| Abstract Detail
Hormone Biology Sukumar, Poornima [1], Muday, Gloria K [2]. Role of auxin and ethylene in adventitious root formation in Arabidopsis. Lateral root development is well studied in Arabidopsis, but much less is known about the molecular mechanisms that control adventitious root formation. Adventitious roots emerge from the stem and provide mechanical support and are essential during vegetative propagation of shoot cuttings. The main aim of this research is to dissect the hormonal mechanisms that drive stems to differentiate into adventitious roots. For this purpose, Arabidopsis plants were grown under low light condition for 5 days and then transferred to high light conditions. Adventitious roots form along intact hypocotyls, but removal of the root tissue from hypocotyls enhanced the frequency of root formation. Increasing the light intensity also induced more adventitious roots. Adventitious roots were also found to be auxin regulated, as auxin treatment enhanced their formation and treatment of plants with the auxin transport inhibitor naphthylphthalamic acid (NPA) or removing the shoot apex inhibited adventitious root formation. Two auxin responsive promoter-GUS fusions, GH3-GUS and DR5-GUS, were expressed above the excision site beginning 9 hrs after excision, consistent with localized auxin accumulation. Flavonoids, which have been suggested to act as endogenous auxin transport inhibitors, were also induced upon wounding. Also, the tt4 mutant which makes no flavonoids has enhanced adventitious root formation. Ethylene may also regulate adventitious root formation since the ethylene insensitive mutants; ein2-5 and etr1-1 have altered adventitious root formation. These results are consistent with cross talk between auxin and ethylene and light levels regulating adventitious root formation. Log in to add this item to your schedule
1 - Wake Forest University, Department of Biology, P.O. Box 7325, Winston salem, NC, 27103, US 2 - Wake Forest University, Department of Biology
Keywords: Adventitious roots Arabidopsis auxin ethylene flavonoids.
Presentation Type: Plant Biology Abstract Session: P Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton Date: Sunday, July 8th, 2007 Time: 8:00 AM Number: P35017 Abstract ID:319 |