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1.
PLoS One ; 15(10): e0239605, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33006971

RESUMO

The lily, a famous bulbous flower, is seriously affected by high temperatures, which affect their growth and production. To date, the signalling pathways and the molecular mechanisms related to heat response in Lilium have not been elucidated. In this study, a comparative transcriptome analysis was performed in an important thermo-tolerant flower, L. longiflorum, and a thermo-sensitive flower, L. distichum. Lily seedlings were first exposed to heat stress at 42°C for different lengths of time, and the optimal time-points (2 h and 24 h) were selected for RNA sequencing (RNA-seq). Approximately 66.51, 66.21, and 65.36 Mb clean reads were identified from three libraries of L. longiflorum (LL_CK, LL_T2h and LL_T24h, respectively) and 66.18, 66.03, and 65.16 Mb clean reads were obtained from three libraries of L. distichum (LD_CK, LD_T2h and LD_T24h, respectively) after rRNA removing. A total of 34,301 unigenes showed similarity to known proteins in the database NCBI non-redundant protein (NR), Swiss-Prot proteins, InterPro proteins, Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG). In addition, 1,621 genes were differentially expressed in the overlapping libraries between LL_DEGs and LD_DEGs; of these genes, 352 DEGs were obviously upregulated in L. longiflorum and downregulated in L. distichum during heat stress, including 4-coumarate, CoA ligase (4CL), caffeoyl-CoA O-methyltransferase (CCoAOMT), peroxidase, pathogenesis-related protein 10 family genes (PR10s), 14-3-3 protein, leucine-rich repeat receptor-like protein kinase, and glycine-rich cell wall structural protein-like. These genes were mainly involved in metabolic pathways, phenylpropanoid biosynthesis, plant-pathogen interactions, plant hormone signal transduction, and kinase signalling pathways. Quantitative RT-PCR was performed to validate the expression profiling of these DEGs in RNA-seq data. Taken together, the results obtained in the present study provide a comprehensive sequence resource for the discovery of heat-resistance genes and reveal potential key components that are responsive to heat stress in lilies, which may help to elucidate the heat signal transcription networks and facilitate heat-resistance breeding in lily.


Assuntos
Lilium/genética , Lilium/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Fatores de Transcrição de Choque Térmico/genética , Fatores de Transcrição de Choque Térmico/fisiologia , Resposta ao Choque Térmico/genética , Resposta ao Choque Térmico/fisiologia , Lilium/crescimento & desenvolvimento , Redes e Vias Metabólicas/genética , Anotação de Sequência Molecular , Família Multigênica , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , RNA-Seq , Transdução de Sinais/genética , Especificidade da Espécie , Termotolerância/genética , Termotolerância/fisiologia
2.
PLoS One ; 15(10): e0239742, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33021997

RESUMO

The yellow-legged hornet, Vespa velutina nigrithorax (Hymenoptera: Vespidae, Lepeletier 1836), is native to Southeast Asia and has been unintentionally introduced in France. The species is spreading in many areas of the world. The European Union has classified V. velutina as a species of concern because the hornet significantly affects beekeeping activities, mostly by preying honeybees (Apis mellifera) at beehive entrances. No current control method is simultaneously eco-friendly and effective. Here, we aimed to develop a greener technique for destroying V. velutina nests, inspired by a defense behavior used by the eastern honeybee (Apis cerana), the "heat ball". In the laboratory, we tested how V. velutina of different sexes, castes, and developmental stages responded to different heat exposure systems employing a range of temperature levels. Overall, the time of death decreased as temperature increased. Hornets died faster when the temperature was gradually increased than when it was instantaneously increased; larvae seemed to be more thermally tolerant. The most promising and potential technique for quickly destroying hornet nests may be steam injection, as the humid airflow system killed all hornets within 13 seconds, and therefore could be a good candidate for a green nest control method.


Assuntos
Controle de Insetos/métodos , Espécies Introduzidas , Termotolerância/fisiologia , Vespas/fisiologia , Animais , Abelhas/fisiologia , Feminino , França , Temperatura Alta , Larva/fisiologia , Masculino , Temperatura
3.
Nat Commun ; 11(1): 5441, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33116138

RESUMO

With global warming and climate change, breeding crop plants tolerant to high-temperature stress is of immense significance. tRNA 2-thiolation is a highly conserved form of tRNA modification among living organisms. Here, we report the identification of SLG1 (Slender Guy 1), which encodes the cytosolic tRNA 2-thiolation protein 2 (RCTU2) in rice. SLG1 plays a key role in the response of rice plants to high-temperature stress at both seedling and reproductive stages. Dysfunction of SLG1 results in plants with thermosensitive phenotype, while overexpression of SLG1 enhances the tolerance of plants to high temperature. SLG1 is differentiated between the two Asian cultivated rice subspecies, indica and japonica, and the variations at both promoter and coding regions lead to an increased level of thiolated tRNA and enhanced thermotolerance of indica rice varieties. Our results demonstrate that the allelic differentiation of SLG1 confers indica rice to high-temperature tolerance, and tRNA thiolation pathway might be a potential target in the next generation rice breeding for the warming globe.


