ARS | Publication request: Lignin modification to improve sorghum for cellulosic and thermal bioenergy

Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2011
Publication Date: August 6, 2011
Citation: Sattler, S.E., Clemente, T.E., Pedersen, J.F., Funnell-Harris, D.L. 2011. Lignin modification to improve sorghum for cellulosic and thermal bioenergy. Plant Biology Annual Meeting. http://abstracts.aspb.org/pb2011/public/P01/P01016.html.

Technical Abstract: Modifying lignin content and composition are major targets for bioenergy feedstock improvement for both cellulosic and thermal bioenergy conversion. Sorghum (Sorghum bicolor) is currently being developed as a dedicated bio-energy feedstock. Our goals are to improve sorghum biomass for both biochemical and thermal bioenergy conversion by developing experimental lines that have altered lignin content and composition beyond normal levels and to understand how these changes impact overall plant fitness. To systematically link steps in lignin biosynthesis with accumulation of metabolites or changes in gene expression, we are using next-generation sequencing technology, biochemistry and metabolite profiling. To reduce lignin content and alter lignin composition for cellulosic bioenergy, brown midrib (bmr) mutants, generated through chemical mutagenesis, are being utilized. bmr6 and 12 sorghum lines, which are currently being deployed, have been shown to significantly increase ethanol conversion efficiency. To increase lignin content for thermal bioenergy conversion, a series of transgenic lines overexpressing phenylpropanoid biosynthetic enzymes and regulatory protein are being developed. In several plant species, lignin has long been implicated as playing a critical role in the plant defense responses to both fungal pathogens and herbivorous insects, which are also the major biotic pressures for sorghum. Thus, it is important to determine how modifications to lignin biosynthesis will affect interactions with pests before bioenergy crops are deployed. Surprisingly, our preliminary findings indicated bmr6 and bmr12 plants have increased resistance to some fungal pathogens. The overall goal is to modify lignin for bioenergy without sacraficing plant fitness.