title: Arabidopsis poly(A) polymerase PAPS1 limits founder-cell recruitment to organ primordia and suppresses the salicylic acid-independent immune response downstream of EDS1/PAD4.
abstract: Polyadenylation of pre-mRNAs by poly(A) polymerase (PAPS) is a critical process in eukaryotic gene expression. As found in vertebrates, plant genomes encode several isoforms of canonical nuclear PAPS enzymes. In Arabidopsis thaliana these isoforms are functionally specialized, with PAPS1 affecting both organ growth and immune response, at least in part by the preferential polyadenylation of subsets of pre-mRNAs. Here, we demonstrate that the opposite effects of PAPS1 on leaf and flower growth reflect the different identities of these organs, and identify a role for PAPS1 in the elusive connection between organ identity and growth patterns. The overgrowth of paps1 mutant petals is due to increased recruitment of founder cells into early organ primordia, and suggests that PAPS1 activity plays unique roles in influencing organ growth. By contrast, the leaf phenotype of paps1 mutants is dominated by a constitutive immune response that leads to increased resistance to the biotrophic oomycete Hyaloperonospora arabidopsidis and reflects activation of the salicylic acid-independent signalling pathway downstream of ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1)/PHYTOALEXIN DEFICIENT4 (PAD4). These findings provide an insight into the developmental and physiological basis of the functional specialization amongst plant PAPS isoforms.
authors.affiliation: Institut für Biochemie und Biologie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany.
authors.forename: Gerda
authors.initials: G
authors.lastname: Trost
authors.forename: Son Lang
authors.initials: SL
authors.lastname: Vi
authors.forename: Hjördis
authors.initials: H
authors.lastname: Czesnick
authors.forename: Peggy
authors.initials: P
authors.lastname: Lange
authors.forename: Nick
authors.initials: N
authors.lastname: Holton
authors.forename: Patrick
authors.initials: P
authors.lastname: Giavalisco
authors.forename: Cyril
authors.initials: C
authors.lastname: Zipfel
authors.forename: Christian
authors.initials: C
authors.lastname: Kappel
authors.forename: Michael
authors.initials: M
authors.lastname: Lenhard
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D035264:Flowers / Q000254:growth & development*; D009154:Mutation; D057865:Plant Immunity; D018515:Plant Leaves / Q000276:immunology*; D026723:Polyadenylation; D011062:Polynucleotide Adenylyltransferase / Q000235:genetics / Q000378:metabolism*; D020156:Salicylic Acid / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C118837:EDS1 protein, Arabidopsis; C000596010:PAPS1 protein, Arabidopsis; D011062:Polynucleotide Adenylyltransferase; D002265:Carboxylic Ester Hydrolases; C400766:PAD4 protein, Arabidopsis; D020156:Salicylic Acid
keywords: founder-cell recruitment; organ growth; poly(A) polymerase; polyadenylation