Range of cell-wall alterations enhance saccharification in Brachypodium distachyon mutants

TY - JOUR

T1 - Range of cell-wall alterations enhance saccharification in Brachypodium distachyon mutants

AU - Marriott, Poppy E

AU - Sibout, Richard

AU - Lapierre, Catherine

AU - Fangel, Jonatan Ulrik

AU - Willats, William George Tycho

AU - Hofte, Herman

AU - Gómez, Leonardo D.

AU - McQueen-Mason, Simon J.

PY - 2014/10/7

Y1 - 2014/10/7

N2 - Lignocellulosic plant biomass is an attractive feedstock for the production of sustainable biofuels, but the commercialization of such products is hampered by the high costs of processing this material into fermentable sugars (saccharification). One approach to lowering these costs is to produce crops with cell walls that are more susceptible to hydrolysis to reduce preprocessing and enzyme inputs. To deepen our understanding of the molecular genetic basis of lignocellulose recalcitrance, we have screened a mutagenized population of the model grass Brachypodium distachyon for improved saccharification with an industrial polysaccharide-degrading enzyme mixture. From an initial screen of 2,400 M2 plants, we selected 12 lines that showed heritable improvements in saccharification, mostly with no significant reduction in plant size or stem strength. Characterization of these putative mutants revealed a variety of alterations in cell-wall components. We have mapped the underlying genetic lesions responsible for increased saccharification using a deep sequencing approach, and here we report the mapping of one of the causal mutations to a narrow region in chromosome 2. The most likely candidate gene in this region encodes a GT61 glycosyltransferase, which has been implicated in arabinoxylan substitution. Our work shows that forward genetic screening provides a powerful route to identify factors that impact on lignocellulose digestibility, with implications for improving feedstock for cellulosic biofuel production.

AB - Lignocellulosic plant biomass is an attractive feedstock for the production of sustainable biofuels, but the commercialization of such products is hampered by the high costs of processing this material into fermentable sugars (saccharification). One approach to lowering these costs is to produce crops with cell walls that are more susceptible to hydrolysis to reduce preprocessing and enzyme inputs. To deepen our understanding of the molecular genetic basis of lignocellulose recalcitrance, we have screened a mutagenized population of the model grass Brachypodium distachyon for improved saccharification with an industrial polysaccharide-degrading enzyme mixture. From an initial screen of 2,400 M2 plants, we selected 12 lines that showed heritable improvements in saccharification, mostly with no significant reduction in plant size or stem strength. Characterization of these putative mutants revealed a variety of alterations in cell-wall components. We have mapped the underlying genetic lesions responsible for increased saccharification using a deep sequencing approach, and here we report the mapping of one of the causal mutations to a narrow region in chromosome 2. The most likely candidate gene in this region encodes a GT61 glycosyltransferase, which has been implicated in arabinoxylan substitution. Our work shows that forward genetic screening provides a powerful route to identify factors that impact on lignocellulose digestibility, with implications for improving feedstock for cellulosic biofuel production.

U2 - 10.1073/pnas.1414020111

DO - 10.1073/pnas.1414020111

M3 - Journal article

C2 - 25246540

SN - 0027-8424

VL - 111

SP - 14601

EP - 14606

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 40

ER -