Mitochondrial dysfunction affects chloroplast functions.

BUSI, M.V.; GOMEZ-LOBATO, M.E.; ARAYA, A; GOMEZ-CASATI, D.F

Potrero de los Funes

Congreso; XLVII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB),; 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB),

There are several reports that address the relationship betweenmitochondrial respiration, photosynthesis and chloroplastfunctions. That process provides energy for biosynthesis, and itsbalance with photosynthesis determines the rate of plant biomassaccumulation. These interactions involve transcriptional control,protein co-localization, distribution of biochemical pathwaysbetween organelles, and the impact of substrate and productconcentrations (metabolic shuttles). Profound changes in geneexpression of nuclear-encoded genes were observed in Arabidopsisplants exhibiting impaired mitochondrial function. This model,where the mitochondrial flaw was induced by the expression of theunedited form of the ATP synthase subunit 9 (u-ATP9), is useful touncover the interactions between organelles in plant cells. Aninteresting point of our work is the fact that mitochondrialdysfunction in transgenic plants can affect photosynthesis byreducing the chlorophyll levels. In fact, degradation of thesepigments may be due to the increase of Mg2+ dechelatase activityand ROS levels, inducing a dysfunction of the light-harvesting(antenna) complex. qRT-PCR analysis of LCHI (At1g19150) andPSBQ2 (AT4g05180) mRNA levels shows an increase of about 5-fold in transgenic lines compared to wild type plants, confirming theinduction observed in microarray experiments.