Brassinosteroids (BRs) are a family of about 70 structurally related polyhydroxy steroidal phytohormones that regulate a number of physiological processes in plants. Among these, brassinolide (BL), 28-homobrassinolide...Brassinosteroids (BRs) are a family of about 70 structurally related polyhydroxy steroidal phytohormones that regulate a number of physiological processes in plants. Among these, brassinolide (BL), 28-homobrassinolide (28-homoBL) and 24-epibrassinolide (24-EpiBL) are more common. The present study aims at studying the usefulness of 24-epiBL in ameliorating the impacts of heat-stress in maize along with its role in regulating cellular antioxidant defense system. Maize hybrid PMH 3 was grown in pots in a green house maintained at 14 hours day (25℃)/10hours night (17℃). A solution of 24-epiBL (1 μM) was applied externally at V4 stage. Leaf tissues were sampled from both treated and control plants. Subsequently, both the groups of pots were placed in plant growth chamber maintained at high temperature (48℃;RH 50%). Plants were sampled for biochemical analysis after 3, 6, 9, 24 and 48 hours of high temperature exposure. Exogenous application of 24-EpiBL arrested protein degradation and enhanced cell membrane stability, as compared to the control. The biochemical activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD) and peroxidase (POX) were found to be dynamically and variably modulated post 24-epiBL treatment. Thus, the study supports the role of BRs as anti-stress agents.展开更多
[Objective]The paper was to investigate the effects of compound acidifier on growth performance and serum biochemical parameters of heat-stressed Wenchang chickens.[Method]A total of 28881-day-old Wenchang chickens wi...[Objective]The paper was to investigate the effects of compound acidifier on growth performance and serum biochemical parameters of heat-stressed Wenchang chickens.[Method]A total of 28881-day-old Wenchang chickens with the same genetic background and similar initial weight(985.63±20.35 g)were randomly divided into four groups,four replicates per group and 18 chickens per replicate.Birds were fed the basal diet supplemented with 0 g/kg(control group),1 g/kg(groupⅠ),2 g/kg(groupⅡ)and 3 g/kg(groupⅢ)compound acidifier.The trial lasted 35 d.[Result]The daily gain of experimental groupⅠwas significantly higher than those of control group and groupⅢ(P<0.05),and the feed intake of experimental groupⅠwas also markedly higher than that of control group(P<0.05),but the feed gain ratio of experimental groupⅠwas significantly lower than that of groupⅢ(P<0.05).Compared with control group,the serum total protein and albumin levels of experimental groupⅠincreased(P>0.05),but the serum uric acid concentration decreased(P>0.05).[Conclusion]Supplementing 1 g/kg compound acidifier could improve the growth performance of heat-stressed Wenchang chickens.展开更多
This experiment was conducted to investigate the effects of heat stress(HS) on the feed intake, milk production and composition and metabolic alterations in the mammary gland of dairy cows. Twenty Holstein cows were r...This experiment was conducted to investigate the effects of heat stress(HS) on the feed intake, milk production and composition and metabolic alterations in the mammary gland of dairy cows. Twenty Holstein cows were randomly assigned to one of two treatments according to a completely randomized design. Half of the cows were allocated to the HS group in August(summer season), and the other half were assigned to the HS-free group in November(autumn season). HS reduced(P<0.01) dry matter intake(DMI), milk yield, milk protein and milk urea nitrogen(MUN) of cows compared with HSfree control, but increased(P<0.01) milk somatic cell counts(SCC). We determined the HS-induced metabolic alterations and the relevant mechanisms in dairy cows using liquid chromatography mass spectrometry combined with multivariate analyses. Thirty-four metabolites were identified as potential biomarkers for the diagnosis of HS in dairy cows. Ten of these metabolites, glucose, lactate, pyruvate, lactose, β-hydroxybutyrate, citric acid, α-ketoglutarate, urea, creatine, and orotic acid, had high sensitivity and specificity for HS diagnoses, and seven metabolites were also identified as potential biomarkers of HS in plasma, milk, and liver. These substances are involved in glycolysis, lactose, ketone, tricarboxylic acid(TCA), amino acid and nucleotide metabolism, indicating that HS mainly affects lactose, energy and nucleotide metabolism in the mammary gland of lactating dairy cows. This study suggested that HS might affect milk production and composition by affecting the feed intake and substance metabolisms in the mammary gland tissue of lactating dairy cows.展开更多
