1. Cinnamic acid increases lignin production and inhibits soybean root growth.
- Author
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Salvador VH, Lima RB, dos Santos WD, Soares AR, Böhm PA, Marchiosi R, Ferrarese Mde L, and Ferrarese-Filho O
- Subjects
- Benzoates pharmacology, Biomass, Lignin chemistry, Peroxidases metabolism, Plant Roots anatomy & histology, Plant Roots enzymology, Seedlings drug effects, Seedlings metabolism, Glycine max drug effects, Trans-Cinnamate 4-Monooxygenase metabolism, Cinnamates pharmacology, Lignin biosynthesis, Plant Roots growth & development, Plant Roots metabolism, Glycine max growth & development, Glycine max metabolism
- Abstract
Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean (Glycine max) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H) reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth.
- Published
- 2013
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