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

Amanda Fanelli,Tatiane Da Franca Silva,John Ralph,Diego Mauricio Riaño-Pachón,David M Rancour,André Ferraz,Renato Vicentini,Elisson Romanel,Steven D Karlen,Michael Sullivan,Ronald D Hatfield

doi:10.3389/fpls.2021.626168

Abstract

The purification of hydroxycinnamic acids [p-coumaric acid (pCA) 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 ScAts 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 ScAT10 in maize resulted in up to 75% increase in total pCA content. Mild hydrolysis and derivatization followed by reductive cleavage (DFRC) analysis showed that pCA 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 pCA/FA ratio. Thus, we functionally characterized a sugarcane gene involved in pCA content on hemicelluloses and generated a C4 plant that is promising for valorizing pCA production in biorefineries.

Highlights

Grasses have great importance to worldwide agriculture, as huge volumes are used as food, animal feed, and bioenergy sources
We used a bioinformatics approach to identify sugarcane genes belonging to the Mitchell clade A (Mitchell et al, 2007; Molinari et al, 2013) of BAHD acyltransferases
BLAST (Altschul et al, 1990) and HMMer (Eddy, 2011) searches against genomic and transcriptomic sugarcane datasets, followed by a phylogenetic analysis for sugarcane, sorghum, Brachypodium, Setaria, rice, maize, and Arabidopsis (Figure 1A) revealed nine sugarcane unigenes in this clade with complete open reading frames (ORFs), which were named as ScAT1 to ScAT10 lacking of ScAT4, based on the nomenclature of Bartley et al (2013) (Supplementary Tables 3A,B)

Summary

Introduction

Grasses have great importance to worldwide agriculture, as huge volumes are used as food, animal feed, and bioenergy sources. The processing of grasses in agroindustry generates several non-grain products, such as stover or straw. The composition of these lignocellulosic materials makes them suitable feedstocks for the production of second-generation fuels and other value-added products, Sugarcane ScAt10 Alters Hydroxycinnamate Content in a biorefinery concept (Chandel et al, 2012; Jin et al, 2018). Hydroxycinnamic acids, both ferulic acid (FA) and p-coumaric acid (pCA), are high-value chemicals that could be produced in this context. Using even part of the massive agroindustry grass biomass leftovers to isolate these phenolic acids could significantly decrease the costs of production (Karlen et al, 2020)

Methods

Results

Conclusion