Towards oilcane: Engineering hyperaccumulation of triacylglycerol into sugarcane stems

Saroj Parajuli, Baskaran Kannan, Ratna Karan, Georgina Sanahuja, Hui Liu, Eva Garcia-Ruiz, Deepak Kumar, Vijay Singh, Huimin Zhao, Stephen Long, John Shanklin, Fredy Altpeter

Research output: Contribution to journalArticle

Abstract

Metabolic engineering to divert carbon flux from sucrose to oil in high biomass crop like sugarcane is an emerging strategy to boost lipid yields per hectare for biodiesel production. Sugarcane stems comprise more than 70% of the crops' biomass and can accumulate sucrose in excess of 20% of their extracted juice. The energy content of oils in the form of triacylglycerol (TAG) is more than twofold that of carbohydrates. Here, we report a step change in TAG accumulation in sugarcane stem tissues achieving an average of 4.3% of their dry weight (DW) in replicated greenhouse experiments by multigene engineering. The metabolic engineering included constitutive co-expression of wrinkled1; diacylglycerol acyltransferase1-2; cysteine-oleosin; and ribonucleic acid interference-suppression of sugar-dependent1. The TAG content in leaf tissue was also elevated by more than 400-fold compared to non-engineered sugarcane to an average of 8.0% of the DW and the amount of total fatty acids reached about 13% of the DW. With increasing TAG accumulation an increase of 18:1 unsaturated fatty acids was observed at the expense of 16:0 and 18:0 saturated fatty acids. Total biomass accumulation, soluble lignin, Brix and juice content were significantly reduced in the TAG hyperaccumulating sugarcane lines. Overcoming this yield drag by engineering lipid accumulation into late stem development will be critical to exceed lipid yields of current oilseed crops.

Original languageEnglish (US)
Pages (from-to)476-490
Number of pages15
JournalGCB Bioenergy
Volume12
Issue number7
DOIs
StatePublished - Jul 1 2020

Keywords

  • RNAi
  • biofuel
  • fatty acids
  • metabolic engineering
  • sugarcane
  • triacylglycerol

ASJC Scopus subject areas

  • Forestry
  • Renewable Energy, Sustainability and the Environment
  • Agronomy and Crop Science
  • Waste Management and Disposal

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  • Cite this

    Parajuli, S., Kannan, B., Karan, R., Sanahuja, G., Liu, H., Garcia-Ruiz, E., Kumar, D., Singh, V., Zhao, H., Long, S., Shanklin, J., & Altpeter, F. (2020). Towards oilcane: Engineering hyperaccumulation of triacylglycerol into sugarcane stems. GCB Bioenergy, 12(7), 476-490. https://doi.org/10.1111/gcbb.12684