Functional testing of xylan-associated genes in Arabidopsis and application of CRISPR/Cas9 gene editing in hybrid poplar trees

Abstract

On a quest to eliminate the use of fossil fuels to alleviate challenges associated with climate change, it has become vital to rely on lignocellulosic biomass as an alternative source for generating value-added products and sustaining the bioeconomy. However, the structure of lignocellulosic biomass contributes to biomass recalcitrance, necessitating genetic engineering of plant cell walls for easier and efficient bioconversion. The success of genetic engineering approach requires a significant understanding of the function and biological roles of cell wall biosynthetic genes. Here, we functionally analysed the impact of knockout mutation of several xylan-associated genes on plant growth and physicochemical properties. We established that XYLANASE 1(XYN1) may be necessary for water and nutrient transport in Arabidopsis thaliana, as xyn1 T-DNA insertional mutants had significantly shorter roots and leaves. More importantly, we show that the Arabidopsis EMP70 is essential during seed germination and mutation thereof leads to early germination and subsequent vegetative growth advantage. Realizing the exact biological roles of these and other novel cell wall biosynthetic genes will be beneficial in understanding the development of cell wall in energy crops such as Eucalyptus, and in future, it may contribute to improving bioprocessing efficiency while reducing the associated bioprocessing costs.