Science2014-06-11 12:42 PM

科学家设计出一种方法改善植物木质素可被消化的能力 Monolignol Ferulate Transferase Introduces Chemically Labile Linkages into the Lignin Backbone


论文摘要 

因为极其渴望能够更容易地将木质素进行分解,科学家们已经尝试了各种化学招数,而现在一项新的研究报告了一个关于这一领域的关键性进展。木质素可保持植物处于直立状态,但它也会使得植物难以在诸如生物燃料的生产或消化苜蓿等工业生产过程中得到分解;而苜蓿是牛的一种重要的饲料作物。

提高木质素的可被消化的能力将在诸多过程中降低所需的能量输入;在全球范围内,对改善该过程感兴趣的研究人员一直对木质素感到困惑,他们尝试了无数的方法来生产具有较弱、更容易被消化细胞壁(内含木质素)的植物。

先前的研究工作提示,木质素被组装的自然过程,即从一个被称作单体的单一分子池装配成为一个较为复杂的多聚物链的过程可通过设计从而并入那些新的并非木质素天然所有的单体。这种方法激起了人们相当大的兴趣,即将木质素主干与可能增加其降解能力的单体浸在一起。被称作阿魏酸盐的酶显得尤其有前途,尽管只是在体外。

现在,一个由Curtis Wilkerson领导的科学家团队已经在体内用阿魏酸盐第一次获得了真正的成功。为了获得在活体植物木质素内的阿魏酸盐复合物,他们必须先确定它已被添加到了木质素的生物合成池。

首先,他们发现了编码阿魏酸盐酶的基因。接着,他们将其在白杨树的形成木质素的组织中进行表达。应用木质素结构分析,他们观察到,以这种方式设计的白杨树样本能够产生新的单体,将这些单体输出到细胞壁,并最终将它们吸收进木质素的主干内。

在温室条件下,由此产生的白杨树没有在生长习性上显出任何的不同,但它们的木质素却显示出了改善了的可被消化的能力。设计出能在组装木质素时使用这种化合物的植物可能是一条用以生产“专门进行解构”的植物的新途径。

Abstract 

Redesigning lignin, the aromatic polymer fortifying Plant Cell walls, to be more amenable to chemical depolymerization can lower the energy required for industrial processing. We have engineered poplar trees to introduce ester linkages into the lignin polymer backbone by augmenting the monomer pool with monolignol ferulate conjugates. Herein, we describe the isolation of a transferase gene capable of forming these conjugates and its xylem-specific introduction into poplar. Enzyme kinetics, in planta expression, lignin structural analysis, and improved cell wall digestibility after mild alkaline pretreatment demonstrate that these trees produce the monolignol ferulate conjugates, export them to the wall, and use them during lignification. Tailoring plants to use such conjugates during cell wall biosynthesis is a promising way to produce plants that are designed for deconstruction.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

Science

Science Magazine

0 Following 18 Fans 0 Projects 236 Articles

SIMILAR ARTICLES

AbstractThe conservation of sleep across all animal species suggests that sleep serves a vital function. We here report that sleep has a critical funct

Read More

Introduction Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but

Read More

IntroductionInitiation of protein synthesis is a key step in the control of gene expression. In eukaryotes, initiation is a highly complex process that

Read More

Abstract For decades, social psychological theories have posited that the automatic processes captured by implicit measures have implications for soci

Read More

论文摘要动物界最复杂的眼睛可以在物种口足类甲壳动物(濑尿虾)中找到,其中一些有12种不同类型的光感受器,每种各取样较窄的一组波长,范围包含了深紫外光到远红光(300到720纳米)。在功能上,这种彩色复杂性被视作是谜。当3种或4种色彩通道对色彩辨认来说已经足够时,为何要使用12种色彩通道?对口足类动物行

Read More

论文摘要 首先,在一篇“评论”文章中,Thomas Piketty 和 Emmanuel Saez用“世界顶级收入数据库(WTID)”来比较这两个数值多年来是如何在欧洲和美国演变的;WTID包括了一个世纪之久的有关全球收入的数据以及2个世纪之久的有关个人财富的数据。据研究人员披露,在20世纪之交的时候

Read More

IntroductionCensorship has a long history in China, extending from the efforts of Emperor Qin to burn Confucian texts in the third century BCE to the c

Read More

Many animals, on air, water, or land, navigate in three-dimensional (3D) environments, yet it remains unclear how brain circuits encode the animal's 3D

Read More

Many animals, on air, water, or land, navigate in three-dimensional (3D) environments, yet it remains unclear how brain circuits encode the animal's 3D

Read More

Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7

Read More