Oxylipins Produced by the 9-Lipoxygenase Pathway in Arabidopsis Regulate Lateral Root Development and Defense Response through a Specific Signaling Cascade

Arabidopsis thaliana seedling growth with pure oxylipins resulted in root waving, loss of root apical dominance, and decreased root elongation. 9-Hydroxyoctadecatrienoic acid (9-HOT) was a potent inducer of root waving. Studies with noxy2 (for nonresponding to oxylipins2), a new 9-HOT-insensitive mu...

Full description

Saved in:
Bibliographic Details
Published in:The Plant cell 2007-03, Vol.19 (3), p.831-846
Main Authors: Vellosillo, Tamara, Martínez, Marta, López, Miguel Angel, Vicente, Jorge, Cascón, Tomas, Dolan, Liam, Hamberg, Mats, Castresana, Carmen
Format: Article
Language:English
Subjects:
Cell walls
Genes
Leaves
Pathogens
Phenotypes
Plant cells
Plant roots
Plants
RNA
Seedlings
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Arabidopsis thaliana seedling growth with pure oxylipins resulted in root waving, loss of root apical dominance, and decreased root elongation. 9-Hydroxyoctadecatrienoic acid (9-HOT) was a potent inducer of root waving. Studies with noxy2 (for nonresponding to oxylipins2), a new 9-HOT-insensitive mutant, and coronatine insensitive1-1 (jasmonate-insensitive) revealed at least three signaling cascades mediating the oxylipin actions. Treatment with 9-HOT resulted in a reduction in lateral roots and an increase in stage V primordia. Roots showed strong 9-lipoxygenase (9-LOX) activity, and root primordia expressed 9-LOX genes. These results, along with findings that noxy2 and mutants with defective 9-LOX activity showed increased numbers of lateral roots, suggest that 9-HOT, or a closely related 9-LOX product, is an endogenous modulator of lateral root formation. Histochemical and molecular analyses revealed that 9-HOT activated events common to development and defense responses. A subset of 9-HOT-responding root genes was also induced in leaves after 9-HOT treatment or pathogen inoculation. The results that noxy2 displayed altered root development, enhanced susceptibility to Pseudomonas, and reduced the activation of 9-HOT-responding genes are consistent with mechanistic links among these processes. The nature of the changes detected suggests that oxylipins from the 9-LOX pathway function in cell wall modifications required for lateral root development and pathogen arrest.
ISSN:1040-4651
DOI:10.1105/tpc.106.046052