Assuntos
Genes de Plantas , Oryza/genética , Oryza/fisiologia , Termotolerância/genética , Termotolerância/fisiologia , Variação Genética , Aquecimento Global , Modelos Biológicos , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Regiões Promotoras Genéticas , Processamento Pós-Transcricional do RNA/genética , Processamento Pós-Transcricional do RNA/fisiologia , RNA de Plantas/metabolismo , RNA de Transferência/metabolismo , Tionucleotídeos/metabolismo
4.
Nat Commun ; 11(1): 5351, 2020 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-33093449

RESUMO

MicroRNAs (miRNAs) and natural antisense transcripts (NATs) control many biological processes and have been broadly applied for genetic manipulation of eukaryotic gene expression. Still unclear, however, are whether and how NATs regulate miRNA production. Here, we report that the cis-NATs of MIR398 genes repress the processing of their pri-miRNAs. Through genome-wide analysis of RNA sequencing data, we identify cis-NATs of MIRNA genes in Arabidopsis and Brassica. In Arabidopsis, MIR398b and MIR398c are coexpressed in vascular tissues with their antisense genes NAT398b and NAT398c, respectively. Knock down of NAT398b and NAT398c promotes miR398 processing, resulting in stronger plant thermotolerance owing to silencing of miR398-targeted genes; in contrast, their overexpression activates NAT398b and NAT398c, causing poorer thermotolerance due to the upregulation of miR398-targeted genes. Unexpectedly, overexpression of MIR398b and MIR398c activates NAT398b and NAT398c. Taken together, these results suggest that NAT398b/c repress miR398 biogenesis and attenuate plant thermotolerance via a regulatory loop.


Assuntos
Arabidopsis/genética , Arabidopsis/fisiologia , Brassica rapa/genética , Brassica rapa/fisiologia , MicroRNAs/genética , RNA Antissenso/genética , Termotolerância/genética , Termotolerância/fisiologia , Regulação da Expressão Gênica de Plantas , Técnicas de Silenciamento de Genes , Genes de Plantas , MicroRNAs/metabolismo , Modelos Biológicos , Mutação , Plantas Geneticamente Modificadas , Processamento Pós-Transcricional do RNA , Estabilidade de RNA , RNA Antissenso/metabolismo
5.
PLoS One ; 15(9): e0239485, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32960914

RESUMO

Environmental temperatures are a major constraint on ectotherm abundance, influencing their distribution and natural history. Comparing thermal tolerances with environmental temperatures is a simple way to estimate thermal constraints on species distributions. We investigate the potential effects of behavioral thermal tolerance (i. e. Voluntary Thermal Maximum, VTMax) on anuran local (habitat) and regional distribution patterns and associated behavioral responses. We tested for differences in Voluntary Thermal Maximum (VTMax) of two sympatric frog species of the genus Physalaemus in the Cerrado. We mapped the difference between VTMax and maximum daily temperature (VTMax-ETMax) and compared the abundance in open and non-open habitats for both species. Physalaemus nattereri had a significantly higher VTMax than P. cuvieri. For P. nattereri, the model including only period of day was chosen as the best to explain variation in the VTMax while for P. cuvieri, the null model was the best model. At the regional scale, VTMax-ETMax values were significantly different between species, with P. nattereri mostly found in localities with maximum temperatures below its VTMax and P. cuvieri showing the reverse pattern. Regarding habitat use, P. cuvieri was in general more abundant in open than in non-open habitats, whereas P. nattereri was similarly abundant in these habitats. This difference seems to reflect their distribution patterns: P. cuvieri is more abundant in open and warmer habitats and occurs mostly in warmer areas in relation to its VTMax, whereas P. nattereri tends to be abundant in both open and non-open (and cooler) areas and occurs mostly in cooler areas regarding its VTMax. Our study indicates that differences in behavioral thermal tolerance may be important in shaping local and regional distribution patterns. Furthermore, small-scale habitat use might reveal a link between behavioral thermal tolerance and natural history strategies.


