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Inhibition of transdifferentiation into tracheary elements by polar auxin transport inhibitors through intracellular auxin depletion.
- Source :
-
Plant & cell physiology [Plant Cell Physiol] 2005 Dec; Vol. 46 (12), pp. 2019-28. Date of Electronic Publication: 2005 Oct 17. - Publication Year :
- 2005
-
Abstract
- Polar auxin transport is essential for the formation of continuous vascular strands in the plant body. To understand its mechanism, polar auxin transport inhibitors have often been used. However, the role of auxin in vascular differentiation at the unicellular level has remained elusive. Using a Zinnia elegans cell culture system, in which single mesophyll cells transdifferentiate into tracheary elements (TEs), we demonstrated that auxin transport inhibitors prevented TE differentiation and that high concentrations of 1-naphthaleneacetic acid (NAA) and IAA overcame the repression of TE differentiation. Measurements of NAA accumulation with 3H-labeled NAA in the presence or absence of 1-N-naphthylphthalamic acid (NPA) revealed enhanced NAA accumulation within the cell. In the NPA-treated cells, intracellular free NAA decreased, while its metabolites increased. Therefore, the polar auxin transport inhibitors may prevent auxin efflux and consequently promote NAA accumulation in Zinnia cells. The excess intracellular NAA may also activate NAA metabolism, resulting in a decrease in free NAA levels. This depletion of free NAA may prevent TE differentiation. The decreased auxin activity in NPA-treated cells was confirmed by the fact that the DR5 (a synthetic auxin-inducible promoter)-mediated expression of a reporter protein was suppressed in such cells. Gene expression analysis indicated that NPA suppressed TE differentiation at an early process of transdifferentiation into TEs. Based on these results, the inter-relationship between auxin and vascular cell development at a cellular level is discussed.
- Subjects :
- Asteraceae chemistry
Asteraceae genetics
Bacterial Proteins analysis
Bacterial Proteins genetics
Benzyl Compounds
Biological Transport
Cell Differentiation drug effects
Cells, Cultured
Gene Expression Regulation, Plant
Gravitropism physiology
Kinetin pharmacology
Luminescent Proteins analysis
Luminescent Proteins genetics
Membrane Transport Proteins genetics
Membrane Transport Proteins metabolism
Microscopy, Fluorescence
Naphthaleneacetic Acids analysis
Naphthaleneacetic Acids pharmacology
Plant Leaves chemistry
Plant Proteins antagonists & inhibitors
Plant Proteins genetics
Purines
RNA, Messenger analysis
Reverse Transcriptase Polymerase Chain Reaction
Triiodobenzoic Acids pharmacology
Asteraceae cytology
Asteraceae metabolism
Indoleacetic Acids metabolism
Plant Leaves cytology
Plant Leaves metabolism
Plant Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0032-0781
- Volume :
- 46
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Plant & cell physiology
- Publication Type :
- Academic Journal
- Accession number :
- 16230330
- Full Text :
- https://doi.org/10.1093/pcp/pci217