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Douglas Koshland - One of the best experts on this subject based on the ideXlab platform.

  • Desiccation Tolerance: an unusual window into stress biology.
    Molecular biology of the cell, 2019
    Co-Authors: Douglas Koshland, Hugo Tapia
    Abstract:

    Climate change has accentuated the importance of understanding how organisms respond to stresses imposed by changes to their environment, like water availability. Unusual organisms, called anhydrobiotes, can survive loss of almost all intracellular water. Desiccation Tolerance of anhydrobiotes provides an unusual window to study the stresses and stress response imposed by water loss. Because of the myriad of stresses that could be induced by water loss, Desiccation Tolerance seemed likely to require many established stress effectors. The sugar trehalose and hydrophilins (small intrinsically disordered proteins) had also been proposed as stress effectors against Desiccation because they were found in nearly all anhydrobiotes, and could mitigate Desiccation-induced damage to model proteins and membranes in vitro. Here, we summarize in vivo studies of Desiccation Tolerance in worms, yeast, and tardigrades. These studies demonstrate the remarkable potency of trehalose and a subset of hydrophilins as the major stress effectors of Desiccation Tolerance. They act, at least in part, by limiting in vivo protein aggregation and loss of membrane integrity. The apparent specialization of individual hydrophilins for Desiccation Tolerance suggests that other hydrophilins may have distinct roles in mitigating additional cellular stresses, thereby defining a potentially new functionally diverse set of stress effectors.

  • increasing intracellular trehalose is sufficient to confer Desiccation Tolerance to saccharomyces cerevisiae
    Proceedings of the National Academy of Sciences of the United States of America, 2015
    Co-Authors: Hugo Tapia, Lindsey N Young, Carolyn R Bertozzi, Douglas Koshland
    Abstract:

    Diverse organisms capable of surviving Desiccation, termed anhydrobiotes, include species from bacteria, yeast, plants, and invertebrates. However, most organisms are sensitive to Desiccation, likely due to an assortment of different stresses such as protein misfolding and aggregation, hyperosmotic stress, membrane fracturing, and changes in cell volume and shape leading to an overcrowded cytoplasm and metabolic arrest. The exact stress(es) that cause lethality in Desiccation-sensitive organisms and how the lethal stresses are mitigated in Desiccation-tolerant organisms remain poorly understood. The presence of trehalose in anhydrobiotes has been strongly correlated with Desiccation Tolerance. In the yeast Saccharomyces cerevisiae, trehalose is essential for survival after long-term Desiccation. Here, we establish that the elevation of intracellular trehalose in dividing yeast by its import from the media converts yeast from extreme Desiccation sensitivity to a high level of Desiccation Tolerance. This trehalose-induced Tolerance is independent of utilization of trehalose as an energy source, de novo synthesis of other stress effectors, or the metabolic effects of trehalose biosynthetic intermediates, indicating that a chemical property of trehalose is directly responsible for Desiccation Tolerance. Finally, we demonstrate that elevated intracellular maltose can also make dividing yeast tolerant to short-term Desiccation, indicating that other disaccharides have stress effector activity. However, trehalose is much more effective than maltose at conferring Tolerance to long-term Desiccation. The effectiveness and sufficiency of trehalose as an antagonizer of Desiccation-induced damage in yeast emphasizes its potential to confer Desiccation Tolerance to otherwise sensitive organisms.

  • Genetic Analysis of Desiccation Tolerance in Sachharomyces cerevisiae
    Genetics, 2011
    Co-Authors: Dean Calahan, Maiterya Dunham, Chris Desevo, Douglas Koshland
    Abstract:

