Lesion mimic mutants (LMMs) are a class of mutants in which hypersensitive cell death and defence responses are constitutively activated in the absence of pathogen attack. Various signalling molecules, such as salicylic acid (SA), reactive oxygen species (ROS), nitric oxide (NO), Ca2+, ethylene, and jasmonate, are involved in the regulation of multiple pathways controlling hypersensitive response (HR) activation, and LMMs are considered useful tools to understand the role played by the key elements of the HR cell death signalling cascade. Here the characterization of an Arabidopsis LMM lacking the function of the FZL gene is reported. This gene encodes a membrane-remodelling GTPase playing an essential role in the determination of thylakoid and chloroplast morphology. The mutant displayed alteration in chloroplast number, size, and shape, and the typical characteristics of an LMM, namely development of chlorotic lesions on rosette leaves and constitutive expression of genetic and biochemical markers associated with defence responses. The chloroplasts are a major source of ROS, and the characterization of this mutant suggests that their accumulation, triggered by damage to the chloroplast membranes, is a signal sufficient to start the HR signalling cascade, thus confrming the central role of the chloroplast in HR activation.
|Titolo:||A mutation in the FZL gene of Arabidopsis causing alteration in chloroplast morphology results in a lesion mimic phenotype|
|Parole Chiave:||Arabidopsis thaliana; chloroplast; double mutants; expression analysis; lesion mimic mutants (LMMs); reactive oxygen species (ROS)|
|Settore Scientifico Disciplinare:||Settore AGR/07 - Genetica Agraria|
|Data di pubblicazione:||nov-2013|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1093/jxb/ert237|
|Appare nelle tipologie:||01 - Articolo su periodico|