Cytochrome c and hormone connections during plant development.

GONZALEZ DH; WELCHEN E; RACCA S

Montpellier

Congreso; 12th Congress of the International Plant Molecular Biology ? (IPMB2018); 2018

Cytochrome c (CYTc) is a heme protein located in the mitochondrial intermembrane space that is required for electron transfer between complex III and IV of the mitochondrial respiratory chain. We obtained two double mutants in both genes coding CTYc in Arabidopsis, and we studied the effect of reducing the levels of CYTc on plant development. Plants with reduced CYTc levels are smaller, reach flowering several days later but with the same number of leaves than wild-type plants (WT), and accumulate starch and glucose during the day. We also could demonstrate an interplay between CYTc and gibberellins (GAs) during Arabidopsis vegetative development. Treatment with GAs abolishes the delay in flowering time and reduces glucose accumulation in double mutant lines. In agreement with this, plants with reduced CYTc levels contain higher levels of DELLA proteins which act as repressors of GA response. All these results suggest that an alteration in CYTc levels may cause changes in gibberellin homeostasis.Additionally, we focus on germination phase of mutant lines. A partially lack of CYTc produce a little delay in germination rate compared to WT, without affecting seedling establishment. Mutant lines also exhibit a higher sensitivity to Abscisic Acid hormone (ABA) and a lower sensitivity to GA-inhibitor paclobutrazol (PAC). We proposed that CYTc establishes a link between mitochondrial energetic metabolism and hormonal pathways to modulate plant growth and development.