The MYB, one of the largest transcription factor families in plants, is related to various biological processes. For an example, the R2R3-MYB family plays an important role in regulation of primary and secondary metabolism, plant growth and development, and responses to hormones and stresses. However, functional studies on the poplar R2R3-MYB genes are limited. In this study, we identified 207 poplar R2R3-MYB genes that are unevenly distributed on the 19 chromosomes of poplar, followed by characterization of their conserved domains. On the basis of phylogenetic analysis, these genes can be divided into 23 groups. Evidence from synteny analyses indicated that the poplar R2R3-MYB gene family is featured by tandem and segmental duplication events. On the basis of RNA-Seq data, we investigated salt responsive genes and explored their expression patterns. Furthermore, we cloned the PsnMYB108 gene from poplar, which is significantly up-regulated in roots and leaves in response to salt stress. To validate its function, we developed transgenic tobacco plants that over-express the PsnMYB108 gene. It appears that the transgenic lines are more tolerant to salt stress than the wild type does. Evidence from physiological analyses demonstrated that over-expression of PsnMYB108 may improve tobacco salt stress tolerance by increasing the reactive oxygen species scavenging ability and the accumulation of proline. These results laid the foundation for future analysis and functional studies of poplar R2R3-MYB family members, and revealed that PsnMYB108 plays an important role in improving plant salt stress tolerance.

MYB是植物中最大的转录因子家族之一，与多种生物过程有关。例如，R2R3-MYB家族在调节一级和二级代谢，植物生长和发育以及对激素和胁迫的反应中起重要作用。但是，对杨R2R3-MYB基因的功能研究是有限的。在这项研究中，我们鉴定了207个杨树R2R3-MYB基因，这些基因在杨树的19个染色体上分布不均，随后对其保守结构域进行了表征。在系统发育分析的基础上，这些基因可分为23组。语序分析的证据表明，杨树R2R3-MYB基因家族具有串联和节段重复事​​件。根据RNA-Seq数据，我们研究了盐反应基因，并探讨了它们的表达模式。此外，我们克隆了PsnMYB108来自杨树的基因，在盐胁迫下根和叶中的基因显着上调。为了验证其功能，我们开发了过量表达转基因烟草的转基因烟草植物。PsnMYB108基因。看来转基因品系比野生型更耐盐胁迫。生理分析的证据表明，过度表达PsnMYB108通过增加活性氧清除能力和脯氨酸的积累，可以提高烟草盐胁迫的耐受性。这些结果为杨树R2R3-MYB家族成员的进一步分析和功能研究奠定了基础，并揭示了：PsnMYB108 在提高植物盐胁迫耐受性中起重要作用。