title: Features of basal and race-specific defences in photosynthetic Arabidopsis thaliana suspension cultured cells.
abstract: Plant suspension cell cultures display many features of the innate immune responses observed in planta and have been extensively applied to the study of basal and race-specific defences. However, no single model including photosynthetic cultured cells has been used for the exhaustive characterization of both basal and race-specific defences to date. In this article, we report the activation of basal and race-specific defences in green cultured cells from Arabidopsis thaliana. Inoculation of cultured cells with isogenic virulent or avirulent strains of Pseudomonas syringae pv. tomato DC3000 (Pst) was used to evaluate race-specific defences. The proliferation of avirulent Pst was found to be lower than that of virulent Pst in the inoculated cultures. Extracellular pH changes, sustained oxidative burst (5-13 h post-inoculation), enhancement of salicylic acid, and massive cell death were specifically stimulated by the avirulent bacterium. Neither avirulent nor virulent Pst induced markers of basal resistance, such as callose deposition or early oxidative burst (1-5 h post-inoculation). However, both basal defences were activated when cells were exposed to Pseudomonas syringae pv. phaseolicola or to the Pst mutant defective in the type III secretion system (TTSS), Pst-hrpL(-). Thus, in these cells, basal defences may be inhibited by Pst in a TTSS-dependent manner. Recapitulation of classical defence features demonstrates the usefulness of this system for the fine characterization of plant innate immune components.
authors.affiliation: CIQUIBIC-CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina.
authors.forename: Nicolás Miguel
authors.initials: NM
authors.lastname: Cecchini
authors.forename: Mariela Inés
authors.initials: MI
authors.lastname: Monteoliva
authors.forename: Francisca
authors.initials: F
authors.lastname: Blanco
authors.forename: Loreto
authors.initials: L
authors.lastname: Holuigue
authors.forename: María Elena
authors.initials: ME
authors.lastname: Alvarez
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000276:immunology* / Q000382:microbiology; D016923:Cell Death; D049109:Cell Proliferation; D002478:Cells, Cultured; D010788:Photosynthesis; D044224:Pseudomonas syringae / Q000502:physiology; D013045:Species Specificity