Biology subjects

Moradi, A.

Publications and source records attributed to Moradi, A..

7 recordsLinked to original sources

bioRxiv2026

Physiological signatures but no evidence for universal genomic predictors of extreme drought responses in European beech

Following a severe 2018 drought affecting much of Europe, European beech (Fagus sylvatica) exhibited patchy canopy dieback. To investigate the drivers of this mortality, we used a paired case-control design across Swiss forests, integrating phenotypic assessments and genomic analyses. Phenotypically, crown transparency and discoloration were used to classify tree damage state, while several other characteristics were measured to evaluate whether paired, neighboring damaged and undamaged trees were otherwise comparable, and to identify physiological stress signatures. Elevated leaf calcium content and red edge reflectance in dried leaves emerged as robust indicators of physiological stress. Genomic association models using reference-based SNP markers and reference-free k-mers were heavily confounded by micro-environmental variance and local population stratification even within our geographically limited study region. Our cross-validated genomic outliers showed no spatial overlap with predictive drought-associated loci previously identified in an independent German cohort. These findings indicate that drought survival in European beech is not governed by a universal set of major-effect alleles. Instead, tree performance appears highly context-dependent, likely shaped by micro-environmental heterogeneity and phenotypic condition. However, our results do not exclude polygenic drought responses involving multiple small-effect loci.

ecology↗

bioRxiv2025

The effects of mindfulness on working memory: a systematic review and meta-analysis

ObjectivesMindfulness is a promising health intervention, showing potential effects on cognitive functions like memory. Despite evidence suggesting mindfulness improves working memory, inconsistencies in results and methodologies prevent definitive conclusions. This meta-analysis examines the effects of mindfulness interventions on working memory across clinical and healthy populations, and various age groups. MethodsA systematic search for relevant English and Persian articles was conducted in WOS, Scopus, PsycINFO, and PubMed databases, along with nine meta-analyses up to February 2023. Included studies consisted of randomized controlled trials (RCTs), controlled trials (CTs), and single-group studies. Overall, 29 studies with 2076 participants aged 5-85 years were analyzed. ResultsMindfulness interventions demonstrated a medium effect size on working memory: RCT two-group studies (Hedges g = 0.438, p < 0.001), CT two-group studies (Hedges g = 0.385, p < 0.005), and single-group studies (Hedges g = 0.583, p < 0.001). These findings confirm the effectiveness of mindfulness interventions in improving working memory. ConclusionsMindfulness interventions exhibit promising effects on working memory. However, further primary research, particularly rigorous RCTs, is needed to better understand their impacts on clinical versus healthy populations and across diverse age groups.

neuroscience↗

bioRxiv2024

Leaf spectroscopy reveals drought response variation in Fagus sylvatica saplings from across the species' range

The common European beech (F. sylvatica), sensitive to prolonged drought, is expected to shift its distribution with climate change. To persist in novel environments, young trees rely on the capacity to express diverse response phenotypes. Several methods exist to study drought effects on trees and their diverse adaptive mechanisms, but these are usually destructive and challenging for the large sample numbers needed to investigate biological variation. We conducted a common garden experiment outdoors, but under controlled watering conditions, with 180 potted two-year-old saplings from 16 beech provenances across the species range, representing three distinct genetic clusters. Drought stress was simulated by interrupting irrigation and stomatal conductance and soil moisture were used to assess drought severity. We measured leaf reflectance of visible to short-wave infrared electromagnetic radiation to determine droughtinduced changes in biochemical and structural traits derived from spectral indices and a model of leaf optical properties. We quantified changes in pigmentation, water balance, nitrogen, lignin, epicuticular wax, and leaf mass per area in drought-treated saplings, revealing differences in likely adaptive responses to drought. Fagus sylvatica saplings from the Iberian Peninsula showed signatures of greater drought resistance, i.e., the least droughtinduced change in spectrally derived traits related to leaf pigments and leaf water content. We demonstrate that high-resolution leaf spectroscopy is an effective and non-destructive tool to assess individual drought responses that can characterize functional intraspecific variation among young beech trees. Next, this approach should be scaled up to canopy-level or airborne spectroscopy to support drought response assessments of forests. Plain language summaryThe common European beech tree, which is sensitive to prolonged droughts, is expected to experience local population declines due to climate change. To survive in a drier and warmer climate, young beech trees must show a variety of adaptive responses. Assessing this variation within the species is challenging, and traditional methods often harm the trees, limiting large-scale studies of their variability. We conducted an outdoor experiment with 180 potted young beech saplings from various European regions, simulating a severe drought by halting irrigation. Using advanced leaf reflectance measurements, we tracked biochemical and structural changes in the leaves, such as pigmentation, water content, and other traits. Our results highlight that beech saplings from the Iberian Peninsula demonstrated greater drought resistance, showing fewer changes compared to saplings from other regions. This study underscores the effectiveness of non-destructive, high-resolution leaf spectroscopy in assessing individual drought responses, revealing important insights into the adaptive capacity of beech trees under changing climatic conditions. Key PointsO_LILeaf reflectance measurements effectively track drought-induced trait changes in beech saplings in a non-destructive way. C_LIO_LIBeech saplings from the Iberian Peninsula show greater drought resistance with fewer biochemical and structural changes. C_LIO_LIHigh-resolution leaf spectroscopy reveals adaptive capacity differences within European beech populations under simulated drought stress. C_LI

ecology↗

bioRxiv2024

Covering the bases: population genomic structure of Lemna minor and the cryptic species L. japonica in Switzerland