Assuntos
Anuros/fisiologia , Comportamento Animal/fisiologia , Simpatria/fisiologia , Termotolerância/fisiologia , Animais , Ecossistema , Temperatura
6.
PLoS One ; 15(4): e0232228, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353077

RESUMO

Heat stress is one of the major abiotic stresses that impair plant growth and crop productivity. Plant growth-promoting endophytic bacteria (PGPEB) and humic acid (HA) are used as bio-stimulants and ecofriendly approaches to improve agriculture crop production and counteract the negative effects of heat stress. Current study aimed to analyze the effect of thermotolerant SA1 an isolate of Bacillus cereus and HA on tomato seedlings. The results showed that combine application of SA1+HA significantly improved the biomass and chlorophyll fluorescence of tomato plants under normal and heat stress conditions. Heat stress increased abscisic acid (ABA) and reduced salicylic acid (SA) content; however, combined application of SA1+HA markedly reduced ABA and increased SA. Antioxidant enzymes activities revealed that SA1 and HA treated plants exhibited increased levels of ascorbate peroxidase (APX), superoxide dismutase (SOD), and reduced glutathione (GSH). In addition, heat stress markedly reduced the amino acid contents; however, the amino acids were increased with co-application of SA1+HA. Similarly, inductively-coupled plasma mass-spectrometry results showed that plants treated with SA1+HA exhibited significantly higher iron (Fe+), phosphorus (P), and potassium (K+) uptake during heat stress. Heat stress increased the relative expression of SlWRKY33b and autophagy-related (SlATG5) genes, whereas co-application of SA1+HA augmented the heat stress response and reduced SlWRKY33b and SlATG5 expression. The heat stress-responsive transcription factor (SlHsfA1a) and high-affinity potassium transporter (SlHKT1) were upregulated in SA1+HA-treated plants. In conclusion, current findings suggest that co-application with SA1+HA can be used for the mitigation of heat stress damage in tomato plants and can be commercialized as a biofertilizer.


Assuntos
Bacillus cereus/metabolismo , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Proteínas de Plantas/metabolismo , Plântula/metabolismo , Termotolerância/fisiologia , Aminoácidos/metabolismo , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Glutationa/metabolismo , Resposta ao Choque Térmico/fisiologia , Substâncias Húmicas , Estresse Fisiológico/fisiologia , Superóxido Dismutase/metabolismo
7.
Proc Biol Sci ; 287(1922): 20193001, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32156215

RESUMO

Exotic species often face new environmental conditions that are different from those that they are adapted to. The tropical seagrass Halophila stipulacea is a Lessepsian migrant that colonized the Mediterranean Sea around 100 years ago, where at present the minimum seawater temperature is cooler than in its native range in the Red Sea. Here, we tested if the temperature range in which H. stipulacea can exist is conserved within the species or if the exotic populations have shifted their thermal breadth and optimum due to the cooler conditions in the Mediterranean. We did so by comparing the thermal niche (e.g. optimal temperatures, and upper and lower thermal limits) of native (Saudi Arabia in the Red Sea) and exotic (Greece and Cyprus in the Mediterranean Sea) populations of H. stipulacea. We exposed plants to 12 temperature treatments ranging from 8 to 40°C for 7 days. At the end of the incubation period, we measured survival, rhizome elongation, shoot recruitment, net population growth and metabolic rates. Upper and lower lethal thermal thresholds (indicated by 50% plant mortality) were conserved across populations, but minimum and optimal temperatures for growth and oxygen production were lower for Mediterranean populations than for the Red Sea one. The displacement of the thermal niche of exotic populations towards the colder Mediterranean Sea regime could have occurred within 175 clonal generations.


Assuntos
Hydrocharitaceae/fisiologia , Termotolerância/fisiologia , Espécies Introduzidas , Mar Mediterrâneo , Rizoma , Água do Mar , Temperatura
8.
J Therm Biol ; 88: 102527, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32126002

RESUMO

Thermal tolerance allows many organisms, including insects, to withstand stressful temperatures. Thermal generalists are expected to have higher thermal tolerance than specialists, but the environmental conditions leading to the evolution of a thermal generalist life history are not fully understood. Thermal variability has been put forth as an evolutionary driver of high thermal tolerance, but rarely has this been empirically tested. We used a generalist agricultural pest grasshopper, Melanoplus differentialis, to test upper and lower thermal limits of populations that experienced different levels of thermal variability. We quantified thermal heterogeneity at five sites in a longitudinal transect in the Midwestern U.S. by examining, over a 101-year period, 1) variance in daily thermal maxima and minima; and 2) daily range. Also, as a measure of a biologically relevant thermal extreme, we depicted days per month at each site that reached a stressfully high temperature for M. differentialis. We collected individuals from these sites and tested their upper and lower thermal limits. We found that most of our metrics of thermal heterogeneity differed among sites, while all sites experienced an average of at least two stressfully high temperature events per month. We found that heavier males from these sites were able to withstand both warmer and colder temperatures than smaller males, while heavier females had no thermal advantage over lighter females. However, site of origin had no effect on thermal tolerance. Our findings indicate three things: 1) there is no clear correlation between thermal variability and thermal tolerance in the populations we studied; 2) weight affects thermal tolerance range among sites for M. differentialis males, and 3) thermal extremes may be more important than thermal variability in determining CTMax in this species.


