Bark beetles vector symbiotic fungal species into their host trees during mass attacks. The symbiotic relationship with blue stain fungi of the Ascomycetes, including genera of Endoconidiophora (syn. = Ceratocystis), promotes successful establishment whereby the microbes help to overcome the host trees' defence and degrade toxic resins. This is the first study to evaluate both the volatile emissions from an insect-associated blue stain fungus over time and the insect response in a field trapping experiment. Volatile emissions from isolates of Endoconidiophora rufipennis (ER) were collected by solid-phase microextraction (SPME) and analysed by gas chromatography-mass spectroscopy (GC-MS) over a period of 30 days. This virulent North American fungus is closely related to E. polonica, a symbiotic fungus known from Eurasian spruce bark beetle Ips typographus.Nine volatiles were emitted by ER in substantial amounts: isoamyl acetate, sulcatone, 2-phenethyl acetate, geranyl acetone, geranyl acetate, citronellyl acetate, (R)- and (S)-sulcatol, and (R)-sulcatol acetate. A late peaking compound was geranyl acetone. In the field trapping experiment, three of the fungal volatiles (geranyl acetone, 2-phenethyl acetate and sulcatone) were tested in combination with a synthetic aggregation pheromone for I. typographus. Traps with geranyl acetone attracted lower numbers of I. typographus compared to traps with 2-phenethyl acetate, sulcatone or the pheromone alone as a control. The results showed that geranyl acetone acts as an anti-attractant and may act naturally on I. typographus as a cue from an associated fungus to signal an overexploited host.
- MeSH
- Ascomycota * fyziologie MeSH
- brouci * fyziologie MeSH
- feromony metabolismus MeSH
- kůra rostlin metabolismus MeSH
- nosatcovití * mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Essential oils can be used in a variety of ways to treat microorganisms that have evolved antibiotic resistance. The research assessed the antimicrobial and antioxidant activities of essential oil obtained from Citrus Limonum, Citrus reticulate, and Citrus sinensis fresh peels using the hydro-distillation method. Their chemical compositions were analyzed by Gas Chromatography-Mass Spectrometer. Citrus oils had antimicrobial and antioxidant properties and their activity was increased with increasing concentrations. Oils had a significant antimicrobial effect on tested bacteria except on P. aeruginosa only C. Limonum had significant (p≤0.05) inhibitory effects at both 100 and 200 mg/ml. There was no significant (p>0.05) difference in the inhibition zone of tested oils against A. baumannii and ciprofloxacin at 25 mg/ml, which was the same as against E. coli at 200 mg/ml. The oil inhibitory effect on K. pneumoniae, P. mirabilis, and S. aureus was less than that obtained from ciprofloxacin at concentrations used. At 100 mg/mL, C. reticulate oil had a 23 mm inhibitory zone, while C. sinensis oil had a 23 mm inhibitory zone at 200 mg/mL, which was the same as the inhibitory area of ciprofloxacin against S. marcescens. Oils had convergent antifungal activity against Candida albicans that increased with increasing concentrations. The extracts competed favorably with voriconazole being used as a positive control. Citrus oils had convergent scavenging activities at the concentrations used. The studies confirmed the medicinal and industrial use of citrus essential oils as a therapeutic and antioxidant agent.
