Examinando por Autor "Illuminati, Angela"

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Ecological drivers of fine-scale distribution of arbuscular mycorrhizal fungi in a semiarid Mediterranean scrubland
(Oxford Academic, 2023-06) López-Angulo, Jesús; Matesanz, Silvia; Illuminati, Angela; Sánchez Pescador, David; Sánchez, Ana María; Pías, Beatriz; Chacón-Labella, Julia; De la Cruz, Marcelino; Escudero, Adrián
Background and Aims Arbuscular mycorrhizal (AM) fungi enhance the uptake of water and minerals by the plant hosts, alleviating plant stress. Therefore, AM fungal–plant interactions are particularly important in drylands and other stressful ecosystems. We aimed to determine the combined and independent effects of above- and below-ground plant community attributes (i.e. diversity and composition), soil heterogeneity and spatial covariates on the spatial structure of the AM fungal communities in a semiarid Mediterranean scrubland. Furthermore, we evaluated how the phylogenetic relatedness of both plants and AM fungi shapes these symbiotic relationships. Methods We characterized the composition and diversity of AM fungal and plant communities in a dry Mediterranean scrubland taxonomically and phylogenetically, using DNA metabarcoding and a spatially explicit sampling design at the plant neighbourhood scale. Key Results The above- and below-ground plant community attributes, soil physicochemical properties and spatial variables explained unique fractions of AM fungal diversity and composition. Mainly, variations in plant composition affected the AM fungal composition and diversity. Our results also showed that particular AM fungal taxa tended to be associated with closely related plant species, suggesting the existence of a phylogenetic signal. Although soil texture, fertility and pH affected AM fungal community assembly, spatial factors had a greater influence on AM fungal community composition and diversity than soil physicochemical properties. Conclusions Our results highlight that the more easily accessible above-ground vegetation is a reliable indicator of the linkages between plant roots and AM fungi. We also emphasize the importance of soil physicochemical properties in addition to below-ground plant information, while accounting for the phylogenetic relationships of both plants and fungi, because these factors improve our ability to predict the relationships between AM fungal and plant communities.
Estimating belowground plant abundance with DNA metabarcoding
(Wiley, 2019-09) Matesanz, Silvia; Pescador, David S.; Pías, Beatriz; Sánchez, Ana M.; Chacón-Labella, Julia; Illuminati, Angela; De la Cruz, Marcelino; López-Angulo, Jesús; Marí-Mena, Neus; Vizcaíno, Antón; Escudero, Adrián
Most work on plant community ecology has been performed above ground, neglecting the processes that occur in the soil. DNA metabarcoding, in which multiple species are computationally identified in bulk samples, can help to overcome the logistical limitations involved in sampling plant communities belowground. However, a major limitation of this methodology is the quantification of species’ abundances based on the percentage of sequences assigned to each taxon. Using root tissues of five dominant species in a semi-arid Mediterranean shrubland (Bupleurum fruticescens, Helianthemum cinereum, Linum suffruticosum, Stipa pennata and Thymus vulgaris), we built pairwise mixtures of relative abundance (20%, 50% and 80% biomass), and implemented two methods (linear model fits and correction indices) to improve estimates of root biomass. We validated both methods with multispecies mixtures that simulate field-collected samples. For all species, we found a positive and highly significant relationship between the percentage of sequences and biomass in the mixtures (R2 = .44–.66), but the equations for each species (slope and intercept) differed among them, and two species were consistently over- and under-estimated. The correction indices greatly improved the estimates of biomass percentage for all five species in the multispecies mixtures, and reduced the overall error from 17% to 6%. Our results show that, through the use of post-sequencing quantification methods on mock communities, DNA metabarcoding can be effectively used to determine not only species’ presence but also their relative abundance in field samples of root mixtures. Importantly, knowledge of these aspects will allow us to study key, yet poorly understood, belowground processes.
