Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration ...Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Iα-loop-helix Iβmotif which corresponds to helix I of other P 450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,theγ-domain.The structure reveals a homodimer in which theγ-domain of one molecule interacts with theβ-domain of another.The plane of heme group makes an angle of approximately 40°with the helix Iα-loop-helix Iβmotif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recognition.Phe-301,Ser-303 and Gly-305 from the helix Iα-loop-helix Iβmotif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.展开更多
Tau oligomers are the etiologic molecules of Alzheimer disease(AD), and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic a...Tau oligomers are the etiologic molecules of Alzheimer disease(AD), and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic aggregate species. The aim of the present study was to investigate the mechanisms of cornel iridoid glycoside(CIG) on tau oligomers and cognitive functions. We injected wortmannin and GF-109203 X(WM/GFX, 200 μmol·L-1 each) into the lateral ventricles to induce tau oligomer and memory impairment in rats. When oral y administered with CIG at 60 and 120 mg·kg-1 per day for 14 d, CIG decreased the escape latency in Morris water maze test. We also found that CIG restored the expression of presynaptic p-synapsin, synaptophysin, and postsynaptic density-95(PSD-95) decreased by WM/GFX in rat cortex. CIG reduced the accumulation of tau oligomers in the brain of WM/GFX rats and in cells transfected with wild type glycogen synthase kinase-3β(wt GSK-3β). In addition, CIG up-regulated the levels of ATG7, ATG12, Beclin-1, and LC3 II in vivo and in vitro, suggesting the restoration of autophagy function. These results suggest that CIG could ameliorate memory deficits and regulate memory-associated synaptic proteins through the clearance of tau oligomers accumulation. Moreover, CIG clears tau oligomers by restoring autophagy function.展开更多
Objective C1q/TNF-related protein(CTRP)1 was initiallyidentified as a paralog of adiponectin based on the similarity in C1q domain of these two proteins.Previously,we showed that CTRP1promotes the development of ather...Objective C1q/TNF-related protein(CTRP)1 was initiallyidentified as a paralog of adiponectin based on the similarity in C1q domain of these two proteins.Previously,we showed that CTRP1promotes the development of atherosclerosis by increasing endothelial adhesiveness.Here,we sought to investigate whether CTRP1 also influences vascular dilatory functions.展开更多
OBJECTIVE To study the function of neuronal nitric oxide synthase(nNOS) in the dentate gyrus(DG) in the pathology of epilepsy.METHODS The expression of nNOS in the DG was measured by qPCR and Western blotting in mice ...OBJECTIVE To study the function of neuronal nitric oxide synthase(nNOS) in the dentate gyrus(DG) in the pathology of epilepsy.METHODS The expression of nNOS in the DG was measured by qPCR and Western blotting in mice 3 and 12 h,1,7,14,and 60 d after treatment with pilocarpine(280 mg·kg-1,ip,one time).We constructed a type of lentiovirus encoding the full length cDNA of nNOS(LV-nNOS-GFP) and injected it and LV-GFP(1 μL) into the DG of the hippocampus 7 d after pilocarpine-induced seizure.The occurrence of epileptic spikes and spontaneous seizure(SRS)were monitored through electroencephalo-graph(EEG) and the protein expression was confirmed by Western blotting.We also constructed a lentioviral vehicle to interfere the expression of nNOS mRNA,which was named as LV-n NOSRNAi-GFP.A volume of 1 μL of LV-nNOS-RNAiGFP or LV-GFP was injected into the DG of the hippocampus 7 d before pilocarpine-induced seizure followed by EEG record and protein detection 2 months later.By EEG,we compared the susceptibility of nNOS knockout and wild-type mice to seizure induction and the development of epilepsy.In addition,we measured the influence of nNOS knockout on the excitability of dentate cells including mEPSC and mIPSC by using patch clamp technique.RESULTS Western blotting and qPCR measurement