This experiment was conducted to evaluate the effects of Bupleurum extract （BE） on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress. Forty lactating Holstein cows were rando...This experiment was conducted to evaluate the effects of Bupleurum extract （BE） on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress. Forty lactating Holstein cows were randomly assigned to 1 of 4 treatments. The treatments consisted of 0, 0.25, 0.5, and 1.0 g of BE kg-1 dry matter. Supplementation with BE decreased （P〈0.05） blood urea nitrogen （BUN） contents and increased blood total protein （TP） and albumin （ALB） levels compared with control cows, but it had no effects （P〉0.05） on blood glucose （GLU）, nonesterified fatty acid （NEFA）, total triglycedde （TG）, low-density lipoprotein cholesterol （LDL-C）, and high density lipoprotein cholesterol （HDL-C）. Compared with control cows, cows fed BE had higher （P〈0.05） superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） activity. However, supplementation with BE had no effect （P〉0.05） on total antioxidant capacity （T-AOC） or malondialdehyde （MDA） levels. The immunoglobulin （Ig） A and G contents increased （P〈0.05） in cows fed 0.25 or 0.5 g of BE kg-1. Interleukin （IL）-2 and IL-4 levels were higher （P〈0.05） in cows fed 0.5 and 1.0 g of BE kg-1, and IL-6 was significantly elevated （P〈0.05） in cows fed 0.5 g of BE kg-1. There were no treatment effects （P〉0.05） on the CD4＋ and CD8＋ T lymphocyte ratios, CD4＋/CD8＋ratio, or tumor necrosis factor-α （TNF-α） level among the groups. These findings suggest that BE supplementation may improve protein metabolism, in addition to enhancing antioxidant activity and immune function in heat-stressed dairy cows.展开更多
Self-Organising Feature Map (SOFM) along with learning vector quantizers (LVQ) have been designed to identify the alterations in brain electrical potentials due to exposure to high environmental heat in rats. Three gr...Self-Organising Feature Map (SOFM) along with learning vector quantizers (LVQ) have been designed to identify the alterations in brain electrical potentials due to exposure to high environmental heat in rats. Three groups of rats were considered—acute heat stressed, chronic heat stressed and control groups. After long EEG recordings following heat exposure, EEG data representing three different vigilance states such as slow wave sleep (SWS), rapid eye movement (REM) sleep and AWAKE were visually selected and further subdivided into 2 seconds long epoch. In order to evaluate the performance of artificial neural network (ANN) in recognizing chronic and acute effects of heat stress with respect to the control subjects, unsupervised learning algorithm was applied on EEG data. Mean performance of SOFM with quadratic taper function was found to be better (chronic-92.6%, acute-93.2%) over the other two tapers. The effect of LVQ after the initial SOFM training seems explicit giving rise to considerable improvements in performance in terms of selectivity and sensitivity. The percentage increase in selectivity with uniform taper function is maximum for chronic and its control group (4.01%) and minimum for acute group (1.29%) whereas, with Gaussian it is almost identical (chronic-2.57%, acute-2.03%, control- 2.33%). Quadratic taper function gives rise to an increase of 2.41% for chronic, 1.96% for acute and 2.91% for control patterns.展开更多
Tropical regions across the globe are characterized by an annually prolonged hot weather conditions that showcase limiting production efficiency in livestock industry, as domesticated animals </span></span>...Tropical regions across the globe are characterized by an annually prolonged hot weather conditions that showcase limiting production efficiency in livestock industry, as domesticated animals </span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">leave</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the zone of maximum comfort, under heat stress, with death and reduced carcass yield accompanying the subsequent alteration in body chemistry and behavior. However, pen house orientation, cooling systems, genetic modification and different dietary manipulations have been employed in poultry industry, but many of such did not account for the body’s acid-base equilibrium and the potentials of aggregate levels of dietary electrolytes in enhancing carcass yield of broilers under severe heat stress conditions. Therefore, this study was conducted to investigate the effects of different electrolyte-balanced diets on overall performance, carcass yield, meat safety potentials and economic value of heat-stressed broilers reared for five weeks. Arbor Acre broiler chicks (n = 300) were randomly allotted to diets with aggregate electrolyte balance of 210 (T1), 240 (T2), 270 (T3), 300 (T4), 330 (T5) and 360 (T6) mEq/Kg, in a completely randomised design. On day 35, birds whose weights were closest to the mean class weight were selected from each replicate pen for carcass yield