title: Ethylene produced by the endosperm is involved in the regulation of nucellus programmed cell death in Sechium edule Sw.
abstract: The nucellus is a maternal tissue that feeds the developing embryo and the secondary endosperm. During seed development the cells of the nucellus suffer a degenerative process early after fertilization as the cellular endosperm expands and accumulates reserves. Nucellar cell degeneration has been characterized as a form of developmentally programmed cell death (PCD). In this work we analysed the role of the endosperm as main regulator of nucellus PCD. We demonstrated that endosperm produces high amount of ethylene, nitric oxide and indoleacetic acid. We examined the role of these small and diffusible signalling molecules in the regulation of nucellus PCD and we tried to elucidate how they can cooperate and regulate each other into the endosperm. We showed that ethylene acts a positive regulator of nucellus PCD and its synthesis can be in part induced by nitric oxide. High levels of IAA were detected both in the endosperm and in dying nucellus but this hormone is not directly involved in the execution of PCD.
authors.affiliation: Department of Biology, University of Pisa, Via Ghini 5, 56126 Pisa, Italy. llombardi@biologia.unipi.it
authors.forename: Lara
authors.initials: L
authors.lastname: Lombardi
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Mariotti
authors.forename: Piero
authors.initials: P
authors.lastname: Picciarelli
authors.forename: Nello
authors.initials: N
authors.lastname: Ceccarelli
authors.forename: Roberto
authors.initials: R
authors.lastname: Lorenzi
mesh_terms: D017209:Apoptosis; D019662:Cucurbitaceae / Q000196:embryology / Q000378:metabolism / Q000502:physiology*; D056625:Endosperm / Q000378:metabolism*; D005030:Ethylenes / Q000096:biosynthesis / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000096:biosynthesis / Q000378:metabolism*; D012639:Seeds / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D005030:Ethylenes; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D009569:Nitric Oxide; C030737:indoleacetic acid; C036216:ethylene