RESUMEN
Our study delved into the relationship between root-associated fungi, gene expression and plant morphology in Norway spruce cuttings derived from both slow-and fast-growing trees. We found no clear link between the gene expression patterns of adventitious roots and the growth phenotype, suggesting no fundamental differences in the receptiveness to fungal symbionts between the phenotypes. Interestingly, saplings from slow-growing parental trees exhibited a higher richness of ectomycorrhizal species and larger roots. Some ectomycorrhizal species, typically found on mature spruces, were more prevalent on saplings from slow-growing spruces. The ericoid mycorrhizal fungus, Hyaloscypha hepaticola, showed a stronger association with saplings from fast-growing spruces. Moreover, saplings from slow-growing spruces had a greater number of Ascomycete taxa and free-living saprotrophic fungi. Aboveground sapling stems displayed some phenotypic variation; saplings from fast-growing phenotypes had longer branches but fewer whorls in their stems compared to those from the slow-growing group. In conclusion, the observed root-associated fungi and phenotypic characteristics in young Norway spruces may play a role in their long-term growth rate. This suggests that the early interactions between spruces and fungi could potentially influence their growth trajectory.
Asunto(s)
Micorrizas , Picea , Raíces de Plantas , Picea/microbiología , Picea/crecimiento & desarrollo , Raíces de Plantas/microbiología , Raíces de Plantas/crecimiento & desarrollo , Micorrizas/genética , Micorrizas/crecimiento & desarrollo , Micorrizas/fisiología , Noruega , Simbiosis , Hongos/genética , Hongos/clasificación , Hongos/crecimiento & desarrollo , Ascomicetos/genética , Ascomicetos/crecimiento & desarrolloRESUMEN
The bark represents the outer protective layer of trees. It contains high concentrations of antimicrobial extractives, in addition to regular wood polymers. It represents a huge underutilized side stream in forestry, but biotechnological valorization is hampered by a lack of knowledge on microbial bark degradation. Many fungi are efficient lignocellulose degraders, and here, spruce bark degradation by five species, Dichomitus squalens, Rhodonia placenta, Penicillium crustosum, Trichoderma sp. B1, and Trichoderma reesei, was mapped, by continuously analyzing chemical changes in the bark over six months. The study reveals how fungi from different phyla degrade bark using diverse strategies, regarding both wood polymers and extractives, where toxic resin acids were degraded by Basidiomycetes but unmodified/tolerated by Ascomycetes. Proteome analyses of the white-rot D. squalens revealed several proteins, with both known and unknown functions, that were specifically upregulated during growth on bark. This knowledge can accelerate improved utilization of an abundant renewable resource.
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Picea , Corteza de la Planta , Polisacáridos , Picea/microbiología , Corteza de la Planta/química , Polisacáridos/metabolismo , Hongos/metabolismo , Lignina/metabolismo , Biodegradación Ambiental , Proteínas Fúngicas/metabolismoRESUMEN
Research has shown that forest management can improve the post-drought growth and resilience of Qinghai spruce in the eastern Qilian Mountains, located on the northeastern Tibetan Plateau. However, the impact of such management on the tree-associated phyllosphere microbiome is not yet fully understood. This study provides new evidence of positive forest management effects on the phyllosphere microbiome after extreme drought, from the perspectives of community diversity, structure, network inference, keystone species, and assembly processes. In managed Qinghai spruce forest, the α-diversity of the phyllosphere bacterial communities increased, whereas the ß-diversity decreased. In addition, the phyllosphere bacterial community became more stable and resistant, yet less complex, following forest management. Keystone species inferred from a bacterial network also changed under forest management. Furthermore, forest management mediated changes in community assembly processes, intensifying the influence of determinacy, while diminishing that of stochasticity. These findings support the hypothesis that management can re-assemble the phyllosphere bacterial community, enhance community stability, and ultimately improve tree growth. Overall, the study highlights the importance of forest management on the phyllosphere microbiome and furnishes new insights into forest conservation from the perspective of managing microbial processes and effects.
