Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background and Aims</jats:title> <jats:p>Nitrogenous fertilizers provide a short-lived benefit to crops in agroecosystems, but stimulate nitrification and denitrification, processes that result in nitrate pollution, N<jats:sub>2</jats:sub>O production, and reduced soil fertility. Recent advances in plant microbiome science suggest that genetic variation in plants can modulate the composition and activity of rhizosphere N-cycling microorganisms. Here we attempted to determine whether genetic variation exists in <jats:italic>Zea mays</jats:italic> for the ability to influence the rhizosphere nitrifier and denitrifier microbiome under “real-world” conventional agricultural conditions.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>To capture an extensive amount of genetic diversity within maize we grew and sampled the rhizosphere microbiome of a diversity panel of germplasm that included ex-PVP inbreds (<jats:italic>Z. mays</jats:italic> ssp. <jats:italic>mays</jats:italic>), ex-PVP hybrids (<jats:italic>Z. mays</jats:italic> ssp. <jats:italic>mays</jats:italic>), and teosinte (<jats:italic>Z. mays</jats:italic> ssp<jats:italic>. mexicana</jats:italic> and <jats:italic>Z. mays</jats:italic> ssp. <jats:italic>parviglumis</jats:italic>). From these samples, we characterized the microbiome, a suite of microbial genes involved in nitrification and denitrification and carried out N-cycling potential assays.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Here we are showing that populations/genotypes of a single species can vary in their ecological interaction with denitrifers and nitrifers. Some hybrid and teosinte genotypes supported microbial communities with lower potential nitrification and potential denitrification activity in the rhizosphere, while inbred genotypes stimulated/did not inhibit these N-cycling activities. These potential differences translated to functional differences in N<jats:sub>2</jats:sub>O fluxes, with teosinte plots producing less GHG than maize plots.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Taken together, these results suggest that <jats:italic>Zea</jats:italic> genetic variation can lead to changes in N-cycling processes that result in N leaching and N<jats:sub>2</jats:sub>O production, and thereby are selectable targets for crop improvement. Understanding the underlying genetic variation contributing to belowground microbiome N-cycling into our conventional agricultural system could be useful for sustainability.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aims</jats:title> <jats:p>The aim of the project was to determine the vertical variability of soil under the influence of deadwood (DWD) in a temperate forest ecosystem.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>The laboratory analyses included soil layers of 0–5 cm, 5–10 cm, 10–20 cm and 20–40 cm, which were taken directly under the deadwood, as well as the forest litter layer and deadwood fragments. The control samples were taken 30 m away.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The decomposition processes of deadwood are associated with a 55% increase in soil organic carbon (SOC) deposition to a depth of -40 cm and a 36% increase in total nitrogen (N) content compared to soils without deadwood. DWD significantly increases exchangeable cations, especially at a depth of -5 cm to -20 cm. Deadwood contains slightly more hydrogen (H<jats:sup>+)</jats:sup> and aluminum ions (Al<jats:sup>3+</jats:sup>) than forest litter, but soil acidification is related to pedogenic processes rather than decomposition of deadwood in hyperacid forest soils. The soil surface under deadwood with a high degree of decomposition is characterised by a lower bulk density (BD) value than the soil where only forest litter was present.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Our studies suggest that the physicochemical properties of forest soils change under the influence of deadwood such that the deeper layers beneath the logs take on propertie8s that make them similar to the shallower layers without deadwood. To summarise, leaving deadwood in the forest has a positive effect on soil fertility by enriching the soil with nutrients (Ca<jats:sup>2+</jats:sup>, K<jats:sup>+</jats:sup>, Na<jats:sup>+</jats:sup>, less Mg<jats:sup>2+</jats:sup>) and improving its physical properties.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background/Aims</jats:title> <jats:p>The European larch is a pioneer tree and a valuable economic resource in subalpine ecosystems, thus playing crucial roles to ecosystem services and human activities. However, their ectomycorrhizal fungal community remains unknown in high altitudinal natural habitats. Here, we explore the mycobiont diversity of <jats:italic>Larix decidua</jats:italic> var. <jats:italic>decidua</jats:italic> between naturally rejuvenated and adult trees, compare ectomycorrhizal colonization patterns in geographically disjunct areas within the Alps of South Tyrol, Italy, characterized by distinct climatic conditions, and explore turnover rates across various seasons.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Our approach combines morphotyping of mycorrhized root tips with molecular analysis. Particular effort was given to monitor both ectomycorrhizal host-specialist and -generalist fungi.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Both adult and young trees show a 100% mycorrhization rate, with a total diversity of 68 ectomycorrhizal species. The ectomycorrhizal composition is dominated by typical host specialists of larch trees (e.g., <jats:italic>Lactarius porninsis</jats:italic>, <jats:italic>Russula laricina</jats:italic>, <jats:italic>Suillus cavipes</jats:italic>, <jats:italic>S. grevillei</jats:italic>, <jats:italic>S. viscidus</jats:italic>), which are widely distributed across sites. A rich diversity of host generalists was also detected. The composition of rare species within a habitat was comparatively consistent during one sampling campaign, but exhibited significant differences among individual sampling campaigns. The ectomycorrhizal compositions were only weakly correlated with distinct climatic conditions and tree ages. However, species richness and diversity, particularly of generalist fungi, was consistently higher in warmer, drier sites compared to cooler, more humid ones.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>This study suggests potential mycobiont community shifts across climatic conditions with significant implications for the adaptability and resilience of subalpine forests in the face of climate change.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Aims</jats:title> <jats:p>The spread of invasive weeds threatens biodiversity and stability of ecosystems. <jats:italic>Jacobaea vulgaris</jats:italic> is an invasive weed in some countries and an outbreak species in its native European range. Although biological control using specialist herbivores is available, controlling with soil microorganisms remains far less explored.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Twenty bacteria strains isolated from roots of <jats:italic>J. vulgaris</jats:italic> were used to examine bacterial effects on seed germination, root morphology and early plant growth. Moreover, we tested direct effects of the bacteria on a specialist herbivore of <jats:italic>J. vulgaris</jats:italic>, the leaf chewing caterpillar (<jats:italic>Tyria jacobaeae</jats:italic>), commonly used in biocontrol. We also tested indirect effects of bacteria, via the plant, on the performance of <jats:italic>T. jacobaeae</jats:italic> and the aphid species <jats:italic>Aphis jacobaeae</jats:italic>. Lastly, we examined the host specificity of two tested bacteria on three other forbs.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Two Gammaproteobacteria, <jats:italic>Pseudomonas brassicacearum</jats:italic> and <jats:italic>Serratia plymuthica</jats:italic>, significantly reduced root growth of seedlings in-vitro, while seed germination was unaffected. However, these negative effects were observed across other forb species as well. <jats:italic>Bacillus</jats:italic> spp. injection led to the highest <jats:italic>T. jacobaeae</jats:italic> caterpillar mortality, while ingestion had no effect. Inoculation of the plants with bacteria did not affect aphid performance, but significantly affected <jats:italic>T. jacobaeae</jats:italic> preference. Specifically, <jats:italic>P. syringae</jats:italic> and one <jats:italic>Bacillus</jats:italic> sp. strain significantly increased <jats:italic>T. jacobaeae</jats:italic> preference.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Our results show that two root-associated bacteria inhibit <jats:italic>J. vulgaris</jats:italic> growth, but their lack of host specificity restricts their potential for biocontrol. Our study also highlights that belowground microorganisms can hamper or enhance the performance of aboveground insects.</jats:p> </jats:sec>