title: Mitochondria change dynamics and morphology during grapevine leaf senescence.
abstract: Leaf senescence is the last stage of development of an organ and is aimed to its ordered disassembly and nutrient reallocation. Whereas chlorophyll gradually degrades during senescence in leaves, mitochondria need to maintain active to sustain the energy demands of senescing cells. Here we analysed the motility and morphology of mitochondria in different stages of senescence in leaves of grapevine (Vitis vinifera), by stably expressing a GFP (green fluorescent protein) reporter targeted to these organelles. Results show that mitochondria were less dynamic and markedly changed morphology during senescence, passing from the elongated, branched structures found in mature leaves to enlarged and sparse organelles in senescent leaves. Progression of senescence in leaves was not synchronous, since changes in mitochondria from stomata were delayed. Mitochondrial morphology was also analysed in grapevine cell cultures. Mitochondria from cells at the end of their growth curve resembled those from senescing leaves, suggesting that cell cultures might represent a useful model system for senescence. Additionally, senescence-associated mitochondrial changes were observed in plants treated with high concentrations of cytokinins. Overall, morphology and dynamics of mitochondria might represent a reliable senescence marker for plant cells.
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Ruberti
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Barizza
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Bodner
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: La Rocca
authors.affiliation: Istituto di Bioscienze e Biorisorse, Consiglio Nazionale delle Ricerche (CNR-IBBR), Corso Calatafimi, Palermo, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: De Michele
authors.affiliation: Istituto di Bioscienze e Biorisorse, Consiglio Nazionale delle Ricerche (CNR-IBBR), Corso Calatafimi, Palermo, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Carimi
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy.
authors.forename: Fiorella
authors.initials: F
authors.lastname: Lo Schiavo
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Zottini
mesh_terms: D002478:Cells, Cultured; D003583:Cytokinins / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000378:metabolism*; D063154:Mitochondrial Dynamics; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D013535:Suspensions; D027843:Vitis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D003583:Cytokinins; D013535:Suspensions; D049452:Green Fluorescent Proteins