title: Non-structural carbohydrate profiles and ratios between soluble sugars and starch serve as indicators of productivity for a bioenergy grass.
abstract: There is a pressing need to find a sustainable alternative to fossil fuels that will not compromise food security or require extensive use of agrochemicals. Miscanthus is a perennial energy grass predominantly used for combustion but with the current advancement of ligno-cellulosic fermentation technologies there is an interest in using Miscanthus for bioethanol production. Currently, the only commercially grown genotype of Miscanthus is M.× giganteus; a high yielding, interspecific hybrid of M. sacchariflorus and M. sinensis. As M.× giganteus is a sterile triploid, it cannot be used as a parent so Miscanthus breeding effort is focused on producing new interspecific varieties that out-perform M.× giganteus. The carbohydrate profiles of four genotypes of Miscanthus, including M. sacchariflorus (Sac-5), M.× giganteus (Gig-311), M. sinensis (Sin-11) and M. sinensis (Goliath), were characterized at replicated field sites in Aberystwyth, West Wales and Harpenden, south-east England. Our hypothesis was that a distinctive carbohydrate profile underlies enhanced biomass accumulation. Biomass accumulation is greatest when day-lengths and solar intensity are highest; so, observations were made in the middle of UK summer (July) for 2 years. Gig-311 had a greater abundance of fructose in its stems at both sites, and both Gig-311 and Sac-5 had low abundance of starch. At both sites, the highest yielding genotype was Gig-311 and Sac-5 was also high yielding at Harpenden, but performed comparatively poorly at Aberystwyth. At both sites Gig-311 had a distinctly high concentration of fructose, low starch and a high ratio of soluble sugars: starch, and at Harpenden, Sac-5 was similar. We conclude that the abundance of starch and fructose and a greater partitioning of soluble sugars, relative to starch, are candidate biomarkers of productivity in Miscanthus.
authors.affiliation: Institute of Biological Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Ceredigion SY23 3EE, UK sap@aber.ac.uk.
authors.forename: Sarah Jane
authors.initials: SJ
authors.lastname: Purdy
authors.affiliation: Institute of Biological Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Ceredigion SY23 3EE, UK.
authors.forename: Anne Louise
authors.initials: AL
authors.lastname: Maddison
authors.affiliation: Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Cunniff
authors.affiliation: Institute of Biological Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Ceredigion SY23 3EE, UK.
authors.forename: Iain
authors.initials: I
authors.lastname: Donnison
authors.affiliation: Institute of Biological Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Ceredigion SY23 3EE, UK.
authors.forename: John
authors.initials: J
authors.lastname: Clifton-Brown
keywords: Bioenergy; Miscanthus; biomarkers; carbohydrate partitioning; carbohydrates; metabolism
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