Asunto(s)
Bacterias , Bosques , Microbiota , Bacterias/clasificación , Agricultura Forestal/métodos , Árboles/microbiología , Picea/microbiología , Biodiversidad , Sequías , Conservación de los Recursos Naturales/métodosRESUMEN
Drought affects the complex interactions between Norway spruce, the bark beetle Ips typographus and associated microorganisms. We investigated the interplay of tree water status, defense and carbohydrate reserves with the incidence of bark beetle attack and infection of associated fungi in mature spruce trees. We installed roofs to induce a 2-yr moderate drought in a managed spruce stand to examine a maximum of 10 roof and 10 control trees for resin flow (RF), predawn twig water potentials, terpene, phenolic and carbohydrate bark concentrations, and bark beetle borings in field bioassays before and after inoculation with Endoconidiophora polonica and Grosmannia penicillata. Drought-stressed trees showed more attacks and significantly longer fungal lesions than controls, but maintained terpene resin defenses at predrought levels. Reduced RF and lower mono- and diterpene, but not phenolic concentrations were linked with increased host selection. Bark beetle attack and fungi stimulated chemical defenses, yet G. penicillata reduced phenolic and carbohydrate contents. Chemical defenses did not decrease under mild, prolonged drought in our simulated small-scale biotic infestations. However, during natural mass attacks, reductions in carbon fixation under drought, in combination with fungal consumption of carbohydrates, may deplete tree defenses and facilitate colonization by I. typographus.
Asunto(s)
Escarabajos , Picea , Gorgojos , Animales , Sequías , Picea/microbiología , Corteza de la Planta/química , Enfermedades de las Plantas/microbiología , Terpenos , Fenoles , Noruega , Agua/análisis , Carbohidratos/análisisRESUMEN
The mycobiome, comprising fungi inhabiting plants, potentially plays a crucial role in tree health and survival amidst environmental stressors like climate change and pathogenic fungi. Understanding the intricate relationships between trees and their microbial communities is essential for developing effective strategies to bolster the resilience and well-being of forest ecosystems as we adopt more sustainable forest management practices. The mycobiome can be considered an integral aspect of a tree's biology, closely linked to its genotype. To explore the influence of host genetics and environmental factors on fungal composition, we examined the mycobiome associated with phloem and roots of Norway spruce (Picea abies (L.) Karst.) cuttings under varying watering conditions. To test the "mycobiome-associated-fitness" hypothesis, we compared seedlings artificially inoculated with Heterobasidion parviporum and control plants to evaluate mycobiome interaction on necrosis development. We aimed to 1) identify specific mycobiome species for the Norway spruce genotypes/families within the phloem and root tissues and their interactions with H. parviporum and 2) assess stability in the mycobiome species composition under abiotic disturbances (reduced water availability). The mycobiome was analyzed by sequencing the ribosomal ITS2 region. Our results revealed significant variations in the diversity and prevalence of the phloem mycobiome among different Norway spruce genotypes, highlighting the considerable impact of genetic variation on the composition and diversity of the phloem mycobiome. Additionally, specific mycobiome genera in the phloem showed variations in response to water availability, indicating the influence of environmental conditions on the relative proportion of certain fungal genera in Norway spruce trees. In the root mycobiome, key fungi such as Phialocephala fortinii and Paraphaeosphaeria neglecta were identified as conferring inhibitory effects against H. parviporum growth in Norway spruce genotypes. Furthermore, certain endophytes demonstrated greater stability in root ecosystems under low water conditions than ectomycorrhizal fungi. This knowledge can contribute to developing sustainable forest management practices that enhance the well-being of trees and their ecosystems, ultimately bolstering forest resilience.
