Genetic optimization of corn lignin biosynthesis for synergistic improvements in forage quality, yield and preservation

As the world's population reaches 9.7 billion in the year 2050 global crop production willneed to double to meet the projected demands for food feed fiber and fuel. Corn themost produced annual crop in the world will have a major role in helping to meet thisneed. In the United States more than a third of the corn produced is used as feed forlivestocks (148 million tons in 2017) and its stover also represents the most abundantagricultural residue for production of clean bioenergy (100 million tons by 2020).Improving the quantity and quality of corn biomass and stress tolerance are essential tosustain global productions of meat and milk as well as biofuels and bio-products.Especially biomass quality for the above agricultural and industrial processes isdetermined by its digestibility or processability a trait associated with biomasscomposition which consists of energy-rich matrix polysaccharides protected byrecalcitrant indigestible lignin polymers. This SBIR Phase I project will develop a moreefficient approach to engineering corn biomass digestibility while improving yields andmaintaining resilience to stress. Although traditional breeding has increased corn yieldsdrastically over the past 50 years modest or no improvements have been achieved forforage quality and digestibility. This is in part due to partial antagonisms between thesetwo traits.This work proposes to fine-tune lignin deposition in corn biomass and thereby reducinglignin content by 20% in a tissue-specific manner as well as increasing biomass yieldsby at least 10%. The quality trait provided by our patent-pending genetic engineeringstrategy will ameliorate biomass degradability. Our molecular metabolic andphenotypic characterizations of these new lines in Phase I will represent valuablematerial for both future field-test validation and introgression of the biomass quality traitinto elite germplasms via modern breeding programs.