Plant Physiol. email content delivery
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on August 17, 2007; 10.1104/pp.107.104646

OPEN ACCESS ARTICLE
This Article
Free via Open Access: OA
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrowOA All Versions of this Article:
145/2/367    most recent
pp.107.104646v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Dong, M. A.
Right arrow Articles by Tallman, G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Dong, M. A.
Right arrow Articles by Tallman, G.
Agricola
Right arrow Articles by Dong, M. A.
Right arrow Articles by Tallman, G.

Received June 26, 2007
Accepted August 13, 2007

Heat Suppresses Activation of an Auxin-responsive Promoter in Cultured Guard Cell Protoplasts of Tree Tobacco

Malia A. Dong , Jennifer L. Bufford , Yutaka Oono , Kacy Church , Minh Q. Dau , Kara Michels , Michael Haughton , and Gary Tallman *

Willamette University, Department of Biology, 900 State Street, Salem, OR 97301, U.S.A.; Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, 370-1292, Japan

* Corresponding author; email: gtallman{at}willamette.edu.

Cultured guard cell protoplasts (GCP) of Nicotiana glauca, tree tobacco, comprise a novel system for investigating the cell signaling mechanisms that lead to acquired thermotolerance and thermoinhibition. At 32°C in a medium containing an auxin (1-naphthaleneacetic acid; NAA) and a cytokinin (6-benzylaminopurine; BAP), GCP expand, regenerate cell walls, dedifferentiate, and divide. At 38°C, GCP acquire thermotolerance within 24 h, but their expansion is limited and they neither regenerate walls nor re-enter the cell cycle. These putative indicators of auxin insensitivity led us to hypothesize that heat suppresses induction of auxin-regulated genes in GCP. Protoplasts were transformed with BA-mgfp5-ER, in which the BA auxin-responsive promoter regulates transcription of mgfp5-ER encoding thermostable green fluorescent protein (GFP), or with a similar 35S-CaMV constitutive promoter construct. Heat suppressed NAA-mediated activation of BA. After 21 h at 32°C in media with NAA, 49.0±3.9% of BA-mgfp5-ER transformants strongly expressed GFP; expression percentages were similar to those of 35S-mgfp5-ER transformants at 32°C or 38°C. After 21 h at 38°C in media with NAA, 7.9±1.6% of BA-mgfp5-ER transformants weakly expressed GFP, similar to GCP cultured at 32°C in media lacking NAA. Expression at 38°C was not increased by incubating for 48 h or increasing NAA concentrations 20X. After 9-12 h at 38°C, BA was no longer activated when cells were transferred to 32°C. Heat-stressed cells accumulate reactive oxygen species, and H2O2 suppresses auxin-responsive promoter activation in Arabidopsis mesophyll protoplasts. H2O2 did not suppress BA activation at 32°C, nor did superoxide and H2O2 scavengers prevent BA suppression at 38°C.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2007 by the American Society of Plant Biologists