Lawrence Berkeley National Laboratory

Alfalfa and sorghum are two major forage crops in the U.S. each offering advantageous traits for the agricultural value chain. Alfalfa, a perennial dicot, generally offers high protein content. Sorghum, an annual monocot, offers more cellulose and other nutritious carbohydrates. As forage crops, traits such as rapid growth rates, increased harvest yields, and high quality (digestibility) are desirable. Improvement of such traits has been the goal of numerous biotechnology efforts. However, alternative biotechnology techniques are typically constitutive and when applied to commercial crops have resulted in net negative consequences. For example, efforts to improve quality by lowering lignin biosynthesis have resulted in plants with poor structural integrity and diminished mass at maturity. - With support by DOE SBIR fasttrack program FY14, LBNL and AFINGEN previously demonstrated engineered healthy switchgrass plants which grew with 22% to 54% more fermentable sugar release, 25% less lignin, faster growth, and more biomass yields than control plants. In this CRADA project, AFINGEN collaborated with JBEI/LBNL again and have transferred the simple tissue-targeting technology from the demonstrated switchgrass to two forage crops, alfalfa and sorghum. In addition to characterizing biomass quality and quantity in transgenic plants, RNAseq detected significant increase of a series of secondary metabolite enzyme gene expression specific to engineered lines, suggesting that enhanced secondary metabolite production contributes to fast-growth and high yielding trait.