Lignin synthesis and accumulation in barley cultivars differing in their resistance to lodging

Abstract

Since lignin greatly affects stem strength, which is an important agronomical trait, understanding the relationship between lodging resistance and lignin synthesis is important in barley breeding and selection processes. The aim of the study was to reveal the connection between physiological aspects of lignin synthesis and genetic background of barley cultivars with different lodging phenotype. Three barley cultivars Astor, Scarlett and Jaran were compared by measuring lignin, cellulose and total soluble phenolics content, phenylalanine ammonia-lyase activity (PAL) and expression of cinnamoyl-CoA reductase (CCR) and cinnamyl-alcohol dehydrogenase (CAD) in three lower internodes at flowering and grain filling stage. To assess their genetic background simple sequence repeats (SSR) markers, connected to lodging resistance and plant height, were analyzed. Compared to lodging susceptible cultivars Scarlett and Jaran, a lodging resistant cultivar Astor revealed different dynamics of lignin synthesis and deposition, showing higher PAL activity and total soluble phenolics content as well as higher expression of CCR and CAD genes in the second internode at grain filling stage. Analysis of SSR markers associated with quantitative trait loci (QTL) for lodging resistance revealed that Astor discriminates from Scarlett and Jaran by marker Bmag337 connected with elongation of the second internode. Lignification process is under a strong influence of genotype and environmental factors which determine lignin synthesis dynamics and deposition of lignin in the cell walls of barley.

Keywords: Cinnamoyl-CoA reductase; Cinnamyl-alcohol dehydrogenase; Hordeum vulgare; Internode; Lignin; Lodging resistance; Phenylalanine ammonia-lyase.