A Novel NAC Transcription Factor From Eucalyptus, EgNAC141, Positively Regulates Lignin Biosynthesis and Increases Lignin Deposition

Abstract

Wood formation is a complicated process under the control of a large set of transcription factors. NAC transcription factors are considered "master switches" in this process. However, few NAC members have been cloned and characterized in <i>Eucalyptus</i>, which is one of the most economically important woody plants. Here, we reported an NAC transcription factor from <i>Eucalyptus grandis</i>, EgNAC141, which has no Arabidopsis orthologs associated with xylogenesis-related processes. <i>EgNAC141</i> was predominantly expressed in lignin-rich tissues, such as the stem and xylem. Overexpression of <i>EgNAC141</i> in Arabidopsis resulted in stronger lignification, larger xylem, and higher lignin content. The expression of lignin biosynthetic genes in transgenic plants was significantly higher compared with wild-type plants. The transient expression of <i>EgNAC141</i> activated the expression of Arabidopsis lignin biosynthetic genes in a dual-luciferase assay. Overall, these results showed that EgNAC141 is a positive regulator of lignin biosynthesis and may help us understand the regulatory mechanism of wood formation.