Transcriptional activity of mitochondrial genes in intraspecific and interspecific sunflower hybrids

Relevance. The genetic structure of plant cells implies the coordinated work of three genomes: nuclear, plastid, and mitochondrial. Hybridization between genetically heterogeneous parents can lead to changes in the established nuclear-cytoplasmic balance, which in turn can affect the level and consistency of their gene expression. Changes in the transcriptional activity of organelle genes (in particular, mitochondria) during distant (interspecific) hybridization remain poorly understood. Results. The present study employed the qPCR technique to evaluate the transcriptional activity level of the mitochondrial genes atp1, atp4, atp6, atp9, nad3, nad6, cox1, and cox3 in intra- and interspecific sunflower hybrids and their parental forms from the VIR collection. According to the analyzed transcriptional activity of mitochondrial genes, they can be divided into three groups: genes with a relatively high level of expression – atp1, atp6, and nad6, those with a medium level of expression – atp4, cox1, cox3, and genes with a low level of expression – atp9 and nad3. Comparative analysis showed no significant difference (P<0.05) between maternal lines and hybrids. However, the expression of the nad6 gene in the case of Helianthus argophyllus (Torr. & A. Gray) was 2.6 times higher than in the cultivated sunflower lines. Conclusion. The absence of substantial changes in the expression of mitochondrial genes both in intra- and interspecific hybrids indicates the lack of significant changes in the regulation of nuclear-cytoplasmic interactions in these hybrids.

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