# These authors contributed equally to this work.
* To whom correspondence should be addressed.
Received March 6, 2019; Revised April 2, 2019; Accepted April 10, 2019
Natural competence of mitochondria for DNA uptake has been known for the last 20 years. Until the present time, all studies of this process have been conducted exclusively in isolated mitochondria, as no system for investigation of the DNA transport into the mitochondria in intact cells has been available. The objective of this work was to improve and standardize the existing approaches for investigating DNA import into plant mitochondria in an in organello system. A method for detecting the import of fluorescently labeled DNA substrates has been developed. Based on the features of DNA import into the mitochondria, we suggested an efficient method for the evaluation of the DNA import efficiency by quantitative PCR. We also developed and characterized the in vivo system that allows to detect DNA transport from the cytoplasm to the mitochondrial matrix in Arabidopsis thaliana protoplasts. A combination of the proposed techniques for studying the DNA uptake by plant mitochondria might be useful for elucidating whether the properties of the mitochondrial DNA import established in the in organello system are preserved in vivo.
KEY WORDS: DNA import, plant mitochondria, fluorescent labeling, protoplasts transformation, Arabidopsis thaliana