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The Journal of Experimental Biology Jun 2024Increased average temperatures and extreme thermal events (such as heatwaves) brought forth by climate change impose important constraints on aerobic metabolism....
Increased average temperatures and extreme thermal events (such as heatwaves) brought forth by climate change impose important constraints on aerobic metabolism. Notably, mitochondrial metabolism, which is affected by both long- and short-term temperature changes, has been put forward as an important determinant for thermal tolerance of organisms. This study examined the influence of phenotypic plasticity on metabolic and physiological parameters in Drosophila melanogaster and the link between mitochondrial function and their upper thermal limits. We showed that D. melanogaster acclimated to 15°C have a 0.65°C lower critical thermal maximum (CTmax) compared with those acclimated to 24°C. Drosophila melanogaster acclimated to 15°C exhibited a higher proportion of shorter saturated and monounsaturated fatty acids, concomitant with lower proportions of polyunsaturated fatty acids. No mitochondrial quantitative changes (fractional area and number) were detected between acclimation groups, but changes of mitochondrial oxidation capacities were observed. Specifically, in both 15°C- and 24°C-acclimated flies, complex I-induced respiration was increased when measured between 15 and 24°C, but drastically declined when measured at 40°C. When succinate and glycerol-3-phosphate were added, this decrease was however compensated for in flies acclimated to 24°C, suggesting an important impact of acclimation on mitochondrial function related to thermal tolerance. Our study reveals that the use of oxidative substrates at high temperatures is influenced by acclimation temperature and strongly related to upper thermal tolerance as a difference of 0.65°C in CTmax translates into significant mitochondrial changes.
Topics: Animals; Drosophila melanogaster; Acclimatization; Mitochondria; Oxidation-Reduction; Hot Temperature; Male; Female
PubMed: 38841909
DOI: 10.1242/jeb.247706 -
The Journal of Experimental Biology Jun 2024The Arctic is a highly variable environment in which extreme daily and seasonal temperature fluctuations can occur. With climate change, an increase in the occurrence of...
The Arctic is a highly variable environment in which extreme daily and seasonal temperature fluctuations can occur. With climate change, an increase in the occurrence of extreme high temperatures and drought events is expected. While the effects of cold and dehydration stress on polar arthropods are well studied in combination, little is known about how these species respond to the combined effects of heat and dehydration stress. In this paper, we investigated how the heat tolerance of the Arctic collembola Megaphorura arctica is affected by combinations of different temperature and humidity acclimation regimes under controlled laboratory conditions. The effect of acclimation temperature was complex and highly dependent on both acclimation time and temperature, and was found to have a positive, negative or no effect depending on experimental conditions. Further, we found marked effects of the interaction between temperature and humidity on heat tolerance, with lower humidity severely decreasing heat tolerance when the acclimation temperature was increased. This effect was more pronounced with increasing acclimation time. Lastly, the effect of acclimation on heat tolerance under a fluctuating temperature regime was dependent on acclimation temperature and time, as well as humidity levels. Together, these results show that thermal acclimation alone has moderate or no effect on heat tolerance, but that drought events, likely to be more frequent in the future, in combination with high temperature stress can have large negative impacts on heat tolerance of some Arctic arthropods.
Topics: Animals; Humidity; Arctic Regions; Acclimatization; Arthropods; Thermotolerance; Temperature; Hot Temperature; Climate Change
PubMed: 38841875
DOI: 10.1242/jeb.247394 -
The New Phytologist Aug 2024
Topics: Salt Tolerance; Quantitative Trait Loci; Genes, Plant; Arabidopsis; Gene Expression Regulation, Plant
PubMed: 38840572
DOI: 10.1111/nph.19887 -
FEMS Microbiology Ecology Jun 2024Rhizosphere microbial communities play a substantial role in plant productivity. We studied the rhizosphere bacteria and fungi of 51 distinct potato cultivars grown...
