Identification and expression analysis of N-methyltransferase and demethylase in rapeseed (Brassica napus L.).

BACKGROUND

N-methyladenosine (mA) modification involves the addition of a methyl group to the nitrogen atom at position six of adenine in RNA. It is the most prevalent type of dynamic internal RNA methylation modification, plays an important role in plant development and abiotic stress. The mA modification is facilitated by mA writers (mA methyltransferases), mA erasers (mA demethylation enzymes), and mA readers (mA methylated reading proteins).

RESULTS

In order to study the characterization and expression of mA methyltransferases and demethylases in Brassica napus (rapeseed), we used five methyltransferases and two demethylases from Arabidopsis thaliana as reference sequences. A total of 34 methyltransferases and 12 demethylases were identified in B. napus, B. oleracea, and B. rapa. We analyzed the physicochemical properties, gene structures, conserved domains, chromosome localization, and expression pattern across all tissues, as well as the effects of hormone and stress treatments on B. napus. Our findings revealed that the methyltransferase BnaHAKAI was highly expressed during the late stages of seed development. It may be related to the synthesis of oil content and seed size in the later stage of seed growth. In contrast, the demethylase BnaALKBH10B exhibited high expression primarily in the petals, followed by the pods, buds. This expression pattern may be associated with flower development and the timing of flowering. Furthermore, BnaALKBH10B primarily responded to abiotic stresses such as salinity, drought, osmotic, cold, and freezing, as well as to hormones like jasmonic acid and gibberellins. The qRT-PCR results showed that BnaALKBH10B responded to freezing and salt stress.

CONCLUSIONS

In summary, a total of 34 methyltransferases and 12 demethylases genes were identified in B. napus, B. oleracea, and B. rapa, and their phylogenetic relationships, structural domains, and expression patterns in tissues and under abiotic stress were comprehensively analyzed. This research will serve as a foundation for future studies on mA in B. napus.