The unhinged gene is essential for vascular complexity in the leaves of Arabidopsis
Date
2006
Authors
Cormack, Ryan David
University of Lethbridge. Faculty of Arts and Science
Journal Title
Journal ISSN
Volume Title
Publisher
Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2006
Abstract
The complex vasculature seen in the vascular plants provides a scaffolding of
structural support and is responsible for the movement of water, minerals, photosynthate
and some hormones. The auxin canalization model proposes that a positive feedback
mechanism causes auxin-transporting cells to become vascular cells. We have isolated a
leaf-patterning mutant, unhinged (unh), which shows a simplified leaf vascular pattern
with more freely ending veins and fewer secondary veins. Expression of the
ATHB8::GUS reporter construct indicates that the UNH gene acts prior to procambial
patterning of the first presumptive secondary veins. Expression of the auxin responsive
reporter gene DR5::GUS is reduced in unh leaves and roots, indicating that UNH may be
involved in auxin signaling. Increasing the level of auxin in unh leaves through the
addition of auxin transport inhibitors, low concentrations of 2,4-dichlorophenoxyacetic
acid, and through introducing unh into mutants in which auxin transport is defective
partially rescues the unh phenotype, supporting this hypothesis. The unh mutation maps
to a 60kb region near the top of chromosome IV. No other leaf vascular mutant or auxinassociated
mutant have been reported in this area, thus UNH represents a novel
component of leaf vascularization and auxin signaling.
Description
xi, 65 leaves : ill. (some col.) ; 29 cm.
Keywords
Dissertations, Academic , Arabidopsis -- Research , Vascular system of plants , Plants -- Effect of auxin on