Novel insights into the unique characterization of N6-methyladenosine RNA modification and regulating cold tolerance in winter Brassica rapa

N6-methyladenosine (m⁶A) is an mRNA modification considered essential in plants, and is a key player in gene regulation at the transcriptional and translational levels. In present study, we mapped Brassica rapa's whole transcriptome m⁶A profile under low-temperature stress in different cold tolerant varieties to elucidate the m⁶A methylation pattern. The distribution of m⁶A modifications changed significantly under low temperature stress. More 5'UTR m⁶A was deposited in strong cold-resistant varieties and responded positively to cold resistance by regulating mRNA expression abundance. The increase in m⁶A abundance was correlated with the increase in mRNA abundance after low temperature stress. ZAT12 might positively regulate its mRNA expression through m⁶A methylation. MYBC1 might be a negative regulator to cope with low-temperature stress. The hypothetical protein was involved in starch and sucrose metabolic pathways, and that the Low-quality protein was involved in the regulation of DNA binding, DNA-binding, transcription factor activity, and proline biosynthetic processes and leaf senescence pathways. In addition, a number of m⁶A methyltransferases and m⁶A demethylases play crucial roles in response to cold stress. These results revealed the critical role of m⁶A -modified genes under cold stress and provide new insights into the study of cold resistance in winter Brassica rapa.