TY - JOUR
T1 - Cell wall modifications triggered by the down-regulation of Coumarate 3-hydroxylase-1 in maize
AU - Fornalé, Silvia
AU - Rencoret, Jorge
AU - Garcia-Calvo, Laura
AU - Capellades, Montserrat
AU - Encina, Antonio
AU - Santiago, Rogelio
AU - Rigau, Joan
AU - Gutiérrez, Ana
AU - del Río, José Carlos
AU - Caparros-Ruiz, David
PY - 2015/7/1
Y1 - 2015/7/1
N2 - © 2015 Elsevier Ireland Ltd. Coumarate 3-hydroxylase (C3H) catalyzes a key step of the synthesis of the two main lignin subunits, guaiacyl (G) and syringyl (S) in dicotyledonous species. As no functional data are available in regards to this enzyme in monocotyledonous species, we generated C3H1 knock-down maize plants. The results obtained indicate that C3H1 participates in lignin biosynthesis as its down-regulation redirects the phenylpropanoid flux: as a result, increased amounts of p-hydroxyphenyl (H) units, lignin-associated ferulates and the flavone tricin were detected in transgenic stems cell walls. Altogether, these changes make stem cell walls more degradable in the most C3H1-repressed plants, despite their unaltered polysaccharide content. The increase in H monomers is moderate compared to C3H deficient Arabidopsis and alfalfa plants. This could be due to the existence of a second maize C3H protein (C3H2) that can compensate the reduced levels of C3H1 in these C3H1-RNAi maize plants. The reduced expression of C3H1 alters the macroscopic phenotype of the plants, whose growth is inhibited proportionally to the extent of C3H1 repression. Finally, the down-regulation of C3H1 also increases the synthesis of flavonoids, leading to the accumulation of anthocyanins in transgenic leaves.
AB - © 2015 Elsevier Ireland Ltd. Coumarate 3-hydroxylase (C3H) catalyzes a key step of the synthesis of the two main lignin subunits, guaiacyl (G) and syringyl (S) in dicotyledonous species. As no functional data are available in regards to this enzyme in monocotyledonous species, we generated C3H1 knock-down maize plants. The results obtained indicate that C3H1 participates in lignin biosynthesis as its down-regulation redirects the phenylpropanoid flux: as a result, increased amounts of p-hydroxyphenyl (H) units, lignin-associated ferulates and the flavone tricin were detected in transgenic stems cell walls. Altogether, these changes make stem cell walls more degradable in the most C3H1-repressed plants, despite their unaltered polysaccharide content. The increase in H monomers is moderate compared to C3H deficient Arabidopsis and alfalfa plants. This could be due to the existence of a second maize C3H protein (C3H2) that can compensate the reduced levels of C3H1 in these C3H1-RNAi maize plants. The reduced expression of C3H1 alters the macroscopic phenotype of the plants, whose growth is inhibited proportionally to the extent of C3H1 repression. Finally, the down-regulation of C3H1 also increases the synthesis of flavonoids, leading to the accumulation of anthocyanins in transgenic leaves.
KW - Cell wall polysaccharides
KW - Degradability
KW - Flavonoids
KW - Lignin
KW - Maize
U2 - 10.1016/j.plantsci.2015.04.007
DO - 10.1016/j.plantsci.2015.04.007
M3 - Article
VL - 236
SP - 272
EP - 282
JO - Plant Science
JF - Plant Science
SN - 0168-9452
ER -