Brassinosteroids (BRs) play an important role in plant growth and development. However, little is known about how BRs affect secondary wall biosynthesis in woody plants. The team of Yun Shen from Southwest University in China studied the brassinosteriod biosynthesis-related genePtoDWF4 from Chinese white poplar (Populus tomentosa).
Using CRISPR-Cas9, the team knocked-out PtoDWF4, resulting in significantly decreased biomass production in the developed plants. Meanwhile, overexpression of PtoDWF4 promoted growth rate and biomass yield, and increased the area and cell layers of xylem. Overexpressing plants also showed a significant increase in plant height and stem diameter.
Further studies revealed that expression of PtoDWF4 upregulates the expression of secondary cell wall (SCW) biosynthesis-related genes. These results indicate that PtoDWF4 plays a positive role in improving growth rate and increasing biomass production in poplar.
For more information, read the article in Tree Physiology.