Asunto(s)
Microbiota , Micobioma , Picea , Humanos , Picea/microbiología , Sequías , Noruega , Microbiota/genética , Árboles/microbiología , AguaRESUMEN
The European spruce bark beetle, Ips typographus, is a serious pest of spruce forests in Europe, and its invasion and development inside spruce tissues are facilitated by microorganisms. We investigated the core gut bacterial and fungal microbiomes of I. typographus throughout its life cycle in spring and summer generations. We used cultivation techniques and molecular identification in combination with DNA and RNA metabarcoding. Our results revealed that communities differ throughout their life cycle and across generations in proportion of dominantly associated microbes, rather than changes in species composition. The bacteriome consisted mostly of the phylum Gammaproteobacteria, with the most common orders and genera being Enterobacteriales (Erwinia and Serratia), Pseudomonadales (Pseudomonas), and Xanthomonadales. The fungal microbiome was dominated by yeasts (Saccharomycetes-Wickerhamomyces, Kuraishia, and Nakazawaea), followed by Sordariomycetes (Ophiostoma bicolor and Endoconidiophora polonica). We did not observe any structure ensuring long-term persistence of microbiota on any part of the gut epithelium, suggesting that microbial cells are more likely to pass through the beetle's gut with chyme. The most abundant taxa in the beetle's gut were also identified as dominant in intact spruce phloem. Therefore, we propose that these taxa are acquired from the environment rather than specifically vectored between generations.
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Escarabajos , Microbioma Gastrointestinal , Picea , Gorgojos , Animales , Escarabajos/microbiología , Corteza de la Planta , Estaciones del Año , Gorgojos/microbiología , Estadios del Ciclo de Vida , Picea/microbiologíaRESUMEN
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.
Asunto(s)
Escarabajos , Picea , Gorgojos , Animales , Femenino , Monoterpenos/análisis , Monoterpenos/metabolismo , Árboles/microbiología , Alcanfor/análisis , Alcanfor/metabolismo , Corteza de la Planta/química , Corteza de la Planta/metabolismo , Corteza de la Planta/microbiología , Fitomejoramiento , Escarabajos/fisiología , Picea/química , Picea/metabolismo , Picea/microbiología , Feromonas/metabolismoRESUMEN
Whether intraspecific phenotypic variation in saprobic fungi may be driven by the host of origin has received little attention. We addressed this issue by testing hypotheses using the model system Phlebiopsis gigantea, a wood destroying fungus associated with Picea abies and Pinus sylvestris, among others, and widely employed in practical forestry as a biological control agent. By examining approximately 60 sympatric P. gigantea isolates from both P. abies and P. sylvestris, we showed that the former grew in vitro significantly (P < 0.05) slower than the latter (average 5.56 mm/day vs. 6.84) while producing 1.8-fold significantly higher number of mitospores. An overall significant trade-off between these two phenotypic traits was detected, in particular for isolates originating from P. abies. Comparative inoculation experiments of a subsample of isolates and the assessment of mycelial growth in logs of both hosts allowed to reject the hypothesis that isolates are equally fit in terms of growth rate in wood of both hosts regardless of the host of origin. Tree models revealed that the growth rate of isolates was associated not only with the wood species in which the isolates were inoculated (P < 0.001), P. sylvestris being more rapidly colonized than P. abies, but also with the host of origin of isolates (P < 0.001). Results showed that P. gigantea isolates originating from different hosts differ phenotypically in terms of some key phenotypic traits demonstrating that a host-driven intraspecific phenotypic variation may occur in saprobic fungi.
Asunto(s)
Abies , Picea , Pinus sylvestris , Polyporales , Hongos , Pinus sylvestris/microbiología , Variación Biológica Poblacional , Picea/microbiologíaRESUMEN
Ips typographus (L.) and Pityogenes chalcographus (L.) (Coleoptera: Curculionidae) are two common bark beetle species on Norway spruce in Eurasia. Multiple biotic and abiotic factors affect the life cycles of these two beetles, shaping their ecology and evolution. In this article, we provide a comprehensive and comparative summary of selected life-history traits. We highlight similarities and differences in biotic factors, like host range, interspecific competition, host colonization, reproductive behaviour and fungal symbioses. Moreover, we focus on the species' responses to abiotic factors and compare their temperature-dependent development and flight behaviour, cold adaptations and diapause strategies. Differences in biotic and abiotic traits might be the result of recent, species-specific evolutionary histories, particularly during the Pleistocene, with differences in glacial survival and postglacial recolonization. Finally, we discuss future research directions to understand ecological and evolutionary pathways of the two bark beetle species, for both basic research and applied forest management.
