Lignified cell walls are widely considered to be key innovations in the evolution of terrestrial plants from aquatic ancestors some 475 million years ago. Lignins, complex aromatic heteropolymers, stiffen and fortify secondary cell walls within xylem tissues, creating a dense matrix that binds cellulose microfibrils and crosslinks other wall components, thereby preventing the collapse of conduc...

Many land plants evolved tall and sturdy growth habits due to specialized cells with thick lignified cell walls: tracheary elements that function in water transport and fibers that function in structural support. The objective of this study was to define how and when diverse cell populations contribute lignin precursors, monolignols, to secondary cell walls during lignification of the Arabidops...

The physicochemical properties of plant fibres are determined by the fibre morphology and structural features of the cell wall, which is composed of three main layers that differ in chemical composition and architecture. This composition and hierarchical structure are responsible for many of the mechanical properties that are desirable for industrial applications. As interactions between the li...

Cereal Chem. 85(l):14-18 Bile acid adsorption by lignified dietary fiber in the human intestine is proposed as a mechanism for lowering blood cholesterol level and reducing colon cancer risk. In this study, we investigated how the concentration and composition of lignin in fiber influences the in vitro adsorption of primary bile acids (glycocholate, taurocholate, and glycochenodeoxycholate) and...

To generate a forage crop with increased biomass density that retains forage quality, we have genetically transformed lines of alfalfa (Medicago sativa L.) expressing antisense constructs targeting two different lignin pathway biosynthetic genes with a construct for down-regulation of a WRKY family transcription factor that acts as a repressor of secondary cell wall formation in pith tissues. P...

Lignin and cellulose represent the two main components of plant secondary walls and the most abundant polymers on Earth. Quantitatively one of the principal products of the phenylpropanoid pathway, lignin confers high mechanical strength and hydrophobicity to plant walls, thus enabling erect growth and high-pressure water transport in the vessels. Lignin is characterized by a high natural heter...

Corn (Zea mays L.) fiber, which is the seed coat and residual endosperm left after grain processing, is a low-value residue that contains carbohydrates and aromatic compounds that could provide value-added coproducts. Treatment of corn fiber with NaOH and assessment by gas chromatography indicated a prevalence of ferulic acid, with about 90% ester-linked in the cell walls. p-coumaric acid was m...

In a biorefinery context it is an advantage to fractionate and extract different wood components in a relatively pure form. However, one major obstacle for efficient extraction of wood polymers (lignin, polysaccharides etc.) is the covalent lignin-polysaccharide networks present in lignified cell walls. Enzymatic catalysis might be a useful tool for a controlled degradation of these networks, t...

In plants, secondary wall thickenings play important roles in various biological processes, although the factors regulating these processes remain to be characterized. We show that expression of chimeric repressors derived from NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1) and NST2 in Arabidopsis thaliana resulted in an anther dehiscence defect due to loss of secondary wall thickening ...

BACKGROUND Lignin and hemicelluloses are the major components limiting enzyme infiltration into cell walls. Determination of the topochemical distribution of lignin and aromatics in sugar cane might provide important data on the recalcitrance of specific cells. We used cellular ultraviolet (UV) microspectrophotometry (UMSP) to topochemically detect lignin and hydroxycinnamic acids in individual...