Epigenetic Mechanism for Regulation of Gene Expression of Membrane-Bound Subunit C Succinate Dehydrogenase in Sprouting Corn Seeds

• Published in: Russian journal of plant physiology 2022-04, Vol.69 (2), Article 24
• Main Authors: Eprintsev, A. T., Fedorin, D. N., Caro, O. J. Florez
• Format: Article
• Language: English
• Subjects: Alternative oxidase; Biomedical and Life Sciences; Bisulfite; Corn; CpG islands; Cultivars; Dehydrogenase; Dehydrogenases; DNA methylation; Electron transport chain; Electrons; Epigenetics; Gene expression; Gene regulation; Gene silencing; Genes; Germination; Life Sciences; Membranes; Methylation; Mitochondria; Nutrition; Plant Physiology; Plant Sciences; Research Papers; Seed germination; Seeds; Succinate dehydrogenase; Zea mays
• ISSN: 1021-4437; 1608-3407
• DOI: 10.1134/S1021443722020054

The activation or repression of gene transcription is mediated by the level of methylation, especially in the CG sequences in the promoter region of the gene. During seed germination, regulation of mitochondrial ETC can be determined at the level of succinate dehydrogenase (SDH), in particular, by the correlation between the level of methylation of gene promoters encoding membrane-bound SDH subunits and their expression. Evaluation was carried out on the degree of methylation of gene promoters SDH3-1 and SDH3-2 encoding the membrane-bound subunit C SDH during germination of maize seeds ( Zea mays L., cultivar Voronezhskaya 76). The results of bisulfite sequencing of the amplicons of the studied genes showed that the CG sequences in the promoter region are hypermethylated on the first day of seed germination; the methyl status was 100%. In the following days, methylation levels decreased significantly, and this figure was 40.0% for SDH3-1 and 30.8% for SDH3-2 on the eighth day of seed germination. The obtained results indicate an increase in the rate of functioning of the alternative oxidase (AOX) with the germination of corn seeds at a stable expression level of the respiratory chain complex I gene. In addition, an increase in the level of transcription of the genes of the membrane-bound subunit C of SDH, together with the activation of AOX, indicates an alternative transport of electrons in the mitochondrial ETC, which is not associated with the synthesis of ATP. An epigenetic mechanism of gene expression regulation of SDH3-1 and SDH3-2 subunits of SDH has been identified , providing an alternative transport of electrons in the late stages of germination of corn seeds. A direct relationship was found between the methylation status of the CpG islands of the gene promoter SDH3-2 and the number of its transcripts, which is apparently associated with the adaptive response of mitochondrial metabolism to the transition of the cell from a heterotrophic type of nutrition to an autotrophic one.