Cold stress severely limits the distribution of mangrove species worldwide and it remains unclear how mangroves respond and adapt to cold temperatures.In this study,we investigated the effects of cold acclimation and/...Cold stress severely limits the distribution of mangrove species worldwide and it remains unclear how mangroves respond and adapt to cold temperatures.In this study,we investigated the effects of cold acclimation and/or inhibition of serotonin levels on reactive oxygen species(ROS),reactive nitrogen species(RNS),melatonin(MEL)and serotonin(SER)accumulation during cold stress in Kandelia obovata.Morphologic observation and param-eter analysis revealed that cold acclimation mitigated the photoinhibition of photosystem I(PSI)and photosystem II(PSII),maintained optimal ROS and RNS redox homeosta-sis,and increased the contents of SER and MEL in leaves.This suggests that cold acclimation reshapes the MEL/ROS/RNS redox network.In particular,the tryptophan/tryptamine/Ser/N-acetylserotonin/MER pathway was identi-fied as a branch of the MEL synthesis pathway.Inhibition of endogenous SER exacerbated damage caused by cold stress,indicating the crosstalk of SER synthesis and cold acclima-tion.In this study,we report a coordinated regulation of cold stress by a complex defense network in K.obovata.展开更多
[Objective]The paper was to investigate the dynamics of essential metal elements（Ca,Mg,Fe,Mn,Zn and Cu）contents in winter oilseed rape（Brassica napus L.）during cold acclimation,and to reveal the effects and mechan...[Objective]The paper was to investigate the dynamics of essential metal elements（Ca,Mg,Fe,Mn,Zn and Cu）contents in winter oilseed rape（Brassica napus L.）during cold acclimation,and to reveal the effects and mechanisms of essential elements in cold resistance of oilseed rape.[Method]Three varieties with different cold resistance including Zhongshuang No.11（ZS,freezing sensitive variety）,Ganyouza No.1（GY）and Jinyuyou No.1（JYY,freezing tolerant varieties）were used in the study,and the changes of necessary metal elements in these oilseed rapes during cold acclimation were studied.[Result]The concentration of metal elements in oilseed rape had significant changes during cold acclimation,and the difference between varieties was significant.In plant roots,the concentrations of Ca,Mg,Fe,Mn,Zn and Cu were significantly increased,this might because that low temperature made the transpiration decreased,thus blocking the upward transport of elements.In plant shoots,the concentrations of Ca,Mg and Zn were significantly decreased,while the concentrations of Fe and Mn were significantly increased;the change extent of various elements in ZS variety was the largest.[Conclusion]Maintaining the stability of Ca,Mg and Zn concentrations and increasing Fe,Mn and Cu concentrations in plant shoots might be benefit for increasing the cold tolerance of winter oilseed rape.展开更多
Populus tomentosa cuttings were treated with 1mmol·L -1 , 5mmol·L -1 , 10mmol·L -1 or 15mmol·L -1 of CaCl 2 for 1\|7 d, respectively, for studying the effects of different conc...Populus tomentosa cuttings were treated with 1mmol·L -1 , 5mmol·L -1 , 10mmol·L -1 or 15mmol·L -1 of CaCl 2 for 1\|7 d, respectively, for studying the effects of different concentrations of CaCl 2 on freezing resistance. Results indicated that 10?mmol·L -1 of CaCl 2 has greater effect than other concentrations on the enhancement of freezing resistance, and the optimum time of pretreatment was 5?d. In addition, cuttings used for cold acclimation at -3℃ were pretreated with or without 10?mmol·L -1 of CaCl 2, 3?mmol·L -1 of Ca 2+ chelator EGTA, 0 05?mmol·L -1 of CaM antagonist CPZ or 0 1?mmol·L -1 of Ca 2+ channel inhibitor LaCl 3 The changes in CaM and freezing resistance of all cuttings were investigated. The results showed that cold acclimation at -3℃ increased CaM content and decreased the minimum temperature for 100% survival. The CaCl 2 pretreatment enhanced the effect of cold acclimation and obviously increased CaM content and decreased the minimum temperature for 100% survival, but this effect was strongly inhibited by the EGTA, CPZ or LaCl 3 It is concluded that the effect of CaCl 2 on freezing resistance is associated with its concentration and time of pretreatment, Ca 2+ CaM may be involved in the induction of freezing resistance of the cuttings.展开更多
Populus tomentosa seedlings used for cold acclimation at -3℃ were pretreated with or without 10?mmol·L -1 CaCl 2, 3?mmol·L -1 of Ca 2+ chelator EGTA, 0 1?mmol·L -1 of Ca 2+ ...Populus tomentosa seedlings used for cold acclimation at -3℃ were pretreated with or without 10?mmol·L -1 CaCl 2, 3?mmol·L -1 of Ca 2+ chelator EGTA, 0 1?mmol·L -1 of Ca 2+ channel inhibitor LaCl 3,and 0 05?mmol·L -1 of CaM antagonist CPZ. The changes in the contents of total soluble protein and CaM, and freezing resistance in all pretreated seedlings in various periods ( viz: following cold acclimation, chilling stress and recovery) were investigated. Results showed that cold acclimation increased the contents of total soluble protein and CaM, and freezing resistance of seedlings, which could be strongly reduced by the pretreatments of EGTA CPZ and LaCl 3 Cold acclimation combined with CaCl 2 pretreatment enhanced the effect of cold acclimation on freezing resistance, and obviously increased the contents of total soluble protein and CaM, reduced the declining degree of the contents of total soluble protein and CaM caused by chilling stress as compared with cold acclimation, augmented the increase in the level of total soluble protein and CaM during the recovery periods. Further analysis found that an increase in total soluble protein content during cold acclimation with or without CaCl 2 pretreatment mainly resulted from the increase in content of heat stable protein in total soluble protein. It is suggested that Ca 2+ calmodulin may be involved in the synthesis of total soluble protein, and the induction of freezing resistance of seedlings.展开更多
The changes in the contents of total soluble protein and RNA, the activity of RNase in leaves and branches of Populus tomentosa cuttings at various periods (viz: cold acclimation, deacclimation, chilling stress an...The changes in the contents of total soluble protein and RNA, the activity of RNase in leaves and branches of Populus tomentosa cuttings at various periods (viz: cold acclimation, deacclimation, chilling stress and the recovery after chilling stress), and the survival rate and the freezing resistance of cuttings during cold acclimation at -3℃ were investigated. Results showed that cold acclimation not only increased the contents of total soluble protein and RNA, the survival rates and the freezing resistance of cuttings, decreased the activity of RNase, but also reduced the declining degree of total soluble protein and RNA contents, and the increasing level of RNase caused by chilling stress as compared with the controls. In addition, cold acclimation augmented the increase in the level of total soluble protein and RNA, and facilitated the decrease of RNase during the recovery periods. Further analysis found that the DNA content of all treatments kept relative stability at various periods. The changes in total soluble protein, RNA and RNase were closely related to the freezing resistance of cuttings. It appears that the increase of RNA content caused by cold acclimation induced decrease of RNase activity may be involved in the accumulation of total soluble protein and the induction of freezing resistance of cuttings.展开更多
