CEAZA
What if the cold days return? Epigenetic mechanisms in plants to cold tolerance
Hereme, R., Galleguillos, C., Morales-Navarro, S., Molina-Montenegro, M.A.
Low temperatures are one of the most critical environmental conditions that negatively affect the growth, development, and geographic distribution of plants. Exposure to low temperatures results in a suit of physiological, biochemical and molecular modifications through the reprogramming of the expression of genes and transcription factors. Scientific evidence shows that the average annual temperature has increased in recent years worldwide, with cold ecosystems (polar and high mountain) being among the most sensitive to these changes. However, scientific evidence also indicates that there would be specific events of low temperatures, due it is highly relevant to know the capacity for adaptation, regulation and epigenetic memory in the face of these events, by plants. Epigenetic regulation has been described to play an important role in the face of environmental stimuli, especially in response to abiotic stress. Several studies on epigenetic mechanisms have focused on responses to stress as drought and/or salinity; however, there is a gap in the current literature considering those related to low temperatures. In this review, we focus on systematizing the information published to date, related to the regulation of epigenetic mechanisms such as DNA methylation, histone modification, and non-coding RNA-dependent silencing mechanisms, in the face of plant´s stress due to low temperatures. Finally, we present a schematic model about the potential responses by plants taking in count their epigenetic memory; considering a global warming scenario and with the presence or absence of extreme specific events of low temperatures.
Año: 2021
Palabras claves:
Referencia APA: Hereme, R., Galleguillos, C., Morales-Navarro, S., Molina-Montenegro, M.A. 2021. What if the cold days return? Epigenetic mechanisms in plants to cold tolerance. Planta 254, 46. https://doi.org/10.1007/s00425-021-03694-1
Early transcriptional responses in Solanum peruvianum and Solanum lycopersicum account for different acclimation processes during water scarcity events
Tapia, G., González, M., Burgos, J., Vega, M.V., Méndez, J., Inostroza, L.
Cultivated tomato Solanum lycopersicum (Slyc) is sensitive to water shortages, while its wild relative Solanum peruvianum L. (Sper), an herbaceous perennial small shrub, can grow under water scarcity and soil salinity environments. Plastic Sper modifies the plant architecture when suffering from drought, which is mediated by the replacement of leaf organs, among other changes. The early events that trigger acclimation and improve these morphological traits are unknown. In this study, a physiological and transcriptomic approach was used to understand the processes that differentiate the response in Slyc and Sper in the context of acclimation to stress and future consequences for plant architecture. In this regard, moderate (MD) and severe drought (SD) were imposed, mediating PEG treatments. The results showed a reduction in water and osmotic potential during stress, which correlated with the upregulation of sugar and proline metabolism-related genes. Additionally, the senescence-related genes FTSH6 protease and asparagine synthase were highly induced in both species. However, GO categories such as “protein ubiquitination” or “endopeptidase inhibitor activity” were differentially enriched in Sper and Slyc, respectively. Genes related to polyamine biosynthesis were induced, while several cyclins and kinetin were downregulated in Sper under drought treatments. Repression of photosynthesis-related genes was correlated with a higher reduction in the electron transport rate in Slyc than in Sper. Additionally, transcription factors from the ERF, WRKY and NAC families were commonly induced in Sper. Although some similar responses were induced in both species under drought stress, many important changes were detected to be differentially induced. This suggests that different pathways dictate the strategies to address the early response to drought and the consequent episodes in the acclimation process in both tomato species.
Año: 2021
Palabras claves:
Referencia APA: Tapia, G., González, M., Burgos, J., Vega, M.V., Méndez, J., Inostroza, L. 2021. Early transcriptional responses in Solanum peruvianum and Solanum lycopersicum account for different acclimation processes during water scarcity events. Sci Rep 11, 15961. https://doi.org/10.1038/s41598-021-95622-2
Evolution of physiological performance in invasive plants under climate change
Gianoli, E. and Molina-Montenegro, M.A.