assessment. Also, data on performance and cost-benefit analysis were analysed using descriptive statistics and ANOVA at </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">α</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;"></i></span></i></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">= </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">0.05. Electrolyte-balanced diets though contained salts that presumably could have improved satiety, yet they do not enhance appetite in heat-stressed broilers. However, dietary protein </span><span style="font-family:Verdana;">efficiency was enhanced at an electrolyte balance levels of 240 and 270 mEq/k</span><span style="font-family:Verdana;">g, which translated into increased body weight gain. Weights of primal parts of birds on 270 mEq/kg DEB were highest at 35 days. Feed cost values (per kilogram weight gain) of rations with 240 mEq/kg and 270 mEq/kg DEB were lower and showcased promising economic buoyancy to both rural and commercial poultry farmers, while ensuring a high food safety standard under tropical conditions.展开更多
Agroecosystems in the Senegalese groundnut basin experience long periods of high temperatures and drought, which disrupt the stability of soil microbial communities. This study evaluated how that stability is affected...Agroecosystems in the Senegalese groundnut basin experience long periods of high temperatures and drought, which disrupt the stability of soil microbial communities. This study evaluated how that stability is affected by homefields and outfields’ agricultural practices and the duration of heat stress. Specifically, we collected soils from organically farmed fields that receive continual high inputs of manure (homefields), and from fields that are rarely manured (outfields). Soil samples were submitted to artificial heat stress at 60°C for 3, 14, and 28 days, followed by 28 days of recovery at 28°C. We examined the functional stability of microbial communities by quantifying C mineralization, and characterized the stability of the communities’ taxonomic compositions via high-throughput DNA sequencing. We found that the microbial communities have a low resistance to heat stress in soils from both types of fields. However, the manuring practice does affect how the functional stability of microbial communities responds to different durations of heat stress. Although functional stability was not recovered fully in either soil, microbial community resilience seemed to be greater in homefield soils. Differences in manuring practices also affected the structural taxonomic stability of microbial communities: relative abundances of Bacilli, Chloroflexia, Actinobacteria and Sordariomycetes increased in the homefield stressed-soils, but decreased significantly in outfield soils. In contrast, relative abundances of α-Proteobacteria, γ-Proteobacteria and Eurotiomycetes increased significantly in outfield stressed-soils, while decreasing significantly in the homefield soils. Relative abundances of Bacilli changed little in outfield soils, indicating that this taxon is resistant to heat stress. In summary, the microbial communities’ capacities to resist heat stress and recover from it depend upon the organic richness of the soil (i.e., manuring practice) and the adaptation of soil microbes to environmental conditions.展开更多
Thellungiella salsuginea （formerly T. halophila）, a species closely related to Arabidopsis （Arabidopsis thali-ana）, is tolerant not only to high salt levels, but also to chilling, freezing, and ozone. Here, we rep...Thellungiella salsuginea （formerly T. halophila）, a species closely related to Arabidopsis （Arabidopsis thali-ana）, is tolerant not only to high salt levels, but also to chilling, freezing, and ozone. Here, we report that T. salsuginea also shows greater heat tolerance than Arabidopsis. We identified T. salsuginea HsfAld （TsHsfAld） as a gene that can confer marked heat tolerance on Arabidopsis. TsHsfAld was identified via Full-length cDNA Over-eXpressing gene （FOX） hunt-ing from among a collection of heat-stress-related T. salsuginea cDNAs. Transgenic Arabidopsis overexpressing TsHsfAld showed constitutive up-regulation of many genes in the Arabidopsis AtHsfA1 regulon under normal growth tempera-ture. in Arabidopsis mesophyll protoplasts, TsHsfAld was localized in both the nucleus and the cytoplasm. TsHsfAld also interacted with AtHSP90, which negatively regulates AtHsfAls by forming HsfA1-HSP90 complexes in the cytoplasm. It is likely that the partial nuclear localization of TsHsfAld induced the expression of the AtHsfAld regulon in the transgenic plants at normal temperature. We also discovered that transgenic Arabidopsis plants overexpressing AtHsfAldwere more heat-tolerant than wild-type plants and up-regulated the expression of the HsfAld regulon, as was observed in TsHsfAld-overexpressing plants. We propose that the products of both TsHsfAld and AtHsfAld function as positive regulators of Arabidopsis heat-stress response and would be useful for the improvement of heat-stress tolerance in other plants.展开更多
