Small auxin-upregulated RNAs(SAURs) are genes regulated by auxin and environmental factors. In this study, we identified a SAUR gene in wheat, Ta SAUR75. Under salt stress,Ta SAUR75 is downregulated in wheat roots. Su...Small auxin-upregulated RNAs(SAURs) are genes regulated by auxin and environmental factors. In this study, we identified a SAUR gene in wheat, Ta SAUR75. Under salt stress,Ta SAUR75 is downregulated in wheat roots. Subcellular localization revealed that Ta SAUR75 was localized in both the cytoplasm and nucleus. Overexpression of Ta SAUR75 increased drought and salt tolerance in Arabidopsis. Transgenic lines showed higher root length and survival rate and higher expression of some stress-responsive genes than control plants under salt and drought stress. Less H_2O_2 accumulated in transgenic lines than in control plants under drought stress. Our findings reveal a positive regulatory role of the auxin-responsive gene Ta SAUR75 in plant responses to drought and salt stress and provide a candidate gene for improvement of abiotic stress tolerance in crop breeding.展开更多
The engineering of plants with enhanced tolerance to abiotic stresses typically involves complex multigene networks and may therefore have a greater potential to introduce unintended effects than the genetic modificat...The engineering of plants with enhanced tolerance to abiotic stresses typically involves complex multigene networks and may therefore have a greater potential to introduce unintended effects than the genetic modification for simple monogenic traits. For this reason, it is essential to study the unintended effects in transgenic plants engineered for stress tolerance. We selected drought-and salt-tolerant transgenic wheat overexpressing the transcription factor, GmDREB1, to investigate unintended pleiotropic effects using RNA-seq analysis. We compared the transcriptome alteration of transgenic plants with that of wild-type plants subjected to salt stress as a control. We found that GmDREB1 overexpression had a minimal impact on gene expression under normal conditions.GmDREB1 overexpression resulted in transcriptional reprogramming of the salt response,but many of the genes with differential expression are known to mitigate salt stress and contribute incrementally to the enhanced stress tolerance of transgenic wheat. GmDREB1 overexpression did not activate unintended gene networks with respect to gene expression in the roots of transgenic wheat. This work is important for establishing a method of detecting unintended effects of genetic engineering and the safety of such traits with the development of marketable transgenic crops in the near future.展开更多
DREBs are transcription factors that regulate abiotic stress tolerance in plants.Previously,we reported that wheat transgenic lines overexpressing Gm DREB1 showed increased tolerance to drought and salt stress.However...DREBs are transcription factors that regulate abiotic stress tolerance in plants.Previously,we reported that wheat transgenic lines overexpressing Gm DREB1 showed increased tolerance to drought and salt stress.However,the molecular basis of increased tolerance is still poorly understood,and whether the overexpression of DREB will cause unexpected effects is also of concern.We performed seed metabolic profiling of the genetically modified(GM)wheat T349 and three non-GM cultivars with LC-MS to identify the metabolic basis of stress tolerance and to assess the unexpected effects of exogenous gene insertion.Although we did not note the appearance of novel metabolites or the disappearance of existing metabolites,overexpression of the transcription factor Gm DREB1 in T349 wheat influenced metabolite levels in seeds.Increased levels of stress tolerance-associated metabolites were found in the stress-sensitive non-transgenic acceptor counterpart J19,while metabolites associated with cell membrane structure and stability accumulated in T349.Among these metabolites in T349,most showed levels similar to those in the non-GM wheats.Overexpression of Gm DREB1 in T349 may cause a shift in its metabolic profile leading to down-regulation of several energy-consuming processes to favor increased yield under stress conditions,which is a reasonable expectation of breeders while creating the GM wheat and Gm DREB1 overexpression did not cause unexpected effects in T349 seeds.These results may be helpful for GM crop research and risk assessment.展开更多
