UK researchers are part of a team that has identified a gene that makes plant cell walls tougher, so making grasses harder to break down in the rumen or by anaerobic digestion systems. They calculate that suppressing this gene could release 60% more plant sugars available energy.
The multinational team of researchers from the UK, Brazil and the US has published its findings in the New Phytologist.
“The impact is potentially global as every country uses grass crops to feed animals and several biofuel plants around the world use this feedstock,” says Rowan Mitchell, a plant biologist at Rothamsted Research and the team’s co-leader. “Increased cell wall stiffening, or feruloylation, reduces digestibility.
“We identified grass-specific genes as candidates for controlling cell wall feruloylation 10 years ago, but it has proved very difficult to demonstrate this role although many labs have tried,” says Dr Mitchell. “We now provide the first strong evidence for one of these genes.”
The researchers genetically modified plants with a transgene to suppress the endogenous gene responsible for feruloylation to around 20% of its normal activity. In this way, the biomass produced is less feruloylated than it would otherwise be in an unmodified plant.
“The suppression has no obvious effect on the plant’s biomass production or on the appearance of the transgenic plants with lower feruloylation,” notes Dr Mitchell. “Scientifically, we now want to find out how the gene mediates feruloylation. In that way, we can see if we can make the process even more efficient.”
Co-leader Hugo Molinari of Brazil’s Agricultural Research Corporation (Embrapa) adds: “Economically and environmentally, our livestock industry will benefit from more efficient foraging and our biofuels industry will benefit from biomass that needs fewer artificial enzymes to break it down during the hydrolysis process.” The advance could benefit the local bioethanol industry through the more efficient breakdown of co-products such as maize stover and sugarcane residues, or from sugar cane grown as an energy crop.