showed that the mRNA and protein expression of nNOS in the DG was not significantly changed in pilocarpinetreated mice compared with control mice.But the both m RNA and protein expression of nNOS decreased 7,14 and 60 d after treatment with pilocarpine(280 mg·kg-1,ip,one time).With infection of LV-nNOS-GFP in the DG,the decreased level of nNOS was recovered 7 d after seizure induction and the frequency of epileptic spikes and SRS were reversed by nNOS overexpression.We found that nNOS knockout caused a higher susceptive level to seizure induction by pilocarpine.Re-expression of nNOS in the DG of nNOS knockout mice relived the severity of epilepsy.By patch clamp recording,we found that there was no significant difference in the amplitude of mEPSC and mIPSC between nNOS knockout and wild-type mice,but the frequency of mEPSC was increased in nN OS knockout mice.Consistently,knockdown of nNOS by injection of LV-nNOS-RNAi-GFP into the DG caused higher frequency of epileptic spikes and SRS 2 months after pilocarpine-induced seizure.CONCLUSION Neurons expressing nNOS in the DG play an important role in the development of epilepsy.展开更多
Aim Inducible nitric oxide synthase （iNOS） makes a great contribution to host defense and inflamma-tion. In many settings, lipopolysaccharide （LPS） induces iNOS expression through activation of the inhibitor of K...Aim Inducible nitric oxide synthase （iNOS） makes a great contribution to host defense and inflamma-tion. In many settings, lipopolysaccharide （LPS） induces iNOS expression through activation of the inhibitor of KB- α （IKB-α） -nuclear factor-KB （NF-KB） cascade, whereas interferon-γ （IFN-γ） acts through Janus kinase （ JAK）- signal transducer and activator of transcription 1 （ STAT1 ） signals. Heat shock factor 1 （ HSF1 ）, a major regulator of heat shock protein transcription, has been shown to regulate the production of pro-inflammatory cytokines such as tumor necrosis factor-α（TNF-α） and interleukin-6 （IL-6）. But it remains obscure whether and how HSF1 affects iNOS induction. Methods Western blot was used to measure the protein expression. The mRNA level was meas- ured by real time-PCR. Silence of HSF1 was achieved by small interfering RNA. Nitric oxide （NO） content and NF-KB binding activity were assayed by commercial kits. Chromatin immunoprecipitation （CHIP） was used to measure the binding activity of NF-KB and STAT1 to iNOS promoters. Results HSF1 inhibition or knockdown pre- vented the LPS- and/or IFN-γ-stimulated iNOS protein expression in cultured microglia. HSF1 inhibition blocked iNOS mRNA transcription. These inhibitory effects of HSF1 inhibition on iNOS expression were confirmed in brain tissues from endotoxemic mice. Further analysis showed that HSF1 inhibition had no effect on IKB-α degradation and NF-KB or STAT1 phosphorylation in LPS/IFN-γ-stimulated cells. The nuclear transport of active NF-KB or STAT1 was also not affected by HSF1 inhibition. But HSF1 inhibition reduced the binding of NF-KB and STAT1 to their DNA elements. In addition, HSF1 inhibition reduced NF-KB and STAT1 bindings to iNOS promoter inside the LPS/IFN-γ-stimulated cells. Conclusions This preventing effect of HSF1 inhibition on iNOS mRNA transcription presents the necessary role of HSF1 in iNOS induction.展开更多
Chitin is the most widespread amino polysaccharide in nature. Chitin synthase （CHS） plays an important role in chitin formation in the cuticle and the peritrophic membrane （PM） lining the midgut. Total RNA was iso...Chitin is the most widespread amino polysaccharide in nature. Chitin synthase （CHS） plays an important role in chitin formation in the cuticle and the peritrophic membrane （PM） lining the midgut. Total RNA was isolated from the cuticle of Mamestra brassicae （L.） fourth instar larva, cDNA sequence was cloned by RT-PCR and Rapid Amplification of cDNA Ends （RACE）. cDNA 5 220 bp in length, contained an open reading frame of 4 704 bp coding for a polypeptide of 1 567 amino acid residues with a predicted molecular weight of 178.3 ku and its pI was 6.42. The deduced amino acid sequence from Mi brassicae （L.） shared the high level of identity with chitin synthase sequences from other insects, especially lepidopteran insects, cDNA sequence has been deposited with GenBank under accession No. GQ281761展开更多