- MeSH
- antifungální látky analýza chemie farmakologie MeSH
- antiinfekční látky analýza chemie farmakologie MeSH
- antioxidancia analýza chemie farmakologie MeSH
- biomedicínský výzkum MeSH
- chemické techniky analytické metody přístrojové vybavení MeSH
- Citrus * chemie MeSH
- destilace metody přístrojové vybavení MeSH
- epidermis rostlin chemie MeSH
- farmakologické účinky MeSH
- fytonutrienty analýza chemie farmakologie MeSH
- oleje prchavé * analýza chemie farmakologie MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- scavengery volných radikálů MeSH
- Geografické názvy
- Irák MeSH
Bark beetles are destructive insect pests known to form symbioses with different fungal taxa, including yeasts. The aim of this study was to (1) determine the prevalence of the rare yeast Hyphopichia heimii in bark beetle frass from wild olive trees in South Africa and to (2) predict the potential interaction of this yeast with trees and bark beetles. Twenty-eight culturable yeast species were isolated from frass in 35 bark beetle galleries, including representatives of H. heimii from nine samples. Physiological characterization of H. heimii isolates revealed that none was able to degrade complex polymers present in hemicellulose; however, all were able to assimilate sucrose and cellobiose, sugars associated with an arboreal habitat. All isolates were able to produce the auxin indole acetic acid, indicative of a potential symbiosis with the tree. Sterol analysis revealed that the isolates possessed ergosterol quantities ranging from 3.644 ± 0.119 to 13.920 ± 1.230 mg/g dry cell weight, which suggested that H. heimii could serve as a source of sterols in bark beetle diets, as is known for other bark beetle-associated fungi. In addition, gas chromatography-mass spectrometry demonstrated that at least one of the isolates, Hyphopichia heimii CAB 1614, was able to convert the insect pheromone cis-verbenol to the anti-aggregation pheromone verbenone. This indicated that H. heimii could potentially influence beetle behaviour. These results support the contention of a tripartite symbiosis between H. heimii, olive trees, and bark beetles.
- MeSH
- brouci * mikrobiologie fyziologie MeSH
- feromony metabolismus MeSH
- kůra rostlin mikrobiologie MeSH
- kvasinky MeSH
- nosatcovití * MeSH
- Olea * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Windfelled Norway spruce (Picea abies) trees play a crucial role in triggering large-scale outbreaks of the European spruce bark beetle Ips typographus. Outbreak management therefore strives to remove windfelled trees to reduce the risk of outbreaks, a measure referred to as sanitation logging (SL). Although this practice has been traditionally applied, its efficiency in preventing outbreaks remains poorly understood. We used the landscape simulation model iLand to investigate the effects of different spatial configurations and intensities of SL of windfelled trees on the subsequent disturbance by bark beetles. We studied differences between SL applied evenly across the landscape, focused on the vicinity of roads (scenario of limited logging resources) and concentrated in a contiguous block (scenario of spatially diversified management objectives). We focused on a 16 050 ha forest landscape in Central Europe. The removal of >80% of all windfelled trees is required to substantially reduce bark beetle disturbances. Focusing SL on the vicinity of roads created a "fire break effect" on bark beetle spread, and was moderately efficient in reducing landscape-scale bark beetle disturbance. Block treatments substantially reduced outbreaks in treated areas. Leaving parts of the landscape untreated (e.g., conservation areas) had no significant amplifying effect on outbreaks in managed areas. Climate change increased bark beetle disturbances and reduced the effect of SL. Our results suggest that past outbreak management methods will not be sufficient to counteract climate-mediated increases in bark beetle disturbance.