Asunto(s)
Escarabajos , Picea , Gorgojos , Animales , Gorgojos/microbiología , Corteza de la Planta/microbiología , Picea/microbiologíaRESUMEN
Clearcutting represents a standard management practice in temperate forests with dramatic consequences for the forest ecosystem. The removal of trees responsible for the bulk of primary production can result in a complex response of the soil microbiome. While studies have shown that tree root-symbiotic ectomycorrhizal fungi disappear from soil and decomposing fine roots of trees become a hotspot for fungal decomposition, the fate of the bacterial component of the soil microbiome following clearcutting is unclear. Here, we investigated the response of bacterial community composition for 2 years following clearcutting of a Picea abies stand in soil, rhizosphere and tree roots, by 16S rRNA amplicon sequencing. While in the first few months after clearcutting there was no significant response of bacterial community composition in the rhizosphere and soil, bacterial communities associated with tree roots underwent more profound changes over time. Acidobacteria were abundant in rhizosphere and soil, while Firmicutes were strongly represented in the roots. In addition, bacterial communities on decomposing roots were significantly different from those on pre-clearcut live roots. Compared with fungi, the response of bacterial communities to clearcutting was much less pronounced, indicating independent development of the two microbial domains.
Asunto(s)
Abies , Microbiota , Micorrizas , Picea , Pinus , Suelo , Picea/microbiología , Microbiología del Suelo , Hongos , ARN Ribosómico 16S/genética , Rizosfera , Bacterias/genética , Raíces de Plantas/microbiologíaRESUMEN
Carbon storage and cycling in boreal forests-the largest terrestrial carbon store-is moderated by complex interactions between trees and soil microorganisms. However, existing methods limit our ability to predict how changes in environmental conditions will alter these associations and the essential ecosystem services they provide. To address this, we developed a metatranscriptomic approach to analyze the impact of nutrient enrichment on Norway spruce fine roots and the community structure, function, and tree-microbe coordination of over 350 root-associated fungal species. In response to altered nutrient status, host trees redefined their relationship with the fungal community by reducing sugar efflux carriers and enhancing defense processes. This resulted in a profound restructuring of the fungal community and a collapse in functional coordination between the tree and the dominant Basidiomycete species, and an increase in functional coordination with versatile Ascomycete species. As such, there was a functional shift in community dominance from Basidiomycetes species, with important roles in enzymatically cycling recalcitrant carbon, to Ascomycete species that have melanized cell walls that are highly resistant to degradation. These changes were accompanied by prominent shifts in transcriptional coordination between over 60 predicted fungal effectors, with more than 5,000 Norway spruce transcripts, providing mechanistic insight into the complex molecular dialogue coordinating host trees and their fungal partners. The host-microbe dynamics captured by this study functionally inform how these complex and sensitive biological relationships may mediate the carbon storage potential of boreal soils under changing nutrient conditions.
