Mitochondria change dynamics and morphology during grapevine leaf senescence

PLoS One. 2014 Jul 10;9(7):e102012. doi: 10.1371/journal.pone.0102012. eCollection 2014.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Cytokinins / metabolism
  • Green Fluorescent Proteins / metabolism
  • Microscopy, Confocal
  • Mitochondria / metabolism*
  • Mitochondrial Dynamics*
  • Plant Leaves / genetics
  • Plant Leaves / growth & development*
  • Plant Leaves / metabolism*
  • Suspensions
  • Vitis / genetics
  • Vitis / growth & development*
  • Vitis / metabolism*

Substances

  • Cytokinins
  • Suspensions
  • Green Fluorescent Proteins

Grants and funding

This work was supported by University of Padova (PRAT 2012), Veneto Region Innovation Grants (Mis. 124 PSR Veneto), Vigoni-DAAD Project, by the Italian Ministry for University and Research (MIUR), Projec (PON01–02286) 'Tecnologie e processi per il miglioramento della shelf-life dei prodotti del comparto agroalimentare attraverso l'uso di film edibili innovativi a base pectinica' and by the grant PRIN200920094CEKT4. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.