Climate change is expected to promote biological invasions. Invasive species often undergo adaptive evolution, but whether invasive species show greater evolutionary potential than their native counterparts under climate change has rarely been evaluated. We conducted experimental evolution trials comparing the evolution of physiological performance (light-saturated photosynthetic rate, Amax) of coexisting and closely related (1) invasive-native species pairs from Arid, Alpine, and Antarctic ecosystems, and (2) an invasive-naturalized species pair from a Mediterranean ecosystem differing in invasiveness. Experiments were conducted over three generations and under four environments of temperature and water availability resembling typical and climate change conditions in each ecosystem. Amax increased across generations for most species. Invasive species from Arid, Alpine, and Antarctic ecosystems showed similar, greater, and lesser evolution of Amax than their native counterparts, respectively. The Mediterranean invasive species showed greater evolution of Amax than its naturalized congener. Similar patterns were observed in all four experimental environments for each ecosystem, suggesting that comparable responses may be expected under climate change scenarios. All study species showed a positive association between Amax and reproductive output. Results suggest that invasive plants and their native (or naturalized) counterparts would show similar evolutionary responses of physiological performance to global warming and drought.
Año: 2021
Palabras claves:
Referencia APA: Gianoli, E. and Molina-Montenegro, M.A. 2021. Evolution of physiological performance in invasive plants under climate change. Evolution. https://doi.org/10.1111/evo.14314
Symbiotic Interaction Enhances the Recovery of Endangered Tree Species in the Fragmented Maulino Forest
Torres-Díaz C, Valladares MA, Acuña-Rodríguez IS, Ballesteros GI, Barrera A, Atala C and Molina-Montenegro MA
Beneficial plant-associated microorganisms, such as fungal endophytes, are key partners that normally improve plant survival under different environmental stresses. It has been shown that microorganisms from extreme environments, like those associated with the roots of Antarctica plants, can be good partners to increase the performance of crop plants and to restore endangered native plants. Nothofagus alessandrii and N. glauca, are among the most endangered species of Chile, restricted to a narrow and/or limited distributional range associated mainly to the Maulino forest in Chile. Here we evaluated the effect of the inoculation with a fungal consortium of root endophytes isolated from the Antarctic host plant Colobanthus quitensis on the ecophysiological performance [photosynthesis, water use efficiency (WUE), and growth] of both endangered tree species. We also, tested how Antarctic root-fungal endophytes could affect the potential distribution of N. alessandrii through niche modeling. Additionally, we conducted a transplant experiment recording plant survival on 2 years in order to validate the model. Lastly, to evaluate if inoculation with Antarctic endophytes has negative impacts on native soil microorganisms, we compared the biodiversity of fungi and bacterial in the rhizospheric soil of transplanted individuals of N. alessandrii inoculated and non-inoculated with fungal endophytes. We found that inoculation with root-endophytes produced significant increases in N. alessandrii and N. glauca photosynthetic rates, water use efficiencies and cumulative growth. In N. alessandrii, seedling survival was significantly greater on inoculated plants compared with non-inoculated individuals. For this species, a spatial distribution modeling revealed that, inoculation with root-fungal endophytes could potentially increase the current distributional range by almost threefold. Inoculation with root-fungal endophytes, did not reduce native rhizospheric microbiome diversity. Our results suggest that the studied consortium of Antarctic root-fungal endophytes improve the ecophysiological performance as well as the survival of inoculated trees and can be used as a biotechnological tool for the restoration of endangered tree species.
Año: 2021
Palabras claves: Nothofagus spp., ruil, hualo, endangered tree species, restoration, Antarctica, fungal endophytes, functional symbiosis
Referencia APA: Torres-Díaz C, Valladares MA, Acuña-Rodríguez IS, Ballesteros GI, Barrera A, Atala C and Molina-Montenegro MA. 2021. Symbiotic Interaction Enhances the Recovery of Endangered Tree Species in the Fragmented Maulino Forest. Front. Plant Sci. 12:663017. doi: 10.3389/fpls.2021.663017
Evaluating optically stimulated luminescence rock surface exposure dating as a novel approach for reconstructing coastal boulder movement on decadal to centennial timescales
Brill, D., May, S. M., Mhammdi, N., King, G., Lehmann, B., Burow, C., Wolf, D., Zander, A., and Brückner, H.