Assuntos
Gafanhotos/fisiologia , Termotolerância/fisiologia , Animais , Feminino , Masculino , Temperatura
9.
Int J Sports Physiol Perform ; 15(6): 892-895, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32023546

RESUMO

PURPOSE: The core temperature responses during exercise and effects of different cooling strategies on endurance performance under heat stress have been investigated in recreational athletes. This investigation aimed to determine peak rectal temperatures during elite racewalking competitions and to detail any cooling strategies used. METHODS: Rectal temperature was measured in 14 heat-adapted elite/preelite race walkers (9 females) via a telemetric capsule across 4 outdoor events, including the 2018 Commonwealth Games (race 1: 20 km, 25°C, 74% relative humidity [RH], n = 2) and 3 International Association of Athletics Federations-sanctioned 10-km events (race 2: 19°C, 34% RH, n = 2; race 3: 29°C, 47% RH, n = 14; and race 4: 23°C, 72% RH, n = 11). All athletes completed race 3, and a subsample completed the other events. Their use of cooling strategies and symptoms of heat illness were determined. RESULTS: Peak rectal temperatures >40°C were observed in all events. The highest rectal temperature observed during an event was 41.2°C. These high rectal temperatures were observed without concomitant heat illness, with the exception of cramping in one athlete during race 1. The rectal temperatures tended to reach a steady state in the second half of the 20-km event, but no steady state was observed in the 10-km events. The athletes used cooling strategies in race 1 only, implementing different combinations of cold-water immersion, ice-slurry ingestion, ice-towel application, ice-vest application, and facial water spraying. CONCLUSIONS: Elite/preelite race walkers experience rectal temperatures >40°C during competition despite only moderate-warm conditions, and even when precooling and midcooling strategies are applied.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Comportamento Competitivo/fisiologia , Transtornos de Estresse por Calor/prevenção & controle , Termotolerância/fisiologia , Caminhada/fisiologia , Adulto , Feminino , Temperatura Alta/efeitos adversos , Humanos , Masculino , Ciclo Menstrual/fisiologia , Adulto Jovem
10.
J Antibiot (Tokyo) ; 73(4): 203-210, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32015464

RESUMO

In actinomycetes, many secondary metabolite biosynthetic genes are not expressed under typical laboratory culture conditions and various efforts have been made to activate these dormant genes. In this study, we focused on high-temperature culture. First, we examined the thermotolerance of 3160 actinomycete strains from our laboratory culture collection and selected 57 thermotolerant actinomycetes that grew well at 45 °C. These 57 thermotolerant actinomycetes were cultured for 5 days in liquid medium at both 30 °C and 45 °C. Culture broths were extracted with 1-butanol, and each extract was subjected to LC/MS analysis. The metabolic profiles of each strain were compared between the 30 °C and 45 °C cultures. We found that almost half of these thermotolerant actinomycetes produced secondary metabolites that were detected only in the 45 °C culture. This result suggests that high-temperature culture induces the production of dormant secondary metabolites. These compounds were named "heat shock metabolites (HSMs)." To examine HSM production in more detail, 18 strains were selected at random from the initial 57 strains and cultivated in six different media at 30 °C and 45 °C; as before, metabolic profiles of each strain in each medium were compared between the 30 °C and 45 °C cultures. From this analysis, we found a total of 131 HSMs. We identified several angucycline-related compounds as HSMs from two thermotolerant Streptomyces species. Furthermore, we discovered a new compound, murecholamide, as an HSM from thermotolerant Streptomyces sp. AY2. We propose that high-temperature culture of actinomycetes is a convenient method for activating dormant secondary metabolite biosynthetic genes.