文摘Brassinosteroids (BRs) are a family of about 70 structurally related polyhydroxy steroidal phytohormones that regulate a number of physiological processes in plants. Among these, brassinolide (BL), 28-homobrassinolide (28-homoBL) and 24-epibrassinolide (24-EpiBL) are more common. The present study aims at studying the usefulness of 24-epiBL in ameliorating the impacts of heat-stress in maize along with its role in regulating cellular antioxidant defense system. Maize hybrid PMH 3 was grown in pots in a green house maintained at 14 hours day (25℃)/10hours night (17℃). A solution of 24-epiBL (1 μM) was applied externally at V4 stage. Leaf tissues were sampled from both treated and control plants. Subsequently, both the groups of pots were placed in plant growth chamber maintained at high temperature (48℃;RH 50%). Plants were sampled for biochemical analysis after 3, 6, 9, 24 and 48 hours of high temperature exposure. Exogenous application of 24-EpiBL arrested protein degradation and enhanced cell membrane stability, as compared to the control. The biochemical activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD) and peroxidase (POX) were found to be dynamically and variably modulated post 24-epiBL treatment. Thus, the study supports the role of BRs as anti-stress agents.
基金Supported by Special Fund for Technology Development of Hainan Provincial Research Institutes(SQ2017JSKF0007)Special Fund for Construction of China Agricultural Industry Research System(CARS-41-Z17)Special Funds for Local Scicncc and Tcchnoloty Development Guided by the Ccntoral Committee (ZY2019HN01)
文摘[Objective]The paper was to investigate the effects of compound acidifier on growth performance and serum biochemical parameters of heat-stressed Wenchang chickens.[Method]A total of 28881-day-old Wenchang chickens with the same genetic background and similar initial weight(985.63±20.35 g)were randomly divided into four groups,four replicates per group and 18 chickens per replicate.Birds were fed the basal diet supplemented with 0 g/kg(control group),1 g/kg(groupⅠ),2 g/kg(groupⅡ)and 3 g/kg(groupⅢ)compound acidifier.The trial lasted 35 d.[Result]The daily gain of experimental groupⅠwas significantly higher than those of control group and groupⅢ(P<0.05),and the feed intake of experimental groupⅠwas also markedly higher than that of control group(P<0.05),but the feed gain ratio of experimental groupⅠwas significantly lower than that of groupⅢ(P<0.05).Compared with control group,the serum total protein and albumin levels of experimental groupⅠincreased(P>0.05),but the serum uric acid concentration decreased(P>0.05).[Conclusion]Supplementing 1 g/kg compound acidifier could improve the growth performance of heat-stressed Wenchang chickens.
基金supported financially by the National Key Research and Development Program of China (2016YFD0500503)the Shanghai Science and Technology Promotion Project for Agriculture (Shanghai Agriculture Science Promotion Project (2019) No. 1-2)
文摘This experiment was conducted to investigate the effects of heat stress(HS) on the feed intake, milk production and composition and metabolic alterations in the mammary gland of dairy cows. Twenty Holstein cows were randomly assigned to one of two treatments according to a completely randomized design. Half of the cows were allocated to the HS group in August(summer season), and the other half were assigned to the HS-free group in November(autumn season). HS reduced(P<0.01) dry matter intake(DMI), milk yield, milk protein and milk urea nitrogen(MUN) of cows compared with HSfree control, but increased(P<0.01) milk somatic cell counts(SCC). We determined the HS-induced metabolic alterations and the relevant mechanisms in dairy cows using liquid chromatography mass spectrometry combined with multivariate analyses. Thirty-four metabolites were identified as potential biomarkers for the diagnosis of HS in dairy cows. Ten of these metabolites, glucose, lactate, pyruvate, lactose, β-hydroxybutyrate, citric acid, α-ketoglutarate, urea, creatine, and orotic acid, had high sensitivity and specificity for HS diagnoses, and seven metabolites were also identified as potential biomarkers of HS in plasma, milk, and liver. These substances are involved in glycolysis, lactose, ketone, tricarboxylic acid(TCA), amino acid and nucleotide metabolism, indicating that HS mainly affects lactose, energy and nucleotide metabolism in the mammary gland of lactating dairy cows. This study suggested that HS might affect milk production and composition by affecting the feed intake and substance metabolisms in the mammary gland tissue of lactating dairy cows.