The changes in activities of superoxide dismutase (SOD), peroxidase (POD) and ATPase in the leaves of Euonymus radicans were studied when seedlings were cold-acclimated (at 4 ℃) for 1 week, 2 weeks, 3 weeks and then ...The changes in activities of superoxide dismutase (SOD), peroxidase (POD) and ATPase in the leaves of Euonymus radicans were studied when seedlings were cold-acclimated (at 4 ℃) for 1 week, 2 weeks, 3 weeks and then treated for 1 d under low temperature stress (at 5 ℃). The semi-lethal temperatures of acclimated and unacclimated seedlings were also investigated. The results indicated that the activities of the three enzymes in the leaves of the seedlings treated at 4 ℃ for 1, 2 and 3 weeks were all higher than those of unacclimated seedings (treated at 22 ℃ as controls). The activities of SOD and POD increased continuously with the prolongation of the time of cold acclimation, but stepped up to summits then down to the levels of the controls. The activities of SOD culminated at the first week, and the activities of POD at the second week. When acclimated and unacclimated seedlings were both treated at 5 ℃ for 1 d, the activities of the three enzymes in the leaves of acclimated seedlings were a little lower than those before stress, but higher than those of the controls. Moreover, the decrease rate of enzyme activities was greatly lower than that of the controls. The results showed that cold acclimation could enhance the stability of the three enzymes in the leaves of seedlings under low temperature stress; the semi-lethal temperature was 19.1 ℃ when the seedlings were treated at 4 ℃ for 3 weeks, but it was 5.4 ℃ when the seedlings were treated at 22 ℃. The decline of the semi-lethal temperature caused by the adaptive changes of enzyme activities was one of the foundations of enhancing the cold tolerance.展开更多
Nine CBF/DREB1 homologous genes in rice were obtained by BLAST search in the NCBI database, which share conserved amino acid sequences with DREB1 protein in Arabidopsis. Three CBF genes organized in tandem, named OsCB...Nine CBF/DREB1 homologous genes in rice were obtained by BLAST search in the NCBI database, which share conserved amino acid sequences with DREB1 protein in Arabidopsis. Three CBF genes organized in tandem, named OsCBF1, OsCBF2 and OsCBF3, showed a transient induction in the process of cold acclimation, much stronger in indica rice 93-11 compared with japonica rice Nipponbare. The candidate downstream genes OsLIP5 and OsLIP9 were induced in 93-11 but not in Nipponbare. The differential expression of CBF regulon might be caused by polymorphisms within promoter sequences between these two rice varieties. These results could be useful for utilization of CBF/DREB1 genes and illustration of differences in chilling tolerance between indica and japonica rice varieties.展开更多
Populus euphratica Olive is the only tree species that can grow in the saline land and also survive cold winters in northwest China, and it plays a very important role in stabilizing the vulnerable ecosystem there. A ...Populus euphratica Olive is the only tree species that can grow in the saline land and also survive cold winters in northwest China, and it plays a very important role in stabilizing the vulnerable ecosystem there. A cell suspension culture was initiated from callus derived from plantlets of Populus euphratica. Cold acclimation was induced (LT50 of 17.5 ℃) in cell suspension at 45 ℃ in the dark for 30 days and the freezing tolerance increased from LT50 of 12.5 ℃ in nonacclimated cells to LT50 of 17.5 ℃ in cold-acclimated cells. Microvacuolation, cytoplasmic augmentation and accumulation of starch granules were observed in cells that were cold-acclimated by exposure to low temperatures. Several qualitative and quantitative changes in proteins were noted during cold acclimation. Antibodies to carrot extracellular (apoplastic) 36 kD antifreeze protein did not cross react on immunoelectroblots with extracellular proteins in cell suspension culture medium of Populus euphratica, indicating no common epitopes in the carrot 36 kD antifreeze protein and P. euphratica extracellular proteins. The relationship of these changes to cold acclimation in Populus euphratica cell cultures was discussed.展开更多
Ammopiptanthus mongolicus, the only freezing tolerant evergreen broad-leaved shrub, local species of the Alashan desert, northwest sand area of China, can survive -30℃ or even lower temperature in winter. In the pres...Ammopiptanthus mongolicus, the only freezing tolerant evergreen broad-leaved shrub, local species of the Alashan desert, northwest sand area of China, can survive -30℃ or even lower temperature in winter. In the present study, the secondary products phenolics in A. mongolicus cotyledons were determined to study the effects of phenolics on cold tolerance. Cytochemical localization of phenolics in cotyledon cells was observed by electron microscopy and the content of phenolic compounds was assayed by spectrophotometric measurement. The results showed that the freezing tolerance ofA. mongolicus seedlings increased after acclimation at 2℃ for 14 days, which accompanied the increase of the content of phenolic compounds in cotyledons. Cytochemical observation showed that phenolic deposits were mainly localized in vacuoles and in close proximity to tonoplast, and also in the cytoplasm. The amount and the size of phenolics droplets increased obviously in cytoplasm and vacuoles after cold acclimation, predominantly aggregated along membranes of vacuoles and tonoplast. No phenolic deposits were found in cell walls. As hydrogen- or elec- tron-donating agents, phenolics may protect plant cells against reactive oxygen species formed during chilling or freezing stress and improve the freezing tolerance of cold-acclimated A. mongolicus seedlings.展开更多
Populus tomentosa seedlings for cold-acclimating were pretreated wit h or without 20% saccharose. Changes in the concentrations of total soluble sugar , the survival rates, and freezing tolerance of seedlings during ...Populus tomentosa seedlings for cold-acclimating were pretreated wit h or without 20% saccharose. Changes in the concentrations of total soluble sugar , the survival rates, and freezing tolerance of seedlings during cold acclimatio n were investigated. The results showed that cold acclimation increased the conc entrations of total soluble sugar, the survival rates and freezing tolerance. Co ld acclimation, combined with the saccharose-pretreatment, enhanced the above- ment ioned effect of cold acclimation, and obviously increased the concentrations of total soluble sugar, the survival rates and freezing tolerance of seedlings. Fur ther analysis found that the concentrations of total soluble sugar in branches i ncreased greater than that in leaves during both cold acclimation with or withou t the pretreatment of saccharose. Moreover, an increase of the concentrations of total soluble sugar in branches and leaves was closely related to the freezing tolerance of seedlings. The results indicate the accumulation of soluble sugar i n seedlings induced by cold acclimation may be involved in the induction of free zing tolerance .展开更多
The process of cold acclimation is an important adaptive response whereby many plants from temperate regions increase their freezing tolerance after being exposed to low non-freezing temperatures. The correct developm...The process of cold acclimation is an important adaptive response whereby many plants from temperate regions increase their freezing tolerance after being exposed to low non-freezing temperatures. The correct development of this response relies on proper accumulation of a number of transcription factors that regulate expression patterns of cold-responsive genes. Multiple studies have revealed a variety of molecular mechanisms involved in promoting the accumulation of these transcription factors. Interestingly, however, the mechanisms implicated in controlling such accumulation to ensure their adequate levels remain largely unknown. In this work, we demonstrate that prefoldins （PFDs） control the levels of HY5, an Arabidopsis transcription factor with a key role in cold acclimation by activating anthocyanin biosynthesis, in response to low temperature. Our results show that, under cold conditions, PFDs accumulate into the nucleus through a DELLA-dependent mechanism, where they interact with HY5, triggering its ubiquitination and subsequent degradation. The degradation of HY5 would result, in turn, in anthocyanin biosynthesis attenuation, ensuring the accurate development of cold acclimation. These findings uncover an unanticipated nuclear function for PFDs in plant responses to abiotic stresses.展开更多