Asunto(s)
Ascomicetos , Basidiomycota , Micorrizas , Picea , Ascomicetos/metabolismo , Basidiomycota/metabolismo , Carbono/metabolismo , Ecosistema , Bosques , Micorrizas/genética , Micorrizas/fisiología , Picea/genética , Picea/microbiología , Suelo/química , Microbiología del Suelo , Taiga , Transcriptoma , Árboles/metabolismo , Árboles/microbiologíaRESUMEN
BACKGROUND: Needle rust caused by the fungus Chrysomyxa rhododendri causes significant growth decline and increased mortality of young Norway spruce trees in subalpine forests. Extremely rare trees with enhanced resistance represent promising candidates for practice-oriented reproduction approaches. They also enable the investigation of tree molecular defence and resistance mechanisms against this fungal disease. Here, we combined RNA-Seq, RT-qPCR and secondary metabolite analyses during a period of 38 days following natural infection to investigate differences in constitutive and infection-induced defence between the resistant genotype PRA-R and three susceptible genotypes. RESULTS: Gene expression and secondary metabolites significantly differed among genotypes from day 7 on and revealed already known, but also novel candidate genes involved in spruce molecular defence against this pathogen. Several key genes related to (here and previously identified) spruce defence pathways to needle rust were differentially expressed in PRA-R compared to susceptible genotypes, both constitutively (in non-symptomatic needles) and infection-induced (in symptomatic needles). These genes encoded both new and well-known antifungal proteins such as endochitinases and chitinases. Specific genetic characteristics concurred with varying phenolic, terpene, and hormone needle contents in the resistant genotype, among them higher accumulation of several flavonoids (mainly kaempferol and taxifolin), stilbenes, geranyl acetone, α-ionone, abscisic acid and salicylic acid. CONCLUSIONS: Combined transcriptional and metabolic profiling of the Norway spruce defence response to infection by C. rhododendri in adult trees under subalpine conditions confirmed the results previously gained on artificially infected young clones in the greenhouse, both regarding timing and development of infection, and providing new insights into genes and metabolic pathways involved. The comparison of genotypes with different degrees of susceptibility proved that several of the identified key genes are differently regulated in PRA-R, and that the resistant genotype combines a strong constitutive defence with an induced response in infected symptomatic needles following fungal invasion. Genetic and metabolic differences between the resistant and susceptible genotypes indicated a more effective hypersensitive response (HR) in needles of PRA-R that prevents penetration and spread of the rust fungus and leads to a lower proportion of symptomatic needles as well as reduced symptom development on the few affected needles.
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Picea , Perfilación de la Expresión Génica , Inmunidad Innata , Picea/microbiología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Árboles/genética , Vejiga UrinariaRESUMEN
Microbial community members are the primary microbial colonizers and active decomposers of deadwood. This study placed sterilized standardized beech and spruce sapwood specimens on the forest ground of 8 beech- and 8 spruce-dominated forest sites. After 370 days, specimens were assessed for mass loss, nitrogen (N) content and 15N isotopic signature, hydrolytic and lignin-modifying enzyme activities. Each specimen was incubated with bromodeoxyuridine (BrdU) to label metabolically active fungal and bacterial community members, which were assessed using amplicon sequencing. Fungal saprotrophs colonized the deadwood accompanied by a distinct bacterial community that was capable of cellulose degradation, aromatic depolymerization, and N2 fixation. The latter were governed by the genus Sphingomonas, which was co-present with the majority of saprotrophic fungi regardless of whether beech or spruce specimens were decayed. Moreover, the richness of the diazotrophic Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium group was significantly correlated with mass loss, N content and 15N isotopic signature. By contrast, presence of obligate predator Bdellovibrio spp. shifted bacterial community composition and were linked to decreased beech deadwood decay rates. Our study provides the first account of the composition and function of metabolically active wood-colonizing bacterial and fungal communities, highlighting cross-kingdom interactions during the early and intermediate stages of wood decay.
Asunto(s)
Microbiota , Picea , Bacterias , Bosques , Hongos , Picea/microbiología , Madera/microbiologíaRESUMEN
The replacement of native birch with Norway spruce has been initiated in Norway to increase long-term carbon storage in forests. However, there is limited knowledge on the impacts that aboveground changes will have on the belowground microbiota. We examined which effects a tree species shift from birch to spruce stands has on belowground microbial communities, soil fungal biomass and relationships with vegetation biomass and soil organic carbon (SOC). Replacement of birch with spruce negatively influenced soil bacterial and fungal richness and strongly altered microbial community composition in the forest floor layer, most strikingly for fungi. Tree species-mediated variation in soil properties was a major factor explaining variation in bacterial communities. For fungi, both soil chemistry and understorey vegetation were important community structuring factors, particularly for ectomycorrhizal fungi. The relative abundance of ectomycorrhizal fungi and the ectomycorrhizal : saprotrophic fungal ratio were higher in spruce compared to birch stands, particularly in the deeper mineral soil layers, and vice versa for saprotrophs. The positive relationship between ergosterol (fungal biomass) and SOC stock in the forest floor layer suggests higher carbon sequestration potential in spruce forest soil, alternatively, that the larger carbon stock leads to an increase in soil fungal biomass.
