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Title: Field Evaluation of Transgenic Switchgrass Plants Overexpressing PvMYB4 for Reduced Biomass Recalcitrance

High biomass yields and minimal agronomic input requirements have made switchgrass, Panicum virgatum L., a leading candidate lignocellulosic bioenergy crop. Large-scale lignocellulosic biofuel production from such crops is limited by the difficulty to deconstruct cell walls into fermentable sugars: the recalcitrance problem. In this study, we assessed the field performance of switchgrass plants overexpressing the switchgrass MYB4 (PvMYB4) transcription factor gene. PvMYB4 transgenic switchgrass can have great lignin reduction, which commensurately increases sugar release and biofuel production. Our results over two growing seasons showed that one transgenic event (out of eight) had important gains in both biofuel (32% more) and biomass (63% more) at the end of the second growing season relative to non-transgenic controls. These gains represent a doubling of biofuel production per hectare, which is the highest gain reported from any field-grown modified feedstock. In contrast to this transgenic event, which had relatively low ectopic overexpression of the transgene, five of the eight transgenic events planted did not survive the first field winter. The dead plants were all high-overexpressing events that performed well in the earlier greenhouse studies. Disease susceptibility was not compromised in any transgenic events over the field experiments. These results demonstrate the power of modifyingmore » the expression of an endogenous transcription factor to improve biofuel and biomass simultaneously, and also highlight the importance of field studies for "sorting" transgenic events. In conclusion, further research is needed to develop strategies for fine-tuning temporal-spatial transgene expression in feedstocks to optimize desired phenotypes.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4] ;  [3] ;  [4] ;  [2] ;  [2] ;  [3] ;  [1]
  1. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC) and Biosciences Divison
  3. Univ. of North Texas, Denton, TX (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
  4. National Renewable Energy Lab. (NREL), Golden, CO (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
BioEnergy Research
Additional Journal Information:
Journal Volume: 8; Journal Issue: 3; Journal ID: ISSN 1939-1234
Publisher:
Springer
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; 59 BASIC BIOLOGICAL SCIENCES; MYB4; Field trial; Lignocellulosic biofuel; Switchgrass
OSTI Identifier:
1327634