title: Bioinformatic and functional characterization of the basic peroxidase 72 from Arabidopsis thaliana involved in lignin biosynthesis.
abstract: Lignins result from the oxidative polymerization of three hydroxycinnamyl (p-coumaryl, coniferyl, and sinapyl) alcohols in a reaction mediated by peroxidases. The most important of these is the cationic peroxidase from Zinnia elegans (ZePrx), an enzyme considered to be responsible for the last step of lignification in this plant. Bibliographical evidence indicates that the arabidopsis peroxidase 72 (AtPrx72), which is homolog to ZePrx, could have an important role in lignification. For this reason, we performed a bioinformatic, histochemical, photosynthetic, and phenotypical and lignin composition analysis of an arabidopsis knock-out mutant of AtPrx72 with the aim of characterizing the effects that occurred due to the absence of expression of this peroxidase from the aspects of plant physiology such as vascular development, lignification, and photosynthesis. In silico analyses indicated a high homology between AtPrx72 and ZePrx, cell wall localization and probably optimal levels of translation of AtPrx72. The histochemical study revealed a low content in syringyl units and a decrease in the amount of lignin in the atprx72 mutant plants compared to WT. The atprx72 mutant plants grew more slowly than WT plants, with both smaller rosette and principal stem, and with fewer branches and siliques than the WT plants. Lastly, chlorophyll a fluorescence revealed a significant decrease in ΦPSII and q L in atprx72 mutant plants that could be related to changes in carbon partitioning and/or utilization of redox equivalents in arabidopsis metabolism. The results suggest an important role of AtPrx72 in lignin biosynthesis. In addition, knock-out plants were able to respond and adapt to an insufficiency of lignification.
authors.affiliation: Department of Plant Biology, University of Alcalá, 28871 Alcalá de Henares (Madrid), Spain. joaquin.herrero@uah.es
authors.forename: Joaquín
authors.initials: J
authors.lastname: Herrero
authors.forename: Francisco
authors.initials: F
authors.lastname: Fernández-Pérez
authors.forename: Tatiana
authors.initials: T
authors.lastname: Yebra
authors.forename: Esther
authors.initials: E
authors.lastname: Novo-Uzal
authors.forename: Federico
authors.initials: F
authors.lastname: Pomar
authors.forename: Ma Ángeles
authors.initials: MÁ
authors.lastname: Pedreño
authors.forename: Juan
authors.initials: J
authors.lastname: Cuello
authors.forename: Alfredo
authors.initials: A
authors.lastname: Guéra
authors.forename: Alberto
authors.initials: A
authors.lastname: Esteban-Carrasco
authors.forename: José Miguel
authors.initials: JM
authors.lastname: Zapata
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019659:Asteraceae / Q000201:enzymology; D002473:Cell Wall / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D019295:Computational Biology; D005453:Fluorescence; D008031:Lignin / Q000096:biosynthesis*; D008958:Models, Molecular; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009195:Peroxidase / Q000737:chemistry / Q000378:metabolism*; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D018547:Plant Stems / Q000033:anatomy & histology; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017550:Spectroscopy, Fourier Transform Infrared; D052584:Xylem / Q000166:cytology / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D002734:Chlorophyll; D008031:Lignin; D010544:Peroxidases; C585390:Prx72 protein, Arabidopsis; D009195:Peroxidase; D000077194:Chlorophyll A