LAUSR

The transcription factor BplMYB46 has been identified as a regulator of abiotic stress responses and promoter of secondary wall deposition in Betula platyphylla. To investigate the downstream targets of BplMYB46, the expression profiles of genes in stems from BplMYB46-overexpressing (OE) and BplMYB46-silencing (SE) plants were studied. In OE stems, 952 genes were upregulated, and 1469 were downregulated in comparison to SE stems. In a KEGG pathway enrichment analysis of differentially expressed genes (DEGs), 1387 differentially expressed genes were annotated for 117 metabolic pathways. DEGs were abundant for metabolic pathway, secondary metabolite biosynthesis, plant hormone signal transduction, phenylpropanoid and flavonoid biosynthesis. DEGs were implicated lignin or cellulose biosynthesis, cell wall modification, xylem development, disease resistance, stress responses, and anthocyanin biosynthesis. These results suggested that BplMYB46 regulates cell wall development and stress resistance by affecting the expression of these genes. Our study further elucidates the mechanism by which BplMYB46 mediates abiotic stress responses and secondary cell wall biosynthesis in birch.