title: Functional characterization of the two ferrochelatases in Arabidopsis thaliana.
abstract: The enzyme ferrochelatase catalyses the formation of protoheme by inserting Fe(2+) into protoporphyrin IX. Although most organisms express only one ferrochelatase, all land plants analysed so far possess at least two ferrochelatase proteins. Analysis of publicly available expression data suggests that the two Arabidopsis thaliana ferrochelatases, FC1 and FC2, serve different functions, corroborating previous assumptions. Co-expression analysis of FC1 and FC2, together with microarray analyses, implies that fc1 and fc2 trigger different modes of plastid signalling in roots and leaves, respectively, and indicates that FC2 might be involved in stress responses. Thus, loss of FC2 increases resistance to salt and flagellin treatment. Whereas fc1 plants showed no obvious mutant phenotype, fc2 mutants formed abnormally small, pale green rosette leaves; were low in chlorophylls, carotenoids and several photosynthetic proteins; and their photosynthetic performance was impaired. These phenotypes are attenuated by growth in continuous light, in agreement with the finding that fc2 plants accumulate protochlorophyllide and display a fluorescent (flu) phenotype in the dark. In consequence we show that, contrary to earlier suggestions, FC2 produces heme not only for photosynthetic cytochromes, but also for proteins involved in stress responses, whereas the impairment of FC1 apparently interferes only marginally with stress responses.
authors: Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-University Munich, 82152, Martinsried, Germany.
authors: Michael
authors: M
authors: Scharfenberg
authors: Lukas
authors: L
authors: Mittermayr
authors: Edda
authors: E
authors: VON Roepenack-Lahaye
authors: Hagen
authors: H
authors: Schlicke
authors: Bernhard
authors: B
authors: Grimm
authors: Dario
authors: D
authors: Leister
authors: Tatjana
authors: T
authors: Kleine
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D005294:Ferrochelatase / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D055785:Gene Knockdown Techniques; D008027:Light; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects; D011521:Protochlorophyllide / Q000378:metabolism; D011524:Protoporphyrins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D059467:Transcriptome / Q000235:genetics / Q000528:radiation effects
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D011524:Protoporphyrins; D012333:RNA, Messenger; C036483:T-DNA; D011521:Protochlorophyllide; D012965:Sodium Chloride; C028025:protoporphyrin IX; D005294:Ferrochelatase
keywords: chloroplast; flagellin; flu; heme; photosynthesis; salt stress; tetrapyrrole