Plant cell wall lignification and monolignol metabolism

Abstract

Plants are built of various specialized cell types that differ in their cell wall composition and structure. The cell walls of certain tissues (xylem, sclerenchyma) are characterized by the presence of the heterogeneous lignin polymer that plays an essential role in their physiology. This phenolic polymer is composed of different monomeric units – the monolignols – that are linked together by several covalent bonds. Numerous studies have shown that monolignol biosynthesis and polymerization to form lignin are tightly controlled in different cell types and tissues. However, our understanding of the genetic control of monolignol transport and polymerization remains incomplete, despite some recent promising results. This situation is made more complex since we know that monolignols or related compounds are sometimes produced in non-lignified tissues. In this review, we focus on some key steps of monolignol metabolism including polymerization, transport, and compartmentation. As well as being of fundamental interest, the quantity of lignin and its nature are also known to have a negative effect on the industrial processing of plant lignocellulose biomass. A more complete view of monolignol metabolism and the relationship that exists between lignin and other monolignol-derived compounds thereby appears essential if we wish to improve biomass quality.

Involvement of peroxidases in structural changes of barley stem

“…These results also coincided with analyses of peroxidase activity using guaiacol as a substrate, which showed that activity was the highest in the first, more lignified internode, and significantly decreased in the second and third internode ( Figure 5). The lignification of the cell wall is a part of development and differentiation processes of distinct cell types in plants ( Wang et al 2013). In crops, lignin is important for stem strength enabling mechanical support for the spikelet, especially during grain filling.…”

Microbial β-Glucosidases: Screening, Characterization, Cloning and Applications

“…Probably the most studied one is the lysosomal acid β-glucosidase (3.2.1.45) which hydrolyzes β-glucosyl linkage of glucosylceramide releasing ceramide and involved in Gaucher's disease pathogenesis [17]. In plants, β-glucosidases are involved in many physiological processes such as cell wall lignification [18], seed germination [19], phytohormones activation [20], indole alkaloids biosynthesis [21], cyanogenesis [22], and defense against biotic stresses by releasing of toxic…”

Lignan accumulation in two-phase cultures of Taxus x media hairy roots

“…Their biosynthesis involves the shikimate pathway providing l-phenylalanine and required multiple enzymatic steps (Vogt 2010;Umezawa 2010;Thoge et al 2013;Wang et al 2013). This pathway originated with a chiral coniferyl alcohol and two units of it are enantioselectively coupled by dirigent protein resulting with pinoresinol.…”