Wave-transported boulders represent important records of storm and tsunami impact over geological timescales. Their use for hazard assessment requires chronological information on their displacement that in many cases cannot be achieved by established dating approaches. To fill this gap, this study investigated, for the first time, the potential of optically stimulated luminescence rock surface exposure dating (OSL-RSED) for estimating cliff-detachment ages of wave-transported coastal boulders. The approach was tested on calcarenite clasts at the Rabat coast, Morocco. Calibration of the OSL-RSED model was based on samples with rock surfaces exposed to sunlight for ∼ 2 years, and OSL exposure ages were evaluated against age control deduced from satellite images. Our results show that the dating precision is limited for all targeted boulders due to the local source rock lithology which has low amounts of quartz and feldspar. The dating accuracy may be affected by erosion rates on boulder surfaces of 0.02–0.18 mm yr−1. Nevertheless, we propose a robust relative chronology for boulders that are not affected by significant post-depositional erosion and that share surface angles of inclination with the calibration samples. The relative chronology indicates that (i) most boulders were detached from the cliff by storm waves; (ii) these storms lifted boulders with masses of up to ∼ 24 t; and (iii) the role of storms in the formation of boulder deposits along the Rabat coast is more significant than previously assumed. Although OSL-RSED cannot provide reliable absolute exposure ages for the coastal boulders in this study, the approach has large potential for boulder deposits composed of rocks with larger amounts of quartz or feldspar and less susceptibility to erosion.
Año: 2021
Palabras claves:
Referencia APA: Brill, D., May, S. M., Mhammdi, N., King, G., Lehmann, B., Burow, C., Wolf, D., Zander, A., and Brückner, H. 2021. Evaluating optically stimulated luminescence rock surface exposure dating as a novel approach for reconstructing coastal boulder movement on decadal to centennial timescales. Earth Surf. Dynam., 9, 205–234, https://doi.org/10.5194/esurf-9-205-2021.
Getting ready for the ozone battle: Vertically transmitted fungal endophytes have transgenerational positive effects in plants
Ueno, A.C, Gundel, P.E., Molina-Montenegro, M.A., Ramos, P., Ghersa, C.M., Martínez-Ghersa, M.A.
Ground-level ozone is a global air pollutant with high toxicity and represents a threat to plants and microorganisms. Although beneficial microorganisms can improve host performance, their role in connecting environmentally induced maternal plant phenotypes to progeny (transgenerational effects [TGE]) is unknown. We evaluated fungal endophyte-mediated consequences of maternal plant exposure to ozone on performance of the progeny under contrasting scenarios of the same factor (high and low) at two stages: seedling and young plant. With no variation in biomass, maternal ozone-induced oxidative damage in the progeny that was lower in endophyte-symbiotic plants. This correlated with an endophyte-mediated higher concentration of proline, a defence compound associated with stress control. Interestingly, ozone-induced TGE was not associated with reductions in plant survival. On the contrary, there was an overall positive effect on seedling survival in the presence of endophytes. The positive effect of maternal ozone increasing young plant survival was irrespective of symbiosis and only expressed under high ozone condition. Our study shows that hereditary microorganisms can modulate the capacity of plants to transgenerationally adjust progeny phenotype to atmospheric change.
Año: 2021
Palabras claves:
Referencia APA: Ueno, AC, Gundel, PE, Molina-Montenegro, MA, Ramos, P, Ghersa, CM, Martínez-Ghersa, MA. Getting ready for the ozone battle: Vertically transmitted fungal endophytes have transgenerational positive effects in plants. Plant Cell Environ. 2021; 1– 13. https://doi.org/10.1111/pce.14047
Evaluating optically stimulated luminescence rock surface exposure dating as a novel approach for reconstructing coastal boulder movement on decadal to centennial timescales
Brill, D., May, S. M., Mhammdi, N., King, G., Lehmann, B., Burow, C., Wolf, D., Zander, A., and Brückner, H.