基金supported financially by the National Key Research and Development Program of China (2016YFD0500503)the Agricultural Science and Technology Innovation Program, China (ASTIP-IAS12)the Anhui International Science and Technology Cooperation Plan Program, China (1503062019)
文摘This experiment was conducted to evaluate the effects of Bupleurum extract （BE） on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress. Forty lactating Holstein cows were randomly assigned to 1 of 4 treatments. The treatments consisted of 0, 0.25, 0.5, and 1.0 g of BE kg-1 dry matter. Supplementation with BE decreased （P〈0.05） blood urea nitrogen （BUN） contents and increased blood total protein （TP） and albumin （ALB） levels compared with control cows, but it had no effects （P〉0.05） on blood glucose （GLU）, nonesterified fatty acid （NEFA）, total triglycedde （TG）, low-density lipoprotein cholesterol （LDL-C）, and high density lipoprotein cholesterol （HDL-C）. Compared with control cows, cows fed BE had higher （P〈0.05） superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） activity. However, supplementation with BE had no effect （P〉0.05） on total antioxidant capacity （T-AOC） or malondialdehyde （MDA） levels. The immunoglobulin （Ig） A and G contents increased （P〈0.05） in cows fed 0.25 or 0.5 g of BE kg-1. Interleukin （IL）-2 and IL-4 levels were higher （P〈0.05） in cows fed 0.5 and 1.0 g of BE kg-1, and IL-6 was significantly elevated （P〈0.05） in cows fed 0.5 g of BE kg-1. There were no treatment effects （P〉0.05） on the CD4＋ and CD8＋ T lymphocyte ratios, CD4＋/CD8＋ratio, or tumor necrosis factor-α （TNF-α） level among the groups. These findings suggest that BE supplementation may improve protein metabolism, in addition to enhancing antioxidant activity and immune function in heat-stressed dairy cows.
文摘Self-Organising Feature Map (SOFM) along with learning vector quantizers (LVQ) have been designed to identify the alterations in brain electrical potentials due to exposure to high environmental heat in rats. Three groups of rats were considered—acute heat stressed, chronic heat stressed and control groups. After long EEG recordings following heat exposure, EEG data representing three different vigilance states such as slow wave sleep (SWS), rapid eye movement (REM) sleep and AWAKE were visually selected and further subdivided into 2 seconds long epoch. In order to evaluate the performance of artificial neural network (ANN) in recognizing chronic and acute effects of heat stress with respect to the control subjects, unsupervised learning algorithm was applied on EEG data. Mean performance of SOFM with quadratic taper function was found to be better (chronic-92.6%, acute-93.2%) over the other two tapers. The effect of LVQ after the initial SOFM training seems explicit giving rise to considerable improvements in performance in terms of selectivity and sensitivity. The percentage increase in selectivity with uniform taper function is maximum for chronic and its control group (4.01%) and minimum for acute group (1.29%) whereas, with Gaussian it is almost identical (chronic-2.57%, acute-2.03%, control- 2.33%). Quadratic taper function gives rise to an increase of 2.41% for chronic, 1.96% for acute and 2.91% for control patterns.
