Conifer-killing bark beetles locate fungal symbionts by detecting volatile fungal metabolites of host tree resin monoterpenes.

Outbreaks of the Eurasian spruce bark beetle (Ips typographus) have decimated millions of hectares of conifer forests in Europe in recent years. The ability of these 4.0 to 5.5 mm long insects to kill mature trees over a short period has been sometimes ascribed to two main factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. Previous evidence indicates that I. typographus can distinguish fungal symbionts of the genera Grosmannia, Endoconidiophora, and Ophiostoma by their de novo synthesized volatile compounds. Here, we hypothesize that the fungal symbionts of this bark beetle species metabolize spruce resin monoterpenes of the beetle's host tree, Norway spruce (Picea abies), and that the volatile products are used as cues by beetles for locating breeding sites with beneficial symbionts. We show that Grosmannia penicillata and other fungal symbionts alter the profile of spruce bark volatiles by converting the major monoterpenes into an attractive blend of oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and ß-pinene to trans-4-thujanol and other oxygenated products. Electrophysiological measurements showed that I. typographus possesses dedicated olfactory sensory neurons for oxygenated metabolites. Both camphor and trans-4-thujanol attracted beetles at specific doses in walking olfactometer experiments, and the presence of symbiotic fungi enhanced attraction of females to pheromones. Another co-occurring nonbeneficial fungus (Trichoderma sp.) also produced oxygenated monoterpenes, but these were not attractive to I. typographus. Finally, we show that colonization of fungal symbionts on spruce bark diet stimulated beetles to make tunnels into the diet. Collectively, our study suggests that the blends of oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by walking bark beetles as attractive or repellent cues to locate breeding or feeding sites containing beneficial microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.

Metabolomics analysis of different diameter classes of Taxus chinensis reveals that the resource allocation is related to carbon and nitrogen metabolism.

Taxus chinensis (Taxus cuspidata Sieb. et Zucc.) is a traditional medicinal plant known for its anticancer substance paclitaxel, and its growth age is also an important factor affecting its medicinal value. However, how age affects the physiological and metabolic characteristics and active substances of T. chinensis is still unclear. In this study, carbon and nitrogen accumulation, contents of active substances and changes in primary metabolites in barks and annual leaves of T. chinensis of different diameter classes were investigated by using diameter classes instead of age. The results showed that leaves and barks of small diameter class (D1) had higher content of non-structural carbohydrates and C, which were effective in enhancing defense capacity, while N content was higher in medium (D2) and large diameter classes (D3). Active substances such as paclitaxel, baccatin III and cephalomannine also accumulated significantly in barks of large diameter classes. Moreover, 21 and 25 differential metabolites were identified in leaves and barks of different diameter classes, respectively. The differential metabolites were enhanced the TCA cycle and amino acid biosynthesis, accumulate metabolites such as organic acids, and promote the synthesis and accumulation of active substances such as paclitaxel in the medium and large diameter classes. These results revealed the carbon and nitrogen allocation mechanism of different diameter classes of T. chinensis, and its relationship with medicinal components, providing a guidance for the harvesting and utilization of wild T. chinensis.

Rhytidome- and cork-type barks of holm oak, cork oak and their hybrids highlight processes leading to cork formation.

