Changes in the relative copy numbers of chloroplast and mitochondrial DNA in the leaves of Vitis vinifera L. after high-temperature treatment in vitro

Abstract

In the context of global warming, studying the consequences of increased temperature on agricultural crops becomes important for predicting the shortand long-term impacts on productivity. The effects of elevated temperature on grapevine plants lead to increased yield losses in viticulture. Micropropagated grapevine plants of the ‘Chardonnay’ variety were grown in vitro on MS medium and subjected to heat treatment at 45°C for 120 minutes. The control group of plants was not exposed to heat treatment. The levels of relative copy numbers of chloroplast and mitochondrial DNA were determined in leaf tissues of all plant groups using the RT-PCR method 30 days after heat treatment. In the group of plants subjected to heat treatment, statistically significant (p>0.05) reductions in the relative copy numbers of mitochondrial and chloroplast DNA were observed compared to the control group, with a decrease of over 30%. The copy number of chloroplast DNA exceeded that of mitochondrial DNA by more than 20 times in both the experimental and control groups. Heat treatment of micropropagated grapevine plants in vitro resulted in a closer correlation (r=+0.86) in the regulation of activity between these organelles, alongside the decrease in relative copy numbers of both mitochondrial and chloroplast DNA. This study demonstrates the promising use of relative copy numbers of chloroplast and mitochondrial DNA in plant leaves to investigate their potential physiological response to adverse environmental factors.