Qualitative and quantitative modifications of root mitochondria during senescence of 2 above-ground parts of Arabidopis thaliana

FANELLO, DIEGO DARÍO; BARTOLI, CARLOS GUILLERMO; GUIAMET, JUAN JOSÉ

PLANT SCIENCE

ELSEVIER IRELAND LTD

Lugar: Amsterdam; Año: 2017 p. 112 - 121

0168-9452

This work studied modifications experienced by rootmitochondria during whole plant senescence or under light deprivation, using Arabidopsis thaliana plants with YFPtagged to mitochondria. During post-bolting development, root respiratoryactivity started to decline after above ground organs (i.e. rosette leaves) hadsenesced. This suggests that carbohydrate starvation may induce rootsenescence. Similarly, darkening the whole plant induced a decrease inrespiration of roots. This was partially due to a decrease in the number oftotal mitochondria (YFP- labelled mitochondria) and most probably to a decreasein the quantity of mitochondria with a developed inner membrane potential (ΔΨm,Mitotracker red- labeled mitochondria). Also the lower amount ofmitochondria with ΔΨmcomparedto YFP-labelled mitochondria at 10 d of whole darkened plant, suggests thepresence of mitochondria in a ?standby state?. The experiments also suggestthat small mitochondria made the main contribution to the respiratory activitythat was lost during root senescence. Sugar supplementation partially restoredthe respiration of mitochondria after 10d of whole plant dark treatment. Theseresults suggest that root senescence is triggered by carbohydrate starvation,with loss of ΔΨmmitochondria and changes in mitochondrial size distribution.