BACKGROUND: The periderm is basic for land plants due to its protective role during radial growth, which is achieved by the polymers deposited in the cell walls. In most trees, like holm oak, the first periderm is frequently replaced by subsequent internal periderms yielding a heterogeneous outer bark made of a mixture of periderms and phloem tissues, known as rhytidome. Exceptionally, cork oak forms a persistent or long-lived periderm which results in a homogeneous outer bark of thick phellem cell layers known as cork. Cork oak and holm oak distribution ranges overlap to a great extent, and they often share stands, where they can hybridize and produce offspring showing a rhytidome-type bark. RESULTS: Here we use the outer bark of cork oak, holm oak, and their natural hybrids to analyse the chemical composition, the anatomy and the transcriptome, and further understand the mechanisms underlying periderm development. We also include a unique natural hybrid individual corresponding to a backcross with cork oak that, interestingly, shows a cork-type bark. The inclusion of hybrid samples showing rhytidome-type and cork-type barks is valuable to approach cork and rhytidome development, allowing an accurate identification of candidate genes and processes. The present study underscores that abiotic stress and cell death are enhanced in rhytidome-type barks whereas lipid metabolism and cell cycle are enriched in cork-type barks. Development-related DEGs showing the highest expression, highlight cell division, cell expansion, and cell differentiation as key processes leading to cork or rhytidome-type barks. CONCLUSION: Transcriptome results, in agreement with anatomical and chemical analyses, show that rhytidome and cork-type barks are active in periderm development, and suberin and lignin deposition. Development and cell wall-related DEGs suggest that cell division and expansion are upregulated in cork-type barks whereas cell differentiation is enhanced in rhytidome-type barks.

Identification of a cinnamoyl-CoA reductase from Cinnamomum cassia involved in trans-cinnamaldehyde biosynthesis.

MAIN CONCLUSION: The identification of a functional cinnamoyl-CoA reductase enzyme from Cinnamomum cassia involved in trans-cinnamaldehyde biosynthesis offers the potential for enhancing trans-cinnamaldehyde production through genetic engineering. A significant accumulation of trans-cinnamaldehyde has been found in the bark tissues of C. cassia, used in traditional Chinese medicine. trans-Cinnamaldehyde exhibits various pharmacological properties such as anti-inflammatory, analgesic, and protection of the stomach and the digestive tract. However, further elucidation and characterization of the biosynthetic pathway for trans-cinnamaldehyde is required. In this study, we conducted an integrated analysis of trans-cinnamaldehyde accumulation profiles and transcriptomic data from five different C. cassia tissues to identify the genes involved in its biosynthesis. The transcriptome data we obtained included nearly all genes associated with the trans-cinnamaldehyde pathway, with the majority demonstrating high abundance in branch barks and trunk barks. We successfully cloned four C. cassia cinnamoyl-CoA reductases (CcCCRs), a key gene in trans-cinnamaldehyde biosynthesis. We found that the recombinant CcCCR1 protein was the only one that more efficiently converted cinnamoyl-CoA into trans-cinnamaldehyde. CcCCR1 exhibited approximately 14.7-fold higher catalytic efficiency (kcat/Km) compared to the Arabidopsis thaliana cinnamoyl-CoA reductase 1 (AtCCR1); therefore, it can be utilized for engineering higher trans-cinnamaldehyde production as previously reported. Molecular docking studies and mutagenesis experiments also validated the superior catalytic activity of CcCCR1 compared to AtCCR1. These findings provide valuable insights for the functional characterization of enzyme-coding genes and hold potential for future engineering of trans-cinnamaldehyde biosynthetic pathways.

Net O2 exchange rates under dark and light conditions across different stem compartments.

Woody plants display some photosynthetic activity in stems, but the biological role of stem photosynthesis and the specific contributions of bark and wood to carbon uptake and oxygen evolution remain poorly understood. We aimed to elucidate the functional characteristics of chloroplasts in stems of different ages in Fraxinus ornus. Our investigation employed diverse experimental approaches, including microsensor technology to assess oxygen production rates in whole stem, bark, and wood separately. Additionally, we utilized fluorescence lifetime imaging microscopy (FLIM) to characterize the relative abundance of photosystems I and II (PSI : PSII chlorophyll ratio) in bark and wood. Our findings revealed light-induced increases in O2 production in whole stem, bark, and wood. We present the radial profile of O2 production in F. ornus stems, demonstrating the capability of stem chloroplasts to perform light-dependent electron transport. Younger stems exhibited higher light-induced O2 production and dark respiration rates than older ones. While bark emerged as the primary contributor to net O2 production under light conditions, our data underscored that wood chloroplasts are also photosynthetically active. The FLIM analysis unveiled a lower PSI abundance in wood than in bark, suggesting stem chloroplasts are not only active but also acclimate to the spectral composition of light reaching inner compartments.