Asunto(s)
Micorrizas , Picea , Betula/microbiología , Biota , Carbono , Bosques , Picea/microbiología , Suelo/química , Microbiología del Suelo , Taiga , ÁrbolesRESUMEN
The factors shaping the composition of the tree mycobiome are still under investigation. We tested the effects of host genotype, site, host phenotypic traits, and air fungal spore communities on the assembly of the fungi inhabiting Norway spruce needles. We used Norway spruce clones and spore traps within the collection sites and characterized both needle and air mycobiome communities by high-throughput sequencing of the ITS2 region. The composition of the needle mycobiome differed between Norway spruce clones, and clones with high genetic similarity had a more similar mycobiome. The needle mycobiome also varied across sites and was associated with the composition of the local air mycobiome and climate. Phenotypic traits such as diameter at breast height or crown health influenced the needle mycobiome to a lesser extent than host genotype and air mycobiome. Altogether, our results suggest that the needle mycobiome is mainly driven by the host genotype in combination with the composition of the local air spore communities. Our work highlights the role of host intraspecific variation in shaping the mycobiome of trees and provides new insights on the ecological processes structuring fungal communities inhabiting woody plants.
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Micobioma , Picea , Hongos/genética , Genotipo , Micobioma/genética , Picea/genética , Picea/microbiología , Esporas Fúngicas/genética , Árboles/microbiologíaRESUMEN
Urban green areas are becoming increasingly recognized for their biodiversity potential. However, little is known about how urbanization shapes cryptic species communities, such as those residing in deadwood. In this study, we investigated downed Norway spruce trunks at intermediate stages of decay, in urban and semi-natural forests in southern Finland. To understand the interconnections between landscape context, deadwood characteristics and wood-inhabiting fungal communities, we studied structural characteristics, surface epiphyte cover and internal moisture and temperature conditions of the tree trunks, and fungal communities residing in the wood. Our findings showed that urban tree trunks had less epiphyte cover and lower moisture than trunks in semi-natural forests. Overall, urban forests provide less favourable habitats for a majority of the dominant wood-inhabiting fungal species and for red-listed species as a group. Yet, 33% of urban trunks hosted at least one red-listed species. While these landscape-scale effects may be driven by local climatic conditions as well as contingencies related to available species pools, our results also highlight the significance of substrate-scale variability of deadwood in shaping wood-inhabiting fungal communities. We show that epiphyte cover is a significant driver or indicator of these small-scale dynamic processes in deadwood.
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Micobioma , Picea , Biodiversidad , Ecosistema , Bosques , Hongos/genética , Picea/microbiología , Árboles/microbiología , Madera/microbiologíaRESUMEN
Developing shoots, i.e., sprouts, and older needles of Norway spruce (Picea abies (L.) Karst.) have traditionally been used for medicinal purposes due to the high content of vitamins and antioxidants. Currently, sprouts are available as, for example, superfood and supplements. However, end-product quality and nutritive value may decline in the value-chain from raw material sourcing to processing and storage. We studied (1) impacts of different drying and extraction methods on nutritional composition and antioxidative properties of sprouts and needles, (2) differences between sprouts and needles in nutritional composition and microbiological quality, and (3) production scale quality of the sprouts. Additionally, (4) sprout powder was applied in products (ice-cream and sorbet) and consumer acceptance was evaluated. According to our results, older needles have higher content of dry matter, energy, and calcium, but lower microbial quality than sprouts. Sprouts showed a higher concentration of vitamin C, magnesium, potassium, and phosphorus than older needles. Freeze-drying was the best drying method preserving the quality of both sprouts and needles, e.g., vitamin C content. The antioxidative activity of the sprout extracts were lower than that of needles. Ethanol-water extraction resulted in a higher content of active compounds in the extract than water extraction. Sensory evaluation of food products revealed that on average, 76% of consumers considered sprout-containing products very good or good, and a creamy product was preferred over a water-based sorbet.
