Development of vegetative oil sorghum: From lab-to-field

Area of Science:

• Biotechnology
• Plant Science
• Biomass Energy

Background:

• Current triacylglycerol (TAG) sources like oil palm and oilseed crops are insufficient to meet renewable fuel demands.
• Vegetative tissues of biomass crops typically accumulate TAG only transiently, limiting their potential for biofuel production.

Purpose of the Study:

• To engineer sorghum, a resilient biomass crop, for enhanced TAG accumulation in vegetative tissues (leaves and stems).
• To evaluate the efficacy of a 'push-pull-protect' genetic strategy for maximizing oil content in sorghum.

Main Methods:

• Utilized grain (TX430) and sweet (Ramada) sorghum genotypes.
• Implemented a five-gene 'push-pull-protect' strategy involving sorghum WRINKLED1, Cuphea DGAT, and modified sesame oleosin.
• Conducted greenhouse and field trials, coupled with transcriptomic and fluxomic analyses.

Main Results:

• Engineered sorghum accumulated TAG up to 2.5% DW in leaves and 2.0% DW in stems in greenhouse conditions (36-49 fold increase vs. WT).
• Field trials showed TAG accumulation of 5.5% DW in leaves and 3.5% DW in stems (58-78 fold increase vs. WT).
• Identified potential bottlenecks in TAG biosynthesis pathways through systems biology analyses.

Conclusions:

• Demonstrated successful engineering of high vegetative oil accumulation in sorghum using a lab-to-field approach.
• Highlighted the potential of high-TAG sorghum as a sustainable feedstock for renewable diesel and SAF.
• Systems biology insights provide a foundation for further optimization of oil production in biomass crops.