Exosome-like nanoparticles from Mulberry bark prevent DSS-induced colitis via the AhR/COPS8 pathway.

Bark protects the tree against environmental insults. Here, we analyzed whether this defensive strategy could be utilized to broadly enhance protection against colitis. As a proof of concept, we show that exosome-like nanoparticles (MBELNs) derived from edible mulberry bark confer protection against colitis in a mouse model by promoting heat shock protein family A (Hsp70) member 8 (HSPA8)-mediated activation of the AhR signaling pathway. Activation of this pathway in intestinal epithelial cells leads to the induction of COP9 Constitutive Photomorphogenic Homolog Subunit 8 (COPS8). Utilizing a gut epithelium-specific knockout of COPS8, we demonstrate that COPS8 acts downstream of the AhR pathway and is required for the protective effect of MBELNs by inducing an array of anti-microbial peptides. Our results indicate that MBELNs represent an undescribed mode of inter-kingdom communication in the mammalian intestine through an AhR-COPS8-mediated anti-inflammatory pathway. These data suggest that inflammatory pathways in a microbiota-enriched intestinal environment are regulated by COPS8 and that edible plant-derived ELNs may hold the potential as new agents for the prevention and treatment of gut-related inflammatory disease.

Signalling responses in the bark and foliage of canker-susceptible and -resistant cypress clones inoculated with Seiridium cardinale.

The necrotrophic fungus Seiridium cardinale is the main responsible for Cypress Canker Disease (CCD), a pandemic affecting many Cupressaceae worldwide. The present study aims to elucidate the signalling of the early responses in the bark and foliage of CCD-susceptible and -resistant C. sempervirens clones to S. cardinale inoculation (SI and RI, respectively). In the bark of SI, a peaking production of ethylene (Et) and jasmonic acid (JA) occurred at 3 and 4 days post inoculation (dpi), respectively, suggesting an attempted plant response to the pathogen. A response that, however, was ineffective, as confirmed by the severe accumulation of malondialdehyde by-products at 13 dpi (i.e., lipid peroxidation). Differently, Et emission peaked in RI bark at 3 and 13 dpi, whereas abscisic acid (ABA) accumulated at 1, 4 and 13 dpi, resulting in a lower MDA accumulation (and unchanged levels of antioxidant capacity). In the foliage of SI, Et was produced at 1 and 9 dpi, whereas JA and salicylic acid (SA) accumulated at 1 and 3 dpi. Conversely, an increase of ABA and SA occurred at 1 dpi in the RI foliage. This outcome indicates that some of the observed metabolic alterations, mainly occurring as local defence mechanisms, might be able to gradually shift to a systemic resistance, although an accumulation of MDA was observed in both SI and RI foliage (but with an increased antioxidant capacity reported only in the resistant clone). We believe that the results reported here will be useful for the selection of clones able to limit the spread and damage of CCD.

Anti-inflammatory effects of naringenin 8-sulphonate from Parinari excelsa Sabine stem bark and its semi-synthetic derivatives.

