Biosynthesis, herbivore induction, and defensive role of phenylacetaldoxime glucoside.

Aldoximes are well-known metabolic precursors for plant defense compounds such as cyanogenic glycosides, glucosinolates, and volatile nitriles. They are also defenses themselves produced in response to herbivory; however, it is unclear whether aldoximes can be stored over a longer term as defense compounds and how plants protect themselves against the potential autotoxic effects of aldoximes. Here, we show that the Neotropical myrmecophyte tococa (Tococa quadrialata, recently renamed Miconia microphysca) accumulates phenylacetaldoxime glucoside (PAOx-Glc) in response to leaf herbivory.

HDR, the last enzyme in the MEP pathway, differently regulates isoprenoid biosynthesis in two woody plants.

Dimethylallyl diphosphate (DMADP) and isopentenyl diphosphate (IDP) serves as the universal C5 precursors of isoprenoid biosynthesis in plants. These compounds are formed by the last step of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, catalyzed by (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate reductase (HDR). In this study, we investigated the major HDR isoforms of two woody plant species, Norway spruce (Picea abies) and gray poplar (Populus × canescens), to determine how they regulate isoprenoid formation.

CRISPR/Cas9 disruption of UGT71L1 in poplar connects salicinoid and salicylic acid metabolism and alters growth and morphology.

Salicinoids are salicyl alcohol-containing phenolic glycosides with strong antiherbivore effects found only in poplars and willows. Their biosynthesis is poorly understood, but recently a UDP-dependent glycosyltransferase, UGT71L1, was shown to be required for salicinoid biosynthesis in poplar tissue cultures. UGT71L1 specifically glycosylates salicyl benzoate, a proposed salicinoid intermediate.

Isotopic Labeling Experiments Solve the Hedycaryol Problem.

Hedycaryol is a widespread sesquiterpene alcohol and important biosynthetic intermediate toward eudesmols and guaiols. A full NMR assignment for this compound has been hampered because of the unique molecular mechanics of its conformers in complex mixtures. This problem was solved through the enzymatic synthesis of isotopically labeled materials using a mutated plant and a bacterial enzyme for access to both enantiomers of hedycaryol, which also allowed us to follow the stereochemical course of its Cope rearrangement.

A peroxisomal β-oxidative pathway contributes to the formation of C6-C1 aromatic volatiles in poplar.

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.

The Sesquiterpene Synthase PtTPS5 Produces (1,5,7,10)-Guaia-4(15)-en-11-ol and (1,7,10)-Guaia-4-en-11-ol in Oomycete-Infected Poplar Roots.

Pathogen infection often leads to the enhanced formation of specialized plant metabolites that act as defensive barriers against microbial attackers. In this study, we investigated the formation of potential defense compounds in roots of the Western balsam poplar () upon infection with the generalist root pathogen (Oomycetes). infection led to an induced accumulation of terpenes, aromatic compounds, and fatty acids in poplar roots.

Allelic differences of clustered terpene synthases contribute to correlated intraspecific variation of floral and herbivory-induced volatiles in a wild tobacco.

Plant volatile emissions can recruit predators of herbivores for indirect defense and attract pollinators to aid in pollination. Although volatiles involved in defense and pollinator attraction are primarily emitted from leaves and flowers, respectively, they will co-evolve if their underlying genetic basis is intrinsically linked, due either to pleiotropy or to genetic linkage. However, direct evidence of co-evolving defense and floral traits is scarce.

Spatial and developmental synthesis of endogenous sesquiterpene lactones supports function in growth regulation of sunflower.

Tissue-specific occurrence and formation of endogenous sesquiterpene lactones has been assessed and suggests physiological function as antagonists of auxin-induced plant growth in sunflower. Sunflower, Helianthus annuus, accumulate high concentrations of bioactive sesquiterpene lactones (STL) in glandular trichomes, but in addition, structurally different STL occur in only trace amounts in the inner tissues. The spatial and temporal production of these endogenous STL during early phases of plant development is widely unknown and their physiological function as putative natural growth regulators is yet speculative.

Growing up aspen: ontogeny and trade-offs shape growth, defence and reproduction in a foundation species.