Traditional Chinese herbal medicine(TCM)has been shown to enhance the efficacy of standard anticancer agents.However,there are only a limited number of well-controlled preclinical and clinical studies documenting the ...Traditional Chinese herbal medicine(TCM)has been shown to enhance the efficacy of standard anticancer agents.However,there are only a limited number of well-controlled preclinical and clinical studies documenting the potential benefit of TCM.OBJECTIVE To identify biologically active formulas that were effective against colorectal cancer(CRC)by screening TCM formulas in in vitro and in vivo animal models.METHODS Cell growth assays,cell cycle analysis,immunoblot analysis and qRT-PCR were performed to investigate the mechanism(s)of action of the formulason human CRC cells.In vivo animal models were used to evaluate the antitumor activity of formulasalone and in combination with 5-FU.RESULTS We identified Huangqin Gegen Tang(HQGGT)which suppressed the in vivo growth of human CRC HT-29 xenografts.HQGGT significantly inhibited the growth of CRC cell lines.HQGGT enhanced the cytotoxicity of 5-FU against human 5-FU-resistant cells(H630R1)and mouse colon cancer cells(MC38).This synergy was the result of suppression of thymidylate synthase expression by HQGGT.HQGGT significantly enhanced the antitumor effect of 5-FU in mice bearing MC38 xenografts.Ongoing studies have identified Huangqin as the herb responsible for TS inhibi⁃tion.CONCLUSION These findings provide support for the potential role of HQGGT as a novel modulator of fluoropyrim⁃idine chemotherapy for CRC treatment.展开更多
Background Herbicide tolerance in crops enables them to survive when lethal doses of herbicides are applied to surrounding weeds.Herbicide-tolerant crops can be developed through transgenic approaches or traditional m...Background Herbicide tolerance in crops enables them to survive when lethal doses of herbicides are applied to surrounding weeds.Herbicide-tolerant crops can be developed through transgenic approaches or traditional mutagenesis approaches.At present,no transgenic herbicide tolerant cotton have been commercialized in China due to the genetically-modified organism(GMO)regulation law.We aim to develop a non-transgenic herbicide-tolerant cotton through ethyl methanesulfonate(EMS)mutagenesis,offering an alternative choice for weed management.Results Seeds of an elite cotton cultivar Lumianyan 37(Lu37)were treated with EMS,and a mutant Lu37-1 showed strong tolerance to imidazolinone(IMI)herbicides was identified.A novel nonsynonymous substitution mutation Ser642Asn at acetolactate synthase(ALS)(Gh_D10G1253)in Lu37-1 mutant line was found to be the potential cause to the IMI herbicides tolerance in cotton.The Ser642Asn mutation in ALS did not present among the genomes of natural Gossypium species.Cleaved amplified polymorphic sequence(CAPS)markers were developed to identify the ALS mutant allele.The Arabidopsis overexpressing the mutanted ALS also showed high tolerance to IMI herbicides.Conclusion The nonsynonymous substitution mutation Ser642Asn of the ALS gene Gh_D10G1253 is a novel identi-fied mutation in cotton.This substitution mutation has also been identified in the orthologous ALS genes in other crops.This mutant ALS allele can be used to develop IMI herbicide-tolerant crops via a non-transgenic or transgenic approach.展开更多
