Abstract
The plant-tumorigenic 6b (AK-6b) gene of Agrobacterium tumefaciens strain AKE10 induces morphological alterations to tobacco plants, Nicotiana tabacum. To investigate the molecular mechanisms underlying these processes, we generated transgenic tobacco harboring the AK-6b gene under the control of a dexamethazone-inducible promoter. Upon induction, transgenic tobacco seedlings exhibited distinct classes of aberrant morphologies, most notably adventitious outgrowths and stunted epicotyls. Histological analysis revealed massive proliferation and altered venation in the newly established outgrowths. Prominent vascular development suggested that auxin metabolism or signaling had been altered. Indeed, basipetal auxin transport in the hypocotyls of the transgenic seedlings was reduced by 50-80%, whereas intracellular auxin contents were only slightly reduced. Analysis of cell extracts by HPLC revealed a large accumulation of phenolic compounds, including the flavonoid kaempferol-3- rutinoside, in transgenic plants compared with wild-type seedlings. As some naturally occurring flavonoids have been shown to affect auxin transport, we suggest that the AK-6b gene expression impairs auxin transport via modulation of phenylpropanoid metabolism, and ultimately results in the observed morphological alterations.
| Original language | English |
|---|---|
| Pages (from-to) | 237-247 |
| Number of pages | 11 |
| Journal | Planta |
| Volume | 223 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Jan 2006 |
| Externally published | Yes |
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Keywords
- Agrobacterium
- Auxin transport
- Flavonoid
- Morphological abnormality
- Tobacco
ASJC Scopus subject areas
- Plant Science
Cite this
Reduction of polar auxin transport in tobacco by the tumorigenic Agrobacterium tumefaciens AK-6b gene. / Kakiuchi, Yasutaka; Galis, Ivan; Tamogami, Shigeru; Wabiko, Hiroetsu.
In: Planta, Vol. 223, No. 2, 01.2006, p. 237-247.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Reduction of polar auxin transport in tobacco by the tumorigenic Agrobacterium tumefaciens AK-6b gene
AU - Kakiuchi, Yasutaka
AU - Galis, Ivan
AU - Tamogami, Shigeru
AU - Wabiko, Hiroetsu
PY - 2006/1
Y1 - 2006/1
N2 - The plant-tumorigenic 6b (AK-6b) gene of Agrobacterium tumefaciens strain AKE10 induces morphological alterations to tobacco plants, Nicotiana tabacum. To investigate the molecular mechanisms underlying these processes, we generated transgenic tobacco harboring the AK-6b gene under the control of a dexamethazone-inducible promoter. Upon induction, transgenic tobacco seedlings exhibited distinct classes of aberrant morphologies, most notably adventitious outgrowths and stunted epicotyls. Histological analysis revealed massive proliferation and altered venation in the newly established outgrowths. Prominent vascular development suggested that auxin metabolism or signaling had been altered. Indeed, basipetal auxin transport in the hypocotyls of the transgenic seedlings was reduced by 50-80%, whereas intracellular auxin contents were only slightly reduced. Analysis of cell extracts by HPLC revealed a large accumulation of phenolic compounds, including the flavonoid kaempferol-3- rutinoside, in transgenic plants compared with wild-type seedlings. As some naturally occurring flavonoids have been shown to affect auxin transport, we suggest that the AK-6b gene expression impairs auxin transport via modulation of phenylpropanoid metabolism, and ultimately results in the observed morphological alterations.
AB - The plant-tumorigenic 6b (AK-6b) gene of Agrobacterium tumefaciens strain AKE10 induces morphological alterations to tobacco plants, Nicotiana tabacum. To investigate the molecular mechanisms underlying these processes, we generated transgenic tobacco harboring the AK-6b gene under the control of a dexamethazone-inducible promoter. Upon induction, transgenic tobacco seedlings exhibited distinct classes of aberrant morphologies, most notably adventitious outgrowths and stunted epicotyls. Histological analysis revealed massive proliferation and altered venation in the newly established outgrowths. Prominent vascular development suggested that auxin metabolism or signaling had been altered. Indeed, basipetal auxin transport in the hypocotyls of the transgenic seedlings was reduced by 50-80%, whereas intracellular auxin contents were only slightly reduced. Analysis of cell extracts by HPLC revealed a large accumulation of phenolic compounds, including the flavonoid kaempferol-3- rutinoside, in transgenic plants compared with wild-type seedlings. As some naturally occurring flavonoids have been shown to affect auxin transport, we suggest that the AK-6b gene expression impairs auxin transport via modulation of phenylpropanoid metabolism, and ultimately results in the observed morphological alterations.
KW - Agrobacterium
KW - Auxin transport
KW - Flavonoid
KW - Morphological abnormality
KW - Tobacco
UR - http://www.scopus.com/inward/record.url?scp=29444440738&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=29444440738&partnerID=8YFLogxK
U2 - 10.1007/s00425-005-0080-4
DO - 10.1007/s00425-005-0080-4
M3 - Article
C2 - 16170561
AN - SCOPUS:29444440738
VL - 223
SP - 237
EP - 247
JO - Planta
JF - Planta
SN - 0032-0935
IS - 2
ER -