Plant biomass is a major source of renewable energy. Two of the prime challenges in bioenergy research are to improve the yield of biomass crops and to make the stored carbon more available for conversion into liquid biofuel.
The most productive biomass crops are fast-growing trees and grasses, which store carbon in their leaves and stems as lignocellulose. This material is hard to convert into liquid biofuel because it is extremely resistant to degradation. In contrast, vegetable oils from seeds can easily be made into biodiesel. This has led some scientists to suggest that biomass crops should be made to store carbon as oil. Radical reprogramming of cell metabolism is required to achieve this goal because oil is normally only present in trace amounts in plant vegetative tissues.
Scientists at Rothamsted Research have used synthetic biology principles and techniques to identify a combination of genes that increases the oil content of vegetative tissues by at least 400-fold in the model plant Arabidopsis. A key to achieving such high levels of oil is the discovery that oil breakdown severely limits oil accumulation in these tissues and can be switched off by removing a single gene called SUGAR-DEPENDENT1. The study is published in the journal Plant Physiology and was supported by strategic funding from the BBSRC.
Dr Peter Eastmond at Rothamsted Research, lead the study and said "The findings are very exciting because they show that plant vegetative tissues such as leaves, stems or roots can be made to accumulate quite substantial quantities of oil that are comparable to those found in seeds. The metabolic rewiring require to achieve this is rather complex and significant challenges remain to refine the technology, and to translate it into crops. However, our work, and that of others, suggests that it is feasible".
Notes to editors
The SUGAR-DEPENDENT1 lipase limits triacylglycerol accumulation in vegetative tissues of Arabidopsis. Plant Physiol http://dx.doi.org/doi:10.1104/pp.113.219840