The inflammatory response is a vital mechanism for repairing damage induced by aberrant health states or external insults; however, persistent activation can be linked to numerous chronic diseases. The nuclear factor kappa ß (NF-κB) inflammatory pathway and its associated mediators have emerged as critical targets for therapeutic interventions aimed at modulating inflammation, necessitating ongoing drug development. Previous studies have reported the inhibitory effect of a hydroethanol extract derived from Parinari excelsa Sabine (Chrysobalanaceae) on tumour necrosis factor-alpha (TNF-α), but the phytoconstituents and mechanisms of action remained elusive. The primary objective of this study was to elucidate the phytochemical composition of P. excelsa stem bark and its role in the mechanisms underpinning its biological activity. Two compounds were detected via HPLC-DAD-ESI(Ion Trap)-MS2 analysis. The predominant compound was isolated and identified as naringenin-8-sulphonate (1), while the identity of the second compound (compound 2) could not be determined. Both compound 1 and the extract were assessed for anti-inflammatory properties using a cell-based inflammation model, in which THP-1-derived macrophages were stimulated with LPS to examine the treatments' effects on various stages of the NF-κB pathway. Compound 1, whose biological activity is reported here for the first time, demonstrated inhibition of NF-κB activity, reduction in interleukin 6 (IL-6), TNF-α, and interleukin 1 beta (IL-1ß) production, as well as a decrease in p65 nuclear translocation in THP-1 cells, thus highlighting the potential role of sulphur substituents in the activity of naringenin (3). To explore the influence of sulphation on the anti-inflammatory properties of naringenin derivatives, we synthesized naringenin-4'-O-sulphate (4) and naringenin-7-O-sulphate (5) and evaluated their anti-inflammatory effects. Naringenin derivatives 4 and 5 did not display potent anti-inflammatory activities; however, compound 4 reduced IL-1ß production, and compound 5 diminished p65 translocation, with both exhibiting the capacity to inhibit TNF-α and IL-6 production. Collectively, the findings demonstrated that the P. excelsa extract was more efficacious than all tested compounds, while providing insights into the role of sulphation in the anti-inflammatory activity of naringenin derivatives.

Antioxidant and Pulmonary Protective Potential of Fraxinus xanthoxyloides Bark Extract against CCl4 -Induced Toxicity in Rats.

Fraxinus xanthoxyloides is a perennial shrub belonging to family Oleaceae, traditionally used for malaria, jaundice, pneumonia, inflammation, and rheumatism. Our study is aimed to assess the total phenolics (TPC), flavonoids (TFC), terpenoids contents (TTC) and antioxidant profiling of F. xanthoxyloides methanol bark extract (FXBM) and its fractions, hexane, chloroform, ethyl acetate and aqueous, along with high-performance liquid chromatography with diode-array detection (HPLC-DAD). Further, the antioxidant and pulmonary protective potential was explored against carbon tetrachloride (CCl4 )-induced CCl4-induced pulmonary tissue damage in rats. The highest TPC, TFC and TTC were found in FXBM (133.29±4.19 mg/g), ethyl acetate fraction (279.55±10.35 mg/g), and chloroform fraction (0.79±0.06 mg/g), respectively. The most potent antioxidant capacity was depicted by FXBM (29.21±2.40 µg/mg) and ethyl acetate fraction (91.16±5.51 µg/mg). The HPLC-DAD analysis revealed the predominance of gallic, chlorogenic, vanillic and ferulic acid in FXBM. The administration of CCl4 induced oxidative stress, suppressed antioxidant enzymes' activities including catalase, peroxidase, superoxide dismutase, glutathione peroxidase, glutathione-S-transferase, and glutathione reductase. Further, it increased thiobarbituric acid reactive substances (TBARS) and H2 O2 levels, induced DNA injuries and reduced the total protein and glutathione content in lung tissues. The treatment of rats with FXBM restored these biochemical parameters to the normal level. Moreover, the histopathological studies of lung tissues demonstrated that FXBM protected rats' lung tissues from oxidative damage restoring normal lung functions. Thus, F. xanthoxyloides bark extract is recommended as adjuvant therapy as protective agent for patients with lung disorders.

Digested Cinnamon (Cinnamomum verum J. Presl) Bark Extract Modulates Claudin-2 Gene Expression and Protein Levels under TNFα/IL-1ß Inflammatory Stimulus.

