Ectopic lignification in primary cellulose‐deficient cell walls of maize cell suspension cultures

Abstract

Maize (Zea mays L.) suspension-cultured cells with up to 70% less cellulose were obtained by stepwise habituation to dichlobenil (DCB), a cellulose biosynthesis inhibitor. Cellulose deficiency was accompanied by marked changes in cell wall matrix polysaccharides and phenolics as revealed by Fourier transform infrared (FTIR) spectroscopy. Cell wall compositional analysis indicated that the cellulosedeficient cell walls showed an enhancement of highly branched and cross-linked arabinoxylans, as well as an increased content in ferulic acid, diferulates and p-coumaric acid, and the presence of a polymer that stained positive for phloroglucinol. In accordance with this, cellulose-deficient cell walls showed a fivefold increase in Klason-type lignin. Thioacidolysis/GC-MS analysis of cellulose-deficient cell walls indicated the presence of a lignin-like polymer with a Syringyl/Guaiacyl ratio of 1.45, which differed from the sensu stricto stress-related lignin that arose in response to shortterm DCB-treatments. Gene expression analysis of these cells indicated an overexpression of genes specific for the biosynthesis of monolignol units of lignin. A study of stress signaling pathways revealed an overexpression of some of the jasmonate signaling pathway genes, which might trigger ectopic lignification in response to cell wall integrity disruptions. In summary, the structural plasticity of primary cell walls is proven, since a lignification process is possible in response to cellulose impoverishment.Keywords: Cellulose; DCB; dichlobenil; ectopic lignin; maize Citation: M elida H, Largo-Gosens A, Novo-Uzal E, Santiago R, Pomar F, Garc ıa P, Garc ıa-Angulo P, Acebes JL, Alvarez J, Encina A (2015) Ectopic lignification in primary cellulose-deficient cell walls of maize cell suspension cultures.

Alleles Causing Resistance to Isoxaben and Flupoxam Highlight the Significance of Transmembrane Domains for CESA Protein Function

“…Ectopic lignin accumulation as a result of cellulose deficiency has been reported in elp1/pom1 (Zhong et al, 2002), eli1 (Cano-Delgado et al, 2003), the1 (Hematy et al, 2007) as well as CESA deficient mutants (Rogers et al, 2005; Steinwand et al, 2014; Mélida et al, 2015). In addition, ectopic lignification is associated with cellulose reductions caused by exposure to CBI application (Bischoff et al, 2009).…”

Monitoring of cell wall modifications during callogenesis in Stylosanthes guianensis (Fabaceae) under salt stress conditions

“…This observed increase of bands corresponding to polyphenols-assigned bands points to an initial lignification process. Recently, a set of works have established a consistent correlation between cellulose reduction and lignin or a lignin-like polymer enrichment, not only in secondary cell walls, but also in cell walls of cell cultures, indicating a contribution of this phenolic polymer in cell wall stiffening (Shen et al 2013;Mélida et al 2015). It is significant that the transcriptomic analysis of roots of Salicornia europaea L. under saline conditions showed a down-regulation of genes involved in cellulose synthesis, joined to an up-regulation of many of the genes implied in lignin biosynthesis (Fan et al 2013).…”

Class III peroxidases in cellulose deficient cultured maize cells during cell wall remodeling

“…One of these compounds, 2,6‐dichlorobenzonitrile (DCB), specifically inhibits polymerization of glucose into β‐1,4‐linked glucans (Montezinos and Delmer ), causing a reduction in the cell wall cellulose content. In the last few decades, several plant cell cultures have been habituated to DCB (Shedletzky et al , Encina et al , , García‐Angulo et al , , Mélida et al , ). The habituation process involves many metabolic modifications, depending on the type of the cell wall, the concentration of DCB, as well as the length of time that the cells are exposed to the inhibitor (Alonso‐Simón et al , de Castro et al , Mélida et al , Largo‐Gosens et al ).…”

“…By compositional analysis and structural characterization of the cell walls of DCB‐habituated cells, it has been demonstrated that maize cells have the capacity to cope with DCB through acquisition of a modified cell wall. In DCB‐habituated cells, cellulosic scaffold was partially replaced by a more extensive network of highly cross‐linked feruloylated arabinoxylans (Mélida et al , , , , , de Castro et al , , Largo‐Gosens et al ). Recently, it has been shown that DCB‐habituated maize cells incorporate to the cell walls lignin‐like polymers (Mélida et al ), which stiffens the structure further (Pomar et al , Kärkönen and Kuchitsu ).…”