Methyl jasmonate and salicylic acid are able to modify cell wall but only salicylic acid alters biomass digestibility in the model grass Brachypodium distachyon

Abstract

In addition to playing a key role in the response to environmental changes, cell walls are also considered as a valuable feedstock for cellulosic ethanol. Here we explored the effects of the stress-response hormones, salicylic acid and methyl jasmonate, on cell wall biosynthesis and biomass digestibility in Brachypodium distachyon, a species recently considered as a suitable model for biomass conversion. We found that in response to salicylic acid or methyl jasmonate treatment, plant growth was reduced coupled with significant changes in cell wall composition. Cellulose content increased in response to methyl jasmonate whereas a reduction in lignin content was found after salicylic acid application. Moreover, hemicellulose composition was altered and increases in caffeic acid, ferulic acid and p-coumaric acid content were detected in response to both treatments. The hormonal profile and the expression pattern of genes involved in cell wall biosynthesis were also modified. Biomass digestibility was reduced in leaf tissue after salicylic acid treatment and was negatively correlated with ferulic acid and p-coumaric acid content. The results obtained here aid in our understanding of cell wall dynamics in response to stress and will enable the development of new strategies to improve cell wall digestibility in bioenergy feedstock.

Response of cell-wall composition and RNA-seq transcriptome to methyl-jasmonate in Brachypodium distachyon callus

“…We hypothesised that this increased expression would result in increased abundance of AX-FA and/or AX- p CA in cell walls. Recently, it has been shown that treatment with MeJA does induce small, but significantly increases in cell-wall FA and p CA in leaves of Brachypodium distachyon (Brachypodium) (Napoleao et al 2017) and we have similar findings (L. S. Hyde, unpublished). However, leaves contain a complex mix of primary and secondary cell walls that contain both Ara f - p CA and lignin- p CA.…”

“…We found some changes in lignin amount, but these were small and inconsistent (Figs. 4b; 5f); JA treatment does not always induce lignin increases in plants (Napoleao et al 2017), although monolignol synthesis was increased in cell cultures (Pauwels et al 2008). No significant changes in polysaccharide composition of the cell walls during the 8-day time course were induced by 50-µM MeJA except for a decrease in hemicellulosic glucose (Fig.…”

“…Peroxidase expression and activity is also known to be drastically increased by JA (Almagro et al 2009). These cell-wall-related changes in response to JA do not necessarily result in detectable increases in total lignin, but are rather associated with a cessation of growth (Napoleao et al 2017), including decreased cell expansion which may be due to increased cross-linking of primary cell walls.…”

Leaf heteroblasty in Passiflora edulis as revealed by metabolic profiling and expression analyses of the microRNAs miR156 and miR172

“…The extraction procedure was repeated on the resulting pellet, and the supernatants were collected. The Agilent 6430 Triple Quadrupole LC/MS system (Agilent Technologies, Waldbronn, Germany) was used for identification and quantification, according to Napoleão et al (2017).…”

Heterologous microProtein expression identifies LITTLE NINJA, a dominant regulator of jasmonic acid signaling

“…Total RNAs were also prepared from leaves of 4-wk-old Brachypodium plants treated by methyl jasmonate for analysis of gene expression in response to JA. For the MeJA application, we followed a treatment regime published earlier ( 42 ). In brief, three independent plant lines with 12 individuals each were treated after 4 wk by spraying with methyl jasmonate (100 μM in 0.15% Tween) or a mock solution (0.15% Tween).…”