Peroxisome proliferation, wound-activated responses and expression of peroxisome-associated genes are cross-regulated but uncoupled in Arabidopsis thaliana.
Plant peroxisomes are multifunctional organelles that show plasticity in number, size, morphology, cellular location and metabolic functions. Many of these changes occur in response to environmental factors and are decisive for the development and defence of the plant. Among them, peroxisomal beta-oxidation-mediated synthesis of jasmonic acid (JA) is a key process in regulating development as well as wound- or pathogen-triggered defence responses. This work seeks for the connection between wound, JA and the proliferation of peroxisomes in Arabidopsis thaliana. The hypolipidemic drug clofibrate (CFB) induced the proliferation of peroxisomes and the expression of the beta-oxidation 3-ketoacyl-CoA thiolase 2 (KAT2) gene, coding for a key enzyme in the biosynthesis of JA, among other wound- and JA-responsive gene transcripts in Arabidopsis leaves. The CFB-activated expression of wound-responsive genes was not dependent on JA synthesis or perception and those responsive to JA required the function of the F-box protein COI1. In turn, wounding neither triggered peroxisome proliferation nor required peroxisome integrity to activate gene expression. Interestingly, cells from JA-treated leaves contained fewer but larger peroxisomes than cells from untreated leaves. The proliferation of peroxisomes, the synthesis of JA and the activation of wound-responsive genes by CFB, although functionally connected, were uncoupled in Arabidopsis.
Castillo
Mari Cruz
MC
Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ciudad Politécnica de la Innovación, 46022 Valencia, Spain.
Sandalio
Luisa María
LM
Del Río
Luís Alfonso
LA
León
José
J
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001696:Biomechanical Phenomena; D002994:Clofibrate / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics*; D054883:Oxylipins / Q000494:pharmacology; D020675:Peroxisomes / Q000235:genetics* / Q000502:physiology*; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000648:ultrastructure; D013997:Time Factors
D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid; D002994:Clofibrate