Cytochrome c and hormone conections during plant development

RACCA, SOFÍA; GONZALEZ, DANIEL H.; WELCHEN, ELINA

Monpellier

Congreso; International congress of plant mitochondrial biology; 2018

IPBM comitee

Cytochrome c (CYTc) is a heme protein located in the mitochondrial intermembrane space required for electron transfer between complexes III and IV of the mitochondrial respiratory chain. We studied the effect of reducing CYTc levels on plant growth and development. Double mutants with reduced CYTc levels are smaller, reach flowering time several days later than wild-type plants, although with the same number of leaves, and accumulate higher levels of starch and glucose during the day. Treatment with gibberellins (GAs) abolishes the delay in flowering and reduces glucose accumulation in the mutants. Plants with reduced CYTc levels also contain higher levels of DELLA proteins which are repressors of GA responses. Treatment of seedlings with antimycin A or the uncoupler dinitrophenol mimicks the effects of CYTc deficiency on GA responses. We additionally focused on germination and observed that altered CYTc levels impact on germination rate, differentially affecting ATP production and the sensitivity to Abscisic acid and paclobutrazol, a GA synthesis inhibitor. Our results suggest that changes in CYTc levels alter hormone homeostasis during germination and vegetative growth. We propose that, through mitochondrial respiration, CYTc establishes a link between energetic metabolism and hormonal pathways to modulate different aspects of plant growth and development.