Assuntos
Actinobacteria/metabolismo , Resposta ao Choque Térmico/fisiologia , Termotolerância/fisiologia , Cromatografia Líquida , Temperatura Alta , Espectrometria de Massas , Metabolismo Secundário , Temperatura
11.
Braz. j. infect. dis ; 24(1): 44-50, Feb. 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1089329

RESUMO

ABSTRACT The yeast phase of 22 Histoplasma capsulatum clinical isolates from Mexico, Argentina, Colombia, and Guatemala and three reference strains, one from Panama and two from the United States of America (USA), were screened for thermosensitivity characteristics using different analyses. Growth curves at 0, 3, 6, 12, 24, and 30 h of incubation at 37 and 40 °C, the growth inhibition percentage at 40 °C, and the doubling time at 37 and 40 °C were determined for all yeasts studied. Most of the isolates examined exhibited thermotolerant phenotypes at 40 °C, whereas a thermosensitive phenotype at 40 °C was only detected in the Downs reference strain from the USA. Growth inhibition values lower than 33.8% supported the predominance of the thermotolerant phenotype at 40 °C. The doubling time means found for the different isolates were 5.14 h ± 1.47 h at 37 °C and 5.55 h ± 1.87 h at 40 °C. This is the first report to underscore the predominance of thermotolerant and delayed doubling time phenotypes in H. capsulatum clinical isolates from different regions of Latin America.


Assuntos
Termotolerância/fisiologia , Histoplasma/isolamento & purificação , Histoplasma/crescimento & desenvolvimento , Fenótipo , Filogenia , Valores de Referência , Temperatura , Fatores de Tempo , Histoplasma/genética , Histoplasmose/microbiologia , América Latina
12.
PLoS One ; 15(1): e0227700, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31971994

RESUMO

In vertebrates, the embryonic environment is known to affect the development and the health of individuals. In broiler chickens, the thermal-manipulation (TM) of eggs during the incubation period was shown to improve heat tolerance at slaughter age (35 days of age) in association with several modifications at the molecular, metabolic and physiological levels. However, little is known about the Japanese quail (Coturnix japonica), a closely related avian species widely used as a laboratory animal model and farmed for its meat and eggs. Here we developed and characterized a TM procedure (39.5°C and 65% relative humidity, 12 h/d, from days 0 to 13 of incubation) in quails by analyzing its short and long-term effects on zootechnical, physiological and metabolic parameters. Heat-tolerance was tested by a heat challenge (36°C for 7h) at 35 days of age. TM significantly reduced the hatching rate of the animals and increased mortality during the first four weeks of life. At hatching, TM animals were heavier than controls, but lighter at 25 days of age for both sexes. Thirty-five days after hatching, TM decreased the surface temperature of the shank in females, suggesting a modulation of the blood flow to maintain the internal temperature. TM also increased blood partial pressure and oxygen saturation percentage at 35 days of age in females, suggesting a long-term modulation of the respiration physiology. Quails physiologically responded to the heat challenge, with a modification of several hematologic and metabolic parameters, including an increase in plasma corticosterone concentration. Several physiological parameters such as beak surface temperature and blood sodium concentration revealed that TM birds responded differently to the heat challenge compared to controls. Altogether, this first comprehensive characterization of TM in Japanese quail showed durable effects that may affect the response of TM quails to heat.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Coturnix/embriologia , Animais , Antioxidantes/metabolismo , Embrião de Galinha , Galinhas/crescimento & desenvolvimento , Galinhas/fisiologia , Coturnix/crescimento & desenvolvimento , Coturnix/fisiologia , Desenvolvimento Embrionário/fisiologia , Feminino , Gases/sangue , Temperatura Alta , Masculino , Termotolerância/fisiologia
13.
Theor Appl Genet ; 133(4): 1161-1175, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31989206

RESUMO

KEY MESSAGE: The qHTB1-1 QTL, controlling heat tolerance at the booting stage in rice, was fine mapped to a 47.1 kb region containing eight candidate genes. Two positional candidate genes showed significant changes in expression levels under heat stress. High-temperature stress at the booting stage has the potential to significantly limit rice production. An interspecific advanced backcrossed population between the Oryza sativa L. cultivar R53 and the wild Oryza rufipogon Griff accession HHT4 was used as the source material to develop a set of chromosome segment introgression lines to elucidate the genetic mechanism of the qHTB1-1 QTL in heat tolerance. A single-chromosome-segment introgression line, IL01-15, was used to develop secondary populations for the mapping of qHTB1-1 on chromosome 1 for heat tolerance at the booting stage. Using the BC5F2, BC5F3, and BC5F4 populations, we first confirmed qHTB1-1 and validated the phenotypic effect. The qHTB1-1 QTL explained 13.1%, 16.9%, and 17.8% of the phenotypic variance observed in the BC5F2, BC5F3, and BC5F4 generations, respectively. Using homozygous recombinants screened from larger BC6F2 and BC6F3 populations, qHTB1-1 was fine mapped within a 47.1 kb region between markers RM11633 and RM11642. Eight putative predicted genes were annotated in the region, and six genes were predicted to encode expressed proteins. The expression patterns of these six genes demonstrated that LOC_Os01g53160 and LOC_Os01g53220 were highly induced by heat stress in IL01-15 compared to R53. Sequence comparison of the gene-coding regions of LOC_Os01g53160 and LOC_Os01g53220 between R53 and IL01-15 revealed one synonymous and two nonsynonymous SNPs in exons, respectively. Our results provide a basis for identifying the genes underlying qHTB1-1 and indicate that markers linked to the qHTB1-1 locus can be used to improve the heat tolerance of rice at the booting stage by marker-assisted selection.


