1. CITRX thioredoxin interacts with the tomato Cf-9 resistance protein and negatively regulates defence.
- Author
-
Rivas, Susana, Rougon-Cardoso, Alejandra, Smoker, Matthew, Schauser, Leif, Yoshioka, Hirofumi, and Jones, Jonathan D. G.
- Subjects
PROTEINS ,APOPTOSIS ,CELL death ,PLANT diseases ,CLADOSPORIUM fulvum ,PROTEIN kinases ,PLANT defenses ,THIOREDOXIN ,TOMATOES - Abstract
To identify proteins involved in tomato Cf-9 resistance protein function, a yeast two-hybrid screen was undertaken using the cytoplasmic C-terminus of Cf-9 as bait. A thioredoxin-homologous clone, interacting specifically with Cf-9, was identified and called CITRX (Cf-9-interacting thioredoxin). Virus-induced gene silencing (VIGS) of CITRX resulted in an accelerated Cf-9/Avr9-triggered hypersensitive response in both tomato and Nicotiana benthamiana, accompanied by enhanced accumulation of reactive oxygen species, alteration of protein kinase activity and induction of defence-related genes. VIGS of CITRX also conferred increased resistance to the fungal pathogen Cladosporium fulvum in the otherwise susceptible Cf0 tomato. CITRX acts as a negative regulator of the cell death and defence responses induced through Cf-9, but not Cf-2. Recognition of the Cf-9 C-terminus by CITRX is necessary and sufficient for this negative regulation. This is the first study that implicates thioredoxin activity in the regulation of plant disease resistance. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF