DNA transport into plant mitochondria under impaired chondriome dynamics

Abstract

The mitochondria of major taxonomic groups possess the ability to import DNA from their environment; however, the cellular role of this process remains not fully understood. Collectively, all mitochondria within a cell form the chondriome, whose structure is crucial for organelle interactions and maintenance of cellular homeostasis. No data are currently available regarding the impact of altered mitochondrial fusion and fission dynamics – which leads to the structural disruption of the chondriome – on DNA import into mitochondria. This study aimed to examine the relationship between chondriome structure and the import of foreign DNA into mitochondria using Arabidopsis knockout lines characterized by impaired fusion and fission processes (drp3, friendly). Inactivation of the mitochondrial fission protein isoform DRP3B, which leads to the formation of highly elongated mitochondria, reduced the import activity of a 2.7 kb fragment. Mitochondrial clustering, characteristic of the friendly knockout mutant, also led to a decrease in the import level of this fragment, while the import activity of a short DNA fragment (0.27 kb) remained unchanged. Thus, the normal functioning of the mechanism responsible for importing larger DNA fragments requires maintaining a balance between mitochondrial fusion and fission. The observed correlation between DNA import activity and changes in chondriome structure provides new insights into the role of DNA import and its contribution to cellular stability.