title: Sugarcane transgenics expressing MYB transcription factors show improved glucose release.
abstract: BACKGROUND
  Sugarcane, a tropical C4 perennial crop, is capable of producing 30-100 tons or more of biomass per hectare annually. The lignocellulosic residue remaining after sugar extraction is currently underutilized and can provide a significant source of biomass for the production of second-generation bioethanol.
  
  
  RESULTS
  MYB31 and MYB42 were cloned from maize and expressed in sugarcane with and without the UTR sequences. The cloned sequences were 98 and 99 % identical to the published nucleotide sequences. The inclusion of the UTR sequences did not affect any of the parameters tested. There was little difference in plant height and the number of internodes of the MYB-overexpressing sugarcane plants when compared with controls. MYB transgene expression determined by qPCR exhibited continued expression in young and maturing internodes. MYB31 downregulated more genes within the lignin biosynthetic pathway than MYB42. MYB31 and MYB42 expression resulted in decreased lignin content in some lines. All MYB42 plants further analyzed showed significant increases in glucose release by enzymatic hydrolysis in 72 h, whereas only two MYB31 plants released more glucose than control plants. This correlated directly with a significant decrease in acid-insoluble lignin. Soluble sucrose content of the MYB42 transgenic plants did not vary compared to control plants.
  
  
  CONCLUSIONS
  This study demonstrates the use of MYB transcription factors to improve the production of bioethanol from sugarcane bagasse remaining after sugar extraction.
authors.affiliation: Department of Biology, Syracuse University, Syracuse, NY 13244 USA.
authors.forename: Charleson R
authors.initials: CR
authors.lastname: Poovaiah
authors.affiliation: Center for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD 4000 Australia.
authors.forename: William P
authors.initials: WP
authors.lastname: Bewg
authors.affiliation: US Department of Energy, Great Lakes Bioenergy Research Center (GLBRC), Wisconsin Energy Institute, University of Wisconsin, Madison, WI 53726 USA ; Department of Biological System Engineering, University of Wisconsin, Madison, WI USA.
authors.forename: Wu
authors.initials: W
authors.lastname: Lan
authors.affiliation: US Department of Energy, Great Lakes Bioenergy Research Center (GLBRC), Wisconsin Energy Institute, University of Wisconsin, Madison, WI 53726 USA ; Department of Biochemistry, University of Wisconsin, Madison, WI 53726 USA.
authors.forename: John
authors.initials: J
authors.lastname: Ralph
authors.affiliation: Department of Biology, Syracuse University, Syracuse, NY 13244 USA.
authors.forename: Heather D
authors.identifier: 0000-0002-4923-601X
authors.initials: HD
authors.lastname: Coleman
keywords: Bioethanol; Biofuel; Lignin modification; Sugarcane bagasse