Biology subjects

Majada, J.

Publications and source records attributed to Majada, J..

3 recordsLinked to original sources

bioRxiv2026

Unveiling the Toxicological and Allelopathic Effects of Pteridium aquilinum: Chemical Profiling and Biological Assays

The fern Pteridium aquilinum (bracken) is among the world most widespread plants and poses serious ecological and health risks due to the presence of illudane glycosides (IGs), carcinogenic compounds that particularly affect grazing livestock. This study determined the presence of IGs in plant extracts and in water samples from the Asturias region (northern Spain), an area characterized by intensive cattle farming, and assessed the genotoxic potential, and allelopathic effects of these samples. The glycosides ptaquiloside (PTA) and ptesculentoside (PTE), together with the degradation products pterosin A and pterosin B, were quantified in in vitro-cultured gametophytes and young sporophytes, spring-collected croziers, and autumn water samples from several bracken-infested sites. All sampling locations contained IGs in both plant and water samples, with particularly high concentrations of PTA detected in croziers from Brana Vieja (Somiedo), where cattle deaths had been reported. In vivo genotoxicity assays, using Drosophila melanogaster, revealed induction of somatic mutations and recombination events by aqueous plant extracts and of somatic mutations by water samples. The genotoxic activity of plant extracts, but not that of water samples, was associated with pterosins A and B. Moreover, comet assays in cultured human cells confirmed the genotoxic activity of plant extracts. Unexpectedly, allelopathic bioassays indicated a possible phytostimulatory rather than inhibitory effect of bracken extracts on the germination of meadow species. These findings underscore the widespread presence and biological activity of bracken in northern Spain and highlight the urgent need for management strategies to mitigate the ecological and toxicological threats posed by bracken proliferation.

pharmacology and toxicology↗

bioRxiv2024

An analysis of natural variation in Pinus pinaster through the lens of systems biology

Pinus pinaster is a main species in Mediterranean forests, being naturally distributed through the Mediterranean basin, covering regions with a variety of geoclimatic conditions. This distribution in different environments leads, by natural selection, to a natural variation within the species that manifests at phenotypic level in populations with different growth features and overall tree architectures. Studying P. pinaster natural variation is necessary to understand the genetic heritage of the species and can provide valuable information for information-based decision-making regarding forest management and breeding programmes. In this paper, we analyzed the natural variation in needles and buds from three provenances from contrasting geoclimatic locations using a common garden approach and proteomics. The integration of the proteomics data with tree growth-related parameters, geoclimatic features at provenances original locations, and sample-matched metabolomics data previously generated provided novel knowledge on metabolism rearrangements related to secondary metabolism and associated to growth features and the adaptation to light and UV-B radiation intensities.

plant biology↗

bioRxiv2020

Polygenic adaptation and negative selection across traits, years and environments in a long-lived plant species (Pinus pinaster Ait.)

A decade of association studies in multiple organisms suggests that most complex traits are polygenic; that is, they have a genetic architecture determined by numerous loci distributed across the genome, each with small effect-size. Thus, determining the degree of polygenicity and its variation across traits, environments and years is useful to understand the genetic basis of phenotypic variation. In this study, we applied multilocus approaches to estimate the degree of polygenicity of fitness-related traits in a long-lived plant (Pinus pinaster Ait., maritime pine) and to analyze how polygenicity changes across environments and years. To do so, we evaluated five categories of fitness-related traits (survival, height, phenology-related, functional, and biotic-stress response traits) in a clonal common garden network, planted in contrasted environments (over 12,500 trees). First, most of the analyzed traits showed evidence of local adaptation based on QST-FST comparisons. Second, we observed a remarkably stable degree of polygenicity, averaging 6% (range of 0-27%), across traits, environments and years. As previously suggested for humans, some of these traits showed also evidence of negative selection, which could explain, at least partially, the high degree of polygenicity. The observed genetic architecture of fitness-related traits in maritime pine supports the polygenic adaptation model. Because polygenic adaptation can occur rapidly, our study suggests that current predictions on the capacity of natural forest tree populations to adapt to new environments should be revised, which is of special relevance in the current context of climate change.

genetics↗