ARS | Publication request: Genetic Dissection of Bioenergy Traits in Sorghum

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 9, 2009
Publication Date: January 9, 2010
Citation: Vermerris, W., Saballos, A., Pedersen, J.F., Sattler, S.E., Kresovich, S., Murray, S., Rooney, W., Xin, Z. 2010. Genetic Dissection of Bioenergy Traits in Sorghum. PAGXVIII Abst. P364

Technical Abstract: Sorghum is a very attractive biomass crop for ethanol production because of its low water and fertilizer requirements, tolerance to heat and drought, high biomass yield, and great genetic diversity. Two traits are of particular interest: The sweet sorghum trait, which results in the accumulation of fermentable sugars in the juice of the stems, and the brown midrib (bmr) trait, which changes the color and the chemical composition of the vascular tissue, and results in improved yields of fermentable sugars after enzymatic saccharification of lignocellulosic biomass. Combining these two traits would result in a dual-use sorghum that generates fermentable sugars from the juice and from the bagasse. The genetic basis of these traits is poorly understood and impedes the full exploitation of sorghum as a bioenergy crop. We are employing high-throughput expression profiling using Solexa-sequencing to identify the gene(s) underlying a recently mapped quantitative trait locus (QTL) for stem sugar concentration. In addition, we are developing a population of recombinant inbred lines to map QTL for juice volume, an important determinant of sugar yield. To identify novel genes affecting cell wall composition, we are using a sorghum TILLING population to identify mutants, including bmr mutants, with improved saccharification properties. The Brown midrib genes from the most promising mutants are being cloned using a candidate-gene approach. This approach recently resulted in the identification of Bmr6 as the gene encoding the lignin biosynthetic enzyme cinnamyl alcohol dehydrogenase. These combined approaches will enable the development of sorghums that offer maximum flexibility for the production of food, feed, fiber and fuel. Funding from the US Department of Energy for this project (DE-FG02-07ER64458) is gratefully acknowledged.