Abstract
N6-methyladenosine (m6A) is the most prevalent internal modification present in the mRNAs of all higher eukaryotes, where it is present within both coding and noncoding regions. In mammals, methylation requires the catalysis of a multicomponent m6A methyltransferase complex. Proposed biological functions for m6A modification include pre-mRNA splicing, RNA stability, cell fate regulation, and embryonic development. However, few studies have been conducted on m6A modification in trees. In particular, the regulation mechanism of RNA m6A in Populus development remains to be further elucidated. Here, we show that PtrMTA (Populus trichocarpa methyltransferase) was colocalized with PtrFIP37 in the nucleus. Importantly, the PtrMTA-overexpressing plants significantly increased the density of trichomes and exhibited a more developed root system than that of wild-type controls. Moreover, we found that PtrMTA-overexpressing plants had better tolerance to drought stress. We also found PtrMTA was a component of the m6A methyltransferase complex, which participated in the formation of m6A methylation in poplar. Taken together, these results demonstrate that PtrMTA is involved in drought resistance by affecting the development of trichomes and roots, which will provide new clues for the study of RNA m6A modification and expand our understanding of the epigenetic molecular mechanism in woody plants.