This study focuses on the transient liquid phase(TLP)bonding of DD5 single-crystal superalloy to Cr Co Nibased medium-entropy alloy(MEA)using a BNi-2 filler alloy.The microstructure and mechanical properties of the TL...This study focuses on the transient liquid phase(TLP)bonding of DD5 single-crystal superalloy to Cr Co Nibased medium-entropy alloy(MEA)using a BNi-2 filler alloy.The microstructure and mechanical properties of the TLP-bonded DD5/MEA joint were evaluated,and the microstructural evolution mechanism was investigated.The formation of the isothermal solidification zone(ISZ)depended on the diffusion of the melting-point depressants(Si and B elements)from the liquid filler into the DD5 and MEA substrates,as well as the dissolution of the substrates.Boron diffused along theγchannel of DD5 and reacted to form M_(5)B_(3)boride,herein referred to as the diffusion-affected zone(DAZ I).Similarly,the Cr_(5)B_(3)boride precipitated in the Ni-rich MEA matrix adjacent to the MEA substrate(i.e.,DAZ II).Additionally,a coherent orientation of[0]_(BCY)//[011]_(FCC)and(002)_(BCY)//(200)_(FCC)was detected between M_(5)B_(3)boride with a body-centered tetragonal(BCT)structure and the face-centered cubic(FCC)matrix.The performance of the joint was dominated by the properties of the bonding seam.As the bonding time increased from 20to 80 min,the athermal solidification zone(including eutectic microstructure)was gradually replaced by the ISZ exhibiting excellent plastic deformation capability,and the shear strength of the joint was improved.The maximum shear strength(752 MPa)was achieved when the eutectic-free joint was bonded at 1050℃ for 80 min.The fracture morphology revealed a mixture mode,indicating the initiation of cracks in the DAZ II,mainly propagating in the ISZ,and passing through the DAZ I.展开更多
基金supported by the National Key Research and Development Program of China (2016YFD0100304)National Transgenic Key Project from the Ministry of Agriculture of China (2016ZX08002-002)Agricultural Science and Technology Program for Innovation Team on the Identification and Excavation of Elite Crop Germplasm, CAAS
文摘Small auxin-upregulated RNAs(SAURs) are genes regulated by auxin and environmental factors. In this study, we identified a SAUR gene in wheat, Ta SAUR75. Under salt stress,Ta SAUR75 is downregulated in wheat roots. Subcellular localization revealed that Ta SAUR75 was localized in both the cytoplasm and nucleus. Overexpression of Ta SAUR75 increased drought and salt tolerance in Arabidopsis. Transgenic lines showed higher root length and survival rate and higher expression of some stress-responsive genes than control plants under salt and drought stress. Less H_2O_2 accumulated in transgenic lines than in control plants under drought stress. Our findings reveal a positive regulatory role of the auxin-responsive gene Ta SAUR75 in plant responses to drought and salt stress and provide a candidate gene for improvement of abiotic stress tolerance in crop breeding.
基金supported by the National Transgenic Key Project of the Ministry of Agriculture of China(2016ZX08011-003)the Agricultural Science and Technology Program for Innovation Team on Identification and excavation of Elite Crop Germplasm,CAAS
文摘The engineering of plants with enhanced tolerance to abiotic stresses typically involves complex multigene networks and may therefore have a greater potential to introduce unintended effects than the genetic modification for simple monogenic traits. For this reason, it is essential to study the unintended effects in transgenic plants engineered for stress tolerance. We selected drought-and salt-tolerant transgenic wheat overexpressing the transcription factor, GmDREB1, to investigate unintended pleiotropic effects using RNA-seq analysis. We compared the transcriptome alteration of transgenic plants with that of wild-type plants subjected to salt stress as a control. We found that GmDREB1 overexpression had a minimal impact on gene expression under normal conditions.GmDREB1 overexpression resulted in transcriptional reprogramming of the salt response,but many of the genes with differential expression are known to mitigate salt stress and contribute incrementally to the enhanced stress tolerance of transgenic wheat. GmDREB1 overexpression did not activate unintended gene networks with respect to gene expression in the roots of transgenic wheat. This work is important for establishing a method of detecting unintended effects of genetic engineering and the safety of such traits with the development of marketable transgenic crops in the near future.