The content of sugar is influenced by sucrose synthase （SS） activity in roots. The effects of nitrogen level in the aminonitrate ratio on SS activity of leaves and roots, roots yield and sugar content in sugar beet ...The content of sugar is influenced by sucrose synthase （SS） activity in roots. The effects of nitrogen level in the aminonitrate ratio on SS activity of leaves and roots, roots yield and sugar content in sugar beet were studied in the field experiment by nutrient solution culture. The results showed that SS activity in leaves was lower than that in roots. With nitrogen level increasing, SS decomposition activity enhanced, and synthesis activity reduced. SS activity was regulated by different nitrogen forms and the ratio of NO3 and NH4^＋. SS synthesis activity was enhanced as NH4^＋ increasing when NO3 ： NH4^＋≥ 1, and it decreased as increasing NH4^＋ when NO3 ： NH4^＋≤ 1, and it was the highest when NO3 ： NH4^＋=1. SS decomposition activity was enhanced as NO3- increasing. Sucrose content in root was lowed as nitrogen level increasing, but it was enhanced as NH4^＋ increasing in the same nitrogen level. Root and sugar yield were the highest in the medium nitrogen level and NO3 ： NH4^＋=1. The result in field experiment corresponded with that in the nutrient fluid culture. It provides a basis for using reasonably nitrogen fertilizer in sugar beet production.展开更多
The experiment of glutamate synthase activity (GOGATA) in both leaf blades and roots under different nitrogen levels was carried out at Northeast Agricultural University in 1993. The result showed that GOGATA rose rap...The experiment of glutamate synthase activity (GOGATA) in both leaf blades and roots under different nitrogen levels was carried out at Northeast Agricultural University in 1993. The result showed that GOGATA rose rapidly to reach its peak from seedling stage to foliage rapid growth stage, and then declined gradually. GOGATA was enhanced with increasing nitrogen levels and had significant positive correlation with nitrogen levels at the middle stage of growth GOGATA in leaf blades was the strongest compared with crowns, petioles and roots, thus, it could represent the highest enzyme activity of the whole plant. GOGATA had quadratic curvilinear correlation with root yield and sugar production. GOGATA in leaf blades had significant positive correlation with α-NH 2-N at the foliage rapid growth stage while GOGATA in roots existed this relation at the latter stage of growth. GOGATA in roots had significant negative correlation with sugar content at harvest.展开更多
The mechanistic basis of cellulose biosynthesis in plants has gained ground during last decade or so.The isolation of plant cDNA clones encoding cotton homologs of the bacterial cellulose
文摘Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Iα-loop-helix Iβmotif which corresponds to helix I of other P 450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,theγ-domain.The structure reveals a homodimer in which theγ-domain of one molecule interacts with theβ-domain of another.The plane of heme group makes an angle of approximately 40°with the helix Iα-loop-helix Iβmotif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recognition.Phe-301,Ser-303 and Gly-305 from the helix Iα-loop-helix Iβmotif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.
文摘Tau oligomers are the etiologic molecules of Alzheimer disease(AD), and correlate strongly with neuronal loss and exhibit neurotoxicity. Recent evidence indicates that small tau oligomers are the most relevant toxic aggregate species. The aim of the present study was to investigate the mechanisms of cornel iridoid glycoside(CIG) on tau oligomers and cognitive functions. We injected wortmannin and GF-109203 X(WM/GFX, 200 μmol·L-1 each) into the lateral ventricles to induce tau oligomer and memory impairment in rats. When oral y administered with CIG at 60 and 120 mg·kg-1 per day for 14 d, CIG decreased the escape latency in Morris water maze test. We also found that CIG restored the expression of presynaptic p-synapsin, synaptophysin, and postsynaptic density-95(PSD-95) decreased by WM/GFX in rat cortex. CIG reduced the accumulation of tau oligomers in the brain of WM/GFX rats and in cells transfected with wild type glycogen synthase kinase-3β(wt GSK-3β). In addition, CIG up-regulated the levels of ATG7, ATG12, Beclin-1, and LC3 II in vivo and in vitro, suggesting the restoration of autophagy function. These results suggest that CIG could ameliorate memory deficits and regulate memory-associated synaptic proteins through the clearance of tau oligomers accumulation. Moreover, CIG clears tau oligomers by restoring autophagy function.