Assuntos
Oryza/genética , Oryza/fisiologia , Mapeamento Físico do Cromossomo , Locos de Características Quantitativas/genética , Termotolerância/fisiologia , Fertilidade/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Endogamia , Anotação de Sequência Molecular , Polimorfismo de Nucleotídeo Único/genética , Reprodutibilidade dos Testes , Estresse Fisiológico/genética
14.
Braz J Infect Dis ; 24(1): 44-50, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31987782

RESUMO

The yeast phase of 22 Histoplasma capsulatum clinical isolates from Mexico, Argentina, Colombia, and Guatemala and three reference strains, one from Panama and two from the United States of America (USA), were screened for thermosensitivity characteristics using different analyses. Growth curves at 0, 3, 6, 12, 24, and 30 h of incubation at 37 and 40 °C, the growth inhibition percentage at 40 °C, and the doubling time at 37 and 40 °C were determined for all yeasts studied. Most of the isolates examined exhibited thermotolerant phenotypes at 40 °C, whereas a thermosensitive phenotype at 40 °C was only detected in the Downs reference strain from the USA. Growth inhibition values lower than 33.8% supported the predominance of the thermotolerant phenotype at 40 °C. The doubling time means found for the different isolates were 5.14 h ±â€¯1.47 h at 37 °C and 5.55 h ±â€¯1.87 h at 40 °C. This is the first report to underscore the predominance of thermotolerant and delayed doubling time phenotypes in H. capsulatum clinical isolates from different regions of Latin America.


Assuntos
Histoplasma/crescimento & desenvolvimento , Histoplasma/isolamento & purificação , Termotolerância/fisiologia , Histoplasma/genética , Histoplasmose/microbiologia , América Latina , Fenótipo , Filogenia , Valores de Referência , Temperatura , Fatores de Tempo
15.
Nat Commun ; 11(1): 551, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992708

RESUMO

The wings of Lepidoptera contain a matrix of living cells whose function requires appropriate temperatures. However, given their small thermal capacity, wings can overheat rapidly in the sun. Here we analyze butterfly wings across a wide range of simulated environmental conditions, and find that regions containing living cells are maintained at cooler temperatures. Diverse scale nanostructures and non-uniform cuticle thicknesses create a heterogeneous distribution of radiative cooling that selectively reduces the temperature of structures such as wing veins and androconial organs. These tissues are supplied by circulatory, neural and tracheal systems throughout the adult lifetime, indicating that the insect wing is a dynamic, living structure. Behavioral assays show that butterflies use wings to sense visible and infrared radiation, responding with specialized behaviors to prevent overheating of their wings. Our work highlights the physiological importance of wing temperature and how it is exquisitely regulated by structural and behavioral adaptations.


Assuntos
Adaptação Fisiológica/fisiologia , Comportamento Animal , Borboletas/fisiologia , Termotolerância/fisiologia , Asas de Animais/fisiologia , Animais , Metabolismo Energético/fisiologia , Hemolinfa/fisiologia , Raios Infravermelhos , Modelos Biológicos , Nanoestruturas , Energia Solar , Temperatura , Termodinâmica , Sensação Térmica , Asas de Animais/anatomia & histologia , Asas de Animais/citologia , Asas de Animais/efeitos da radiação
16.
Proc Natl Acad Sci U S A ; 117(3): 1596-1605, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31907313

RESUMO

Hybrid-poplar tree plantations provide a source for biofuel and biomass, but they also increase forest isoprene emissions. The consequences of increased isoprene emissions include higher rates of tropospheric ozone production, increases in the lifetime of methane, and increases in atmospheric aerosol production, all of which affect the global energy budget and/or lead to the degradation of air quality. Using RNA interference (RNAi) to suppress isoprene emission, we show that this trait, which is thought to be required for the tolerance of abiotic stress, is not required for high rates of photosynthesis and woody biomass production in the agroforest plantation environment, even in areas with high levels of climatic stress. Biomass production over 4 y in plantations in Arizona and Oregon was similar among genetic lines that emitted or did not emit significant amounts of isoprene. Lines that had substantially reduced isoprene emission rates also showed decreases in flavonol pigments, which reduce oxidative damage during extremes of abiotic stress, a pattern that would be expected to amplify metabolic dysfunction in the absence of isoprene production in stress-prone climate regimes. However, compensatory increases in the expression of other proteomic components, especially those associated with the production of protective compounds, such as carotenoids and terpenoids, and the fact that most biomass is produced prior to the hottest and driest part of the growing season explain the observed pattern of high biomass production with low isoprene emission. Our results show that it is possible to reduce the deleterious influences of isoprene on the atmosphere, while sustaining woody biomass production in temperate agroforest plantations.


