Genome-Wide Identification and Expression Analysis of Members in the YT521-B Homology Domain-Containing RNA Binding Protein Family in Ginkgo biloba

<i>N⁶</i>-methyladenosine (m⁶A) is a widespread post-transcriptional modification of RNA in eukaryotes. The conserved YTH-domain-containing RNA binding protein has been widely reported to serve as a typical m⁶A reader in various species. However, no studies have reported the m⁶A readers in <i>Ginkgo biloba</i> (<i>G. biloba</i>). In this study, a systematic analysis of the m⁶A reader (YTH) gene family was performed on <i>G. biloba</i>, identifying 10 <i>YTH</i> genes in its genome. Phylogenetic analysis of protein-coding sequences revealed that <i>YTH</i> genes from <i>G. biloba</i> could be classified into two subgroups: <i>GbDC1</i> and <i>GbDC2</i> in <i>GbDC</i> and <i>GbDF1-8</i> in <i>GbDF</i>, each with similar motifs and gene structures. In <i>G. biloba</i>, the predicated aromatic cage pocket of the YTH domains in the <i>YTH</i> gene family is uniformly composed of tryptophan residues (WWW). Subcellular localization experiments verified that <i>GbDC1</i> is indeed localized in the nucleus, while <i>GbDF1</i> is localized in both the nucleus and the cytoplasm. The expression patterns of the identified m⁶A reader genes showed a wide distribution but were tissue-specific. Most genes were highly expressed in leaves, followed by the stem, while the lowest expression tendency was found in the roots. Cis-regulatory element analysis predicted the possible functions of <i>YTH</i> genes in <i>G. biloba</i>, which were mainly responsive to plant hormones such as ABA and MeJA, as well as stress responses. Furthermore, the expression levels of <i>YTH</i> genes indeed changed significantly after ABA, MeJA, and NaCl treatments, suggesting that they can be affected by these abiotic factors. In addition, the PLAAC prediction results indicate that prion domains exist in <i>GbDF1</i>, <i>GbDF2</i>, <i>GbDF3</i>, <i>GbDF4</i>, <i>GbDF6</i>, <i>GbDF7</i>, <i>GbDF8</i>, and <i>GbDC1</i>, and phase separation is possible. This study provides a foundation for further investigation of the effects of m⁶A methylation on gene expression regulation in <i>G. biloba</i> and other forest trees.