Mytochondrial dysfunction affects chloroplast functions

BUSI, M. V.; GOMEZ LOBATO, M.E.; ARAYA, A.; DIEGO FABIAN GOMEZ CASATI

Potrero de los Funes

Congreso; XLVII Reunion SAIB; 2011

SAIB

There are several reports that address the relationship between mitochondrial respiration, photosynthesis and chloroplast functions. That process provides energy for biosynthesis, and its balance with photosynthesis determines the rate of plant biomass accumulation. These interactions involve transcriptional control, protein co-localization, distribution of biochemical pathways between organelles, and the impact of substrate and product concentrations (metabolic shuttles). Profound changes in gene expression of nuclear-encoded genes were observed in Arabidopsis plants exhibiting impaired mitochondrial function. This model, where the mitochondrial flaw was induced by the expression of the unedited form of the ATP synthase subunit 9 (u-ATP9), is useful to uncover the interactions between organelles in plant cells. An interesting point of our work is the fact that mitochondrial dysfunction intransgenic plants can affect photosynthesisby reducing the chlorophyll levels. In fact, degradationof these pigments may be due to the increase of Mg2+ dechelatase activity and ROS levels, inducing a dysfunctionof the light-harvesting (antenna) complex. qRT-PCR analysis of LCHI (At1g19150) and PSBQ2 (AT4g05180) mRNA levels shows an increase of about 5-fold in transgenic lines compared to wild type plants, confirming the induction observed in microarray experiments.