Role of Plant Laccases in Lignin Polymerization

Abstract

Laccases are ubiquitous oxidases present in animals, plants, bacteria, and fungi. In plant species, they occur as large multigenic families. The involvement of peroxidases in lignification is supported by a wealth of literature data. In contrast, the role of laccases in this major plant process is less firmly established. The large number of plant laccases, which argues for a variety of functions in plant development, makes the identification of lignin-specific laccases a challenge. However, in the past decade, the development of new genetic technologies and tools has played a central role towards resolving this issue. In addition, the plant model, Arabidopsis thaliana, has recently provided novel insights about the occurrence of laccases involved in stem lignification. Information about lignin-related laccases is also available from other species, such as poplar, or other organs and tissues, such as seed coats. This review brings a short and cutting edge survey of laccases and lignification.

Studying Secondary Growth and Bast Fiber Development: The Hemp Hypocotyl Peeks behind the Wall

“…Such a signal peptide was also detected in two (AtLAC5 and AtLAC13 hemp orthologs) out of the five laccase isoforms (see Results section), which may be involved in lignin polymerisation in Arabidopsis . Indeed, AtLAC4, AtLAC12, and AtLAC17 have a putative role in stem lignification in Arabidopsis (Berthet et al, 2012). AtLAC5 and AtLAC13 may be secreted because of the presence of a signal peptide (Turlapati et al, 2011), but their involvement in lignification has not yet been proven; they cluster together, while AtLAC4, AtLAC12, and AtLAC17 are in three separate clusters according to Turlapati et al (2011).…”

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

“…They perform several functions in plant development, rendering the identification of lignin-specific laccases difficult. [125] Nevertheless,d ownregulation of various specific laccases has resulted in significantly altered lignification, implying that they certainly play ar ole in lignification. [61,[129][130] Further investigation is also required to identify individual (or groups of) peroxidases involved in lignin biosynthesis.…”

“…[41] Thep recise roles of laccases/peroxidases in the final polymerisation of lignin monomers are at present only partially understood. [41,61,64,70,[124][125][126][127][128] Laccases, though capable of inducing the radical reactions for the polymerisation of lignin subunits,are many and varied. They perform several functions in plant development, rendering the identification of lignin-specific laccases difficult.…”

A cerato-platanin-like protein HaCPL2 from Heterobasidion annosum sensu stricto induces cell death in Nicotiana tabacum and Pinus sylvestris

“…This branch of transcriptional regulation is known to be preferentially induced by necrotrophic pathogens (Lorenzo et al, 2004). Furthermore, TPS, PME and LAC, encoding for enzymes implicated in biosynthesis of terpenes, cell wall modification or lignification, are induced (Micheli, 2001;Tholl, 2006;Berthet et al, 2012). PAL1, NPR1 (a positive regulator of SA signal transduction) or LURP1 (required for full basal defenses against pathogens) were not differentially expressed, so no evidence was found for induction of SA-dependent defenses or the phenylpropanoid pathway (Asai et al, 2000;Knoth and Eulgem, 2008).…”