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Análisis de los Alimentos/métodos , Industria de Alimentos/métodos , Picea/química , Brotes de la Planta/química , Antioxidantes/farmacología , Ácido Ascórbico/química , Finlandia , Manipulación de Alimentos/métodos , Magnesio/química , Noruega , Fósforo/química , Picea/microbiología , Hojas de la Planta/química , Potasio/química , Polvos , VitaminasRESUMEN
Lodgepole pine, a prominent Pinaceae tree species native to western North America, is well-known for its ability to thrive in highly disturbed and degraded areas. One such area is the Sub-Boreal Pine-Spruce xeric-cold (SBPSxc) region in British Columbia, Canada, which is characterized by weakly-developed, parched soils that lack an organic forest floor and essential plant-available nutrients. We hypothesized that plant growth-promoting bacteria could play a significant role in sustaining the growth of lodgepole pine trees in the SBPSxc region. Testing this hypothesis, we evaluated plant growth-promoting abilities of six endophytic bacterial strains previously isolated from lodgepole pine trees growing in this region. These bacterial strains significantly enhanced the length and biomass of their natural host (lodgepole pine) as well as a foreign host (hybrid white spruce) in a 540-day long greenhouse trial. This growth stimulation could be linked to the diverse plant growth-promoting (PGP) abilities detected in these strains using in vitro assays for inorganic/organic phosphate-solubilization, siderophore production IAA production, ACC deaminase activity, lytic enzymes (chitinase, ß-1,3-glucanase, protease, and cellulase) activity, ammonia production and catalase activity. ACC deaminase activity was also detected in vivo for all strains using ethylene-sensitive plants-canola and tomato. Notably, strains belonging to the Burkholderiaceae family (HP-S1r, LP-R1r and LP-R2r) showed the greatest potential in all PGP assays and enhanced pine and spruce seedling length and biomass by up to 1.5-fold and 4-fold, respectively. Therefore, such bacterial strains with multifarious PGP abilities could be crucial for survival and growth of lodgepole pine trees in the SBPSxc region and could potentially be utilized as bioinoculant for Pinaceae trees in highly disturbed and nutrient-poor ecosystems.
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Bacterias/aislamiento & purificación , Pinaceae/crecimiento & desarrollo , Biomasa , Fosfatos de Calcio/química , Fosfatos de Calcio/metabolismo , Liasas de Carbono-Carbono/genética , Liasas de Carbono-Carbono/metabolismo , Ecosistema , Etilenos/metabolismo , Ácidos Indolacéticos/metabolismo , Picea/crecimiento & desarrollo , Picea/metabolismo , Picea/microbiología , Pinaceae/metabolismo , Pinaceae/microbiología , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Plantones/microbiología , Plantones/fisiología , Sideróforos/metabolismoRESUMEN
BACKGROUND: The Qinghai-Tibetan Plateau represents one of the most important component of the terrestrial ecosystem and a particularly vulnerable region, which harbouring complex and diverse microbiota. The knowledge about their underground microorganisms have largely been studied, but the characteristics of rhizosphere microbiota, particularly archaeal communities remains unclear. RESULTS: High-throughput Illumina sequencing was used to investigate the rhizosphere archaeal communities of two native alpine trees (Picea crassifolia and Populus szechuanica) living on the Qinghai-Tibetan Plateau. The archaeal community structure in rhizospheres significantly differed from that in bulk soil. Thaumarchaeota was the dominant archaeal phylum in all soils tested (92.46-98.01%), while its relative abundance in rhizospheres were significantly higher than that in bulk soil. Ammonium nitrogen, soil organic matter, available phosphorus and pH were significantly correlated with the archaeal community structure, and the deterministic processes dominated the assembly of archaeal communities across all soils. In addition, the network structures of the archaeal community in the rhizosphere were less complex than they were in the bulk soil, and an unclassified archaeal group (Unclassified_k_norank) was identified as the keystone species in all archaeal networks. CONCLUSIONS: Overall, the structure, assembly and co-occurrence patterns of archaeal communities are significantly affected by the presence of roots of alpine trees living on the Qinghai-Tibetan Plateau. This study provides new insights into our understanding of archaeal communities in vulnerable ecosystems.