Assuntos
Atmosfera , Hemiterpenos/biossíntese , Hibridização Genética , Populus/crescimento & desenvolvimento , Populus/metabolismo , Poluição do Ar , Arizona , Biocombustíveis , Biomassa , Butadienos , Dióxido de Carbono/metabolismo , Carotenoides/metabolismo , Clima , Oregon , Fotossíntese , Folhas de Planta/metabolismo , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo , Populus/genética , Proteoma , Interferência de RNA , Estações do Ano , Estresse Fisiológico , Terpenos/metabolismo , Termotolerância/fisiologia , Madeira
17.
Plant Cell Physiol ; 61(1): 169-177, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31596474

RESUMO

Heat stress poses a major threat to plant productivity and crop yields. The induction of heat shock proteins (HSPs) by heat shock factors is a principal defense response of plants exposed to heat stress. In this study, we identified and analyzed the heat stress-induced Whirly1 (SlWHY1) gene in tomato (Solanum lycopersicum). We generated various SlWHY1-overexpressing (OE) and SlWHY1-RNA interference (RNAi) lines to investigate the role of WHIRLY1 in thermotolerance. Compared with the wild type (WT), the OE lines showed less wilting, as reflected by their increased membrane stability and soluble sugar content and reduced reactive oxygen species (ROS) accumulation under heat stress. By contrast, RNAi lines with inhibited SlWHY1 expression showed the opposite phenotype and corresponding physiological indices under heat stress. The heat-induced gene SlHSP21.5A, encoding an endoplasmic reticulum-localized HSP, was upregulated in the OE lines and downregulated in the RNAi lines compared with the WT. RNAi-mediated inhibition of SlHSP21.5A expression also resulted in reduced membrane stability and soluble sugar content and increased ROS accumulation under heat stress compared with the WT. SlWHY1 binds to the elicitor response element-like element in the promoter of SlHSP21.5A to activate its transcription. These findings suggest that SlWHY1 promotes thermotolerance in tomato by regulating SlHSP21.5A expression.


Assuntos
Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Choque Térmico/genética , Lycopersicon esculentum/genética , Proteínas de Plantas/genética , Termotolerância/genética , Arabidopsis/genética , Proteínas de Arabidopsis , Clorofila , Proteínas de Ligação a DNA/metabolismo , Proteínas de Choque Térmico/metabolismo , Resposta ao Choque Térmico/genética , Temperatura Alta , Lycopersicon esculentum/fisiologia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Espécies Reativas de Oxigênio/metabolismo , Termotolerância/fisiologia , Tabaco/genética
18.
Planta ; 251(1): 26, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797121

RESUMO

MAIN CONCLUSION: Silencing of CI-sHsps by RNAi negatively affected the seed germination process and heat stress response of rice seedlings. Seed size of RNAiCI-sHsp was reduced as compared to wild-type plants. Small heat shock proteins (sHsps) are the ATP-independent chaperones ubiquitously expressed in response to diverse environmental and developmental cues. Cytosolic sHsps constitute the major repertoire of sHsp family. Rice cytosolic class I (CI)-sHsps consists of seven members (Hsp16.9A, Hsp16.9B, Hsp16.9C, Hsp17.4, Hsp17.7, Hsp17.9A and Hsp18). Purified OsHsp17.4 and OsHsp17.9A proteins exhibited chaperone activity by preventing formation of large aggregates with model substrate citrate synthase. OsHsp16.9A and OsHsp17.4 showed nucleo-cytoplasmic localization, while the localization of OsHsp17.9A was preferentially in the nucleus. Transgenic tobacco plants expressing OsHsp17.4 and OsHsp17.9A proteins and Arabidopsis plants ectopically expressing OsHsp17.4 protein showed improved thermotolerance to the respective trans-hosts during the post-stress recovery process. Single hairpin construct was designed to generate all CI-sHsp silenced (RNAiCI-sHsp) rice lines. The major vegetative and reproductive attributes of the RNAiCI-sHsp plants were comparable to the wild-type rice plants. Basal and acquired thermotolerance response of RNAiCI-sHsp seedlings of rice was mildly affected. The seed length of RNAiCI-sHsp rice plants was significantly reduced. The seed germination process was delayed and seed thermotolerance of RNAiCI-sHsp was negatively affected than the non-transgenic seeds. We, thus, implicate that sHsp genes are critical in seedling thermotolerance and seed physiology.