Rhizosphere microbial communities play a substantial role in plant productivity. We studied the rhizosphere bacteria and fungi of 51 distinct potato cultivars grown under similar greenhouse conditions using a metabarcoding approach. As expected, individual cultivars were the most important determining factor of the rhizosphere microbial composition; however, differences were also obtained when grouping cultivars according to their growth characteristics. We demonstrated that plant growth characteristics were strongly related to deterministic and stochastic assembly processes of bacterial and fungal communities, respectively. The bacterial genera Arthrobacter and Massilia (known to produce IAA and siderophores) exhibited greater relative abundance in high- and medium performing cultivars. Bacterial co-occurrence networks were larger in the rhizosphere of these cultivars and were characterized by a distinctive combination of plant beneficial Proteobacteria and Actinobacteria along with a module of diazotrophs namely Azospira, Azoarcus, Azohydromonas. Conversely, the network within low performing cultivars revealed the lowest nodes, hub taxa, edges density, robustness and the highest average path length resulting in reduced microbial associations, which may potentially limit their effectiveness in promoting plant growth. Our findings established a clear pattern between plant productivity and the rhizosphere microbiome composition and structure for the investigated potato cultivars, offering insights for future management practices.
PubMed: 38839598
DOI: 10.1093/femsec/fiae088 -
Biochemical and Biophysical Research... Sep 2024Soil salinity pose a significant challenge to global agriculture, threatening crop yields and food security. Understanding the salt tolerance mechanisms of plants is...
Soil salinity pose a significant challenge to global agriculture, threatening crop yields and food security. Understanding the salt tolerance mechanisms of plants is crucial for improving their survival under salt stress. AFP2, a negative regulator of ABA signaling, has been shown to play a crucial role in salt stress tolerance during seed germination. Mutations in AFP2 gene lead to increased sensitivity to salt stress. However, the underline mechanisms by which AFP2 regulates seed germination under salt stress remain elusive. In this study, we identified a protein interaction between AFP2 and SOS2, a Ser/Thr protein kinase known to play a critical role in salt stress response. Using a combination of genetic, biochemical, and physiological approaches, we investigated the role of the SOS2-AFP2 module in regulating seed germination under salt stress. Our findings reveal that SOS2 physically interacts with AFP2 and stabilizes it, leading to the degradation of the ABI5 protein, a negative transcription factor in seed germination under salt stress. This study sheds light on previously unknown connections within salt stress and ABA signaling, paving the way for novel strategies to enhance plant resilience against environmental challenges.
Topics: Arabidopsis; Germination; Arabidopsis Proteins; Salt Stress; Seeds; Gene Expression Regulation, Plant; Basic-Leucine Zipper Transcription Factors; Proteolysis; Protein Serine-Threonine Kinases; Salt Tolerance; Signal Transduction
PubMed: 38838447
DOI: 10.1016/j.bbrc.2024.150190 -
Global Change Biology Jun 2024Thermal acclimation can provide an essential buffer against heat stress for host populations, while acting simultaneously on various life-history traits that determine...
Thermal acclimation can provide an essential buffer against heat stress for host populations, while acting simultaneously on various life-history traits that determine population growth. In turn, the ability of a pathogen to invade a host population is intimately linked to these changes via the supply of new susceptible hosts, as well as the impact of warming on its immediate infection dynamics. Acclimation therefore has consequences for hosts and pathogens that extend beyond simply coping with heat stress-governing both population growth trajectories and, as a result, an inherent propensity for a disease outbreak to occur. The impact of thermal acclimation on heat tolerances, however, is rarely considered simultaneously with metrics of both host and pathogen population growth, and ultimately fitness. Using the host Daphnia magna and its bacterial pathogen, we investigated how thermal acclimation impacts host and pathogen performance at both the individual and population scales. We first tested the effect of maternal and direct thermal acclimation on the life-history traits of infected and uninfected individuals, such as heat tolerance, fecundity, and lifespan, as well as pathogen infection success and spore production. We then predicted the effects of each acclimation treatment on rates of host and pathogen population increase by deriving a host's intrinsic growth rate (r) and a pathogen's basic reproductive number (R). We found that direct acclimation to warming enhanced a host's heat tolerance and rate of population growth, despite a decline in life-history traits such as lifetime fecundity and lifespan. In contrast, pathogen performance was consistently worse under warming, with within-host pathogen success, and ultimately the potential for disease spread, severely hampered at higher temperatures. Our results suggest that hosts could benefit more from warming than their pathogens, but only by linking multiple individual traits to population processes can the full impact of higher temperatures on host and pathogen population dynamics be realised.
