Biology subjects

Vidal, J. d. D.

Publications and source records attributed to Vidal, J. d. D..

3 recordsLinked to original sources

bioRxiv2024

Molecular attributes of the tropical tree Avicennia schaueriana involved in the response and tolerance to low temperatures

Mangroves are coastal ecosystems of great socioenvironmental importance that are highly threatened by human activities. Mangrove trees live under harsh environmental conditions, which makes them sensitive to extreme weather events, particularly freezing events. Such events are unpredictable and have catastrophic consequences for mangrove trees; therefore, understanding and anticipating the impacts of such events are essential for directing future mitigation measures. Freezing cold currently limits the distribution of mangroves to tropical and subtropical latitudes worldwide. Mangrove trees are seriously affected by freezing conditions and suffer severe metabolic fluctuations due to photosystem and cellular structure damage. However, land plants more broadly have developed sophisticated mechanisms of resistance to freezing during their evolution, and the central molecular mechanisms involved in this process are consistent. However, the known information is restricted to models of herbaceous plants, such as Arabidopsis thaliana, that are native to temperate habitats, and there is a research gap regarding tropical trees such as mangroves. This work aimed to improve the understanding of the molecular aspects of the response and tolerance to freezing in mangrove trees using Avicennia schaueriana as a model. This species occurs within the colder range limits of South American mangroves and shows evidence of the existence of two functional groups that are locally adapted to the equatorial (EQ) and subtropical (ST) portions of the Brazilian coast. We investigated the transcriptional profiles of seedlings from both functional groups under freezing shock (-4{degrees}C) in a time series. We analyzed transcriptomic data by combining differential expression, coexpression network and protein interaction data. Our results allowed us to describe the profile of the molecular response of A. schaueriana to freezing and the divergence in the behavior of the EQ and ST functional groups. In EQ plants, the response strongly depended on the action of abscisic acid (ABA) and stress signals throughout the experiment. Notably, ABA negatively affects plant growth and promotes the accumulation of carotenoids, anthocyanins and lipids through chlorophyll degradation. On the other hand, in the ST, there were fewer hormones active in the process of primary growth maintenance and metabolic normalization. The accumulation of substances is mainly based on sucrose, anthocyanin and lipid levels, and lipid synthesis is not dependent on chlorophyll degradation. Based on these results, we hypothesize that susceptibility to freezing damage is greater in EQ mangroves than in ST mangroves. Therefore, we recommend that this fact be considered when managing this species, especially at higher latitudes, which are more prone to lower temperatures and extreme freezing events.

plant biology↗

bioRxiv2022

Differential adaptive potential and vulnerability to climate-driven habitat loss in Brazilian mangroves

Geographic and environmental differences have been identified as factors influencing Brazilian mangrove trees genetic diversity. Geographically, distinct species have convergent spatial genetic structures, indicating a limited gene flow between northern and southern populations. Environmentally, genomic studies and common garden experiments have found evidence of local adaptations along the latitudinal gradient of the Brazilian coast. However, little is known about how such adaptive heterogeneity could be affected by a rapidly changing climate in the coming decades, and the combination of deforestation and climate-induced habitat loss may affect these forests and their genetic diversity. Here, we applied two genomic-environmental association methods to model the turnover of potentially adaptive alleles for two dominant mangrove trees: Avicennia germinans and A. schaueriana. We analyzed a total of 134 individuals from six populations of A. germinans and ten populations of A. schaueriana spanning the Brazilian coast from 1 {degrees}S to 28 {degrees}S. Gradient forest models identified temperature-related variables as the most important predictors for A. germinans outlier loci, whereas both temperature and precipitation were important for A. schaueriana. We modeled allele frequencies and projected them for future climatic scenarios to estimate adaptively driven vulnerability. We assessed climate-driven habitat loss through climate-only distribution models and calculated annual deforestation rates for each sampled region. Finally, to assess the vulnerability of individual populations, we combined the environmental suitability, deforestation data, and adaptive vulnerability projections. For both species, subtropical populations presented a higher vulnerability than equatorial populations to climate-driven habitat loss. We also identified deforestation rates at the sampled sites that were alarmingly higher than the global average mangrove deforestation rate. Our results provide improved estimates of the impacts of ongoing climate change and human-caused habitat loss on the distribution of mangroves and highlight the importance of site-based conservation strategies that consider individual subtropical and equatorial mangrove forests.

evolutionary biology↗

bioRxiv2018

The impacts of landscape composition, marginality and climatic stability on the patterns of endemism of Cerrado woody plants

AimAlthough various theories have been proposed to explain the outstanding endemism of plants in the Cerrado, four hypotheses about the mechanisms of diversification and distribution are most supported: (1) plateau/valley, (2) stable/unstable climate, (3) core/peripheral distribution, and (4) soil fertility. The first argues that plateaus harbor more ancient lineages than valleys and therefore presents higher endemism. The second theory suggests that climatic stable environments maintained more paleoendemic species. The third scenario attributes the distribution of endemism to gradients of conditions available to locally adapted species and predicts higher endemism in nuclear than in marginal areas. The last theory suggests that lower fertility soils account for higher endemism due to the habitat specialization of its species. We compared endemism patterns with the predictions of each theory to discuss their importance.\n\nLocationBrazil.\n\nTime periodQuaternary.\n\nMajor taxa studiedAngiosperms.\n\nMethodsWe mapped the endemism using records of 311 plant species of the Cerrado and applied spatial analysis and distribution models to summarize the importance of each predictor of endemism.\n\nResultsWe identified 28 areas in which the higher endemism of Cerrado plants were concentrated and presented a map of its distribution. We found correlations among endemism, climate stability, elevation, and marginality, which supported the plateau/valley, core/peripheral, and stable/unstable hypotheses. No association between soil fertility and endemism was detected. We propose that plateaus are more stable climatic environments, and this characteristic along with their elevation and centrality are predictive of endemism.\n\nMain conclusionsWe concluded that most of the endemism is concentrated in overlapping areas of stability of species, which are concentrated in higher elevation central regions. Soil fertility was not linked to endemism. We recommend that central plateaus in the Cerrado require special attention in conservation to optimize the protection of endemic species in the biome.

ecology↗