The Asian citrus psyllid,Diaphorina citri,is the vector of the pathogenic bacteria that causes Huanglongbing,the most devasting disease affecting citrus worldwide.As cultivation of citrus tends to expand northward,the...The Asian citrus psyllid,Diaphorina citri,is the vector of the pathogenic bacteria that causes Huanglongbing,the most devasting disease affecting citrus worldwide.As cultivation of citrus tends to expand northward,the tolerance of psyllids to freezing temperatures needs to be investigated.While mortality of D.citri to cold temperature has been previously studied,much less is known regarding the acclimation potential of psyllids to cold temperatures.We first evaluated cold resistance of D.citri depending on color morph and sex.Subsequently,we compared mortality of D.citri at−4°C for 10 hours between unacclimated psyllids,psyllids that were gradually acclimated to cold over 1 or 2 weeks,and psyllids intermittently acclimated also for 1 or 2 weeks.We did not find major differences in cold resistance between color morphs and sex.We found that after 1 week of gradual acclimation,the survival of psyllids at−4°C increased to 86%,compared to 20%in the control group.Survival did not increase after the second week of gradual acclimation.Although intermittent acclimation improved survival compared to the control group,it was less effective than gradual acclimation with a survival at 30%and 70%after 1 and 2 weeks of acclimation,respectively,although this difference with gradual acclimation was not significant at week 2.These data show that gradual cold acclimation allows D.citri to survive brief periods below freezing.It may serve as a mechanism responsible for increasing northern establishment of this pest.展开更多
CDC48 is a highly conserved protein in eukaryotes and belongs to the AAA （ATPase associated with a variety of cellular activities） superfamily. It can interact with many different cofactors and form protein complexe...CDC48 is a highly conserved protein in eukaryotes and belongs to the AAA （ATPase associated with a variety of cellular activities） superfamily. It can interact with many different cofactors and form protein complexes that play important roles in various cellular processes. According to the Physcomitrella patens database, one member of the ATPases, the cell cycle gene PpCDC4811, was cloned. PpCDC48II contains two typical ATPase modules and is highly homologous to AtCDC48A. PpCDC4811 was up-regulated in mRNA levels after incubation at 0~C for 36 and 72 h. To further elucidate protein function, we disrupted the PpCDC4811 gene by transforming P. patens with the corresponding linear genomic sequences. When treated to the same freezing stress, it was found that PpCDC4811 knockout plants were less resistant to freezing treatment than wild type after acclimation. This suggested that PpCDC481I was an essential gene for low-temperature-induced freezing tolerance in P. patens cells.展开更多
Cold acclimation is associated with many metabolic changes that lead to an increase of freezing tolerance. In order to investigate the biochemical process of cold acclimation in Ammopiptanthus mongolicus, seedlings we...Cold acclimation is associated with many metabolic changes that lead to an increase of freezing tolerance. In order to investigate the biochemical process of cold acclimation in Ammopiptanthus mongolicus, seedlings were acclimated at 2℃ under 16-h photoperiod （150 μmol·m^-2·s^-1 photosynthetically active radiation） for 14 d. Freezing tolerance in seedlings increased after 14 d of cold-hardening. Contents of protein, proline and solute carbohydrate in cotyledon increased after cold acclimation. Patterns of isozymes of superoxide dismutase （SOD）, peroxidase, catalase and polyphenol oxidase （PPO） were investigated. The activities of SOD, peroxidase and PPO in cold acclimated plants were increased during cold-hardening. We deduced that compatible solutes and antioxidant enzymes play important roles in development of freezing tolerance during cold acclimation in this evergreen woody plant.展开更多
Putrescine is reported to be necessary for cold acclimation under low-temperature stress.In this study,the effect of low-temperature on some physiological and biochemical parameters has been investigated using the gre...Putrescine is reported to be necessary for cold acclimation under low-temperature stress.In this study,the effect of low-temperature on some physiological and biochemical parameters has been investigated using the green algae Chlamydomonas reinhardtii.The lipid peroxidation rate,amount of Rubisco protein,activities of antioxidant enzymes and gene expression of polyamine biosynthesis(odc2,and spd1),heat shock proteins(hsp70c,hsp90a,and hsp90c),and PSII repair mechanisms(psba,rep27,and tba1)were determined to understand the low-temperature response.Exogenous putrescine application significantly increased Rubisco protein concentration and catalase enzyme activities under low-temperature stress.Moreover,real-time RT-PCR results and gene expression analysis showed that polyamine metabolism induced gene expression at low-temperatures in the first 24 h.In the same way,the gene expression of heat shock proteins(hsp70c,hsp90a,and hsp90c)decreased under low-temperature treatment for 72 h;however,application of putrescine enhanced the gene expression in the first 24 h.The results obtained indicated that molecular response in the first 24 h could be important for cold acclimation.The psba and tba1 expressions were reduced under low-temperatures depending on the exposure time.In contrast,the exogenous putrescine enhanced the expression level of the psba response to low-temperature at 24 and 72 h.The results obtained in this study indicate that putrescine could play a role in the PS II repair mechanisms under low-temperature stress.展开更多
Freezing injury is one of the major disasters for the production of winter wheat in the North China Plain, which leads to a significant decrease of wheat yield. This study was conducted to investigate the impact of su...Freezing injury is one of the major disasters for the production of winter wheat in the North China Plain, which leads to a significant decrease of wheat yield. This study was conducted to investigate the impact of subfreezing temperature on freezing injury of various winter wheat cultivars at different sowing time. Three wheat cultivars, including Zhengmai 9023, Wanmai 48 and Wanmai 50, were sowed on 25 September and 5 October, respectively. Plant anatomy was applied to investi- gate the impact of subfreezing temperature on cells of three wheat cultivars, results showed that severe plasmolysis occurred in wheat sowed earlier suddenly encoun- tered subfreezing temperature without cold acclimation, compared with wheat sowed at proper sowing time. The degree of plasmolysis of different cultivars and tissues of wheat had significant differences and showed positive correlation with subfreezing temperature. Wanmai 50 had the highest cold resistance compared with Zhengmai 9023 and Wanmai 48, and there was no significant difference between Zhengmai 9023 and Wanmai 48. This study concluded that wheat cold resistance may be im- proved by adopting proper cultivars and sowing dates.展开更多
