The Dynamics of DNA methylation in the maize (Zea mays L.) inbred line B73 response to heat stress at the seedling stage.

High temperature stress has become a major concern for crop production worldwide because it greatly affects the growth, development, and productivity of plants. The mechanisms underlying the development of heat-tolerance need to be better understood for important agricultural crops. Recent research shows that DNA methylation is dynamic during plant development. However, the molecular mechanism regulating these dynamic DNA methylation patterns remains to be elucidated. In this study, six MethylRAD libraries were constructed using DNA isolated from leaves of maize. A total of 42,561,144 and 48,157,284 clean reads were generated from CK (Control condition) and HTP (Heat stress condition) treatments, respectively. The results showed that a total of 25,470 methylated genes were found in six tested samples, including 325 differentially methylated genes (200 in CCGG sites and 125 in CCWGG sites) between the CK and HTP samples. KEGG pathway enrichment analysis for DMGs indicated that Spliceosome, Homologous recombination, RNA transport, Ubiquitin mediated proteolysis and Carbon metabolism pathways play a central role in maize response to heat stress. Taken together, this research revealed the genome-wide DNA methylation pattern of maize leaves in response to heat exposure and identified candidate genes potentially involved in response to heat stress at the methylation level, which will facilitate future studies to elucidate the epigenetic mechanisms underlying the responses of maize to heat stress.