基金supported by the National Natural Science Foundation of China(31601302)National Transgenic Key Project from the Ministry of Agriculture of China(2016ZX08011-003)+1 种基金National Key Research and Development Program of China(2016YFD0100304)the Agricultural Science and Technology Program for Innovation Team(Evaluation on the Quality and Stress Tolerance of Crop Germplasm),CAAS。
文摘DREBs are transcription factors that regulate abiotic stress tolerance in plants.Previously,we reported that wheat transgenic lines overexpressing Gm DREB1 showed increased tolerance to drought and salt stress.However,the molecular basis of increased tolerance is still poorly understood,and whether the overexpression of DREB will cause unexpected effects is also of concern.We performed seed metabolic profiling of the genetically modified(GM)wheat T349 and three non-GM cultivars with LC-MS to identify the metabolic basis of stress tolerance and to assess the unexpected effects of exogenous gene insertion.Although we did not note the appearance of novel metabolites or the disappearance of existing metabolites,overexpression of the transcription factor Gm DREB1 in T349 wheat influenced metabolite levels in seeds.Increased levels of stress tolerance-associated metabolites were found in the stress-sensitive non-transgenic acceptor counterpart J19,while metabolites associated with cell membrane structure and stability accumulated in T349.Among these metabolites in T349,most showed levels similar to those in the non-GM wheats.Overexpression of Gm DREB1 in T349 may cause a shift in its metabolic profile leading to down-regulation of several energy-consuming processes to favor increased yield under stress conditions,which is a reasonable expectation of breeders while creating the GM wheat and Gm DREB1 overexpression did not cause unexpected effects in T349 seeds.These results may be helpful for GM crop research and risk assessment.
基金financially supported by the National Natural Science Foundation of China(52005410 and 52375146)China Postdoctoral Science Foundation(2019TQ0263 and 2020M683560)the Fundamental Research Funds for the Central Universities.
基金supported by the fund of Natural Science Basic Research Program of Shaanxi(Grant No.2020JQ-190)National Natural Science Foundations of China(Grant Nos.51975480,52075449,and U1737205)China Postdoctoral Science Foundation funded project(Grant Nos.2019TQ0263,and 2020M683560)。
文摘This study focuses on the transient liquid phase(TLP)bonding of DD5 single-crystal superalloy to Cr Co Nibased medium-entropy alloy(MEA)using a BNi-2 filler alloy.The microstructure and mechanical properties of the TLP-bonded DD5/MEA joint were evaluated,and the microstructural evolution mechanism was investigated.The formation of the isothermal solidification zone(ISZ)depended on the diffusion of the melting-point depressants(Si and B elements)from the liquid filler into the DD5 and MEA substrates,as well as the dissolution of the substrates.Boron diffused along theγchannel of DD5 and reacted to form M_(5)B_(3)boride,herein referred to as the diffusion-affected zone(DAZ I).Similarly,the Cr_(5)B_(3)boride precipitated in the Ni-rich MEA matrix adjacent to the MEA substrate(i.e.,DAZ II).Additionally,a coherent orientation of[0]_(BCY)//[011]_(FCC)and(002)_(BCY)//(200)_(FCC)was detected between M_(5)B_(3)boride with a body-centered tetragonal(BCT)structure and the face-centered cubic(FCC)matrix.The performance of the joint was dominated by the properties of the bonding seam.As the bonding time increased from 20to 80 min,the athermal solidification zone(including eutectic microstructure)was gradually replaced by the ISZ exhibiting excellent plastic deformation capability,and the shear strength of the joint was improved.The maximum shear strength(752 MPa)was achieved when the eutectic-free joint was bonded at 1050℃ for 80 min.The fracture morphology revealed a mixture mode,indicating the initiation of cracks in the DAZ II,mainly propagating in the ISZ,and passing through the DAZ I.