Background:The thermoregulatory ability of animals is strongly influenced by the temperature of their environment.Acclimation to cold requires a range of physiological and morphological adjustments.In this study,we te...Background:The thermoregulatory ability of animals is strongly influenced by the temperature of their environment.Acclimation to cold requires a range of physiological and morphological adjustments.In this study,we tested the hypothesis that a small passerine,the Red-billed Leiothrix(Leiothrix lutea),can maintain homeothermy in cold conditions by adjusting the physiology and biochemistry of its tissue and organs and return to its former physiological and biochemical state when moved to a warm temperature.Methods:Phenotypic variation in thermogenic activity of the Red-billed Leiothrixs(Leiothrix lutea)was investigated under warm(35℃),normal(25℃)or cold(15℃)ambient temperature conditions.Oxygen consumption was measured using an open-circuit respirometry system.Mitochondrial state-4 respiration and cytochrome-c oxidase(COX)activity in liver,kidney heart and pectoral muscle were measured with a Clark electrode.Results:Birds acclimated to an ambient temperature of 15℃ for 4 weeks significantly increased their basal metabolic rate(BMR)compared to a control group kept at 25℃.Birds acclimated to 35℃ decreased their BMR,gross energy intake(GEI)and digestible energy intake(DEI).Furthermore,birds acclimated to 15℃ increased state-4 respiration in their pectoral muscles and cytochrome-c oxidase(COX)activity in their liver and pectoral muscle,compared to the 25℃ control group.Birds acclimated to 35℃ also displayed lower state-4 respiration and COX activity in the liver,heart and pectoral muscles,compared to those kept at 25℃.There was a positive correlation between BMR and state-4 respiration,and between BMR and COX activity,in all of the above organs except the liver and heart.Conclusions:Our study illustrates that the morphological,physiological,and enzymatic changes are associated with temperature acclimation in the Red-billed Leiothrix,and supports the notion that the primary means by which small birds meet the energetic challenges of cold conditions is through metabolic adjustments.展开更多
Temperature is one of the major environmental signals controlling plant development,geographical distribution,and seasonal behavior.Plants perceive adverse temperatures,such as high,low,and freezing temperatures,as st...Temperature is one of the major environmental signals controlling plant development,geographical distribution,and seasonal behavior.Plants perceive adverse temperatures,such as high,low,and freezing temperatures,as stressful signals that can cause physiological defects and even death.As sessile organisms,plants have evolved sophisticated mechanisms to adapt to recurring stressful environments through changing gene expression or transcriptional reprogramming.Transcriptional memory refers to the ability of primed plants to remember previously experienced stress and acquire enhanced tolerance to similar or different stresses.Epigenetic modifications mediate transcriptional memory and play a key role in adapting to adverse temperatures.Understanding the mechanisms of the formation,maintenance,and resetting of stress-induced transcriptional memory will not only enable us to understand why there is a trade-off between plant defense and growth,but also provide a theoretical basis for generating stress-tolerant crops optimized for future climate change.In this review,we summarize recent advances in dissecting the mechanisms of plant transcriptional memory in response to adverse temperatures,based mainly on studies of the model plant Arabidopsis thaliana.We also discuss remaining questions that are important for further understanding the mechanisms of transcriptional memory during the adverse temperature response.展开更多
Plants need to constantly surveil their surroundings to adapt to environmental fluctuations, which theyachieve primarily through transcriptional reprogramming. Thus, plants are excellent models for identifyingnovel tr...Plants need to constantly surveil their surroundings to adapt to environmental fluctuations, which theyachieve primarily through transcriptional reprogramming. Thus, plants are excellent models for identifyingnovel transcriptional regulatory mechanisms. In this study, we characterize the regulation mediated by longnon-coding transcription that initiates on the complementary strand in the 5' end of coding genes (convergentantisense transcription, CASt). In Arabidopsis, CASt is associated with stress-responsive genes thatare highly expressed. Our analysis shows that CASt depends on a specific gene architecture that is evolutionarilyconserved in higher plants. CASt is present in genes with an extended first intron and overrepresentedin genes encoding functional transporters in Arabidopsis, such as the AMiNo ACIDPERMEASE (AAP) transporter family. Experimental evidence points to a role for CASt in priming theirhost genes for stress responsiveness in evolutionary divergent plant species. Furthermore, we were ableto predict stress responsiveness in rice AAP genes based on the presence of a long first intron andCASt. Collectively, we show an evolutionary strategy and regulatory mechanism specific to plants forenhancing stress responsiveness through modification of gene architecture and antisense transcription.展开更多
Leaves from annual young grape plants （Vitis vinifera L. cv. Jingxiu） were used as experimental materials. The ultrastructural characteristics of mesophyll cells in chilling-treated plants after heat acclimation （H...Leaves from annual young grape plants （Vitis vinifera L. cv. Jingxiu） were used as experimental materials. The ultrastructural characteristics of mesophyll cells in chilling-treated plants after heat acclimation （HA） and in heat-treated plants after cold acclimation （CA） were observed and compared using transmission electron microscopy. The results showed that slight injury appeared in the ultrastructure of mesophyll cells after either HA （38℃ for 10 h） or CA （8℃ for 2.5 d）, but the tolerance to subsequent extreme temperature stress was remarkably improved by HA or CA pretreatment. The increases in membrane permeability and malondialdehyde concentration under chilling （0℃） or heat （45℃） stress were markedly inhibited by HA or CA pretreatment. The mesophyll cells of plants not pretreated with HA were markedly damaged following chilling stress. The chloroplasts appeared irregular in shape, the arrangement of the stroma lamellae was disordered, and no starch granules were present. The cristae of the mitochondria were disrupted and became empty. The nucleus became irregular in shape and the nuclear membrane was digested. In contrast, the mesophyll cells of HA-pretreated plants maintained an intact ultrastructure under chilling stress. The mesophyll cells of control plants were also severely damaged under heat stress. The chloroplast became round in shape, the stroma lamellae became swollen, and the contents of vacuoles formed clumps. In the case of mitochondria of control plants subjected to heat stress, the outer envelope was digested and the cristae were disrupted and became many small vesicles. Compared with cellular organelles in control plants, those in CA plant cells always maintained an integrated state during whole heat stress, except for the chloroplasts, which became round in shape after 10 h heat stress. From these data, we suggest that the stability of mesophyll cells under chilling stress can be increased by HA pretreatment. Similarly, CA pretreatment can protect chloroplasts, mitochondria, and the nucleus against subsequent heat stress; thus, the thermoresistance of grape seedlings was improved. The results obtained in the present study are the first, to our knowledge, to offered cytological evidence of cross-adaptation to temperature stresses in grape plants.展开更多
基金supported by the National Science Foundation of China (32071503)the project of Wenzhou Science and Technology Plan (S20220011)
文摘Cold stress severely limits the distribution of mangrove species worldwide and it remains unclear how mangroves respond and adapt to cold temperatures.In this study,we investigated the effects of cold acclimation and/or inhibition of serotonin levels on reactive oxygen species(ROS),reactive nitrogen species(RNS),melatonin(MEL)and serotonin(SER)accumulation during cold stress in Kandelia obovata.Morphologic observation and param-eter analysis revealed that cold acclimation mitigated the photoinhibition of photosystem I(PSI)and photosystem II(PSII),maintained optimal ROS and RNS redox homeosta-sis,and increased the contents of SER and MEL in leaves.This suggests that cold acclimation reshapes the MEL/ROS/RNS redox network.In particular,the tryptophan/tryptamine/Ser/N-acetylserotonin/MER pathway was identi-fied as a branch of the MEL synthesis pathway.Inhibition of endogenous SER exacerbated damage caused by cold stress,indicating the crosstalk of SER synthesis and cold acclima-tion.In this study,we report a coordinated regulation of cold stress by a complex defense network in K.obovata.