ETHNOPHARMACOLOGICAL RELEVANCE: The use of Hazomalania voyronii, popularly known as hazomalana, to repel mosquitoes and resist against insect attacks is handed down from generation to generation in Madagascar. In the present study, we investigated the ability of the essential oils (EOs) obtained from the stem wood, fresh and dry bark of H. voyronii to keep important mosquito vectors (Aedes aegypti and Culex quinquefasciatus) away, as well as their toxicity on three insect species of agricultural and public health importance (Cx. quinquefasciatus, Musca domestica and Spodoptera littoralis). MATERIALS AND METHODS: Hydrodistillation was used to obtain EOs from stem wood, fresh and dry bark. The chemical compositions were achieved by gas chromatography-mass spectrometry (GC-MS). Toxicity assays using stem wood and bark EOs were performed on larvae of Cx. quinquefasciatus and S. littoralis, and adults of M. domestica by WHO and topical application methods, respectively. Mosquito repellent activity of the most effective EO, i.e. the bark one, was determined on human volunteers by arm-in-cage tests, and results were compared with that of the commercial repellent N,N-ddiethyl-m-toluamide (DEET). RESULTS: The H. voyronii EOs were characterized by oxygenated monoterpenes with perilla aldehyde (30.9-47.9%) and 1,8-cineole (19.7-33.2%) as the main constituents. The fresh and dry bark EOs were the most active on Cx. quinquefasciatus and S. littoralis larvae, respectively, with LC50/LD50 of 65.5 mg L-1, and 50.5 μg larva-1; the EOs from wood and fresh bark displayed the highest toxicity on M. domestica (LD50 values 60.8 and 65.8 μg adult-1, respectively). Repellence assay revealed an almost complete protection (>80%) from both mosquito species for 30 min when pure fresh bark EO was applied on the volunteers' arm, while DEET 10% repelled >80% of the mosquitoes up to 120 min from application. CONCLUSION: The traditional use of the bark EO to repel insects has been demonstrated although an extended-release formulation based on H. voyronii EOs is needed to increase the repellent effect over time. A wide spectrum of insecticidal activity has been provided as well, suggesting a possible use of H. voyronii EOs in the fabrication of green repellents and insecticides useful to control mosquito vectors and agricultural pests.
- MeSH
- Aedes účinky léků růst a vývoj MeSH
- časové faktory MeSH
- Culex účinky léků embryologie MeSH
- diethyltoluamid farmakologie MeSH
- dřevo * chemie MeSH
- Hernandiaceae * chemie MeSH
- kůra rostlin * chemie MeSH
- larva účinky léků růst a vývoj MeSH
- lidé MeSH
- moskyti - kontrola * MeSH
- moucha domácí účinky léků růst a vývoj MeSH
- oleje prchavé izolace a purifikace farmakologie MeSH
- oleje rostlin izolace a purifikace farmakologie MeSH
- repelenty proti hmyzu izolace a purifikace farmakologie MeSH
- Spodoptera účinky léků embryologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
The spectrum of Mesostigmata mite species that are phoretic on the bark beetle Ips typographus has been well described. However, phoretic mite abundance has mostly been quantified by researchers who used only a single method for capturing bark beetles: pheromone traps. We therefore compared mite abundance using two beetle-capture methods. At a single location with high numbers of I. typographus in the eastern Czech Republic in 2013, beetles were collected with pheromone traps and from infested logs placed in emergence traps. In total 29,589 I. typographus beetles were captured using the two methods. Mite abundance was assessed on 2400 beetles from pheromone traps and on 955 beetles from emergence traps; in total 5805 phoretic mesostigmatid mites were detected. Six species of phoretic mites were captured using pheromone traps and four species using emergence traps. The number of phoretic mites per beetle was higher for beetles captured in emergence traps than for beetles captured in pheromone traps. The most abundant mite species overall were Dendrolaelaps quadrisetus, Uroobovella ipidis, and Trichouropoda polytricha. The seasonal dynamics of phoretic mites paralleled the seasonal dynamics of their hosts.
- MeSH
- feromony MeSH
- kůra rostlin MeSH
- nosatcovití * MeSH
- roční období * MeSH
- roztoči * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Element content and expression of genes of interest on single cell types, such as stomata, provide valuable insights into their specific physiology, improving our understanding of leaf gas exchange regulation. We investigated how far differences in stomatal conductance (gs ) can be ascribed to changes in guard cells functioning in amphistomateous leaves. gs was measured during the day on both leaf sides, on well-watered and drought-stressed trees (two Populus euramericana Moench and two Populus nigra L. genotypes). In parallel, guard cells were dissected for element content and gene expressions analyses. Both were strongly arranged according to genotype, and drought had the lowest impact overall. Normalizing the data by genotype highlighted a structure on the basis of leaf sides and time of day both for element content and gene expression. Guard cells magnesium, phosphorus, and chlorine were the most abundant on the abaxial side in the morning, where gs was at the highest. In contrast, genes encoding H+ -ATPase and aquaporins were usually more abundant in the afternoon, whereas genes encoding Ca2+ -vacuolar antiporters, K+ channels, and ABA-related genes were in general more abundant on the adaxial side. Our work highlights the unique physiology of each leaf side and their analogous rhythmicity through the day.