Assuntos
Inativação Gênica , Proteínas de Choque Térmico Pequenas/metabolismo , Oryza/genética , Oryza/fisiologia , Proteínas de Plantas/metabolismo , Plântula/fisiologia , Sementes/fisiologia , Termotolerância/fisiologia , Arabidopsis/genética , Arabidopsis/fisiologia , Citrato (si)-Sintase/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação/genética , Proteínas de Choque Térmico Pequenas/genética , Fenótipo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Ligação Proteica , Multimerização Proteica , Protoplastos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sementes/genética , Termotolerância/genética , Tabaco/genética , Transcriptoma/genética
19.
PLoS One ; 14(11): e0224218, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31693675

RESUMO

Tropical plant species are expected to have high heat tolerance reflecting phenotypic adjustments to warm regions or their evolutionary adaptation history. However, tropical highland specialists adapted to the colder temperatures found in the highlands, where short and prostrated vegetation decouples plants from ambient conditions, could exhibit different upper thermal limits than those of their lowland counterparts. Here we evaluated leaf heat tolerance of 21 tropical alpine paramo species to determine: 1) whether species with restricted distribution (i.e., highland specialists) have lower heat tolerance and are more vulnerable to warming than species with widespread distribution; 2) whether different growth forms have different heat tolerance; and 3) whether species height (i.e., microhabitat) influences its heat tolerance. We quantified heat tolerance by evaluating T50, which is the temperature that causes a reduction in 50% of initial Fv/Fm values and reflects an irreversible damage to the photosynthetic apparatus. Additionally, we estimated the thermal safety margins as the difference between T50 and the maximum leaf temperature registered for the species. All species presented high T50 values ranging between 45.4°C and 53.9°C, similar to those found for tropical lowland species. Heat tolerance was not correlated with species distributions or plant height, but showed a strong relationship with growth form, with rosettes having the highest heat tolerance. Thermal safety margins ranged from 12.1 to 31.0°C. High heat tolerance and broad thermal safety margins suggest low vulnerability of paramo species to warming as long as plants are capable of regulating the leaf temperature within this threshold. Whether paramo plants would be able to regulate leaf temperature if drought episodes become more frequent and transpirational cooling is compromised is the next question that needs to be answered.


Assuntos
Mudança Climática , Folhas de Planta/fisiologia , Termotolerância/fisiologia , Clima Tropical/efeitos adversos , Tundra , Colômbia , Temperatura Alta/efeitos adversos , Dispersão Vegetal/fisiologia
20.
Sci Rep ; 9(1): 17036, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31745168

RESUMO

Candida glabrata is a human commensal and an opportunistic human fungal pathogen. It is more closely related to the model yeast Saccharomyces cerevisiae than other Candida spp. Compared with S. cerevisiae, C. glabrata exhibits higher innate tolerance to various environmental stressors, including hyperthermal stress. Here we investigate the molecular mechanisms of C. glabrata adaptation to heat stress via adaptive laboratory evolution. We show that all parallel evolved populations readily adapt to hyperthermal challenge (from 47 °C to 50 °C) and exhibit convergence in evolved phenotypes with extensive cross-tolerance to various other environmental stressors such as oxidants, acids, and alcohols. Genome resequencing identified fixation of mutations in CgSTE11 in all parallel evolved populations. The CgSTE11 homolog in S. cerevisiae plays crucial roles in various mitogen-activated protein kinase (MAPK) signaling pathways, but its role is less understood in C. glabrata. Subsequent verification confirmed that CgSTE11 is important in hyperthermal tolerance and the observed extensive cross-tolerance to other environmental stressors. These results support the hypothesis that CgSTE11 mediates cross-talks between MAPK signaling pathways in C. glabrata in response to environmental challenges.


Assuntos
Candida glabrata/fisiologia , MAP Quinase Quinase Quinases/metabolismo , Termotolerância/fisiologia , Biofilmes/crescimento & desenvolvimento , Candida glabrata/genética , Meio Ambiente , Regulação Fúngica da Expressão Gênica/genética , Genoma Fúngico/genética , MAP Quinase Quinase Quinases/genética , Sistema de Sinalização das MAP Quinases/fisiologia , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Saccharomyces cerevisiae/fisiologia , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Termotolerância/genética
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