Overexpression of a Sugarcane BAHD Acyltransferase Alters Hydroxycinnamate Content in Maize Cell Wall.

The purification of hydroxycinnamic acids [-coumaric acid (CA) and ferulic acid (FA)] from grass cell walls requires high-cost processes. Feedstocks with increased levels of one hydroxycinnamate in preference to the other are therefore highly desirable. We identified and conducted expression analysis for nine BAHD acyltransferase genes from sugarcane. The high conservation of AT10 proteins, together with their similar gene expression patterns, supported a similar role in distinct grasses. Overexpression of in maize resulted in up to 75% increase in total CA content. Mild hydrolysis and derivatization followed by reductive cleavage (DFRC) analysis showed that CA increase was restricted to the hemicellulosic portion of the cell wall. Furthermore, total FA content was reduced up to 88%, resulting in a 10-fold increase in the CA/FA ratio. Thus, we functionally characterized a sugarcane gene involved in CA content on hemicelluloses and generated a C4 plant that is promising for valorizing CA production in biorefineries.