    Desiccation Tolerance, the ability to survive nearly total dehydration, is a rare strategy for survival and reproduction observed in all taxa. However, the mechanism and regulation of this phenomenon are poorly understood. Correlations between Desiccation Tolerance and potential effectors have been reported in many species, but their physiological significance has not been established in vivo. Although the budding yeast Saccharomyces cerevisiae exhibits extreme Desiccation Tolerance, its usefulness has been hampered by an inability to reduce Tolerance more than a few fold by physiological or genetic perturbations. Here we report that fewer than one in a million yeast cells from low-density logarithmic cultures survive Desiccation, while 20–40% of cells from saturated cultures survive. Using this greatly expanded metric, we show that mutants defective in trehalose biosynthesis, hydrophilins, responses to hyperosmolarity, and hypersalinity, reactive oxygen species (ROS) scavenging and DNA damage repair nevertheless retain wild-type levels of Desiccation Tolerance, suggesting that this trait involves a unique constellation of stress factors. A genome-wide screen for mutants that render stationary cells as sensitive as log phase cells identifies only mutations that block respiration. Respiration as a prerequisite for acquiring Desiccation Tolerance is corroborated by respiration inhibition and by growth on nonfermentable carbon sources. Suppressors bypassing the respiration requirement for Desiccation Tolerance reveal at least two pathways, one of which, involving the Mediator transcription complex, is associated with the shift from fermentative to respiratory metabolism. Further study of these regulators and their targets should provide important clues to the sensors and effectors of Desiccation Tolerance.

Maria Cecilia D Costa - One of the best experts on this subject based on the ideXlab platform.

  • a footprint of Desiccation Tolerance in the genome of xerophyta viscosa
    Nature plants, 2017
    Co-Authors: Eef Jonkheer, Harm Nijveen, Martijn F L Derks, Maria Cecilia D Costa, Mariana Aline Silva Artur, Julio Maia, Brett Williams, Sagadevan G Mundree, Jose M Jimenezgomez
    Abstract:

    Desiccation Tolerance is common in seeds and various other organisms, but only a few angiosperm species possess vegetative Desiccation Tolerance. These ‘resurrection species’ may serve as ideal models for the ultimate design of crops with enhanced drought Tolerance. To understand the molecular and genetic mechanisms enabling vegetative Desiccation Tolerance, we produced a high-quality whole-genome sequence for the resurrection plant Xerophyta viscosa and assessed transcriptome changes during its dehydration. Data revealed induction of transcripts typically associated with Desiccation Tolerance in seeds and involvement of orthologues of ABI3 and ABI5, both key regulators of seed maturation. Dehydration resulted in both increased, but predominantly reduced, transcript abundance of genomic ‘clusters of Desiccation-associated genes’ (CoDAGs), reflecting the cessation of growth that allows for the expression of Desiccation Tolerance. Vegetative Desiccation Tolerance in X. viscosa was found to be uncoupled from drought-induced senescence. We provide strong support for the hypothesis that vegetative Desiccation Tolerance arose by redirection of genetic information from Desiccation-tolerant seeds.

  • A footprint of Desiccation Tolerance in the genome of Xerophyta viscosa
    Nature Plants, 2017
    Co-Authors: Maria Cecilia D Costa, Eef Jonkheer, Harm Nijveen, Martijn F L Derks, Mariana Aline Silva Artur, Julio Maia, Brett Williams, José M. Jiménez-gómez, Sagadevan G Mundree, Thamara Hesselink
    Abstract:

    The mechanism underlying vegetative Desiccation Tolerance (DT) of plants remains elusive. A study now sequences the genome and transcriptome for the resurrection plant, Xerophyta viscosa , and supports that vegetative DT arose by redirection of the seed DT pathway. Desiccation Tolerance is common in seeds and various other organisms, but only a few angiosperm species possess vegetative Desiccation Tolerance. These ‘resurrection species’ may serve as ideal models for the ultimate design of crops with enhanced drought Tolerance. To understand the molecular and genetic mechanisms enabling vegetative Desiccation Tolerance, we produced a high-quality whole-genome sequence for the resurrection plant Xerophyta viscos a and assessed transcriptome changes during its dehydration. Data revealed induction of transcripts typically associated with Desiccation Tolerance in seeds and involvement of orthologues of ABI3 and ABI5, both key regulators of seed maturation. Dehydration resulted in both increased, but predominantly reduced, transcript abundance of genomic ‘clusters of Desiccation-associated genes’ (CoDAGs), reflecting the cessation of growth that allows for the expression of Desiccation Tolerance. Vegetative Desiccation Tolerance in X. viscosa was found to be uncoupled from drought-induced senescence. We provide strong support for the hypothesis that vegetative Desiccation Tolerance arose by redirection of genetic information from Desiccation-tolerant seeds.

