Transcriptome Analysis of Cell Wall Related Genes in High Biomass Energy Sorghum

The increasing cost of energy and finite oil and gas reserves has created a worldwide need to improve energy production and specifically biofuels from biomass. The low-input requirements, drought tolerance, and high biomass yield potential of sorghum (Sorghum bicolorL. Moench) make this species uniquely suited as a bioenergy crop. Since the efficiency of biomass conversion to fermentable sugars depends to a large extent on cell wall composition, characterization of the sorghum secondary cell wall biosynthesis gene regulatory network will be beneficial for high biomass energy sorghum improvement.

RNA-Seq analysis was used to characterize cell wall biosynthesis gene regulatory networks in two high biomass energy genotypes and one grain sorghum genotype. Three internodes along the stem from each genotype were collected in triplicate at 60 days after planting during the phase of linear stem elongation. RNA was extracted from each internode pool and used for TruSeq RNA template library production. The bar-coded libraries were pooled and sequenced on an Illumina HiSeq2000 using a 70bp paired-end strategy. Differential gene and transcript expression analysis between basal non-elongating stem segments that are laying down secondary cell walls, elongating internodes where rapid cell wall biosynthesis is occurring, and upper internodes that are enriched in primary cell walls was conducted using TopHat and Cufflinks. Analysis of differentially expressed cell wall biosynthesis genes between the different stem internodes as well as between the energy and grain sorghum genotypes will be presented.