Engineering secondary cell wall deposition in plants

30 September 2014 - By: Neal Stewart and Henry Daniell

Engineering secondary cell wall deposition in plants 

Model of secondary cell wall engineering
Model of secondary cell wall engineering


By Neal Stewart and Henry Daniell


Plant Biotechnology Journal 11: 325- 335, 2013 Fan Yang, Prajakta Mitra, Ling Zhang, Lina Prak, Yves Verhertbruggen, Jin-Sun Kim, Lan Sun, Kejian Zheng, Kexuan Tang, Manfred Auer, Henrik V. Scheller and Dominique Loque http://onlinelibrary.wiley.com/ doi/10.1111/pbi.12016/abstract 

The authors describe engineeringof secondary cell wall deposition in plants, which is the most cited article in the Plant Biotechnology Journal published in 2013. 

The replacement of fossil fuels by sustainable bioenergy is a long term goal that is coming to fruition. Ligno-cellulosic biomass historically used for animal feed or burning is now developed as a source of sugar for fermentation into biofuels. This article illustrates how synthetic biology can be used in a powerful way to alter plant cell wall construction to facilitate increased saccharification. 

Lignin is mostly responsible for biomass recalcitrance to enzymatic hydrolysis. Therefore, this team reduced lignin using a very specific gene expression strategy that left cell walls in vascular tissue intact. Therefore plants would retain their strength and structure in the field. 

The important feature of the plant engineering was the selection of key promoters and transcription factors affecting lignin biosynthesis, while boosting polysaccharide production. The promoter of a key lignin gene (C4H) was replaced by the vessel-specific promoter of the transcription factor VND6. This rewired lignin biosynthesis specifically for vessel formation, while disconnecting C4H expression from the fiber regulatory network. 

The multiple constructs were designed to create an artificial positive feedback loop that increased sugars in cell walls relative to lignin. The researchers performed the modification to Arabidopsis, the most commonly-used plant model. When this strategy is implemented into bioenergy feed stocks, increased biofuel yield would be expected. 

 

 
Category: Plant Biology
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