Wave-transported boulders represent important records of storm and tsunami impact over geological timescales. Their use for hazard assessment requires chronological information on their displacement that in many cases cannot be achieved by established dating approaches. To fill this gap, this study investigated, for the first time, the potential of optically stimulated luminescence rock surface exposure dating (OSL-RSED) for estimating cliff-detachment ages of wave-transported coastal boulders. The approach was tested on calcarenite clasts at the Rabat coast, Morocco. Calibration of the OSL-RSED model was based on samples with rock surfaces exposed to sunlight for ∼ 2 years, and OSL exposure ages were evaluated against age control deduced from satellite images. Our results show that the dating precision is limited for all targeted boulders due to the local source rock lithology which has low amounts of quartz and feldspar. The dating accuracy may be affected by erosion rates on boulder surfaces of 0.02–0.18 mm yr−1. Nevertheless, we propose a robust relative chronology for boulders that are not affected by significant post-depositional erosion and that share surface angles of inclination with the calibration samples. The relative chronology indicates that (i) most boulders were detached from the cliff by storm waves; (ii) these storms lifted boulders with masses of up to ∼ 24 t; and (iii) the role of storms in the formation of boulder deposits along the Rabat coast is more significant than previously assumed. Although OSL-RSED cannot provide reliable absolute exposure ages for the coastal boulders in this study, the approach has large potential for boulder deposits composed of rocks with larger amounts of quartz or feldspar and less susceptibility to erosion.
Año: 2021
Palabras claves:
Referencia APA: Brill, D., May, S. M., Mhammdi, N., King, G., Lehmann, B., Burow, C., Wolf, D., Zander, A., and Brückner, H. (2021). Evaluating optically stimulated luminescence rock surface exposure dating as a novel approach for reconstructing coastal boulder movement on decadal to centennial timescales, Earth Surf. Dynam., 9, 205–234, https://doi.org/10.5194/esurf-9-205-2021.
Climate models capture key features of extreme precipitation probabilities across regions
Cristian Martinez-Villalobos and J David Neelin
Quantitative simulation of precipitation in current climate has been an ongoing challenge for global climate models. Despite serious biases in correctly simulating probabilities of extreme rainfall events, model simulations under global warming scenarios are routinely used to provide estimates of future changes in these probabilities. To minimize the impact of model biases, past literature tends to evaluate fractional (instead of absolute) changes in probabilities of precipitation extremes under the assumption that fractional changes would be more reliable. However, formal tests for the validity of this assumption have been lacking. Here we evaluate two measures that address properties important to the correct simulation of future fractional probability changes of precipitation extremes, and that can be assessed with current climate data. The first measure tests climate model performance in simulating the characteristic shape of the probability of occurrence of daily precipitation extremes and the second measure tests whether the key parameter governing the scaling of this shape is well reproduced across regions and seasons in current climate. Contrary to concerns regarding the reliability of global models for extreme precipitation assessment, our results show most models lying within the current range of observational uncertainty in these measures. Thus, most models in the Coupled Model Intercomparison Project Phase 6 ensemble pass two key tests in current climate that support the usefulness of fractional measures to evaluate future changes in the probability of precipitation extremes.
Año: 2021
Palabras claves:
Referencia APA: Martinez-Villalobos, C., and Neelin, J.D. (2021). Climate models capture key features of extreme precipitation probabilities across regions. Environ. Res. Lett. 16 024017
Combined effect of pCO2 and temperature levels on the thermal niche in the early benthic ontogeny of a keystone species
Manríquez, P., Jara, M., González, C., Díaz, M., Brokordt, K., & Lattuca, M., Peck, M.A., Alter, K., Marras, S., Domenici, P.