Epigenetic changes, host-gut microbiota interactions, and environmental factors contribute to inflammatory bowel disease (IBD) onset and progression. A healthy lifestyle may help to slow down the chronic or remitting/relapsing intestinal tract inflammation characteristic of IBD. In this scenario, the employment of a nutritional strategy to prevent the onset or supplement disease therapies included functional food consumption. Its formulation consists of the addition of a phytoextract enriched in bioactive molecules. A good candidate as an ingredient is the Cinnamon verum aqueous extract. Indeed, this extract, subjected to a process of gastrointestinal digestion simulation (INFOGEST), exhibits beneficial antioxidant and anti-inflammatory properties in an in vitro model of the inflamed intestinal barrier. Here, we deepen the study of the mechanisms related to the effect of digested cinnamon extract pre-treatment, showing a correlation between transepithelial electrical resistance (TEER) decrement and alterations in claudin-2 expression under Tumor necrosis factor-α/Interleukin-1ß (TNF-α/IL-1) ß cytokine administration. Our results show that pre-treatment with cinnamon extract prevents TEER loss by claudin-2 protein level regulation, influencing both gene transcription and autophagy-mediated degradation. Hence, cinnamon polyphenols and their metabolites probably work as mediators in gene regulation and receptor/pathway activation, leading to an adaptive response against renewed insults.

The Related Mechanisms Predicted through Network-Based Pharmacological Analysis and the Anti-Inflammatory Effects of Fraxinus rhynchophylla Hance Bark on Contact Dermatitis in Mice.

Fraxinus rhynchophylla Hance bark has been used to treat patients with inflammatory or purulent skin diseases in China, Japan, and Korea. This study was undertaken to determine the mechanism responsible for the effects of F. rhynchophylla and whether it has a therapeutic effect in mice with contact dermatitis (CD). In this study, the active compounds in F. rhynchophylla, their targets, and target gene information for inflammatory dermatosis were investigated using network-based pharmacological analysis. Docking analysis was conducted using AutoDock Vina. In addition, the therapeutic effect of an ethanolic extract of F. rhynchophylla (EEFR) on skin lesions and its inhibitory effects on histopathological abnormalities, inflammatory cytokines, and chemokines were evaluated. Finally, its inhibitory effects on the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signalling pathways were observed in RAW 264.7 cells. In our results, seven active compounds were identified in F. rhynchophylla, and six were associated with seven genes associated with inflammatory dermatosis and exhibited a strong binding affinity (<-6 kcal/mol) to prostaglandin G/H synthase 2 (PTGS2). In a murine 1-fluoro-2,4-dinitrobenzene (DNFB) model, topical EEFR ameliorated the surface symptoms of CD and histopathological abnormalities. EEFR also reduced the levels of tumour necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-6, and monocyte chemotactic protein (MCP)-1 in inflamed tissues and inhibited PTGS2, the nuclear translocation of NF-κB (p65), and the activation of c-Jun N-terminal kinases (JNK) in RAW 264.7 cells. In conclusion, the bark of F. rhynchophylla has potential use as a therapeutic or cosmetic agent, and the mechanism responsible for its effects involves the suppression of inflammatory mediators, nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IκB)-α degradation, the nuclear translocation of NF-κB, and JNK phosphorylation.

"Pathomorphogenic" Changes Caused by Citrus Bark Cracking Viroid and Transcription Factor TFIIIA-7ZF Variants Support Viroid Propagation in Tobacco.

Viroids are small, non-coding, pathogenic RNAs with the ability to disturb plant developmental processes. This dysregulation redirects the morphogenesis of plant organs, significantly impairing their functionality. Citrus bark cracking viroid (CBCVd) causes detrimental developmental distortions in infected hops (Humulus lupulus) and causes significant economic losses. CBCVd can infect cells and tissues of the model plant tobacco (Nicotiana tabacum), provided it is delivered via transgenesis. The levels of CBCVd in tobacco were enhanced in plant hybrids expressing CBCVd cDNAs and either the tobacco or hop variant of TFIIIA-7ZF, a viroid-mediated splicing derivative of transcription factor IIIA, which is important for viroid replication by DNA-dependent RNA polymerase II. The TFIIIA-7ZF variants can change the tobacco morphogenesis if expressed in leaves and shoots. In addition to the splitting of shoots, the "pathomorphogenic" network in hybrid plants expressing CBCVd and HlTFIIIA-7ZF induced leaf fusions and malformations. Moreover, CBCVd can dramatically change another morphogenesis into teratomic and petal-like tissues if propagated above some limit in young transgenic tobacco microspores and anthers. By comparative RNA profiling of transgenic tobacco shoots bearing TFIIIA-7ZFs and CBCVd-transformed/infected anthers, we found a differential expression of many genes at p < 0.05. As the main common factor showing the differential up-regulation in shoot and anther tissues, a LITTLE ZIPPER 2-like transcription factor was found. We propose that this factor, which can interact as a competitive inhibitor of the also dysregulated homeobox-leucin zipper family protein (HD-ZIPIII) in apical meristem, is essential for a network responsible for some morphological changes and modifications of plant degradome within shoot meristem regulation and secondary xylem differentiation.