Robert Vanburen - One of the best experts on this subject based on the ideXlab platform.

  • Unexplored dimensions of variability in vegetative Desiccation Tolerance.
    American journal of botany, 2021
    Co-Authors: Rose A. Marks, Jill M. Farrant, D. Nicholas Mcletchie, Robert Vanburen
    Abstract:

    Desiccation Tolerance has evolved recurrently across diverse land plant lineages as an adaptation for survival in regions where seasonal rainfall drives periodic drying of vegetative tissues. Growing interest in this phenomenon has fueled recent physiological, biochemical, and genomic insights into the mechanistic basis of Desiccation Tolerance. Although, Desiccation Tolerance is often viewed as binary and monolithic, substantial variation exists in the phenotype and underlying mechanisms across diverse lineages, heterogeneous populations, and throughout the development of individual plants. Most studies have focused on conserved responses in a subset Desiccation-tolerant plants under laboratory conditions. Consequently, the variability and natural diversity of Desiccation-tolerant phenotypes remains largely uncharacterized. Here, we discuss the natural variation in Desiccation Tolerance and argue that leveraging this diversity can improve our mechanistic understanding of Desiccation Tolerance. We summarize information collected from ~600 Desiccation-tolerant land plants and discuss the taxonomic distribution and physiology of Desiccation responses. We point out the need to quantify natural diversity of Desiccation Tolerance on three scales: variation across divergent lineages, intraspecific variation across populations, and variation across tissues and life stages of an individual plant. We conclude that this variability should be accounted for in experimental designs and can be leveraged for deeper insights into the intricacies of Desiccation Tolerance.

  • massive tandem proliferation of elips supports convergent evolution of Desiccation Tolerance across land plants
    Plant Physiology, 2019
    Co-Authors: Robert Vanburen, Jeremy Pardo, Ching Man Wai, Sterling Evans, Dorothea Bartels
    Abstract:

    Desiccation Tolerance was a critical adaptation for the colonization of land by early nonvascular plants. Resurrection plants have maintained or rewired these ancestral protective mechanisms, and Desiccation-tolerant species are dispersed across the land plant phylogeny. Although common physiological, biochemical, and molecular signatures are observed across resurrection plant lineages, features underlying the recurrent evolution of Desiccation Tolerance are unknown. Here we used a comparative approach to identify patterns of genome evolution and gene duplication associated with Desiccation Tolerance. We identified a single gene family with dramatic expansion in all sequenced resurrection plant genomes and no expansion in Desiccation-sensitive species. This gene family of early light-induced proteins (ELIPs) expanded in resurrection plants convergent through repeated tandem gene duplication. ELIPs are universally highly expressed during Desiccation in all surveyed resurrection plants and may play a role in protecting against photooxidative damage of the photosynthetic apparatus during prolonged dehydration. Photosynthesis is particularly sensitive to dehydration, and the increased abundance of ELIPs may help facilitate the rapid recovery observed for most resurrection plants. Together, these observations support convergent evolution of Desiccation Tolerance in land plants through tandem gene duplication.

  • Desiccation Tolerance: Seedy origins of resurrection.
    Nature plants, 2017
    Co-Authors: Robert Vanburen
    Abstract:

    Resurrection plants can survive extreme drying during periods of prolonged drought stress, maintaining a quiescent state for months to years until the return of water. Analysis of the genome and transcriptome of the resurrection plant Xerophyta viscosa links the evolution of Desiccation Tolerance to rewired pre-existing seed pathways.

Nicola J Mitchell - One of the best experts on this subject based on the ideXlab platform.