文摘Objective C1q/TNF-related protein(CTRP)1 was initiallyidentified as a paralog of adiponectin based on the similarity in C1q domain of these two proteins.Previously,we showed that CTRP1promotes the development of atherosclerosis by increasing endothelial adhesiveness.Here,we sought to investigate whether CTRP1 also influences vascular dilatory functions.
基金National Natural Science Foundation of China(81571269)Science Technology Innovation Fund of Nanjing Medical University (2017NJMUCX008).
文摘OBJECTIVE To study the function of neuronal nitric oxide synthase(nNOS) in the dentate gyrus(DG) in the pathology of epilepsy.METHODS The expression of nNOS in the DG was measured by qPCR and Western blotting in mice 3 and 12 h,1,7,14,and 60 d after treatment with pilocarpine(280 mg·kg-1,ip,one time).We constructed a type of lentiovirus encoding the full length cDNA of nNOS(LV-nNOS-GFP) and injected it and LV-GFP(1 μL) into the DG of the hippocampus 7 d after pilocarpine-induced seizure.The occurrence of epileptic spikes and spontaneous seizure(SRS)were monitored through electroencephalo-graph(EEG) and the protein expression was confirmed by Western blotting.We also constructed a lentioviral vehicle to interfere the expression of nNOS mRNA,which was named as LV-n NOSRNAi-GFP.A volume of 1 μL of LV-nNOS-RNAiGFP or LV-GFP was injected into the DG of the hippocampus 7 d before pilocarpine-induced seizure followed by EEG record and protein detection 2 months later.By EEG,we compared the susceptibility of nNOS knockout and wild-type mice to seizure induction and the development of epilepsy.In addition,we measured the influence of nNOS knockout on the excitability of dentate cells including mEPSC and mIPSC by using patch clamp technique.RESULTS Western blotting and qPCR measurement showed that the mRNA and protein expression of nNOS in the DG was not significantly changed in pilocarpinetreated mice compared with control mice.But the both m RNA and protein expression of nNOS decreased 7,14 and 60 d after treatment with pilocarpine(280 mg·kg-1,ip,one time).With infection of LV-nNOS-GFP in the DG,the decreased level of nNOS was recovered 7 d after seizure induction and the frequency of epileptic spikes and SRS were reversed by nNOS overexpression.We found that nNOS knockout caused a higher susceptive level to seizure induction by pilocarpine.Re-expression of nNOS in the DG of nNOS knockout mice relived the severity of epilepsy.By patch clamp recording,we found that there was no significant difference in the amplitude of mEPSC and mIPSC between nNOS knockout and wild-type mice,but the frequency of mEPSC was increased in nN OS knockout mice.Consistently,knockdown of nNOS by injection of LV-nNOS-RNAi-GFP into the DG caused higher frequency of epileptic spikes and SRS 2 months after pilocarpine-induced seizure.CONCLUSION Neurons expressing nNOS in the DG play an important role in the development of epilepsy.
