Abstract
N(1)-methyladenosine (m(1)A) serves as a critical regulatory modification in plant mRNA. In Arabidopsis, the TRM61/TRM6 complex functions as m(1)A58 methyltransferase writers essential for organogenesis, reproduction, and hormonal signaling. However, the evolutionary dynamics of the TRM61/TRM6 complex across plant lineages remain poorly understood. In this study, we systematically identified TRM6 and TRM61 homologs across 306 plant species and uncovered the conserved evolutionary trajectories between them. These two methyltransferase subunits retain conserved structural motifs, respectively, and exhibit coordinated expression patterns in plants. In wheat (Triticum aestivum L.) and its progenitors, TRM6 and TRM61 proteins demonstrate polyploidization-associated evolutionary coordination. Their promoters harbor stress-, light-, and hormone-responsive cis-elements. Furthermore, the TRM6 and TRM61 genes in wheat exhibit diverse expression profiles across developmental tissues and under abiotic stress conditions. The differences in allelic frequency among TRM6 and TRM61 variants between wild and domesticated wheat populations suggest that they may have undergone selection during wheat domestication and improvement. This study provides an evolutionary framework for the TRM61/TRM6 complex.