title: An effector of apple proliferation phytoplasma targets TCP transcription factors-a generalized virulence strategy of phytoplasma?
abstract: The plant pathogen Candidatus Phytoplasma mali (P. mali) is the causative agent of apple proliferation, a disease of increasing importance in apple-growing areas within Europe. Despite its economic importance, little is known about the molecular mechanisms of disease manifestation within apple trees. In this study, we identified two TCP (TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTOR) transcription factors of Malus x domestica as binding partners of the P. mali SAP11-like effector ATP_00189. Phytohormone analyses revealed an effect of P. mali infection on jasmonates, salicylic acid and abscisic acid levels, showing that P. mali affects phytohormonal levels in apple trees, which is in line with the functions of the effector assumed from its binding to TCP transcription factors. To our knowledge, this is the first characterization of the molecular targets of a P. mali effector and thus provides the basis to better understand symptom development and disease progress during apple proliferation. As SAP11 homologues are found in several Phytoplasma species infecting a broad range of different plants, SAP11-like proteins seem to be key players in phytoplasmal infection.
authors.affiliation: Research Centre for Agriculture and Forestry Laimburg, Laimburg 6, Auer/Ora, BZ, 39040, Italy.
authors.forename: Katrin
authors.initials: K
authors.lastname: Janik
authors.affiliation: Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Str. 8, Jena, 07745, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Mithöfer
authors.affiliation: Research Centre for Agriculture and Forestry Laimburg, Laimburg 6, Auer/Ora, BZ, 39040, Italy.
authors.forename: Margot
authors.initials: M
authors.lastname: Raffeiner
authors.affiliation: Department for Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, Halle, 06120, Germany.
authors.forename: Hagen
authors.initials: H
authors.lastname: Stellmach
authors.affiliation: Department for Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, Halle, 06120, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Hause
authors.affiliation: Research Centre for Agriculture and Forestry Laimburg, Laimburg 6, Auer/Ora, BZ, 39040, Italy.
authors.forename: Katja
authors.initials: K
authors.lastname: Schlink
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D005231:Fatty Acids, Unsaturated; D007532:Isoleucine / Q000031:analogs & derivatives / Q000378:metabolism; D027845:Malus / Q000378:metabolism* / Q000382:microbiology*; D045582:Phytoplasma / Q000472:pathogenicity*; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014774:Virulence
chemical_list: D003517:Cyclopentanes; D005231:Fatty Acids, Unsaturated; D010940:Plant Proteins; D014157:Transcription Factors; C532883:jasmonoyl-isoleucine; D007532:Isoleucine; C025999:12-oxophytodienoic acid; D000040:Abscisic Acid; D020156:Salicylic Acid
keywords: ATP_00189; TCP; apple proliferation; effector protein; phytohormones; transcription factor; yeast two hybrid