基金Supported by Special Funds for Public Welfare Industry(Agricul-ture)Study of China(200903003)Subjects of Special Funds of Public Welfare Institutes of China(1610172011016)~~
文摘[Objective]The paper was to investigate the dynamics of essential metal elements（Ca,Mg,Fe,Mn,Zn and Cu）contents in winter oilseed rape（Brassica napus L.）during cold acclimation,and to reveal the effects and mechanisms of essential elements in cold resistance of oilseed rape.[Method]Three varieties with different cold resistance including Zhongshuang No.11（ZS,freezing sensitive variety）,Ganyouza No.1（GY）and Jinyuyou No.1（JYY,freezing tolerant varieties）were used in the study,and the changes of necessary metal elements in these oilseed rapes during cold acclimation were studied.[Result]The concentration of metal elements in oilseed rape had significant changes during cold acclimation,and the difference between varieties was significant.In plant roots,the concentrations of Ca,Mg,Fe,Mn,Zn and Cu were significantly increased,this might because that low temperature made the transpiration decreased,thus blocking the upward transport of elements.In plant shoots,the concentrations of Ca,Mg and Zn were significantly decreased,while the concentrations of Fe and Mn were significantly increased;the change extent of various elements in ZS variety was the largest.[Conclusion]Maintaining the stability of Ca,Mg and Zn concentrations and increasing Fe,Mn and Cu concentrations in plant shoots might be benefit for increasing the cold tolerance of winter oilseed rape.
文摘Populus tomentosa cuttings were treated with 1mmol·L -1 , 5mmol·L -1 , 10mmol·L -1 or 15mmol·L -1 of CaCl 2 for 1\|7 d, respectively, for studying the effects of different concentrations of CaCl 2 on freezing resistance. Results indicated that 10?mmol·L -1 of CaCl 2 has greater effect than other concentrations on the enhancement of freezing resistance, and the optimum time of pretreatment was 5?d. In addition, cuttings used for cold acclimation at -3℃ were pretreated with or without 10?mmol·L -1 of CaCl 2, 3?mmol·L -1 of Ca 2+ chelator EGTA, 0 05?mmol·L -1 of CaM antagonist CPZ or 0 1?mmol·L -1 of Ca 2+ channel inhibitor LaCl 3 The changes in CaM and freezing resistance of all cuttings were investigated. The results showed that cold acclimation at -3℃ increased CaM content and decreased the minimum temperature for 100% survival. The CaCl 2 pretreatment enhanced the effect of cold acclimation and obviously increased CaM content and decreased the minimum temperature for 100% survival, but this effect was strongly inhibited by the EGTA, CPZ or LaCl 3 It is concluded that the effect of CaCl 2 on freezing resistance is associated with its concentration and time of pretreatment, Ca 2+ CaM may be involved in the induction of freezing resistance of the cuttings.
文摘Populus tomentosa seedlings used for cold acclimation at -3℃ were pretreated with or without 10?mmol·L -1 CaCl 2, 3?mmol·L -1 of Ca 2+ chelator EGTA, 0 1?mmol·L -1 of Ca 2+ channel inhibitor LaCl 3,and 0 05?mmol·L -1 of CaM antagonist CPZ. The changes in the contents of total soluble protein and CaM, and freezing resistance in all pretreated seedlings in various periods ( viz: following cold acclimation, chilling stress and recovery) were investigated. Results showed that cold acclimation increased the contents of total soluble protein and CaM, and freezing resistance of seedlings, which could be strongly reduced by the pretreatments of EGTA CPZ and LaCl 3 Cold acclimation combined with CaCl 2 pretreatment enhanced the effect of cold acclimation on freezing resistance, and obviously increased the contents of total soluble protein and CaM, reduced the declining degree of the contents of total soluble protein and CaM caused by chilling stress as compared with cold acclimation, augmented the increase in the level of total soluble protein and CaM during the recovery periods. Further analysis found that an increase in total soluble protein content during cold acclimation with or without CaCl 2 pretreatment mainly resulted from the increase in content of heat stable protein in total soluble protein. It is suggested that Ca 2+ calmodulin may be involved in the synthesis of total soluble protein, and the induction of freezing resistance of seedlings.
文摘The changes in the contents of total soluble protein and RNA, the activity of RNase in leaves and branches of Populus tomentosa cuttings at various periods (viz: cold acclimation, deacclimation, chilling stress and the recovery after chilling stress), and the survival rate and the freezing resistance of cuttings during cold acclimation at -3℃ were investigated. Results showed that cold acclimation not only increased the contents of total soluble protein and RNA, the survival rates and the freezing resistance of cuttings, decreased the activity of RNase, but also reduced the declining degree of total soluble protein and RNA contents, and the increasing level of RNase caused by chilling stress as compared with the controls. In addition, cold acclimation augmented the increase in the level of total soluble protein and RNA, and facilitated the decrease of RNase during the recovery periods. Further analysis found that the DNA content of all treatments kept relative stability at various periods. The changes in total soluble protein, RNA and RNase were closely related to the freezing resistance of cuttings. It appears that the increase of RNA content caused by cold acclimation induced decrease of RNase activity may be involved in the accumulation of total soluble protein and the induction of freezing resistance of cuttings.
