Cell-to-Cell and Long Distance Signaling
Deak, Karen , Muday, Gloria K , Malamy, Jocelyn .
Long Distance Signals Regulate Lateral Root Emergence in Arabidopsis thaliana.
The number and placement of a plantís lateral roots (LR) are the primary parameters that define root system architecture. LR formation can be regulated at several stages, including the development of lateral root primordia (LRP) into mature LR (LRP emergence). To determine whether emergence is regulated by LRP-autonomous signals, I developed a root explant system. While LRP emergence is regulated by environmental cues in an intact WT plant, I have found that LRP in explants lack the ability to respond correctly to their environment. This demonstrates that long-distance signals are required to properly regulate LRP emergence in response to environmental cues.
We have previously shown that plants with mutations in ABA biosynthetic enzymes have increased LRP emergence. New experiments demonstrate that LRP emergence in explants from these mutants occurs at similar levels to emergence in WT explants. This suggests that the mutant phenotype of these plants is due to the disruption of proper long-distance signaling.
A long-distance signaling molecule known to be important for root system development is the hormone auxin. Experiments have measured the transport of exogenously applied 3H-IAA: auxin transport is higher in ABA-deficient seedlings.
Auxin transport is also increased in plants grown in environmental conditions in which LRP emergence is enhanced. Furthermore, pRD29B::GUS, which reports ABA activity, shows enhanced expression in seedlings grown in environmental conditions permissive to LRP emergence. Together, these results provide the first mechanistic link between environmental perception, auxin transport, ABA signaling and a plantís physiological response.
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1 - University of Chicago, Committee on Genetics, 1103 E. 57th St., EBC 209, Chicago, IL, 60637, USA
2 - Wake Forest University, Biology
3 - University of Chicago, Molecular genetics and cell biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM