April 18, 2016
Lignification And Recalcitrance Affected By Age And Season In Field-Grown COMT-Downregulated Switchgrass
Previous field and greenhouse studies have shown that COMT-downregulation in switchgrass decreases lignin content and reduces the S/G ratio, thereby lowering recalcitrance and improving ethanol yields. Trends in lignification and recalcitrance differ between growing seasons. Third-year results showed an increase in lignification and decrease in sugar release across the season. S/G ratios increased over time in non-transgenic control lines, but were relatively stable in COMT-downregulated lines. During early (elongation) growth stages, cell wall chemistry was similar between COMT-downregulated and control lines. After reaching the reproductive growth stage in July, COMT-downregulated lines maintained reduced lignin content, decreased S/G ratios, and improved sugar release through December. No differences in rust susceptibility were observed.