文摘The changes in activities of superoxide dismutase (SOD), peroxidase (POD) and ATPase in the leaves of Euonymus radicans were studied when seedlings were cold-acclimated (at 4 ℃) for 1 week, 2 weeks, 3 weeks and then treated for 1 d under low temperature stress (at 5 ℃). The semi-lethal temperatures of acclimated and unacclimated seedlings were also investigated. The results indicated that the activities of the three enzymes in the leaves of the seedlings treated at 4 ℃ for 1, 2 and 3 weeks were all higher than those of unacclimated seedings (treated at 22 ℃ as controls). The activities of SOD and POD increased continuously with the prolongation of the time of cold acclimation, but stepped up to summits then down to the levels of the controls. The activities of SOD culminated at the first week, and the activities of POD at the second week. When acclimated and unacclimated seedlings were both treated at 5 ℃ for 1 d, the activities of the three enzymes in the leaves of acclimated seedlings were a little lower than those before stress, but higher than those of the controls. Moreover, the decrease rate of enzyme activities was greatly lower than that of the controls. The results showed that cold acclimation could enhance the stability of the three enzymes in the leaves of seedlings under low temperature stress; the semi-lethal temperature was 19.1 ℃ when the seedlings were treated at 4 ℃ for 3 weeks, but it was 5.4 ℃ when the seedlings were treated at 22 ℃. The decline of the semi-lethal temperature caused by the adaptive changes of enzyme activities was one of the foundations of enhancing the cold tolerance.
基金supported by the Key Project of the National Twelve-Five Year Research Program of China(Grant No.2012BAD20B05-01-1)the Projects from the National Rice Industrial Technology System(Grant No.nycytx-001)the Grant Special Foundation of Transgenic Plants in China(Grant No.2009ZX08001-009B)
文摘Nine CBF/DREB1 homologous genes in rice were obtained by BLAST search in the NCBI database, which share conserved amino acid sequences with DREB1 protein in Arabidopsis. Three CBF genes organized in tandem, named OsCBF1, OsCBF2 and OsCBF3, showed a transient induction in the process of cold acclimation, much stronger in indica rice 93-11 compared with japonica rice Nipponbare. The candidate downstream genes OsLIP5 and OsLIP9 were induced in 93-11 but not in Nipponbare. The differential expression of CBF regulon might be caused by polymorphisms within promoter sequences between these two rice varieties. These results could be useful for utilization of CBF/DREB1 genes and illustration of differences in chilling tolerance between indica and japonica rice varieties.
基金the National Natural Science Foundation of China (Grant No. 30271067)Fok Ying Tung Education Foundation (71030)+1 种基金 Key Teachers Foundation of the Educational Ministry of China and the State Key Basic Research and Development Plan of China (G199901600
文摘Populus euphratica Olive is the only tree species that can grow in the saline land and also survive cold winters in northwest China, and it plays a very important role in stabilizing the vulnerable ecosystem there. A cell suspension culture was initiated from callus derived from plantlets of Populus euphratica. Cold acclimation was induced (LT50 of 17.5 ℃) in cell suspension at 45 ℃ in the dark for 30 days and the freezing tolerance increased from LT50 of 12.5 ℃ in nonacclimated cells to LT50 of 17.5 ℃ in cold-acclimated cells. Microvacuolation, cytoplasmic augmentation and accumulation of starch granules were observed in cells that were cold-acclimated by exposure to low temperatures. Several qualitative and quantitative changes in proteins were noted during cold acclimation. Antibodies to carrot extracellular (apoplastic) 36 kD antifreeze protein did not cross react on immunoelectroblots with extracellular proteins in cell suspension culture medium of Populus euphratica, indicating no common epitopes in the carrot 36 kD antifreeze protein and P. euphratica extracellular proteins. The relationship of these changes to cold acclimation in Populus euphratica cell cultures was discussed.
基金the National Natural Science Foundation of China （Grant No. 30671476 , 30271067）.
文摘Ammopiptanthus mongolicus, the only freezing tolerant evergreen broad-leaved shrub, local species of the Alashan desert, northwest sand area of China, can survive -30℃ or even lower temperature in winter. In the present study, the secondary products phenolics in A. mongolicus cotyledons were determined to study the effects of phenolics on cold tolerance. Cytochemical localization of phenolics in cotyledon cells was observed by electron microscopy and the content of phenolic compounds was assayed by spectrophotometric measurement. The results showed that the freezing tolerance ofA. mongolicus seedlings increased after acclimation at 2℃ for 14 days, which accompanied the increase of the content of phenolic compounds in cotyledons. Cytochemical observation showed that phenolic deposits were mainly localized in vacuoles and in close proximity to tonoplast, and also in the cytoplasm. The amount and the size of phenolics droplets increased obviously in cytoplasm and vacuoles after cold acclimation, predominantly aggregated along membranes of vacuoles and tonoplast. No phenolic deposits were found in cell walls. As hydrogen- or elec- tron-donating agents, phenolics may protect plant cells against reactive oxygen species formed during chilling or freezing stress and improve the freezing tolerance of cold-acclimated A. mongolicus seedlings.
文摘Populus tomentosa seedlings for cold-acclimating were pretreated wit h or without 20% saccharose. Changes in the concentrations of total soluble sugar , the survival rates, and freezing tolerance of seedlings during cold acclimatio n were investigated. The results showed that cold acclimation increased the conc entrations of total soluble sugar, the survival rates and freezing tolerance. Co ld acclimation, combined with the saccharose-pretreatment, enhanced the above- ment ioned effect of cold acclimation, and obviously increased the concentrations of total soluble sugar, the survival rates and freezing tolerance of seedlings. Fur ther analysis found that the concentrations of total soluble sugar in branches i ncreased greater than that in leaves during both cold acclimation with or withou t the pretreatment of saccharose. Moreover, an increase of the concentrations of total soluble sugar in branches and leaves was closely related to the freezing tolerance of seedlings. The results indicate the accumulation of soluble sugar i n seedlings induced by cold acclimation may be involved in the induction of free zing tolerance .