Functional differences between herbs and woody species in a semiarid Mediterranean plant community: A whole-plant perspective on growth, nutrient-use and size
(Wiley, 2024-11-10) Illuminati, Angela; Matesanz, Silvia; Pías, Beatriz; Sánchez, Ana M.; Cruz, Marcelino de la; Ramos-Muñoz, Marina; López-Angulo, Jesús; Pescador, Daid S.; Escudero, Adrián
Despite decades of research, a comprehensive understanding of trait coordination at the whole-plant level remains elusive. Furthermore, while the link between above-ground growth rates and leaf traits related to nutrient use is well established, much less is known about the below-ground compartment. Herbs and woody species exhibit distinct above-ground growth and nutrient-use strategies, but whether these differences extend to root traits below-ground remains unclear. We carried out a common garden experiment with 23 perennials (7 herbs and 16 woody species) coexisting in a Mediterranean shrubland and measured 17 above-ground and below-ground traits related to growth, nutrient use and size. We analysed the links between growth rate and nutrient use focusing especially on roots and considering potential differences between herbs and woody species. We also combined plant size data from experimental juveniles and field-sampled adults to determine the effects of life stage on whole-plant phenotypic integration. We found a significant relationship between growth rates (both above-ground and below-ground) and root nutrient-use strategies. Root diameter was negatively associated to growth rate only in herbs. Specific root area and root tissue density were positively and negatively correlated with growth rate, respectively, in both herbs and woody species. Moreover, we found significant differences in roots traits between herbs and woody species. Plant growth rate and root nutrient-use strategies were both positively associated to plant size (height and above-ground diameter) in juveniles, while a negative relationship was observed in adults. Our work provides insights on the links between whole-plant growth rate and nutrient-use strategies in species from a dry Mediterranan shrubland. Specifically, we show that whole-plant growth rate is strongly associated to root traits, with more acquisitive root nutrient-use strategies related to faster growth rates, which in turn translated to greater plant size in juveniles but smaller in adults. Our results also highlight root functional differences and contrasting patterns of whole-plant phenotypic integration between herbs and woody species, offering deeper insights into species coexistence in species-rich dry Mediterranean environments
Larger aboveground neighbourhood scales maximise similarity but do not eliminate discrepancies with belowground plant diversity in a Mediterranean shrubland
(Springer, 2021-01-15) Illuminati, Angela; López-Angulo, Jesús; De la Cruz, Marcelino; Chacón-Labella, Julia; Pescador, David S.; Pías, Beatriz; Sánchez, Ana M.; Escudero, Adrián; Matesanz, Silvia
Aims An unresolved question in plant ecology is whether diversity of the aboveground and belowground compartments of a plant community is similar at different neighbourhood scales. We investigated how the similarity between both compartments varies with the aboveground sampling grain and if significant discrepancies exist between aboveground and belowground plant diversity at the maximum similarity scale. Methods We fully mapped the aboveground perennial plant community of a 64 m2 plot in a Mediterranean shrubland and analysed this compartment by assessing diversity in 5 to 50 cm radii circles centred in soil cores. We sampled 2.5 cm radius root cores at two different depths and identified plant species by using DNA metabarcoding to characterise the belowground compartment. We quantified differences in species richness, composition and species’ spatial distribution above- and belowground. Results The differences between aboveground and belowground communities were affected by the size of the aboveground sampling grain and were minimised when considering a circle of 20 cm radius in the aboveground. We found a significant dissimilarity in richness and composition between the two compartments, with larger differences when considering the deeper soil layer only. Conclusions Our results showed that the spatial grain selected to sample a plant community aboveground and belowground is critical to characterise them in a comparable manner. Although their composition is related, species distribution patterns strongly differ, suggesting the simultaneous action of different assembly mechanisms. Our results call for caution when studying community assembly considering only the standing vegetation, since total plant diversity can be underappreciated.
The importance of belowground processes in drylands: from an individual to a whole plant community perspective
(Universidad Rey Juan Carlos, 2022) Illuminati, Angela
A plant trait-based approach and the identification of functional trade-offs are key tools in plant ecology to link plant form and function. In the last decades, increasing attention has been given to root traits to integrate them with leaf and stem traits and achieve a whole-individual perspective of plant functional strategies. The gap between aboveground and belowground data is still very high, hampering the development of a general framework and theory describing plant functioning and sources of phenotypic variation. In this context, in drylands, where soil water and nutrients represent the main constraints for plant survival and development, plant strategies related to both water and nutrient use are of special interest as they are directly connected to plant performance and community dynamics. A growing body of evidence points out that the spatial scale of the study strongly affects the observed patterns of trait coordination and functional trade-offs, because the processes that filter the traits shaping plant communities are spatial-scale dependent. Furthermore, evolutionary history exerts a strong effect on the functional characterization of the plant community, thus demanding its consideration when searching for plant functional trade-offs. Recently, increasing efforts have been carried out to characterize species distribution belowground, as a result of new straightforward techniques, such as DNA metabarcoding, which provide the necessary tools to investigate what for long has been coined the hidden part of plant communities. Given the importance of plant-plant and plant-soil (including both biotic and abiotic factors) interactions in arid environments, the assessment of both taxonomical and functional diversity patterns belowground will likely shed some light on the mechanistic aspects of community assembly and species coexistence.
The role of root community attributes in predicting soil fungal and bacterial community patterns
(Wiley, 2020-11) López-Angulo, Jesús; De la Cruz, Marcelino; Chacón-Labella, Julia; Illuminati, Angela; Matesanz, Silvia; Pescador, David S.; Pías, Beatriz; Sánchez, Ana M.; Escudero, Adrián
Roots are assumed to play a major role in structuring soil microbial communities, but most studies exploring the relationships between microbes and plants at the community level have only used aboveground plant distribution as a proxy. However, a decoupling between belowground and aboveground plant components may occur due to differential spreading of plant canopies and root systems. Thus, soil microbe–plant links are not completely understood. Using a combination of DNA metabarcoding and spatially explicit sampling at the plant neighbourhood scale, we assessed the influence of the plant root community on soil bacterial and fungal diversity (species richness, composition and β-diversity) in a dry Mediterranean scrubland. We found that root composition and biomass, but not richness, predict unique fractions of variation in microbial richness and composition. Moreover, bacterial β-diversity was related to root β-diversity, while fungal β-diversity was related to aboveground plant β-diversity, suggesting that plants differently influence both microbial groups. Our study highlights the role of plant distribution both belowground and aboveground, soil properties and other spatially structured factors in explaining the heterogeneity in soil microbial diversity. These results also show that incorporating data on both plant community compartments will further our understanding of the relationships between soil microbial and plant communities.