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


     

Plant Physiology Preview
Published on April 6, 2007; 10.1104/pp.107.097543

This Article
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrow All Versions of this Article:
144/2/1223    most recent
pp.107.097543v1
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 Barazani, O.
Right arrow Articles by Baldwin, I. T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Barazani, O.
Right arrow Articles by Baldwin, I. T.
Agricola
Right arrow Articles by Barazani, O.
Right arrow Articles by Baldwin, I. T.

Received February 5, 2007
Accepted March 27, 2007

Sebacina vermifera Promotes the Growth and Fitness of Nicotiana attenuata by Inhibiting Ethylene Signaling

Oz Barazani , Caroline C. von Dahl , and Ian T. Baldwin *

Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll Strasse 8, 07745 Jena, Germany

* Corresponding author; email: baldwin{at}ice.mpg.de.

Sebacina vermifera, a growth-promoting endophytic fungus, significantly increases Nicotiana attenuata's growth but impairs both its herbivore resistance and its accumulation of the costly, jasmonate (JA)-regulated, defense protein, trypsin proteinase inhibitor (TPI). To determine if the fungi's growth-promoting effects can be attributed to lower TPI-related defense costs, we inoculated transformed N. attenuata plants silenced in their ability to synthesize JA, JA-isoleucine (Ile), and TPI by antisense (as-lox3 and as-td) and inverted repeat (ir-tpi) expression, and found that inoculation promoted plant growth as in untransformed (WT) plants. Moreover, herbivore-elicited increases in JA and JA-Ile concentrations did not differ between inoculated and uninoculated WT plants. However, inoculation significantly reduced the morphological effect of 1-aminocyclopropane-1-carboxylic acid (ACC) on WT seedlings in a triple response assay, suggesting that ethylene signaling was impaired. Furthermore, S. vermifera failed to promote the growth of N. attenuata plants transformed to silence ethylene production (ir-aco). Inoculating WT plants with S. vermifera decreased the ethylene burst elicited by applying Manduca sexta oral secretions (OS) to mechanical wounds. Accordingly, OS-elicited transcript levels of the ethylene synthesis genes NaACS3, NaACO1, and NaACO3 in inoculated plants were significantly lower compared to these levels in uninoculated WT plants. Inoculation accelerated germination in WT seeds; however, uninoculated WT seeds germinated as rapidly as inoculated seeds in the presence of the ethylene scrubber KMnO4. In contrast, neither inoculation nor KMnO4 exposure influenced the germination of ir-aco seeds. We conclude that S. vermifera increases plant growth by impairing ethylene production independently of JA signaling and TPI production.






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