Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Maintenance of protein quality control and turnover is essential for cellular homeostasis. In plant organelles this biological process is predominantly performed by ATP-dependent proteases. Here, a genetic screen was performed that led to the identification of Arabidopsis thaliana Lon1 protease mutants that exhibit a post-embryonic growth retardation phenotype. Translational fusion to yellow fluorescent protein revealed AtLon1 subcellular localization in plant mitochondria, and the AtLon1 gene could complement the respiratory-deficient phenotype of the yeast PIM1 gene homolog. AtLon1 is highly expressed in rapidly growing plant organs of embryonic origin, including cotyledons and primary roots, and in inflorescences, which have increased mitochondria numbers per cell to fulfill their high energy requirements. In lon1 mutants, the expression of both mitochondrial and nuclear genes encoding respiratory proteins was normal. However, mitochondria isolated from lon1 mutants had a lower capacity for respiration of succinate and cytochrome c via complexes II and IV, respectively. Furthermore, the activity of key enzymes of the tricarboxylic acid (TCA) cycle was significantly reduced. Additionally, mitochondria in lon1 mutants had an aberrant morphology. These results shed light on the developmental mechanisms of selective proteolysis in plant mitochondria and suggest a critical role for AtLon1 protease in organelle biogenesis and seedling establishment.

Original publication




Journal article


New Phytol

Publication Date





588 - 600


ATP-Dependent Proteases, Arabidopsis, Arabidopsis Proteins, Cell Respiration, Citric Acid Cycle, Cloning, Molecular, Gene Expression Regulation, Plant, Genes, Plant, Genetic Complementation Test, Germination, Heat-Shock Response, Hypocotyl, Mitochondria, Mitochondrial Proteins, Mutation, Phenotype, Protease La, Protein Transport, RNA, Messenger, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Seedlings, Serine Endopeptidases