Duckweeds, including the common duckweed Lemna minor, are increasingly used to test eco-evolutionary theories. Yet, despite its popularity and near-global distribution, the understanding of its population structure (and genetic variation therein) is still limited. It is essential that this is resolved, because of the impact genetic diversity has on experimental responses and scientific understanding. Through whole-genome sequencing, we assessed the genetic diversity and population genomic structure of 23 natural Lemna spp. populations from their natural range in Switzerland. We used two distinct analytical approaches, a reference-free kmer approach and the classical reference-based one. Two genetic clusters were identified across the described species distribution of L. minor, surprisingly corresponding to species-level divisions. The first cluster contained the targeted L. minor individuals and the second contained individuals from a cryptic species: Lemna japonica. Within the L. minor cluster, we identified a well-defined population structure with little intra-population genetic diversity (i.e. within ponds) but high inter-population diversity (i.e. between ponds). In L. japonica, the population structure was significantly weaker and genetic variation between a subset of populations was as low as within populations. This study revealed that Lemna japonica is more widespread than previously thought. Our findings signify that thorough genotype-to-phenotype analyses are needed in duckweed experimental ecology and evolution.

genomics↗

bioRxiv2023

Photoemission electron microscopy for connectomics

1Detailing the physical basis of neural circuits with large-volume serial electron microscopy (EM), connectomics, has emerged as an invaluable tool in the neuroscience armamentarium. However, imaging synaptic resolution connectomes is currently limited to either transmission electron microscopy (TEM) or scanning electron microscopy (SEM). Here, we describe a third way, using photoemission electron microscopy (PEEM) which illuminates ultra-thin brain slices collected on solid substrates with UV light and images the photoelectron emission pattern with a wide-field electron microscope. PEEM works with existing sample preparations for EM and routinely provides sufficient resolution and contrast to reveal myelinated axons, somata, dendrites, and sub-cellular organelles. Under optimized conditions, PEEM provides synaptic resolution; and simulation and experiments show that PEEM can be transformatively fast, at Gigahertz pixel rates. We conclude that PEEM imaging leverages attractive aspects of SEM and TEM, namely reliable sample collection on robust substrates combined with fast wide-field imaging, and could enable faster data acquisition for next-generation circuit mapping.

neuroscience↗

bioRxiv2023

Inferring genetic structure of European beech from observations of spectral phenotypes

Biodiversity loss presents a growing threat to the global environment, and systematic and spatially contiguous monitoring is needed to inform mitigation strategies. Monitoring of genetic diversity within species, a key factor when assessing biodiversity loss, is laborious and could be supported by scalable phenotypic observations allowing inferences about genetic variation. We studied genetic and phenotypic variation in one of Europes most prevalent forest-forming trees, the common beech Fagus sylvatica L., using whole-genome sequence data and spectral phenotypes from 219 individuals at 23 sites across the species natural range. Spectral phenotypes were collected under standardized illumination and observation conditions from the same top-of-canopy leaves used for nuclear DNA extraction. We found that spectral and environmental information accounted for 77% of the variance along the first two principal coordinates representing genetic structure among sampled individuals, where spectral phenotypes contributed 12% to the prediction of genetic structure. Further, we identified 14 SNPs (single nucleotide polymorphisms), of which two were located within annotated genes, that showed significant associations with variation in leaf reflectance. Our study demonstrates how linking spectral and genomic variation in tree species may be upscaled to the remote observations to support monitoring, understanding and mitigating loss of genetic diversity within species.

plant biology↗

bioRxiv2021

Expression of a fungal lectin in Arabidopsis enhances plant growth and resistance towards microbial pathogens and plant-parasitic nematode

Coprinopsis cinerea lectin 2 (CCL2) is a fucoside-binding lectin from the basidiomycete C. cinerea that is toxic to the bacterivorous nematode Caenorhabditis elegans as well as animal-parasitic and fungivorous nematodes. We expressed CCL2 in Arabidopsis to assess its protective potential towards plant-parasitic nematodes. Our results demonstrate that expression of CCL2 enhances host resistance against the cyst nematode Heterodera schachtii. Surprisingly, CCL2-expressing plants were also more resistant to fungal pathogens including Botrytis cinerea, and the phytopathogenic bacterium Pseudomonas syringae. In addition, CCL2 expression positively affected plant growth indicating that CCL2 has the potential to improve two important agricultural parameters namely biomass production and general disease resistance. The mechanism of the CCL2-mediated enhancement of plant disease resistance depended on fucoside-binding by CCL2 as transgenic plants expressing a mutant version of CCL2 (Y92A), compromised in fucoside-binding, exhibited wild type disease susceptibility. The protective effect of CCL2 did not seem to be direct as the lectin showed no growth-inhibition towards B. cinerea in in vitro assays. We detected, however, a significantly enhanced transcriptional induction of plant defense genes in CCL2- but not CCL2-Y92A-expressing lines in response to infection with B. cinerea compared to wild type plants. This study demonstrates a potential of fungal defense lectins in plant protection beyond their use as toxins.

plant biology↗