Topics: Animals; Acclimatization; Daphnia; Hot Temperature; Host-Pathogen Interactions; Heat-Shock Response; Fertility; Thermotolerance; Longevity
PubMed: 38837568
DOI: 10.1111/gcb.17341 -
Endocrinology May 2024About half of the world population carries at least one allele of the Ala92-DIO2, which slows down the activity of the type 2 deiodinase (D2), the enzyme that activates...
About half of the world population carries at least one allele of the Ala92-DIO2, which slows down the activity of the type 2 deiodinase (D2), the enzyme that activates T4 to T3. Carrying the Ala92-DIO2 allele has been associated with increased body mass index and insulin resistance, but this has not been reproduced in all populations. To test if the genetic background affects the impact of this polymorphism, here we studied the genetically distant C57Bl/6J (B6) and FVB/N (FVB) mice carrying the Ala92-Dio2 allele as compared to control mice carrying the Thr92-Dio2 allele. Whereas B6-Ala92-Dio2 and B6-Thr92-Dio2 mice-fed chow or high-fat diet-behaved metabolically similar in studies using indirect calorimetry, glucose- and insulin tolerance tests, and measuring white adipose tissue (WAT) weight and liver steatosis, major differences were observed between FVB-Ala92-Dio2 and FVB-Thr92-Dio2 mice: carrying the Ala92-Dio2 allele (on a chow diet) resulted in hypercholesterolemia, smaller WAT pads, hepatomegaly, steatosis, and transcriptome changes in the interscapular brown adipose tissue (iBAT) typical of ER stress and apoptosis. Acclimatization at thermoneutrality (30 °C) eliminated most of the metabolic phenotype, indicating that impaired adaptive (BAT) thermogenesis can be involved. In conclusion, the metabolic impact of carrying the Ala92-Dio2 allele depends greatly on the genetic background of the mouse, varying from no phenotype in B6 mice to a major phenotype in FVB mice. These results will help the planning of future clinical trials studying the Thr92Ala-DIO2 polymorphism and may explain why some clinical studies performed in different populations across the globe have obtained inconsistent results.
Topics: Animals; Male; Iodide Peroxidase; Iodothyronine Deiodinase Type II; Mice; Mice, Inbred C57BL; Diet, High-Fat; Genetic Background; Adipose Tissue, White; Adipose Tissue, Brown; Polymorphism, Genetic; Insulin Resistance; Fatty Liver
PubMed: 38836615
DOI: 10.1210/endocr/bqae064 -
Journal of Applied Physiology... Jun 2024
Topics: Climate Change; Humans; Acclimatization; Hot Temperature; Animals
PubMed: 38836542
DOI: 10.1152/japplphysiol.00265.2024 -
Journal of Applied Physiology... Jun 2024
Topics: Humans; Climate Change; Hot Temperature; Adaptation, Physiological; Animals; Acclimatization; Thermotolerance
PubMed: 38836538
DOI: 10.1152/japplphysiol.00212.2024 -
Molecular Breeding : New Strategies in... Jun 2024(, kiwiberry) is a perennial deciduous vine with a strong overwintering ability. We hypothesized that trehalose metabolism, which plays a pivotal role in the stress...
UNLABELLED
(, kiwiberry) is a perennial deciduous vine with a strong overwintering ability. We hypothesized that trehalose metabolism, which plays a pivotal role in the stress tolerance of plants, may be involved in the cold acclimatization of . Transcriptome analysis showed that the expression of , which encodes a trehalose-6-phosphate phosphatase (TPP), was upregulated in response to low temperatures. expression levels were much higher in lateral buds, roots, and stem cambia than in leaves in autumn. In -overexpressing (OE) (), trehalose levels were 8-11 times higher than that of the wild type (WT) and showed different phenotypic characteristics from WT and () overexpressing lines. -OE exhibited significantly higher freezing tolerance than WT and -OE lines. Transient overexpression of in leaves increased the scavenging ability of reactive oxygen species (ROS) and the soluble sugar and proline contents. , an ethylene-responsive transcription factor, was induced by ethylene treatment and bound to the GCC-box of the promoter to activate its expression. expression was also induced by abscisic acid. In summary, the temperature decrease in autumn is likely to induce expression through an ethylene-dependent pathway, which consequently upregulates expression, leading to the accumulation of osmotic protectants such as soluble sugars and proline in the overwintering tissues of .
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s11032-024-01475-8.
PubMed: 38836186
DOI: 10.1007/s11032-024-01475-8