  • geographic variation in adult and embryonic Desiccation Tolerance in a terrestrial breeding frog
    Evolution, 2020
    Co-Authors: Tabitha Silja Rudinbitterli, Jonathan P Evans, Nicola J Mitchell
    Abstract:

    Intraspecific variation in the ability of individuals to tolerate environmental perturbations is often neglected when considering the impacts of climate change. Yet this information is potentially crucial for mitigating deleterious effects of climate change on threatened species. Here we assessed patterns of intraspecific variation in Desiccation Tolerance in the frog Pseudophryne guentheri, a terrestrial-breeding species experiencing a drying climate. Adult frogs were collected from six populations across a rainfall gradient and their dehydration and rehydration rates were assessed. We also compared Desiccation Tolerance of embryos and hatchlings originating from within-population parental crosses from four of the populations. Embryos were reared on soil at three soil-water potentials and their Desiccation Tolerance was assessed across a range of traits. We found significant and strong patterns of intraspecific variation in almost all traits, both in adults and first-generation offspring. Adult frogs exhibited clinal variation in their water balance responses, with populations from drier sites both dehydrating and rehydrating more slowly compared to frogs from more mesic sites. Similarly, Desiccation Tolerance of first-generation offspring was significantly greater in populations from xeric sites. Our findings suggest that populations within this species will respond differently to the regional reduction in rainfall predicted by climate change models.

  • geographic variation in adult and embryonic Desiccation Tolerance in a terrestrial breeding frog
    bioRxiv, 2018
    Co-Authors: Tabitha Silja Rudinbitterli, Jonathan P Evans, Nicola J Mitchell
    Abstract:

    Intra-specific variation in the ability of individuals to tolerate environmental perturbations is often neglected when considering the impacts of climate change. Yet this information is potentially crucial for mitigating any deleterious effects of climate change on threatened species. Here we assessed patterns of intra-specific variation in Desiccation Tolerance in the frog Pseudophryne guentheri , a terrestrial-breeding species experiencing a drying climate. Adult frogs were collected from six populations across a rainfall gradient and their dehydration and rehydration rates were assessed. We also compared Desiccation Tolerance of embryos and hatchlings originating from within-population parental crosses from four of the six populations. Embryos were reared on soil at three soil-water potentials, ranging from wet to dry (ψ = -10, -100 & -400 kPa), and their Desiccation Tolerance was assessed across a range of traits including survival, time to hatch after inundation, wet mass at hatching, hatchling malformations and swimming performance. We found significant and strong patterns of intra-specific variation in almost all traits, both in adults and first generation offspring. Adult frogs exhibited clinal variation in their water balance responses, with populations from drier sites both dehydrating and rehydrating more slowly compared to frogs from more mesic sites. Similarly, Desiccation Tolerance of embryos and hatchlings was significantly greater in populations from xeric sites. Taken together, our findings suggest that populations within this species will respond differently to the regional reduction in rainfall predicted by climate change models. We emphasise the importance of considering geographic variation in phenotypic plasticity when predicting how species will respond to climate change.

Paul S. Schmidt - One of the best experts on this subject based on the ideXlab platform.

  • spatiotemporal dynamics and genome wide association analysis of Desiccation Tolerance in drosophila melanogaster
    Molecular Ecology, 2018
    Co-Authors: Subhash Rajpurohit, Allen G. Gibbs, Eran Gefen, Alan O. Bergland, Dmitri A. Petrov, Paul S. Schmidt
    Abstract:

    Water availability is a major environmental challenge to a variety of terrestrial organisms. In insects, Desiccation Tolerance varies predictably over spatial and temporal scales and is an important physiological determinant of fitness in natural populations. Here, we examine the dynamics of Desiccation Tolerance in North American populations of Drosophila melanogaster using: (a) natural populations sampled across latitudes and seasons; (b) experimental evolution in field mesocosms over seasonal time; (c) genome-wide associations to identify SNPs/genes associated with variation for Desiccation Tolerance; and (d) subsequent analysis of patterns of clinal/seasonal enrichment in existing pooled sequencing data of populations sampled in both North America and Australia. A cline in Desiccation Tolerance was observed, for which Tolerance exhibited a positive association with latitude; Tolerance also varied predictably with culture temperature, demonstrating a significant degree of thermal plasticity. Desiccation Tolerance evolved rapidly in field mesocosms, although only males showed differences in Desiccation Tolerance between spring and autumn collections from natural populations. Water loss rates did not vary significantly among latitudinal or seasonal populations; however, changes in metabolic rates during prolonged exposure to dry conditions are consistent with increased Tolerance in higher latitude populations. Genome-wide associations in a panel of inbred lines identified twenty-five SNPs in twenty-one loci associated with sex-averaged Desiccation Tolerance, but there is no robust signal of spatially varying selection on genes associated with Desiccation Tolerance. Together, our results suggest that Desiccation Tolerance is a complex and important fitness component that evolves rapidly and predictably in natural populations.

