BRC Science Highlight Suppression of the lignin biosynthetic gene CCR1 results in decreased lignin recalcitrance and increased digestibility Objective In this study, we examined features of a lignin biosynthetic mutant in maize that we hypothesized could result in an increase in the levels of more readily cleavable ester bonds in the lignin backbone (“zip-lignin”). Approach Analyze a maize ccr1 insertion mutant for CCR1 transcript level, plant growth and development, total lignin content, monolignol ferulate (zip-lignin) levels, and release of glucose and xylose. Results/Impacts Maize ccr1 mutant plants, in comparison to wild-type plants, have reduced total lignin levels, normal growth and development, increased zip-lignin levels, and increased digestibility as measured by glucose and xylose release. The increased monolignol ferulate incorporation into lignins (i.e., higher zip-lignin levels) in ccr1 mutant maize plants suggests that downregulation of CCR may be a viable biosynthetic strategy for increasing zip levels in other biofuel crops as well. Notes: text Title again: Text 1-2 sentence summary? An abbreviated version of the lignin biosynthetic pathways highlighting the effects of the ccr1 mutation. The mutated CCR1 gene results in reduced CCR1 transcript, and presumably less CCR1 enzyme, and a pool of feruloyl-CoA (FA reservoir). The conjugates formed between the monolignols and feruloyl-CoA by ZmFMT are incorporated into the lignin polymer, generating a zip-lignin in which the ester bonds in the backbone are readily cleaved by base. Smith, R. A. et al. “Suppression of CINNAMOYL-CoA REDUCTASE increases the level of monolignol ferulates incorporated into maize lignins.” Biotechnology for Biofuels 10, 109 (2017) [DOI: 10.1186/s13068-017-0793-1]. GLBRC May 2017