title: Roles of Ethylene Production and Ethylene Receptor Expression in Regulating Apple Fruitlet Abscission.
abstract: Apple (Malus × domestica) is increasingly being considered an interesting model species for studying early fruit development, during which an extremely relevant phenomenon, fruitlet abscission, may occur as a response to both endogenous and/or exogenous cues. Several studies were carried out shedding light on the main physiological and molecular events leading to the selective release of lateral fruitlets within a corymb, either occurring naturally or as a result of a thinning treatment. Several studies pointed out a clear association between a rise of ethylene biosynthetic levels in the fruitlet and its tendency to abscise. A direct mechanistic link, however, has not yet been established between this gaseous hormone and the generation of the abscission signal within the fruit. In this work, the role of ethylene during the very early stages of abscission induction was investigated in fruitlet populations with different abscission potentials due either to the natural correlative inhibitions determining the so-called physiological fruit drop or to a well-tested thinning treatment performed with the cytokinin benzyladenine. A crucial role was ascribed to the ratio between the ethylene produced by the cortex and the expression of ethylene receptor genes in the seed. This ratio would determine the final probability to abscise. A working model has been proposed consistent with the differential distribution of four receptor transcripts within the seed, which resembles a spatially progressive cell-specific immune-like mechanism evolved by apple to protect the embryo from harmful ethylene.
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, Agripolis, 35020 Legnaro, Italy (G.E., M.B., B.R., A.Bot.); andNanoscience Research Unit, Bruno Kessler Foundation, National Research Council-Institute of Materials for Electronics and Magnetism, 38123 Trento, Italy (A.Bos.).
authors.forename: Giulia
authors.initials: G
authors.lastname: Eccher
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, Agripolis, 35020 Legnaro, Italy (G.E., M.B., B.R., A.Bot.); andNanoscience Research Unit, Bruno Kessler Foundation, National Research Council-Institute of Materials for Electronics and Magnetism, 38123 Trento, Italy (A.Bos.).
authors.forename: Maura
authors.initials: M
authors.lastname: Begheldo
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, Agripolis, 35020 Legnaro, Italy (G.E., M.B., B.R., A.Bot.); andNanoscience Research Unit, Bruno Kessler Foundation, National Research Council-Institute of Materials for Electronics and Magnetism, 38123 Trento, Italy (A.Bos.).
authors.forename: Andrea
authors.initials: A
authors.lastname: Boschetti
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, Agripolis, 35020 Legnaro, Italy (G.E., M.B., B.R., A.Bot.); andNanoscience Research Unit, Bruno Kessler Foundation, National Research Council-Institute of Materials for Electronics and Magnetism, 38123 Trento, Italy (A.Bos.).
authors.forename: Benedetto
authors.initials: B
authors.lastname: Ruperti
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals, and Environment, University of Padova, Agripolis, 35020 Legnaro, Italy (G.E., M.B., B.R., A.Bot.); andNanoscience Research Unit, Bruno Kessler Foundation, National Research Council-Institute of Materials for Electronics and Magnetism, 38123 Trento, Italy (A.Bos.) alessandro.botton@unipd.it.
authors.forename: Alessandro
authors.identifier: http://orcid.org/0000-0001-5054-1479
authors.initials: A
authors.lastname: Botton
mesh_terms: D005030:Ethylenes / Q000378:metabolism*; D005638:Fruit / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D027845:Malus / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C083750:ethylene receptors, plant; C036216:ethylene