文摘Aim Inducible nitric oxide synthase （iNOS） makes a great contribution to host defense and inflamma-tion. In many settings, lipopolysaccharide （LPS） induces iNOS expression through activation of the inhibitor of KB- α （IKB-α） -nuclear factor-KB （NF-KB） cascade, whereas interferon-γ （IFN-γ） acts through Janus kinase （ JAK）- signal transducer and activator of transcription 1 （ STAT1 ） signals. Heat shock factor 1 （ HSF1 ）, a major regulator of heat shock protein transcription, has been shown to regulate the production of pro-inflammatory cytokines such as tumor necrosis factor-α（TNF-α） and interleukin-6 （IL-6）. But it remains obscure whether and how HSF1 affects iNOS induction. Methods Western blot was used to measure the protein expression. The mRNA level was meas- ured by real time-PCR. Silence of HSF1 was achieved by small interfering RNA. Nitric oxide （NO） content and NF-KB binding activity were assayed by commercial kits. Chromatin immunoprecipitation （CHIP） was used to measure the binding activity of NF-KB and STAT1 to iNOS promoters. Results HSF1 inhibition or knockdown pre- vented the LPS- and/or IFN-γ-stimulated iNOS protein expression in cultured microglia. HSF1 inhibition blocked iNOS mRNA transcription. These inhibitory effects of HSF1 inhibition on iNOS expression were confirmed in brain tissues from endotoxemic mice. Further analysis showed that HSF1 inhibition had no effect on IKB-α degradation and NF-KB or STAT1 phosphorylation in LPS/IFN-γ-stimulated cells. The nuclear transport of active NF-KB or STAT1 was also not affected by HSF1 inhibition. But HSF1 inhibition reduced the binding of NF-KB and STAT1 to their DNA elements. In addition, HSF1 inhibition reduced NF-KB and STAT1 bindings to iNOS promoter inside the LPS/IFN-γ-stimulated cells. Conclusions This preventing effect of HSF1 inhibition on iNOS mRNA transcription presents the necessary role of HSF1 in iNOS induction.
基金Supported by Natural Science Foundation of Heilongjiang Province (C2007-7)Scientific and Technical Innovation Fund of Harbin (RC2006QN002027)Northeast Agricultural University Research Fund (2005)
文摘Chitin is the most widespread amino polysaccharide in nature. Chitin synthase （CHS） plays an important role in chitin formation in the cuticle and the peritrophic membrane （PM） lining the midgut. Total RNA was isolated from the cuticle of Mamestra brassicae （L.） fourth instar larva, cDNA sequence was cloned by RT-PCR and Rapid Amplification of cDNA Ends （RACE）. cDNA 5 220 bp in length, contained an open reading frame of 4 704 bp coding for a polypeptide of 1 567 amino acid residues with a predicted molecular weight of 178.3 ku and its pI was 6.42. The deduced amino acid sequence from Mi brassicae （L.） shared the high level of identity with chitin synthase sequences from other insects, especially lepidopteran insects, cDNA sequence has been deposited with GenBank under accession No. GQ281761
文摘Traditional Chinese herbal medicine(TCM)has been shown to enhance the efficacy of standard anticancer agents.However,there are only a limited number of well-controlled preclinical and clinical studies documenting the potential benefit of TCM.OBJECTIVE To identify biologically active formulas that were effective against colorectal cancer(CRC)by screening TCM formulas in in vitro and in vivo animal models.METHODS Cell growth assays,cell cycle analysis,immunoblot analysis and qRT-PCR were performed to investigate the mechanism(s)of action of the formulason human CRC cells.In vivo animal models were used to evaluate the antitumor activity of formulasalone and in combination with 5-FU.RESULTS We identified Huangqin Gegen Tang(HQGGT)which suppressed the in vivo growth of human CRC HT-29 xenografts.HQGGT significantly inhibited the growth of CRC cell lines.HQGGT enhanced the cytotoxicity of 5-FU against human 5-FU-resistant cells(H630R1)and mouse colon cancer cells(MC38).This synergy was the result of suppression of thymidylate synthase expression by HQGGT.HQGGT significantly enhanced the antitumor effect of 5-FU in mice bearing MC38 xenografts.Ongoing studies have identified Huangqin as the herb responsible for TS inhibi⁃tion.CONCLUSION These findings provide support for the potential role of HQGGT as a novel modulator of fluoropyrim⁃idine chemotherapy for CRC treatment.
