title: SlTPR1, a tomato tetratricopeptide repeat protein, interacts with the ethylene receptors NR and LeETR1, modulating ethylene and auxin responses and development.
abstract: The gaseous hormone ethylene is perceived by a family of ethylene receptors which interact with the Raf-like kinase CTR1. SlTPR1 encodes a novel TPR (tetratricopeptide repeat) protein from tomato that interacts with the ethylene receptors NR and LeETR1 in yeast two-hybrid and in vitro protein interaction assays. SlTPR1 protein with a GFP fluorescent tag was localized in the plasmalemma and nuclear membrane in Arabidopsis, and SlTPR1-CFP and NR-YFP fusion proteins were co-localized in the plasmalemma and nuclear membrane following co-bombardment of onion cells. Overexpression of SlTPR1 in tomato resulted in ethylene-related pleiotropic effects including reduced stature, delayed and reduced production of inflorescences, abnormal and infertile flowers with degenerate styles and pollen, epinasty, reduced apical dominance, inhibition of abscission, altered leaf morphology, and parthenocarpic fruit. Similar phenotypes were seen in Arabidopsis overexpressing SlTPR1. SlTPR1 overexpression did not increase ethylene production but caused enhanced accumulation of mRNA from the ethylene responsive gene ChitB and the auxin-responsive gene SlSAUR1-like, and reduced expression of the auxin early responsive gene LeIAA9, which is known to be inhibited by ethylene and to be associated with parthenocarpy. Cuttings from the SlTPR1-overexpressors produced fewer adventitious roots and were less responsive to indole butyric acid. It is suggested that SlTPR1 overexpression enhances a subset of ethylene and auxin responses by interacting with specific ethylene receptors. SlTPR1 shares features with human TTC1, which interacts with heterotrimeric G-proteins and Ras, and competes with Raf-1 for Ras binding. Models for SlTPR1 action are proposed involving modulation of ethylene signalling or receptor levels.
authors.affiliation: Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
authors.forename: Zhefeng
authors.initials: Z
authors.lastname: Lin
authors.forename: Luis
authors.initials: L
authors.lastname: Arciga-Reyes
authors.forename: Silin
authors.initials: S
authors.lastname: Zhong
authors.forename: Lucy
authors.initials: L
authors.lastname: Alexander
authors.forename: Rachel
authors.initials: R
authors.lastname: Hackett
authors.forename: Ian
authors.initials: I
authors.lastname: Wilson
authors.forename: Don
authors.initials: D
authors.lastname: Grierson
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D005030:Ethylenes / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D007210:Indoleacetic Acids / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000737:chemistry / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D020798:Two-Hybrid System Techniques
chemical_list: D005030:Ethylenes; D007210:Indoleacetic Acids; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C083750:ethylene receptors, plant; C036216:ethylene