Mechanistic Understanding of Tyrosinase Inhibition by Polymeric Proanthocyanidins from Acacia confusa Stem Bark and Their Effect on the Browning Resistance of Fresh-Cut Asparagus Lettuce.

Tyrosinase inhibitors are capable of preventing unfavorable enzymatic browning of fruits and vegetables. In this study, the capacity of Acacia confusa stem bark proanthocyanidins (ASBPs) to inhibit tyrosinase activity was evaluated. ASBPs were shown to be a high-potential inhibitor of tyrosinase with IC50 values of 92.49 ± 4.70 and 61.74 ± 8.93 µg/mL when using L-tyrosine and L-DOPA as the substrate, respectively. The structural elucidation performed with UV-vis, FT-IR spectroscopy, ESI-MS and thiolysis coupled to HPLC-ESI-MS suggested that ASBPs had structural heterogeneity in monomer units and interflavan linkages and consisted mainly of procyanidins dominant with B-type linkages. To gain insights into the inhibitory mechanisms of ASBPs against tyrosinase, different spectroscopic and molecular docking methods were further conducted. Results validated that ASBPs possessed the ability to chelate copper ions and could prevent the oxidation process of substrates by tyrosinase. The hydrogen bond formed with Lys-376 residue played a key role in the binding force of ASBPs with tyrosinase that induced a certain alteration in the microenvironment and secondary structure of tyrosinase, resulting in the enzymatic activity being ultimately restricted. It was also observed that ASBPs treatment effectively inhibited the activities of PPO and POD to retard the surface browning of fresh-cut asparagus lettuce and thus extended their shelf-life. The results provided preliminary evidence supporting the exploitation of ASBPs into potential antibrowning agents for the fresh-cut food industry.

Fundamental Insights on the Physical and Chemical Properties of Organosolv Lignin from Norway Spruce Bark.

The interest in the bark and the attempt to add value to its utilization have increased over the last decade. By applying an integrated bark biorefinery approach, it is possible to investigate the recovery of compounds that can be used to develop green and sustainable alternatives to fossil-based materials. In this work, the focus is on extracting Norway spruce (Picea abies) bark lignin via organosolv extraction. Following the removal of the extractives and the subcritical water extraction to remove the polysaccharides, a novel cyclic organosolv extraction procedure was applied, which enabled the recovery of lignin with high quality and preserved structure. Main indicators for low degradation and preservation of the lignin structure were a high ß-O-4' content and low amounts of condensed structures. Furthermore, high purity and low polydispersity of the lignin were observed. Thus, the obtained lignin exhibits high potential for use in the direct development of polymer precursors and other bio-based materials. During the extraction sequence, around 70% of the bark was extracted. Besides the lignin, the extractives as well as pectic polysaccharides and hemicelluloses were recovered with only minor degradation, which could potentially be used for the production of biofuel or other high-value products such as emulsifiers or adhesives.

Cinnamomum verum J. Presl Bark Contains High Contents of Nicotinamide Mononucleotide.

