA ou 2iP. Culturas de raízes foram estabelecidas em meio MS suplementado com 1,1 µM NAA. Os protocolos otimizados de micropropagação, cultura de calos e de raízes possibilitam a utilização das técnicas de cultura de células/órgãos para a propagação vegetativa e estudos sobre o metabolismo secundário.

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Section: Resultsmentioning

confidence: 99%

In vitro culture of Phyllanthus stipulatus (Euphorbiaceae)

Catapan¹,

Otuki²,

Viana³

2001

Rev. bras. Bot.

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“…According to the chemiosmotic model of auxin transport [11][12][13][14], a substantial portion of IAA is protonated in the apoplast and able to enter cells via bilayer diffusion, whereas IAA inside the cells is less protonated and its efflux requires active transport. As to our knowledge, whether this is completely so has never been proven experimentally.…”

Section: Auxin Transport Across Biological Membranesmentioning

confidence: 99%

Master and servant: Regulation of auxin transporters by FKBPs and cyclophilins

2016

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Plant development and architecture are greatly influenced by the polar distribution of the essential hormone auxin. The directional influx and efflux of auxin from plant cells depends primarily on AUX1/LAX, PIN, and ABCB/PGP/MDR families of auxin transport proteins. The functional analysis of these proteins has progressed rapidly within the last decade thanks to the establishment of heterologous auxin transport systems. Heterologous co-expression allowed also for the testing of protein-protein interactions involved in the regulation of transporters and identified relationships with members of the FK506-Binding Protein (FKBP) and cyclophilin protein families, which are best known in non-plant systems as cellular receptors for the immunosuppressant drugs, FK506 and cyclosporin A, respectively. Current evidence that such interactions affect membrane trafficking, and potentially the activity of auxin transporters is reviewed. We also propose that FKBPs andcyclophilins might integrate the action of auxin transport inhibitors, such as NPA, on members of the ABCB and PIN family, respectively. Finally, we outline open questions that might be useful for further elucidation of the role of immunophilins as regulators (servants) of auxin transporters (masters).

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“…If gravitropism involves the redistribution of IAA in response to gravity, then there must be transporters that alter the distribution of IAA within the root tissue (Goldsmith 1977;Lomax et al 1995). IAA is thought to be transported down to the root tip via the vascular system of the root, and then transported up from the root tip to the elongation zone where it is probably localized in the epidermis.…”

mentioning

confidence: 99%

EIR1, a root-specific protein involved in auxin transport, is required for gravitropism inArabidopsis thaliana

et al. 1998

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The EIR1 gene of Arabidopsis is a member of a family of plant genes with similarities to bacterial membrane transporters. This gene is expressed only in the root, which is consistent with the phenotypes of the eir1 mutants-the roots are agravitropic and have a reduced sensitivity to ethylene. The roots of eir1 mutants are also insensitive to the excess auxin produced by alf1-1 and fail to induce an auxin-inducible gene in the expansion zone. Although they fail to respond to internally generated auxin, they respond normally to externally applied auxin. Expression of the EIR1 gene in Saccharomyces cerevisiae confers resistance to fluorinated indolic compounds. Taken together, these data suggest that the EIR1 protein has a root-specific role in the transport of auxin.

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Auxin Transport

Cited by 252 publications

References 57 publications

In vitro culture of Phyllanthus stipulatus (Euphorbiaceae)

In vitro culture of Phyllanthus stipulatus (Euphorbiaceae)

Master and servant: Regulation of auxin transporters by FKBPs and cyclophilins

EIR1, a root-specific protein involved in auxin transport, is required for gravitropism inArabidopsis thaliana

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