  • Spatiotemporal dynamics and genome‐wide association analysis of Desiccation Tolerance in Drosophila melanogaster
    Molecular ecology, 2018
    Co-Authors: Subhash Rajpurohit, Allen G. Gibbs, Eran Gefen, Alan O. Bergland, Dmitri A. Petrov, Paul S. Schmidt
    Abstract:

    Water availability is a major environmental challenge to a variety of terrestrial organisms. In insects, Desiccation Tolerance varies predictably over spatial and temporal scales and is an important physiological determinant of fitness in natural populations. Here, we examine the dynamics of Desiccation Tolerance in North American populations of Drosophila melanogaster using: (a) natural populations sampled across latitudes and seasons; (b) experimental evolution in field mesocosms over seasonal time; (c) genome-wide associations to identify SNPs/genes associated with variation for Desiccation Tolerance; and (d) subsequent analysis of patterns of clinal/seasonal enrichment in existing pooled sequencing data of populations sampled in both North America and Australia. A cline in Desiccation Tolerance was observed, for which Tolerance exhibited a positive association with latitude; Tolerance also varied predictably with culture temperature, demonstrating a significant degree of thermal plasticity. Desiccation Tolerance evolved rapidly in field mesocosms, although only males showed differences in Desiccation Tolerance between spring and autumn collections from natural populations. Water loss rates did not vary significantly among latitudinal or seasonal populations; however, changes in metabolic rates during prolonged exposure to dry conditions are consistent with increased Tolerance in higher latitude populations. Genome-wide associations in a panel of inbred lines identified twenty-five SNPs in twenty-one loci associated with sex-averaged Desiccation Tolerance, but there is no robust signal of spatially varying selection on genes associated with Desiccation Tolerance. Together, our results suggest that Desiccation Tolerance is a complex and important fitness component that evolves rapidly and predictably in natural populations.

  • Spatiotemporal patterns of Desiccation Tolerance in natural populations of Drosophila melanogaster
    2016
    Co-Authors: Subhash Rajpurohit, Allen G. Gibbs, Eran Gefen, Alan O. Bergland, Dmitri A. Petrov, Paul S. Schmidt
    Abstract:

    Water availability is a major environmental challenge to a variety of terrestrial organisms. In insects, Desiccation Tolerance varies predictably over various spatial and temporal scales and is an important physiological basis of fitness variation among natural populations. Here, we examine the dynamics of Desiccation Tolerance in North American populations of Drosophila melanogaster using: 1) natural populations sampled across latitudes and seasons in the eastern USA; 2) experimental evolution in the field in response to changing seasonal environments; 3) a sequenced panel of inbred lines (DGRP) to perform genome wide associations and examine whether SNPs/genes associated with variation in Desiccation Tolerance exhibit patterns of clinal and/or seasonal enrichment in pooled sequencing of populations. In natural populations we observed a shallow cline in Desiccation Tolerance, for which Tolerance exhibited a positive association with latitude; the steepness of this cline increased with decreasing culture temperature, demonstrating a significant degree of thermal plasticity. No differences in Desiccation Tolerance were observed between spring and autumn collections from three mid-to-northern latitude populations, or as a function of experimental evolution to seasonality. Similarly, water loss rates did not vary significantly among latitudinal, seasonal or experimental evolution populations. However, changes in metabolic rates during prolonged exposure to dry conditions indicate increased Tolerance in higher latitude populations. Genome wide association studies identified thirty-six SNPs in twenty-eight genes associated with sex-averaged drought Tolerance. Among North American populations, genes associated with drought Tolerance do not show increased signatures of spatially varying selection relative to the rest of the genome, whereas among Australian populations they do.