The global population is aging, and intervention strategies for anti-aging and the prevention of aging-related diseases have become a topic actively explored today. Nicotinamide adenine dinucleotide (NAD+) is an important molecule in the metabolic process, and its content in tissues and cells decreases with age. The supplementation of nicotinamide mononucleotide (NMN), an important intermediate and precursor of NAD+, has increased NAD+ levels, and its safety has been demonstrated in rodents and human studies. However, the high content of NMN in natural plants has not been fully explored as herbal medicines for drug development. Here, we identified that the leaf of Cinnamomum verum J. Presl (C. verum) was the highest NMN content among the Plant Extract Library (PEL) with food experience, using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). To validate this result, the extraction and quantitative analysis of bark, leaf, root, and stem of fresh C. verum was conducted. The results revealed that the bark had the highest NMN content in C. verum (0.471 mg/100 g). Our study shed light on the prospects of developing natural plants in the context of NMN as drugs for anti-aging and prevention of aging-related diseases. The future should focus on the development and application of C. verum pharmaceutical formulations.

Oak bark (Quercus sp. cortex) protects plants through the inhibition of quorum sensing mediated virulence of Pectobacterium carotovorum.

Bacterial intercellular communication mediated by small diffusible molecules, known as quorum sensing (QS), is a common mechanism for regulating bacterial colonisation strategies and survival. Influence on QS by plant-derived molecules is proposed as a strategy for combating phytopathogens by modulating their virulence. This work builds upon other studies that have revealed plant-derived QS inhibitors extracted from oak bark (Quercus sp.). It was found that co-incubation of Pectobacterium carotovorum VKM-B-1247 with oak bark extract (OBE) reduced the production of acyl-HSL. This was accompanied by a dose-dependent decrease in the bacterial cellulolytic and protease activity. At the transcriptomic level, the OBE treatment suppressed the main QS-related genes expR/expI. Potato tubers pre-treated with OBE showed resistance to a manifestation of soft-rot symptoms. Analysis of the component composition of the OBE identified several biologically active molecules, such as n-hexadecanoic acid, 2,6-di-tert-butyl-4-methylphenol, butylated hydroxytoluene (BHT), gamma-sitosterol, lupeol, and others. Molecular docking of the binding energy between identified molecules and homology models of LuxR-LuxI type proteins allow to identify potential inhibitors. Collectively, obtained results figure out great potential of widely distributed oak-derived plant material for bacterial control during storage of potato.

Phosphoproteome analysis reveals an extensive phosphorylation of proteins associated with bast fiber growth in ramie.

BACKGROUND: Phosphorylation modification, one of the most common post-translational modifications of proteins, widely participates in the regulation of plant growth and development. Fibers extracted from the stem bark of ramie are important natural textile fibers; however, the role of phosphorylation modification in the growth of ramie fibers is largely unknown. RESULTS: Here, we report a phosphoproteome analysis for the barks from the top and middle section of ramie stems, in which the fiber grows at different stages. A total of 10,320 phosphorylation sites from 9,170 unique phosphopeptides that were assigned to 3,506 proteins was identified, and 458 differentially phosphorylated sites from 323 proteins were detected in the fiber developmental barks. Twelve differentially phosphorylated proteins were the homologs of Arabidopsis fiber growth-related proteins. We further focused on the function of the differentially phosphorylated KNOX protein whole_GLEAN_10029667, and found that this protein dramatically repressed the fiber formation in Arabidopsis. Additionally, using a yeast two-hybridization assay, we identified a kinase and a phosphatase that interact with whole_GLEAN_10029667, indicating that they potentially target this KNOX protein to regulate its phosphorylation level. CONCLUSION: The finding of this study provided insights into the involvement of phosphorylation modification in ramie fiber growth, and our functional characterization of whole_GLEAN_10029667 provide the first evidence to indicate the involvement of phosphorylation modification in the regulation of KNOX protein function in plants.

Inner bark as a crucial tissue for non-structural carbohydrate storage across three tropical woody plant communities.

