FISSION1A: initial investigations on its function in Arabidopsis thaliana

In A. thaliana, FIS1A is a protein localized in the outer chloroplast membrane, outer mitochondrial membrane and peroxisomal membrane. Its function in this species is not totally known. In this work, many experiments to further elucidate its role have been conducted. The hypothesis on the FIS1A involvement in the establishment of membrane contact sites between mitochondria and chloroplasts has still to be confirmed or refuted. A Fis1A loss-of-function mutant was studied under standard growth conditions and upon heat shock (HS) treatment. Qualitative analyses of the mitochondrial and plastidial morphology and distribution pattern at the root level were carried out. Little differences of the mitochondrial and plastidial shape respectively in the area between the root hair and root tip and in the root hair zone were observed. Quantitative analysis will assess the validity of the observations made. Expression analysis of genes involved in mitochondrial and cellular dysfunction or HS response was performed. The mutant displayed lower genes expression levels in control conditions than in the wild-type and little difficulties in restoring the mitochondrial/cellular homeostasis. A direct link between changes in gene expression between wild-type and mutant and the plastidial/mitochondrial morphology and distribution was not found. Further experiments are required.