文摘Tropical regions across the globe are characterized by an annually prolonged hot weather conditions that showcase limiting production efficiency in livestock industry, as domesticated animals </span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">leave</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the zone of maximum comfort, under heat stress, with death and reduced carcass yield accompanying the subsequent alteration in body chemistry and behavior. However, pen house orientation, cooling systems, genetic modification and different dietary manipulations have been employed in poultry industry, but many of such did not account for the body’s acid-base equilibrium and the potentials of aggregate levels of dietary electrolytes in enhancing carcass yield of broilers under severe heat stress conditions. Therefore, this study was conducted to investigate the effects of different electrolyte-balanced diets on overall performance, carcass yield, meat safety potentials and economic value of heat-stressed broilers reared for five weeks. Arbor Acre broiler chicks (n = 300) were randomly allotted to diets with aggregate electrolyte balance of 210 (T1), 240 (T2), 270 (T3), 300 (T4), 330 (T5) and 360 (T6) mEq/Kg, in a completely randomised design. On day 35, birds whose weights were closest to the mean class weight were selected from each replicate pen for carcass yield assessment. Also, data on performance and cost-benefit analysis were analysed using descriptive statistics and ANOVA at </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">α</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;"></i></span></i></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">= </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">0.05. Electrolyte-balanced diets though contained salts that presumably could have improved satiety, yet they do not enhance appetite in heat-stressed broilers. However, dietary protein </span><span style="font-family:Verdana;">efficiency was enhanced at an electrolyte balance levels of 240 and 270 mEq/k</span><span style="font-family:Verdana;">g, which translated into increased body weight gain. Weights of primal parts of birds on 270 mEq/kg DEB were highest at 35 days. Feed cost values (per kilogram weight gain) of rations with 240 mEq/kg and 270 mEq/kg DEB were lower and showcased promising economic buoyancy to both rural and commercial poultry farmers, while ensuring a high food safety standard under tropical conditions.
文摘Agroecosystems in the Senegalese groundnut basin experience long periods of high temperatures and drought, which disrupt the stability of soil microbial communities. This study evaluated how that stability is affected by homefields and outfields’ agricultural practices and the duration of heat stress. Specifically, we collected soils from organically farmed fields that receive continual high inputs of manure (homefields), and from fields that are rarely manured (outfields). Soil samples were submitted to artificial heat stress at 60°C for 3, 14, and 28 days, followed by 28 days of recovery at 28°C. We examined the functional stability of microbial communities by quantifying C mineralization, and characterized the stability of the communities’ taxonomic compositions via high-throughput DNA sequencing. We found that the microbial communities have a low resistance to heat stress in soils from both types of fields. However, the manuring practice does affect how the functional stability of microbial communities responds to different durations of heat stress. Although functional stability was not recovered fully in either soil, microbial community resilience seemed to be greater in homefield soils. Differences in manuring practices also affected the structural taxonomic stability of microbial communities: relative abundances of Bacilli, Chloroflexia, Actinobacteria and Sordariomycetes increased in the homefield stressed-soils, but decreased significantly in outfield soils. In contrast, relative abundances of α-Proteobacteria, γ-Proteobacteria and Eurotiomycetes increased significantly in outfield stressed-soils, while decreasing significantly in the homefield soils. Relative abundances of Bacilli changed little in outfield soils, indicating that this taxon is resistant to heat stress. In summary, the microbial communities’ capacities to resist heat stress and recover from it depend upon the organic richness of the soil (i.e., manuring practice) and the adaptation of soil microbes to environmental conditions.
文摘Thellungiella salsuginea （formerly T. halophila）, a species closely related to Arabidopsis （Arabidopsis thali-ana）, is tolerant not only to high salt levels, but also to chilling, freezing, and ozone. Here, we report that T. salsuginea also shows greater heat tolerance than Arabidopsis. We identified T. salsuginea HsfAld （TsHsfAld） as a gene that can confer marked heat tolerance on Arabidopsis. TsHsfAld was identified via Full-length cDNA Over-eXpressing gene （FOX） hunt-ing from among a collection of heat-stress-related T. salsuginea cDNAs. Transgenic Arabidopsis overexpressing TsHsfAld showed constitutive up-regulation of many genes in the Arabidopsis AtHsfA1 regulon under normal growth tempera-ture. in Arabidopsis mesophyll protoplasts, TsHsfAld was localized in both the nucleus and the cytoplasm. TsHsfAld also interacted with AtHSP90, which negatively regulates AtHsfAls by forming HsfA1-HSP90 complexes in the cytoplasm. It is likely that the partial nuclear localization of TsHsfAld induced the expression of the AtHsfAld regulon in the transgenic plants at normal temperature. We also discovered that transgenic Arabidopsis plants overexpressing AtHsfAldwere more heat-tolerant than wild-type plants and up-regulated the expression of the HsfAld regulon, as was observed in TsHsfAld-overexpressing plants. We propose that the products of both TsHsfAld and AtHsfAld function as positive regulators of Arabidopsis heat-stress response and would be useful for the improvement of heat-stress tolerance in other plants.