We evaluated the effects of projected, near future ocean acidification (OA) and extreme events of temperature (warming or cooling) on the thermal tolerance of Concholepas concholepas, a coastal benthic keystone species. Three separate trials of an experiment were conducted by exposing juvenile C. concholepas for 1 month to one of two contrasting pCO2 levels (~500 and ~1200 μatm). In addition, each pCO2 level was combined with one of four temperature treatments. The control was 15 °C, whilst the other temperatures were 10 °C (Trial 1), 20 °C (Trial 2) and 25 °C (Trial 3). At the end of each trial, we assessed Critical Thermal maximum (CTmax) and min- imum (CTmin) via self-righting success, calculated partial thermal tolerance polygons, measured somatic growth, determined transcription of Heat Shock Proteins 70 (HSP70) and measured oxygen consumption rates. Regardless of pCO2 level, HSP70 transcript levels were significantly higher in juveniles after exposure to extreme temperatures (10 °C and 25 °C) indicating physiological stress. Oxygen consumption rates increased with in- creasing temperature from 10 °C to 20 °C though showed a decrease at 25 °C. This rate was not affected by pCO2 or the interaction between temperature and pCO2. Juveniles exposed to present-day and near future pCO2 levels at 20 °C showed similar thermal tolerance polygonal areas; whilst changes in both CTmin and CTmax at 25 °C and 10 °C caused narrower and broader areas, respectively. Temperature affected growth, oxygen consumption and HSP70 transcription in small juvenile C. concholepas. Exposure to elevated pCO2 did not affect thermal tolerance, growth or oxygen consumption at temperatures within the thermal range normally experi- enced by this species in northern Chile (15-20 °C). At elevated pCO2 conditions, however, exposure to warmer (25 °C) or colder (10 °C) temperatures reduced or increased the thermal area, respectively. This study demon- strates the importance of examining the thermal-tolerance edges to better understand how OA and temperature will combine to physiologically challenge inter-tidal organisms.
Año: 2020
Palabras claves:
Referencia APA: Manríquez, P., Jara, M., González, C., Díaz, M., Brokordt, K., & Lattuca, M., Peck, M.A., Alter, K., Marras, S., Domenici, P. (2020). Combined effect of pCO2 and temperature levels on the thermal niche in the early benthic ontogeny of a keystone species. Science Of The Total Environment, 719, 137239. doi: 10.1016/j.scitotenv.2020.137239
pH and other upwelling hydrographic drivers in regulating copepod reproduction during the 2015 El Niño event: A follow-up study
Aguilera, V.
The combined upwelling-El Niño (EN) event regulation of the numerically dominant Acartia tonsa (Crustacea, Copepoda) reproduction was examined in a year-round upwelling system (23°S) of the Humboldt Eastern Boundary Upwelling System (EBUS) during the EN 2015. A previous analysis of the environmental regulation of this system is extended here by considering complementary oceanographic information (sea level, stratification indexes) and additional reproductive traits, such as maximum (MaxEPR), median (MedianEPR) and prevalence of egg producing females over a period of six months. Furthermore, field minimum-maximum pH levels were reproduced in three 96-h incubation experiments conducted under variable salinity conditions to evaluate copepod mean EPR, egg size and hatching success. Supporting previous assertions, the warm-high salinity EN 2015 was observed in the study site separately from hydrographic conditions associated with upwelling to non-upwelling regimes. Analysis of similarity-distance (Distance based Linear Model (DistLM)) and normalized data (separate-slope comparison under a General Linear Model (GLM)) showed that reproductive traits were regulated by specific combinations of ambient conditions, and that this regulation was also sensitive to the prevailing hydrographic regime. Thus, upwelling to non-upwelling transitions changing the pH, and EN-associated salinity and stratification shifts, were significantly and strongly linked to almost all reproductive traits (DistLM). Slope comparison (GLM) indicated MaxEPR and MedianEPR variations also underlie the phenology, highlighting the relationship between pH and salinity with biological variations. In conjunction with experimental observations, the current study consistently suggests that pH-variations in the upwelling realm, and EN hydrographic perturbations might underpin responses of plankton populations to climate change in productive EBUS.
