Journal Article

Transgenic ZmMYB167 Miscanthus sinensis with increased lignin to boost bioenergy generation for the bioeconomy

Hauck, Barbara, Timms-Taravella, Emma, Roberts, Luned A., Clifton-Brown, John, Dalton, Sue, Moron-Garcia, Odin M., Wagner, Moritz, Bhatia, Rakesh, Gallagher, Joe A., Bosch, Maurice

2023

Overview

Background Perennial C 4 grasses from the genus Miscanthus are widely regarded as leading and promising dedicated bioenergy crops due to their high biomass accumulation on marginal land with low environmental impacts and maintenance requirements over its productive life. There is an urgent socio-political and environmental need to ramp up the production of alternative, affordable and green bioenergy sources and to re-direct the net zero carbon emissions trajectory. Hence, up-scaling of Miscanthus cultivation as a source of biomass for renewable energy could play an important role to strategically address sustainable development goals for a growing bio-based economy. Certain Miscanthus sinensis genotypes are particularly interesting for their biomass productivity across a wide range of locations. As the aromatic biomass component lignin exhibits a higher energy density than cell wall polysaccharides and is generally used as an indicator for heating or calorific value, genetic engineering could be a feasible strategy to develop M. sinensis biomass with increased lignin content and thus improving the energetic value of the biomass. Results For this purpose, transgenic M. sinensis were generated by Agrobacterium- mediated transformation for expression of ZmMYB167 , a MYB transcription factor known for regulating lignin biosynthesis in C 3 and C 4 grasses. Four independent transgenic ZmMYB167 Miscanthus lines were obtained. Agronomic traits such as plant height, tillering and above-ground dry weight biomass of the transgenic plants were not different to that of wild-type control plants. Total lignin content of the transgenic plants was ~ 15–24% higher compared with control plants. However, the structural carbohydrates, glucan and xylan, were decreased by ~ 2–7% and ~ 8–10%, respectively, in the transgenic plants. Moreover, expression of ZmMYB167 in transgenic plants did not alter lignin composition, phenolic compounds or enzymatic saccharification efficiency yields but importantly improved total energy levels in Miscanthus biomass, equivalent to 10% higher energy yield per hectare. Conclusions This study highlights ZmMYB167 as a suitable target for genetic lignin bioengineering interventions aimed at advancing and developing lignocellulosic biomass supply chains for sustainable production of renewable bioenergy.

• Publisher: BioMed Central,BioMed Central Ltd,Nature Publishing Group,BMC
• Subject: Bio-based economy / Biodiesel fuels / bioeconomics / Bioenergy / Bioengineering / Biofuels / Biomass / Biomass energy / Biomass energy production / biomass production / Biosynthesis / Biotechnology / Calorific value / Carbohydrates / Carbon / Cell wall / Cell walls / Cellulose / Chemical properties / Chemistry / Chemistry and Materials Science / Economic aspects / Emissions / energy / Energy crops / energy density / Environmental Engineering/Biotechnology / Environmental impact / Genes / Genetic aspects / Genetic engineering / Genetic transformation / genetically modified organisms / Genetically modified plants / Genotypes / genus / Glucan / glucans / Grasses / Lignin / lignin content / Lignocellulose / Microbiology / Miscanthus / Miscanthus sinensis / Net zero / Phenolic compounds / Phenols / Physiological aspects / Plant Breeding/Biotechnology / plant height / Polysaccharides / Production processes / Raw materials / Renewable and Green Energy / Renewable energy / Saccharides / Saccharification / Senescence / Sorghum / Supply chains / Sustainable development / Sustainable production / tillering / transcription factors / Transgenic plants / Xylan