- MeSH
- genotyp MeSH
- komplementární DNA genetika izolace a purifikace MeSH
- listy rostlin genetika metabolismus MeSH
- mikroanalýza elektronovou sondou MeSH
- období sucha MeSH
- Populus klasifikace genetika metabolismus MeSH
- protonové ATPasy genetika metabolismus MeSH
- průduchy rostlin genetika metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- RNA rostlin genetika izolace a purifikace MeSH
- rostlinné proteiny genetika metabolismus MeSH
- stromy genetika metabolismus MeSH
- transpirace rostlin fyziologie MeSH
- voda fyziologie MeSH
- vývoj rostlin MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND AND AIMS: The idea that genome (size) evolution in eukaryotes could be driven by environmental factors is still vigorously debated. In extant plants, genome size correlates positively with stomatal size, leading to the idea that conditions enabling the existence of large stomata in fossil plants also supported growth of their genome size. We test this inductive assumption in drought-adapted, prostrate-leaved Cape (South Africa) geophytes where, compared with their upright-leaved geophytic ancestors, stomata develop in a favourably humid microclimate formed underneath their leaves. METHODS: Stomatal parameters (leaf cuticle imprints) and genome size (flow cytometry) were measured in 16 closely related geophytic species pairs from seven plant families. In each pair, representing a different genus, we contrasted a prostrate-leaved species with its upright-leaved phylogenetic relative, the latter whose stomata are exposed to the ambient arid climate. KEY RESULTS: Except for one, all prostrate-leaves species had larger stomata, and in 13 of 16 pairs they also had larger genomes than their upright-leaved relatives. Stomatal density and theoretical maximum conductance were less in prostrate-leaved species with small guard cells (<1 pL) but showed no systematic difference in species pairs with larger guard cells (>1 pL). Giant stomata were observed in the prostrate-leaved Satyrium bicorne (89-137 µm long), despite its relatively small genome (2C = 9 Gbp). CONCLUSIONS: Our results imply that climate, through selection on stomatal size, might be able to drive genome size evolution in plants. The data support the idea that plants from 'greenhouse' geological periods with large stomata might have generally had larger genome sizes when compared with extant plants, though this might not have been solely due to higher atmospheric CO2 in these periods but could also have been due to humid conditions prevailing at fossil deposit sites.
- MeSH
- délka genomu MeSH
- fylogeneze MeSH
- genom rostlinný genetika MeSH
- listy rostlin MeSH
- průduchy rostlin genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Jihoafrická republika MeSH
Guard cells on the leaf epidermis regulate stomatal opening for gas exchange between plants and the atmosphere, allowing a balance between photosynthesis and transpiration. Given that guard cells possess several characteristics of sink tissues, their metabolic activities should largely depend on mesophyll-derived sugars. Early biochemical studies revealed sugar uptake into guard cells. However, the transporters that are involved and their relative contribution to guard cell function are not yet known. Here, we identified the monosaccharide/proton symporters Sugar Transport Protein 1 and 4 (STP1 and STP4) as the major plasma membrane hexose sugar transporters in the guard cells of Arabidopsis thaliana. We show that their combined action is required for glucose import to guard cells, providing carbon sources for starch accumulation and light-induced stomatal opening that are essential for plant growth. These findings highlight mesophyll-derived glucose as an important metabolite connecting stomatal movements with photosynthesis.
