Introducing curcumin biosynthesis in Arabidopsis enhances lignocellulosic biomass processing

First author: Paula Oyarce; Affiliations: Ghent University (根特大学): Ghent, Belgium

Corresponding author: Wout Boerjan

Lignin is the main cause of lignocellulosic biomass recalcitrance to industrial enzymatic hydrolysis. By partially replacing the traditional lignin monomers by alternative ones, lignin extractability can be enhanced. To design a lignin that is easier to degrade under alkaline conditions, curcumin (diferuloylmethane) was produced in the model plant Arabidopsis thaliana via simultaneous expression of the turmeric (Curcuma longa) genes DIKETIDE-CoA SYNTHASE (DCS) and CURCUMIN SYNTHASE 2 (CURS2). The transgenic plants produced a plethora of curcumin- and phenylpentanoid-derived compounds with no negative impact on growth. Catalytic hydrogenolysis gave evidence that both curcumin and phenylpentanoids were incorporated into the lignifying cell wall, thereby significantly increasing saccharification efficiency after alkaline pretreatment of the transgenic lines by 14–24% as compared with the wild type. These results demonstrate that non-native monomers can be synthesized and incorporated into the lignin polymer in plants to enhance their biomass processing efficiency.

木质素是木质纤维素生物量对抗工业酶水解的主要抗力。通过人为替换部分的木质素单体，可以增强木质素的可获取性。为了设计出一种在碱性条件下更加容易降解的木质素，作者通过在模式植物拟南芥中同时表达姜黄的基因DCS和CURS2来合成姜黄素。在转基因植物中会产生过多的源自姜黄素及苯基戊烷的复合物，并且对于植株的生长没有负面影响。催化氢解试验证明姜黄素和苯基戊烷会被整合进木质化的细胞壁上，因此相比于野生型，使用碱性预处理的转基因植株糖化效率显著增加。本文的研究结果显示可以用合成的非天然单体整合进植物中的木质素聚合物以增强生物量的处理效率。

通讯：Wout Boerjan (http://www.vib.be/en/research/scientists/Pages/Wout-Boerjan-Lab.aspx)

研究方向：植物细胞壁。

doi: https://doi.org/10.1038/s41477-018-0350-3

Journal: Nature Plants

First Published: January 28, 2019