Background And Aims: Intraspecific variation in foundation species of forest ecosystems can shape community and ecosystem properties, particularly when that variation has a genetic basis. Traits mediating interactions with other species are predicted by simple allocation models to follow ontogenetic patterns that are rarely studied in trees. The aim of this research was to identify the roles of genotype, ontogeny and genotypic trade-offs shaping growth, defence and reproduction in aspen.

The Occurrence of Sulfated Salicinoids in Poplar and Their Formation by Sulfotransferase1.

Salicinoids form a specific class of phenolic glycosides characteristic of the Salicaceae. Although salicinoids accumulate in large amounts and have been shown to be involved in plant defense, their biosynthesis is unclear. We identified two sulfated salicinoids, salicin-7-sulfate and salirepin-7-sulfate, in black cottonwood ().

Evolution of a Novel and Adaptive Floral Scent in Wild Tobacco.

Many plants emit diverse floral scents that mediate plant-environment interactions and attain reproductive success. However, how plants evolve novel and adaptive biosynthetic pathways for floral volatiles remains unclear. Here, we show that in the wild tobacco, Nicotiana attenuata, a dominant species-specific floral volatile (benzyl acetone, BA) that attracts pollinators and deters florivore is synthesized by phenylalanine ammonia-lyase 4 (NaPAL4), isoflavone reductase 3 (NaIFR3), and chalcone synthase 3 (NaCHAL3).

Aboveground phytochemical responses to belowground herbivory in poplar trees and the consequence for leaf herbivore preference.

Belowground (BG) herbivory can influence aboveground (AG) herbivore performance and food preference via changes in plant chemistry. Most evidence for this phenomenon derives from studies in herbaceous plants but studies in woody plants are scarce. Here we investigated whether and how BG herbivory on black poplar (Populus nigra) trees by Melolontha melolontha larvae influences the feeding preference of Lymantria dispar (gypsy moth) caterpillars.

Identification and Characterization of -Isopentenyl Diphosphate Synthases Involved in Herbivory-Induced Volatile Terpene Formation in .

In response to insect herbivory, poplar releases a blend of volatiles that plays important roles in plant defense. Although the volatile bouquet is highly complex and comprises several classes of compounds, it is dominated by mono- and sesquiterpenes. The most common precursors for mono- and sesquiterpenes, geranyl diphosphate (GPP) and ()-farnesyl diphosphate (FPP), respectively, are in general produced by homodimeric or heterodimeric -isopentenyl diphosphate synthases (-IDSs) that belong to the family of prenyltransferases.

Separate Pathways Contribute to the Herbivore-Induced Formation of 2-Phenylethanol in Poplar.

Upon herbivory, the tree species western balsam poplar () produces a variety of Phe-derived metabolites, including 2-phenylethylamine, 2-phenylethanol, and 2-phenylethyl-β-d-glucopyranoside. To investigate the formation of these potential defense compounds, we functionally characterized aromatic l-amino acid decarboxylases (AADCs) and aromatic aldehyde synthases (AASs), which play important roles in the biosynthesis of specialized aromatic metabolites in other plants. Heterologous expression in and showed that all five / genes identified in the genome encode active enzymes.

The occurrence and formation of monoterpenes in herbivore-damaged poplar roots.

Volatiles are often released upon herbivory as plant defense compounds. While the formation of volatiles above-ground has been intensively studied, little is known about herbivore-induced root volatiles. Here, we show that cockchafer larvae-damaged roots of Populus trichocarpa and P.

The nitrilase PtNIT1 catabolizes herbivore-induced nitriles in Populus trichocarpa.

Background: Nitrilases are nitrile-converting enzymes commonly found within the plant kingdom that play diverse roles in nitrile detoxification, nitrogen recycling, and phytohormone biosynthesis. Although nitrilases are present in all higher plants, little is known about their function in trees. Upon herbivory, poplars produce considerable amounts of toxic nitriles such as benzyl cyanide, 2-methylbutyronitrile, and 3-methylbutyronitrile.

Tissue-Specific Emission of (E)-α-Bergamotene Helps Resolve the Dilemma When Pollinators Are Also Herbivores.

More than 87% of flowering plant species are animal-pollinated [1] and produce floral scents and other signals to attract pollinators. These floral cues may however also attract antagonistic visitors, including herbivores [2]. The dilemma is exacerbated when adult insects pollinate the same plant that their larvae consume.