Insight into the maize CMS-associated mitochondrial–nuclear interaction at the DNA methylation level

The mitochondrial–nuclear interaction is essential for cellular homeostasis and proper function. DNA methylation plays an important role in gene expression regulation, as well as in maintaining genomic stability. Isonuclear-alloplasmic and isoplasmic-allonuclear lines were used as materials in this study. The mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) from maize tassels were used for DNA methylation analysis with high-performance liquid chromatography. The results were as follows. (i) Different mtDNA methylation levels were detected within the isoplasmic-allonuclear lines and varied nDNA methylation levels were also detected among the isonuclear-alloplasmic lines. (ii) From the pollen mother cell stage to the binucleate stage, the change pattern of DNA methylation levels varied among cytoplasmic male sterility (CMS) lines CMS-C, CMS-T, and CMS-S (CMS Charrua, Texas, and USDA, respectively). The DNA methylation level peaked at the tetrad stage for the CMS-C line, at the mononuclear stage for the CMS-...