基金This research was funded by the National Key Research and Development Program of China,grant number 2016YFD0101418the National Natural Science Foundation of China,grant number 32172047.
文摘Background Herbicide tolerance in crops enables them to survive when lethal doses of herbicides are applied to surrounding weeds.Herbicide-tolerant crops can be developed through transgenic approaches or traditional mutagenesis approaches.At present,no transgenic herbicide tolerant cotton have been commercialized in China due to the genetically-modified organism(GMO)regulation law.We aim to develop a non-transgenic herbicide-tolerant cotton through ethyl methanesulfonate(EMS)mutagenesis,offering an alternative choice for weed management.Results Seeds of an elite cotton cultivar Lumianyan 37(Lu37)were treated with EMS,and a mutant Lu37-1 showed strong tolerance to imidazolinone(IMI)herbicides was identified.A novel nonsynonymous substitution mutation Ser642Asn at acetolactate synthase(ALS)(Gh_D10G1253)in Lu37-1 mutant line was found to be the potential cause to the IMI herbicides tolerance in cotton.The Ser642Asn mutation in ALS did not present among the genomes of natural Gossypium species.Cleaved amplified polymorphic sequence(CAPS)markers were developed to identify the ALS mutant allele.The Arabidopsis overexpressing the mutanted ALS also showed high tolerance to IMI herbicides.Conclusion The nonsynonymous substitution mutation Ser642Asn of the ALS gene Gh_D10G1253 is a novel identi-fied mutation in cotton.This substitution mutation has also been identified in the orthologous ALS genes in other crops.This mutant ALS allele can be used to develop IMI herbicide-tolerant crops via a non-transgenic or transgenic approach.
基金Supported by National Natural Science Fund (30671229)
文摘The content of sugar is influenced by sucrose synthase （SS） activity in roots. The effects of nitrogen level in the aminonitrate ratio on SS activity of leaves and roots, roots yield and sugar content in sugar beet were studied in the field experiment by nutrient solution culture. The results showed that SS activity in leaves was lower than that in roots. With nitrogen level increasing, SS decomposition activity enhanced, and synthesis activity reduced. SS activity was regulated by different nitrogen forms and the ratio of NO3 and NH4^＋. SS synthesis activity was enhanced as NH4^＋ increasing when NO3 ： NH4^＋≥ 1, and it decreased as increasing NH4^＋ when NO3 ： NH4^＋≤ 1, and it was the highest when NO3 ： NH4^＋=1. SS decomposition activity was enhanced as NO3- increasing. Sucrose content in root was lowed as nitrogen level increasing, but it was enhanced as NH4^＋ increasing in the same nitrogen level. Root and sugar yield were the highest in the medium nitrogen level and NO3 ： NH4^＋=1. The result in field experiment corresponded with that in the nutrient fluid culture. It provides a basis for using reasonably nitrogen fertilizer in sugar beet production.
文摘The experiment of glutamate synthase activity (GOGATA) in both leaf blades and roots under different nitrogen levels was carried out at Northeast Agricultural University in 1993. The result showed that GOGATA rose rapidly to reach its peak from seedling stage to foliage rapid growth stage, and then declined gradually. GOGATA was enhanced with increasing nitrogen levels and had significant positive correlation with nitrogen levels at the middle stage of growth GOGATA in leaf blades was the strongest compared with crowns, petioles and roots, thus, it could represent the highest enzyme activity of the whole plant. GOGATA had quadratic curvilinear correlation with root yield and sugar production. GOGATA in leaf blades had significant positive correlation with α-NH 2-N at the foliage rapid growth stage while GOGATA in roots existed this relation at the latter stage of growth. GOGATA in roots had significant negative correlation with sugar content at harvest.
文摘The mechanistic basis of cellulose biosynthesis in plants has gained ground during last decade or so.The isolation of plant cDNA clones encoding cotton homologs of the bacterial cellulose