Non-structural carbohydrates (NSC) are crucial for forest resilience, but little is known regarding the role of bark in NSC storage. However, bark's abundance in woody stems and its large living fraction make it potentially key for NSC storage. We quantified total NSC, soluble sugar (SS) and starch concentrations in the most living region of bark (inner bark, IB), and sapwood of twigs, trunks and roots of 45 woody species from three contrasting tropical climates spanning global extremes of bark diversity and wide phylogenetic diversity. NSC concentrations were similar (total NSC, starch) or higher (SS) in IB than wood, with concentrations co-varying strongly. NSC concentrations varied widely across organs and species within communities and were not significantly affected by climate, leaf habit or the presence of photosynthetic bark. Starch concentration tended to increase with density, but only in wood. IB contributed substantially to NSC storage, accounting for 17-36% of total NSC, 23-47% of SS and 15-33% of starch pools. Further examination of the drivers of variation in IB NSC concentration, and taking into account the substantial contribution of IB to NSC pools, will be crucial to understand the role of storage in plant environmental adaptation.

Anti-Herbivore Activity of Oregonin, a Diarylheptanoid Found in Leaves and Bark of Red Alder (Alnus rubra).

Plants synthesize a wide range of bioactive secondary metabolites to defend against pests and pathogens. Red alder (Alnus rubra) bark, root, and leaf extract have a long history of use in traditional medicine and hygiene. Diarylheptanoids, especially oregonin ((5S)-1,7-bis(3,4-dihydroxyphenyl)-5-(ß-D-xylopyranosyloxy)-heptan-3-one), have been identified as major bioactive constituents. Diarylheptanoids have become a focus of research following reports of their antioxidant, antifungal, and anti-cancer activities. Recent data suggest that high oregonin concentration is associated with resistance of red alder leaves to western tent caterpillar (Malacosoma californicum) defoliation. Here we test effects of this compound directly on leaf-eating insects. Purified oregonin was examined in insect choice and toxicity tests using lepidopteran caterpillars. The compound exhibited significant anti-feedant activity against cabbage looper (Trichoplusia ni), white-marked tussock moth (Orgyia leucostigma), fall webworm (Hyphantria cunea), and M. californicum at concentrations corresponding to oregonin content of the most resistant alder clones in previous experiments. Toxicity tests were carried out with cabbage looper larvae only, but no contact or ingested toxicity was detected. Our results suggest that oregonin at levels found in red alder leaves early in the growing season may contribute to protecting red alder from leaf-eating insects.

Off-line two-dimensional liquid chromatography separation for the quality control of saponins samples from Quillaja Saponaria.

Quil-A is a purified extract of saponins with strong immunoadjuvant activity. While specific molecules have been identified and tested in clinical trials, Quil-A is mostly used as a totum of the Quillaja Saponaria bark extract. Quality control of the extract stability is usually based on the monitoring of specific saponins, whereas the comparison of samples with an initial chromatogram seems more appropriate. A reference fingerprint based on comprehensive two-dimensional liquid chromatography offers a rapid detection of nonconform samples. To fulfill quality control constraints, off-line configuration using basic instrumentation was promoted. Hence, reversed-phase liquid chromatography × reversed-phase liquid chromatography and hydrophilic interaction chromatography × reversed-phase liquid chromatography methods with ultraviolet and single-quadrupole mass spectrometry detection were kinetically optimized. The reversed-phase liquid chromatography × reversed-phase liquid chromatography method used a pH switch between dimensions to maximize orthogonality. Despite diagonalization, it led to a high peak capacity of 831 in 2 h. On the other hand, the combination of hydrophilic interaction chromatography and reversed-phase liquid chromatography offered a larger orthogonality but a lower, yet satisfactory peak capacity of 673. The advantages of both methods were illustrated on degraded samples, where the reversed-phase liquid chromatography × reversed-phase liquid chromatography contour plot highlighted the loss of fatty acid chains, while the hydrophilic interaction chromatography × reversed-phase liquid chromatography method was found useful to evidence enzymatic loss of sugar moieties.