文摘The process of cold acclimation is an important adaptive response whereby many plants from temperate regions increase their freezing tolerance after being exposed to low non-freezing temperatures. The correct development of this response relies on proper accumulation of a number of transcription factors that regulate expression patterns of cold-responsive genes. Multiple studies have revealed a variety of molecular mechanisms involved in promoting the accumulation of these transcription factors. Interestingly, however, the mechanisms implicated in controlling such accumulation to ensure their adequate levels remain largely unknown. In this work, we demonstrate that prefoldins （PFDs） control the levels of HY5, an Arabidopsis transcription factor with a key role in cold acclimation by activating anthocyanin biosynthesis, in response to low temperature. Our results show that, under cold conditions, PFDs accumulate into the nucleus through a DELLA-dependent mechanism, where they interact with HY5, triggering its ubiquitination and subsequent degradation. The degradation of HY5 would result, in turn, in anthocyanin biosynthesis attenuation, ensuring the accurate development of cold acclimation. These findings uncover an unanticipated nuclear function for PFDs in plant responses to abiotic stresses.
基金the Citrus Research Board(Grant#5500-222)for funding.
文摘The Asian citrus psyllid,Diaphorina citri,is the vector of the pathogenic bacteria that causes Huanglongbing,the most devasting disease affecting citrus worldwide.As cultivation of citrus tends to expand northward,the tolerance of psyllids to freezing temperatures needs to be investigated.While mortality of D.citri to cold temperature has been previously studied,much less is known regarding the acclimation potential of psyllids to cold temperatures.We first evaluated cold resistance of D.citri depending on color morph and sex.Subsequently,we compared mortality of D.citri at−4°C for 10 hours between unacclimated psyllids,psyllids that were gradually acclimated to cold over 1 or 2 weeks,and psyllids intermittently acclimated also for 1 or 2 weeks.We did not find major differences in cold resistance between color morphs and sex.We found that after 1 week of gradual acclimation,the survival of psyllids at−4°C increased to 86%,compared to 20%in the control group.Survival did not increase after the second week of gradual acclimation.Although intermittent acclimation improved survival compared to the control group,it was less effective than gradual acclimation with a survival at 30%and 70%after 1 and 2 weeks of acclimation,respectively,although this difference with gradual acclimation was not significant at week 2.These data show that gradual cold acclimation allows D.citri to survive brief periods below freezing.It may serve as a mechanism responsible for increasing northern establishment of this pest.
基金supported by the National Natural Science Foundation of China (Grant No. 30700404)
文摘CDC48 is a highly conserved protein in eukaryotes and belongs to the AAA （ATPase associated with a variety of cellular activities） superfamily. It can interact with many different cofactors and form protein complexes that play important roles in various cellular processes. According to the Physcomitrella patens database, one member of the ATPases, the cell cycle gene PpCDC4811, was cloned. PpCDC48II contains two typical ATPase modules and is highly homologous to AtCDC48A. PpCDC4811 was up-regulated in mRNA levels after incubation at 0~C for 36 and 72 h. To further elucidate protein function, we disrupted the PpCDC4811 gene by transforming P. patens with the corresponding linear genomic sequences. When treated to the same freezing stress, it was found that PpCDC4811 knockout plants were less resistant to freezing treatment than wild type after acclimation. This suggested that PpCDC481I was an essential gene for low-temperature-induced freezing tolerance in P. patens cells.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.30671476 and 30271067).
文摘Cold acclimation is associated with many metabolic changes that lead to an increase of freezing tolerance. In order to investigate the biochemical process of cold acclimation in Ammopiptanthus mongolicus, seedlings were acclimated at 2℃ under 16-h photoperiod （150 μmol·m^-2·s^-1 photosynthetically active radiation） for 14 d. Freezing tolerance in seedlings increased after 14 d of cold-hardening. Contents of protein, proline and solute carbohydrate in cotyledon increased after cold acclimation. Patterns of isozymes of superoxide dismutase （SOD）, peroxidase, catalase and polyphenol oxidase （PPO） were investigated. The activities of SOD, peroxidase and PPO in cold acclimated plants were increased during cold-hardening. We deduced that compatible solutes and antioxidant enzymes play important roles in development of freezing tolerance during cold acclimation in this evergreen woody plant.
基金This study was partially supported by the Bilecik Seyh Edebali University Research Foundation(2014-02-BIL-04-03).
文摘Putrescine is reported to be necessary for cold acclimation under low-temperature stress.In this study,the effect of low-temperature on some physiological and biochemical parameters has been investigated using the green algae Chlamydomonas reinhardtii.The lipid peroxidation rate,amount of Rubisco protein,activities of antioxidant enzymes and gene expression of polyamine biosynthesis(odc2,and spd1),heat shock proteins(hsp70c,hsp90a,and hsp90c),and PSII repair mechanisms(psba,rep27,and tba1)were determined to understand the low-temperature response.Exogenous putrescine application significantly increased Rubisco protein concentration and catalase enzyme activities under low-temperature stress.Moreover,real-time RT-PCR results and gene expression analysis showed that polyamine metabolism induced gene expression at low-temperatures in the first 24 h.In the same way,the gene expression of heat shock proteins(hsp70c,hsp90a,and hsp90c)decreased under low-temperature treatment for 72 h;however,application of putrescine enhanced the gene expression in the first 24 h.The results obtained indicated that molecular response in the first 24 h could be important for cold acclimation.The psba and tba1 expressions were reduced under low-temperatures depending on the exposure time.In contrast,the exogenous putrescine enhanced the expression level of the psba response to low-temperature at 24 and 72 h.The results obtained in this study indicate that putrescine could play a role in the PS II repair mechanisms under low-temperature stress.
