Edinburgh, Scotland, United Kingdom - TAIR

Towards a spatiotemporal understanding of
the salt stress response
Plants are intimately associated with their environment and have developed
complex mechanisms to perceive, respond and adapt to fluctuations that may
arise. Recently, several studies have revealed the important contribution that
cell identity has in guiding the response to salt stress and other environmental
stimuli. While this work has revealed the vast complexity of the transcriptional
response, very little is known regarding the molecular mechanisms that control
these changes and how the initial responses assayed ultimately lead to stable
changes in the plant that enable adaptation. To shed light on these areas, we are
utilizing mutants defective in cell-type specification to determine what role each
cell layer plays in affecting salt response. Using the genetic pathway controlling
ground tissue development, we have been able to show that SHORTROOT, a
GRAS-family transcription factor, is necessary for responses to salt in the cortex
and epidermal cell layers. Furthermore, our preliminary data indicate that SHR
regulates the expression of ethylene biosynthetic genes in internal tissue layers
of the root, which may account for the non-cell-autonomous role of SHR in the
salt stress response. We have also expanded our studies to examine the
temporal regulation of salt response. Based on previous microarray analysis, we
have found that salt stress is characterized by waves of transcriptional activity.
We have used this temporal dynamism to identify “marker genes” whose
expression is associated with particular phases of the salt response. We are
analyzing the temporal expression of these markers under various salt
treatments to understand how the time course is modified. These studies are
accompanied by live-imaging analysis of roots to determine how the changes in
the transcriptional program correlate with the observed phenotypic changes. Our
results indicate that the concentration of salt has an important role in determining
the timing of transcriptional events.
61
C10
Wednesday 15:05 - 15:20
Environmental Responses
Jose Dinneny1
Xie Fei1
Penny Chan2
1Temasek Lifesciences
Laboratory
Singapore
2National University of
Singapore
Singapore