Biology subjects

Winters, G.

Publications and source records attributed to Winters, G..

4 recordsLinked to original sources

bioRxiv2026

Decadal warming is linked to thermal tolerance and transcriptome reprogramming in a seagrass

Ocean warming and marine heatwaves threaten seagrasses, which are considered highly vulnerable to rising temperatures. We compared thermal stress responses of the tropical seagrass Halophila stipulacea collected from the Gulf of Aqaba in 2017 and 2022. Under mesocosm-applied thermal stress, 2017 plants showed reduced growth, impaired photochemistry, and extensive transcriptomic changes. In contrast, 2022 plants maintained normal growth and photochemistry with minimal transcriptional responses. The enhanced thermal stress tolerance of 2022 plants was associated with a "stress-ready" transcriptome, with many stress-response genes already up/downregulated under control conditions. These changes coincided with local ocean warming and a shift from episodic to chronic thermal stress. Our findings provide the first longitudinal dataset in a seagrass that tracks physiological and molecular changes occurring concurrently with documented ocean warming.

plant biology↗

bioRxiv2025

Transcriptome responses of two Halophila stipulacea seagrass populations from pristine and impacted habitats, to single and combined thermal and excess nutrient stressors, reveal local adaptive features and core stress-response genes

In their natural habitats, seagrasses face multiple abiotic stressors, which can often occur simultaneously. However, most studies investigating the effects of environmental stressors on seagrasses have focused on growth and physiological responses to single stressors. Here, we examined the transcriptome responses of the tropical seagrass Halophila stipulacea collected from a northern Gulf of Aqaba pristine site (South Beach - SB) and an anthropogenically-impacted site (Tur Yam - TY), grown in a mesocosm, and exposed to ecologically-relevant, single and combined, thermal and excess nutrient stressors. The combined thermal and nutrient stressor elicited greater transcriptome reprogramming than the single stressors in both populations and induced the expression of a combination-specific set of genes involved in abiotic and biotic stress responses. Furthermore, thermal stress exerted a more dominant influence than excess nutrient stress upon the transcriptome response to the combined stress. Transcriptomes of plants from the impacted TY site displayed reduced plasticity, the presence of genes exhibiting a "stress-ready" mode of expression under all stresses, and increased resilience (recovery to control transcriptomes). We also identified core stress-response genes that could be leveraged as early indicators of stress in the field. Overall, our data suggest that environmental conditions in seagrass habitats can drive local molecular adaptation, and that the response of seagrasses to combined stressors associated with climate change and coastal anthropogenic stressors cannot be predicted from the response to single stressors.

plant biology↗

bioRxiv2021

Teasing apart the host-related, nutrient-related and temperature-related effects shaping the phenology and microbiome of the tropical seagrass Halophila stipulacea

BackgroundHalophila stipulacea seagrass meadows are an ecologically important and threatened component of the ecosystem in the Gulf of Aqaba. Recent studies have demonstrated correlated geographic patterns for leaf endophytic community composition and leaf morphology, also coinciding with different levels of water turbidity and nutrient concentrations. Based on these observations, workers have suggested an environmental microbial fingerprint, which may reflect various environmental stress factors seagrasses have experienced, and may add a holobiont level of plasticity to seagrasses, assisting their acclimation to changing environments and through range expansion. However, it is difficult to tease apart environmental effects from host-diversity dependent effects, which have covaried in field studies, although this is required in order to establish that differences in microbial community compositions among sites are driven by environmental conditions rather than by features governed by the host. ResultsIn this study we carried out a mesocosm experiment, in which we studied the effects of warming and nutrient stress on the composition of epiphytic bacterial communities and on some phenological traits. We studied H. stipulacea collected from two different meadows in the Gulf of Aqaba, representing differences in the host and the environment alike. We found that the source site from which seagrasses were collected was the major factor governing seagrass phenology, although heat increased shoot mortality and nutrient loading delayed new shoot emergence. Bacterial diversity, however, mostly depended on the environmental conditions. The most prominent pattern was the increase in Rhodobacteraceae under nutrient stress without heat stress, along with an increase in Microtrichaceae. Together, the two taxa have the potential to maintain nitrate reduction followed by an anammox process, which can together buffer the increase in nutrient concentrations across the leaf surface. ConclusionsOur results thus corroborate the existence of environmental microbial fingerprints, which are independent from the host diversity, and support the notion of a holobiont level plasticity, both important to understand and monitor H. stipulacea ecology under the changing climate.

microbiology↗

bioRxiv2020

Temporal and spatial changes in phyllosphere microbiome of acacia trees growing in super arid environments

Along the arid Arava, southern Israel, acacia trees (Acacia raddiana and Acacia tortilis) are considered keystone species. In this study, we investigated the ecological effects of plant species, microclimate (different areas within the tree canopies) and seasonality on the endophytic and epiphytic microbiome associated with these two tree species. 186 leaf samples were collected along different seasons throughout the year and their microbial communities were studied using the diversity of the 16S rDNA gene sequenced on the 150-PE Illumina sequencing platform. Results show that endophytic, but not epiphytic, microbiome communities were different between the two acacia species. Endophytic, but not epiphytic, microbiome was affected by temporal changes (seasons) in air temperature. Acacia canopy microclimate was also found to have a significant effect on exosphere microbiome, with A. tortilis having a higher microbial diversity than A. raddiana with significantly different community compositions in different seasons. ImportanceThe evolutionary relationships and interactions between plants and their microbiome are of high importance to the survival of plants in extreme conditions. Changes in microbiome of plants can affect plant development, growth and health. In this study, we explored the relationship between keystone desert trees and their microbiome along seasonal variation. These results shed light on the importance and uniqueness of desert phyllosphere microbiome. Although acacia trees are considered keystone species in many arid regions, to the best of our knowledge, this is the first time that microbial descriptors have been applied in these systems. This work constitutes a new approach to the assessment of these important trees and a stepping stone in the application of microbial communities as a putative marker in a changing environment.

ecology↗