基金Supported by National Science and Technology Support Program of China(2011BAD16B06,2012BAD04B09)~~
文摘Freezing injury is one of the major disasters for the production of winter wheat in the North China Plain, which leads to a significant decrease of wheat yield. This study was conducted to investigate the impact of subfreezing temperature on freezing injury of various winter wheat cultivars at different sowing time. Three wheat cultivars, including Zhengmai 9023, Wanmai 48 and Wanmai 50, were sowed on 25 September and 5 October, respectively. Plant anatomy was applied to investi- gate the impact of subfreezing temperature on cells of three wheat cultivars, results showed that severe plasmolysis occurred in wheat sowed earlier suddenly encoun- tered subfreezing temperature without cold acclimation, compared with wheat sowed at proper sowing time. The degree of plasmolysis of different cultivars and tissues of wheat had significant differences and showed positive correlation with subfreezing temperature. Wanmai 50 had the highest cold resistance compared with Zhengmai 9023 and Wanmai 48, and there was no significant difference between Zhengmai 9023 and Wanmai 48. This study concluded that wheat cold resistance may be im- proved by adopting proper cultivars and sowing dates.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.31470472 and 31971420)the National Undergraduate “Innovation” Projectthe “Xinmiao” Project in Zhejiang Province
文摘Background:The thermoregulatory ability of animals is strongly influenced by the temperature of their environment.Acclimation to cold requires a range of physiological and morphological adjustments.In this study,we tested the hypothesis that a small passerine,the Red-billed Leiothrix(Leiothrix lutea),can maintain homeothermy in cold conditions by adjusting the physiology and biochemistry of its tissue and organs and return to its former physiological and biochemical state when moved to a warm temperature.Methods:Phenotypic variation in thermogenic activity of the Red-billed Leiothrixs(Leiothrix lutea)was investigated under warm(35℃),normal(25℃)or cold(15℃)ambient temperature conditions.Oxygen consumption was measured using an open-circuit respirometry system.Mitochondrial state-4 respiration and cytochrome-c oxidase(COX)activity in liver,kidney heart and pectoral muscle were measured with a Clark electrode.Results:Birds acclimated to an ambient temperature of 15℃ for 4 weeks significantly increased their basal metabolic rate(BMR)compared to a control group kept at 25℃.Birds acclimated to 35℃ decreased their BMR,gross energy intake(GEI)and digestible energy intake(DEI).Furthermore,birds acclimated to 15℃ increased state-4 respiration in their pectoral muscles and cytochrome-c oxidase(COX)activity in their liver and pectoral muscle,compared to the 25℃ control group.Birds acclimated to 35℃ also displayed lower state-4 respiration and COX activity in the liver,heart and pectoral muscles,compared to those kept at 25℃.There was a positive correlation between BMR and state-4 respiration,and between BMR and COX activity,in all of the above organs except the liver and heart.Conclusions:Our study illustrates that the morphological,physiological,and enzymatic changes are associated with temperature acclimation in the Red-billed Leiothrix,and supports the notion that the primary means by which small birds meet the energetic challenges of cold conditions is through metabolic adjustments.
基金This work was supported by the National Natural Science Foundation of China(No.31970534)the Fundamental Research Funds for the Central Universities(No.2019QNA6014),China.
文摘Temperature is one of the major environmental signals controlling plant development,geographical distribution,and seasonal behavior.Plants perceive adverse temperatures,such as high,low,and freezing temperatures,as stressful signals that can cause physiological defects and even death.As sessile organisms,plants have evolved sophisticated mechanisms to adapt to recurring stressful environments through changing gene expression or transcriptional reprogramming.Transcriptional memory refers to the ability of primed plants to remember previously experienced stress and acquire enhanced tolerance to similar or different stresses.Epigenetic modifications mediate transcriptional memory and play a key role in adapting to adverse temperatures.Understanding the mechanisms of the formation,maintenance,and resetting of stress-induced transcriptional memory will not only enable us to understand why there is a trade-off between plant defense and growth,but also provide a theoretical basis for generating stress-tolerant crops optimized for future climate change.In this review,we summarize recent advances in dissecting the mechanisms of plant transcriptional memory in response to adverse temperatures,based mainly on studies of the model plant Arabidopsis thaliana.We also discuss remaining questions that are important for further understanding the mechanisms of transcriptional memory during the adverse temperature response.
基金funded by the Swedish Research Council(2018-03926),Formas(2021-01065),Carl Trygger Foundation(20:224),and grants from the Knut and Alice Wallenberg Foundation and the Swedish Governmental Agency for Innovation Systems(KAW 2016.0355 and 2020.0240,VINNOVA 2016-00504)Grants and financial support was provided to E.M.from FEDER/Ministerio de Ciencia,Innovación y Universidades-Agencia Estatal de Investigación(PID2021-122288NB-I00)+2 种基金from the CERCA Programme/Generalitat de Catalunya(2021SGR-792)from the Spanish Ministry of Economy and Competitiveness through the Severo Ochoa Programme for Centers of Excellence in CEX2019-000902-S funded by MCIN/AEI/10.13039/501100011033M.Q.received postdoctoral funding from the European Union's Horizon 2020 research and innovation program under the Marie Sktodowska-Curie grant agreement no.945043.
文摘Plants need to constantly surveil their surroundings to adapt to environmental fluctuations, which theyachieve primarily through transcriptional reprogramming. Thus, plants are excellent models for identifyingnovel transcriptional regulatory mechanisms. In this study, we characterize the regulation mediated by longnon-coding transcription that initiates on the complementary strand in the 5' end of coding genes (convergentantisense transcription, CASt). In Arabidopsis, CASt is associated with stress-responsive genes thatare highly expressed. Our analysis shows that CASt depends on a specific gene architecture that is evolutionarilyconserved in higher plants. CASt is present in genes with an extended first intron and overrepresentedin genes encoding functional transporters in Arabidopsis, such as the AMiNo ACIDPERMEASE (AAP) transporter family. Experimental evidence points to a role for CASt in priming theirhost genes for stress responsiveness in evolutionary divergent plant species. Furthermore, we were ableto predict stress responsiveness in rice AAP genes based on the presence of a long first intron andCASt. Collectively, we show an evolutionary strategy and regulatory mechanism specific to plants forenhancing stress responsiveness through modification of gene architecture and antisense transcription.
文摘Leaves from annual young grape plants （Vitis vinifera L. cv. Jingxiu） were used as experimental materials. The ultrastructural characteristics of mesophyll cells in chilling-treated plants after heat acclimation （HA） and in heat-treated plants after cold acclimation （CA） were observed and compared using transmission electron microscopy. The results showed that slight injury appeared in the ultrastructure of mesophyll cells after either HA （38℃ for 10 h） or CA （8℃ for 2.5 d）, but the tolerance to subsequent extreme temperature stress was remarkably improved by HA or CA pretreatment. The increases in membrane permeability and malondialdehyde concentration under chilling （0℃） or heat （45℃） stress were markedly inhibited by HA or CA pretreatment. The mesophyll cells of plants not pretreated with HA were markedly damaged following chilling stress. The chloroplasts appeared irregular in shape, the arrangement of the stroma lamellae was disordered, and no starch granules were present. The cristae of the mitochondria were disrupted and became empty. The nucleus became irregular in shape and the nuclear membrane was digested. In contrast, the mesophyll cells of HA-pretreated plants maintained an intact ultrastructure under chilling stress. The mesophyll cells of control plants were also severely damaged under heat stress. The chloroplast became round in shape, the stroma lamellae became swollen, and the contents of vacuoles formed clumps. In the case of mitochondria of control plants subjected to heat stress, the outer envelope was digested and the cristae were disrupted and became many small vesicles. Compared with cellular organelles in control plants, those in CA plant cells always maintained an integrated state during whole heat stress, except for the chloroplasts, which became round in shape after 10 h heat stress. From these data, we suggest that the stability of mesophyll cells under chilling stress can be increased by HA pretreatment. Similarly, CA pretreatment can protect chloroplasts, mitochondria, and the nucleus against subsequent heat stress; thus, the thermoresistance of grape seedlings was improved. The results obtained in the present study are the first, to our knowledge, to offered cytological evidence of cross-adaptation to temperature stresses in grape plants.
