title: Spermine either delays or promotes cell death in Nicotiana tabacum L. corolla depending on the floral developmental stage and affects the distribution of transglutaminase.
abstract: The role of spermine (SM) was studied to verify if SM supplied to Nicotiana tabacum flower can modulate programmed cell death (PCD) of the corolla. SM has strong effects on the development and senescence of excised flowers despite its low physiological levels. The timing and duration of SM treatment is a key factor; SM counteracts PCD (verified by morphological observations, pigment contents and DNA laddering) only in the narrow developmental window of corolla expansion. Before and after, SM promotes PCD. SM exerts its pro-survival role by delaying fresh weight loss, by inhibiting reduction of pigments and finally by preventing DNA degradation. Moreover, SM deeply alters the distribution of the PA-conjugating enzyme transglutaminase (TGase). TGase is present in the epidermis during development, but it sprays also in the cell walls of inner parenchyma at senescence. After SM treatment, parenchyma cells accumulate TGase, increase in size and their cell walls do not undergo stiffening contrarily to control cells. The subcellular localization of TGase has been validated by biolistic-transformation of onion epidermal cells. Results indicated that SM is a critical factor in the senescence of N. tabacum corolla by controlling biochemical and morphological parameters; the lasts are probably interconnected with the action of TGase.
authors.affiliation: Dipartimento di Scienze della Vita, Università di Siena, Siena 53100, Italy. Electronic address: cai@unisi.it.
authors.forename: Giampiero
authors.initials: G
authors.lastname: Cai
authors.affiliation: Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università degli Studi di Bologna, Bologna 40126, Italy. Electronic address: massimiliano.dellamea@unibo.it.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Della Mea
authors.affiliation: Dipartimento di Scienze della Vita, Università di Siena, Siena 53100, Italy. Electronic address: faleric@unisi.it.
authors.forename: Claudia
authors.initials: C
authors.lastname: Faleri
authors.affiliation: Dipartimento di Biologia Ambientale, Sapienza Università di Roma, I-00185, Italy. Electronic address: laura.fattorini@uniroma1.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Fattorini
authors.affiliation: Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università degli Studi di Bologna, Bologna 40126, Italy. Electronic address: iris.aloisi2@unibo.it.
authors.forename: Iris
authors.initials: I
authors.lastname: Aloisi
authors.affiliation: Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università degli Studi di Bologna, Bologna 40126, Italy. Electronic address: donatella.serafini@unibo.it.
authors.forename: Donatella
authors.initials: D
authors.lastname: Serafini-Fracassini
authors.affiliation: Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università degli Studi di Bologna, Bologna 40126, Italy. Electronic address: stefano.delduca@unibo.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Del Duca
mesh_terms: D017209:Apoptosis; D002473:Cell Wall / Q000378:metabolism; D035264:Flowers / Q000187:drug effects / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism*; D013096:Spermine / Q000378:metabolism* / Q000494:pharmacology; D014026:Nicotiana / Q000187:drug effects / Q000502:physiology*; D011503:Transglutaminases / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D013096:Spermine; D011503:Transglutaminases
keywords: Cell wall; Development; Nicotiana tabacum corolla; Programmed cell death; Spermine; Transglutaminase