title: Ethylene negatively regulates transcript abundance of ROP-GAP rheostat-encoding genes and affects apoplastic reactive oxygen species homeostasis in epicarps of cold stored apple fruits.
abstract: Apple (Malus×domestica Borkh) fruits are stored for long periods of time at low temperatures (1 °C) leading to the occurrence of physiological disorders. 'Superficial scald' of Granny Smith apples, an economically important ethylene-dependent disorder, was used as a model to study relationships among ethylene action, the regulation of the ROP-GAP rheostat, and maintenance of H2O2 homeostasis in fruits during prolonged cold exposure. The ROP-GAP rheostat is a key module for adaptation to low oxygen in Arabidopsis through Respiratory Burst NADPH Oxidase Homologs (RBOH)-mediated and ROP GTPase-dependent regulation of reactive oxygen species (ROS) homeostasis. Here, it was shown that the transcriptional expression of several components of the apple ROP-GAP machinery, including genes encoding RBOHs, ROPs, and their ancillary proteins ROP-GEFs and ROP-GAPs, is coordinately and negatively regulated by ethylene in conjunction with the progressive impairment of apoplastic H2O2 homeostatic levels. RNA sequencing analyses showed that several components of the known ROP- and ROS-associated transcriptional networks are regulated along with the ROP-GAP rheostat in response to ethylene perception. These findings may extend the role of the ROP-GAP rheostat beyond hypoxic responses and suggest that it may be a functional regulatory node involved in the integration of ethylene and ROS signalling pathways in abiotic stress.
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Zermiani
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Zonin
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Nonis
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Maura
authors.initials: M
authors.lastname: Begheldo
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Ceccato
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Vezzaro
authors.affiliation: Department of Biology, University of Padova, 35121 Padova, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Baldan
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Annarita
authors.initials: A
authors.lastname: Trentin
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Masi
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Pegoraro
authors.affiliation: Edmund Mach Foundation, San Michele all'Adige, 38123 Trento, Italy.
authors.forename: Livio
authors.initials: L
authors.lastname: Fadanelli
authors.affiliation: Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, D-79104 Freiburg, Germany.
authors.forename: William
authors.initials: W
authors.lastname: Teale
authors.affiliation: Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, D-79104 Freiburg, Germany Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, D-79104 Freiburg, Germany Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, D-79104 Freiburg, Germany Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University of Freiburg, D-79104 Freiburg, Germany Freiburg Initiative for Systems Biology (FRISYS), Albert-Ludwigs-University of Freiburg, D-79104 Freiburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Palme
authors.affiliation: Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, 35131 Padova, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Quintieri
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, 35020 Legnaro, Italy benedetto.ruperti@unipd.it.
authors.forename: Benedetto
authors.initials: B
authors.lastname: Ruperti
mesh_terms: D003080:Cold Temperature; D005030:Ethylenes / Q000378:metabolism*; D061353:Food Storage; D005638:Fruit / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D006861:Hydrogen Peroxide / Q000378:metabolism; D027845:Malus / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D005030:Ethylenes; D017382:Reactive Oxygen Species; C036216:ethylene; D006861:Hydrogen Peroxide; D020558:GTP Phosphohydrolases
keywords: Abiotic stress; NADPH oxidase; RBOH; ROP GTPases; ROS homeostasis.; ethylene; fruit senescence; ionotropic glutamate receptors