Intracellular selective proteolysis is an important post-translational 
regulatory mechanism maintaining protein quality control by removing defective, 
damaged or even deleterious protein aggregates. The ATP-dependent Lon protease 
is a key component of protein quality control that is highly conserved across 
the kingdoms of living organisms. Major advancements have been made in bacteria 
and in non-plant organisms to understand the role of Lon in protection against 
protein oxidation, ageing and neurodegenerative diseases. This review presents 
the progress currently made in plants. The Lon gene family in Arabidopsis 
consists of four members that produce distinct protein isoforms localized in 
several organelles. Lon1 and Lon4 that potentially originate from a recent gene 
duplication event are dual-targeted to mitochondria and chloroplasts through 
distinct mechanisms revealing divergent evolution. Arabidopsis mutant analysis 
showed that mitochondria and peroxisomes biogenesis or maintenance of function 
is modulated by Lon1 and Lon2, respectively. Consequently, the lack of Lon 
selective proteolysis leading to growth retardation and impaired seedling 
establishment can be attributed to defects in the oil reserve mobilization 
pathway. The current progress in Arabidopsis research uncovers the role of Lon 
in the proteome homeostasis of plant organelles and stimulates biotechnology 
scenarios of plant tolerance against harsh abiotic conditions because of climate 
instability.