A peroxisomal β-oxidative pathway contributes to the formation of C(6)–C(1) aromatic volatiles in poplar
| Autor: | Nathalie D. Lackus, Axel Schmidt, Tobias G. Köllner, Jonathan Gershenzon |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
0106 biological sciences
Populus trichocarpa Physiology Plant Science 01 natural sciences Petunia Hydrocarbons Aromatic Cinnamic acid 03 medical and health sciences chemistry.chemical_compound Genetics Plant defense against herbivory Benzene Derivatives Oils Volatile Peroxisomes Animals Herbivory Research Articles 030304 developmental biology Plant Proteins 0303 health sciences biology Thiolase fungi Peroxisome biology.organism_classification Coleoptera Chrysomela populi Populus Biochemistry chemistry Cinnamates RNA Interference Heterologous expression Acyl Coenzyme A Oxidation-Reduction 010606 plant biology & botany |
| Zdroj: | Plant Physiol Plant Physiology |
| Popis: | Benzenoids (C6–C1 aromatic compounds) play important roles in plant defense and are often produced upon herbivory. Black cottonwood (Populus trichocarpa) produces a variety of volatile and nonvolatile benzenoids involved in various defense responses. However, their biosynthesis in poplar is mainly unresolved. We showed feeding of the poplar leaf beetle (Chrysomela populi) on P. trichocarpa leaves led to increased emission of the benzenoid volatiles benzaldehyde, benzylalcohol, and benzyl benzoate. The accumulation of salicinoids, a group of nonvolatile phenolic defense glycosides composed in part of benzenoid units, was hardly affected by beetle herbivory. In planta labeling experiments revealed that volatile and nonvolatile poplar benzenoids are produced from cinnamic acid (C6–C3). The biosynthesis of C6–C1 aromatic compounds from cinnamic acid has been described in petunia (Petunia hybrida) flowers where the pathway includes a peroxisomal-localized chain shortening sequence, involving cinnamate-CoA ligase (CNL), cinnamoyl-CoA hydratase/dehydrogenase (CHD), and 3-ketoacyl-CoA thiolase (KAT). Sequence and phylogenetic analysis enabled the identification of small CNL, CHD, and KAT gene families in P. trichocarpa. Heterologous expression of the candidate genes in Escherichia coli and characterization of purified proteins in vitro revealed enzymatic activities similar to those described in petunia flowers. RNA interference-mediated knockdown of the CNL subfamily in gray poplar (Populus x canescens) resulted in decreased emission of C6–C1 aromatic volatiles upon herbivory, while constitutively accumulating salicinoids were not affected. This indicates the peroxisomal β-oxidative pathway participates in the formation of volatile benzenoids. The chain shortening steps for salicinoids, however, likely employ an alternative pathway. |
| Databáze: | OpenAIRE |
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