title: Exogenous caffeic acid inhibits the growth and enhances the lignification of the roots of soybean (Glycine max).
abstract: The allelopathic effect of caffeic acid was tested on root growth, phenylalanine ammonia-lyase (PAL) and peroxidase (POD) activities, hydrogen peroxide (H(2)O(2)) accumulation, lignin content and monomeric composition of soybean (Glycine max) roots. We found that exogenously applied caffeic acid inhibited root growth, decreased the PAL activity and H(2)O(2) content and increased the soluble and cell wall-bound POD activities. The p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) monomers and total lignin (H+G+S) increased in the caffeic acid-exposed roots. When applied in conjunction with piperonylic acid (PIP, an inhibitor of the cinnamate 4-hydroxylase, C4H), caffeic acid equalized the inhibitory effect of PIP, whereas the application of methylene dioxocinnamic acid (MDCA, an inhibitor of the 4-coumarate:CoA ligase, 4CL) plus caffeic acid decreased lignin production. These results indicate that exogenously applied caffeic acid can be channeled into the phenylpropanoid pathway via the 4CL reaction, resulting in an increase of lignin monomers that solidify the cell wall and inhibit root growth.
authors.affiliation: Laboratory of Plant Biochemistry, Department of Biochemistry, University of Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil.
authors.forename: Gisele Adriana
authors.initials: GA
authors.lastname: Bubna
authors.forename: Rogério Barbosa
authors.initials: RB
authors.lastname: Lima
authors.forename: Daniele Yara Lucca
authors.initials: DY
authors.lastname: Zanardo
authors.forename: Wanderley Dantas
authors.initials: WD
authors.lastname: Dos Santos
authors.forename: Maria de Lourdes Lucio
authors.initials: Mde L
authors.lastname: Ferrarese
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Ferrarese-Filho
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001565:Benzoates / Q000494:pharmacology; D002109:Caffeic Acids / Q000494:pharmacology*; D002473:Cell Wall / Q000201:enzymology / Q000378:metabolism; D002934:Cinnamates / Q000494:pharmacology; D003066:Coenzyme A Ligases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003373:Coumaric Acids / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000032:analysis / Q000378:metabolism; D008031:Lignin / Q000032:analysis / Q000378:metabolism*; D009195:Peroxidase / Q000187:drug effects / Q000378:metabolism; D010650:Phenylalanine Ammonia-Lyase / Q000187:drug effects / Q000378:metabolism; D010940:Plant Proteins / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D013025:Glycine max / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D050564:Trans-Cinnamate 4-Monooxygenase / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000975:Antioxidants; D001565:Benzoates; D002109:Caffeic Acids; D002934:Cinnamates; D003373:Coumaric Acids; D004791:Enzyme Inhibitors; D010940:Plant Proteins; D008031:Lignin; D006861:Hydrogen Peroxide; D009195:Peroxidase; D050564:Trans-Cinnamate 4-Monooxygenase; D010650:Phenylalanine Ammonia-Lyase; D003066:Coenzyme A Ligases; C019943:4-coumarate-CoA ligase; C005455:piperonylic acid; C040048:caffeic acid