Año: 2020
Palabras claves: Eastern boundary upwelling systems, Intra-seasonal variationsInter-annual variations, Ocean acidification, Zooplankton physiology
Referencia APA: Aguilera, V. (2020). pH and other upwelling hydrographic drivers in regulating copepod reproduction during the 2015 El Niño event: A follow-up study. Estuarine, Coastal And Shelf Science, 234, 106640. doi: 10.1016/j.ecss.2020.106640
Antagonistic interplay between pH and food resources affects copepod traits and performance in a year-round upwelling system
Aguilera, V., Vargas, C., & Dam, H.
Linking pH/pCO2 natural variation to phenotypic traits and performance of foundational species provides essential information for assessing and predicting the impact of ocean acidification (OA) on marine ecosystems. Yet, evidence of such linkage for copepods, the most abundant metazoans in the oceans, remains scarce, particularly for naturally corrosive Eastern Boundary Upwelling systems (EBUs). This study assessed the relationship between pH levels and traits (body and egg size) and performance (ingestion rate (IR) and egg reproduction rate (EPR)) of the numerically dominant neritic copepod Acartia tonsa, in a year-round upwelling system of the northern (23° S) Humboldt EBUs. The study revealed decreases in chlorophyll (Chl) ingestion rate, egg production rate and egg size with decreasing pH as well as egg production efficiency, but the opposite for copepod body size. Further, ingestion rate increased hyperbolically with Chl, and saturated at ~1 µg Chl. L−1. Food resources categorized as high (H, >1 µg L−1) and low (L, <1 µg L−1) levels, and pH-values categorized as equivalent to present day (≤400 µatm pCO2, pH > 7.89) and future (>400 µatm pCO2, pH < 7.89) were used to compare our observations to values globally employed to experimentally test copepod sensitivity to OA. A comparison (PERMANOVA) test with Chl/pH (2*2) design showed that partially overlapping OA levels expected for the year 2100 in other ocean regions, low-pH conditions in this system negatively impacted traits and performance associated with copepod fitness. However, interacting antagonistically with pH, food resource (Chl) maintained copepod production in spite of low pH levels. Thus, the deleterious effects of ocean acidification are modulated by resource availability in this system.
Año: 2020
Palabras claves: Scientific Reports
Referencia APA: Aguilera, V., Vargas, C., & Dam, H. (2020). Antagonistic interplay between pH and food resources affects copepod traits and performance in a year-round upwelling system. Scientific Reports, 10(1). doi: 10.1038/s41598-019-56621-6
Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia
Fretwell, P., Jackson, J., Ulloa Encina, M., Häussermann, V., Perez Alvarez, M., Olavarría, C., & Gutstein, C.
We test the ability of Very High Resolution satellite (VHR) imagery to detect stranded whales using both manual and automated methods. We use the 2015 mass mortality event in the Gulf of Penas locality, central Patagonia, Chile, as an initial case study. This event was the largest known mass mortality of baleen whales, with at least 343 whales, mainly sei whales (Balaenoptera borealis), documented as stranding. However, even with such a large number of whales, due to the remote location of the gulf the strandings went unrecorded for several weeks. Aerial and boat surveys of the area were conducted two to four months after the mortality event. In this study we use 50cm resolution WorldView2 imagery to identify and count strandings from two archival images acquired just after the stranding event and two months before the aerial and ground surveys, and to test manual and automated methods of detecting stranded whales. Our findings show that whales are easily detected manually in the images but due to the heterogeneous colouration of decomposing whales, spectral indices are unsuitable for automatic detection. Our satellite counts suggest that, at the time the satellite images were taken, more whales were stranded than recorded in the aerial survey, possibly due to the non-comprehensive coverage of the aerial survey or movement of the carcases between survey acquisition. With even higher resolution imagery now available, satellite imagery may be a cost effective alternative to aerial surveys for future assessment of the extent of mass whale stranding events, especially in remote and inaccessible areas.
Año: 2019
Palabras claves: Whales, Islands, Image analysis, Boats, Beaches, Remote areas, Geological surveys, Marine mammals
Referencia APA: Fretwell, P., Jackson, J., Ulloa Encina, M., Häussermann, V., Perez Alvarez, M., Olavarría, C., & Gutstein, C. (2019). Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. PLOS ONE, 14(10), e0222498. doi: 10.1371/journal.pone.0222498