Elucidating crops'physiological and molecular mechanisms to adapt to low nitrogen environment and promoting nitrogen transfer from senescent leaves to new leaves is crucial in improving Brassica's nitrogen use...Elucidating crops'physiological and molecular mechanisms to adapt to low nitrogen environment and promoting nitrogen transfer from senescent leaves to new leaves is crucial in improving Brassica's nitrogen use efficiency(NUE).Glutamine synthetase gene(GS)plays a vital role in helping plants reassimilate ammonium released from protein degradation in leaves,and it was the focus of our research on this topic.In this study,we identified high(H141)and low(L65)NUE genotypes of Brassica juncea with different responses to low-nitrogen stress.We found that H141 has a lower nitrate content but higher ammonium and free amino acid contents as well as higher nitrate reductase and GS activities in the shoots.These physiological indicators are responsible for the high NUE of H141.Wholegenome resequencing data revealed that 5,880 genes associated with NUE are polymorphic between H141 and L65.These genes participate in various amino acid,carbohydrate,and energy metabolic pathways.Haplotype analysis revealed two haplotypes for BjuB05.GS1.4,Hap1 and Hap2,which have multiple single nucleotide polymorphisms or insertions/deletions in the regulatory regions of the 5′and 3′untranslated regions and introns.Furthermore,the shoot NUE of Hap1 is significantly lower than that of Hap2.These two haplotypes of BjuB05.GS1.4 lead to differences in the shoot NUEs of different genetic populations of mustard and are associated with the local soil nitrogen content,suggesting that they might help mustard to adapt to different geographic localities.In conclusion,the results of our study shed light on the physiological and molecular mechanisms underlying different mustard NUE genotypes and demonstrate the enormous potential of NUE breeding in B.juncea.展开更多
BACKGROUND Hepatic stellate cell(HSC)activation is key to liver fibrosis.Targeting DNA methylation shows promise.Zebularine,a methylation inhibitor,may suppress HSC activation via the calcineurin(CaN)/NFAT3 pathway.Ma...BACKGROUND Hepatic stellate cell(HSC)activation is key to liver fibrosis.Targeting DNA methylation shows promise.Zebularine,a methylation inhibitor,may suppress HSC activation via the calcineurin(CaN)/NFAT3 pathway.Magnetic resonance imaging(MRI)is a noninvasive tool for evaluating liver fibrosis evaluation tool,but multiparametric MRI for zebularine’s effects in liver fibrosis mouse models has not been studied.AIM To clarify the anti-fibrosis mechanism and MRI-evaluated efficacy of zebularine.METHODS In vitro,transforming growth factor(TGF)-β1-stimulated human HSCs(LX-2)were treated with zebularine.α-smooth muscle actin,fibrotic and anti-fibrotic gene levels,and regulator of calcineurin1(RCAN1)regulation were measured.In vivo,carbon tetrachloride(CCl_(4))-induced liver fibrosis in mice was treated with zebularine,and fibrosis was evaluated using various biochemical,histopathological,and MRI methods.RESULTS Zebularine upregulated RCAN1.4 protein(P<0.01)and inhibited the CaN/NFAT3 pathway(P<0.05).In HSCs,TGF-β1 reduced anti-fibrotic gene massage RNA(mRNA)and increased fibrotic mRNA(P<0.05),whereas zebularine had the opposite effects(P<0.01,P<0.05).CCl4-treated mice exhibited increases in various fibrosis-related indices,all of which were reversed by zebularine treatment(P<0.05).CONCLUSION Zebularine may reduce LX-2 activation and extracellular matrix deposition via RCAN1.4 and CaN/NFAT3 path-ways.Multiparametric MRI can assess its efficacy,suggesting zebularine’s potential as a liver fibrosis treatment.展开更多
基金supported by the National Natural Science Foundation of China(U21A20236,32072664)the Natural Science Foundation of Hunan Province,China(2022RC3053,2021JC0001,2021RC3086,2022NK2009)+1 种基金the China Agriculture Research System(CARS-01-30)the Innovation Foundation for Graduate of Hunan Agricultural University,China(2023XC116)。
文摘Elucidating crops'physiological and molecular mechanisms to adapt to low nitrogen environment and promoting nitrogen transfer from senescent leaves to new leaves is crucial in improving Brassica's nitrogen use efficiency(NUE).Glutamine synthetase gene(GS)plays a vital role in helping plants reassimilate ammonium released from protein degradation in leaves,and it was the focus of our research on this topic.In this study,we identified high(H141)and low(L65)NUE genotypes of Brassica juncea with different responses to low-nitrogen stress.We found that H141 has a lower nitrate content but higher ammonium and free amino acid contents as well as higher nitrate reductase and GS activities in the shoots.These physiological indicators are responsible for the high NUE of H141.Wholegenome resequencing data revealed that 5,880 genes associated with NUE are polymorphic between H141 and L65.These genes participate in various amino acid,carbohydrate,and energy metabolic pathways.Haplotype analysis revealed two haplotypes for BjuB05.GS1.4,Hap1 and Hap2,which have multiple single nucleotide polymorphisms or insertions/deletions in the regulatory regions of the 5′and 3′untranslated regions and introns.Furthermore,the shoot NUE of Hap1 is significantly lower than that of Hap2.These two haplotypes of BjuB05.GS1.4 lead to differences in the shoot NUEs of different genetic populations of mustard and are associated with the local soil nitrogen content,suggesting that they might help mustard to adapt to different geographic localities.In conclusion,the results of our study shed light on the physiological and molecular mechanisms underlying different mustard NUE genotypes and demonstrate the enormous potential of NUE breeding in B.juncea.
基金Supported by the Health Research Foundation of Hunan Provincial Health Commission,No.W20243192Natural Science Foundation of Changsha,No.kq2403086+1 种基金National Natural Science Foundation of China,No.81571784Hunan Provincial Health Commission Hunan Provincial High-level Health Talent Major Scientific Research Project,No.R2023022.
文摘BACKGROUND Hepatic stellate cell(HSC)activation is key to liver fibrosis.Targeting DNA methylation shows promise.Zebularine,a methylation inhibitor,may suppress HSC activation via the calcineurin(CaN)/NFAT3 pathway.Magnetic resonance imaging(MRI)is a noninvasive tool for evaluating liver fibrosis evaluation tool,but multiparametric MRI for zebularine’s effects in liver fibrosis mouse models has not been studied.AIM To clarify the anti-fibrosis mechanism and MRI-evaluated efficacy of zebularine.METHODS In vitro,transforming growth factor(TGF)-β1-stimulated human HSCs(LX-2)were treated with zebularine.α-smooth muscle actin,fibrotic and anti-fibrotic gene levels,and regulator of calcineurin1(RCAN1)regulation were measured.In vivo,carbon tetrachloride(CCl_(4))-induced liver fibrosis in mice was treated with zebularine,and fibrosis was evaluated using various biochemical,histopathological,and MRI methods.RESULTS Zebularine upregulated RCAN1.4 protein(P<0.01)and inhibited the CaN/NFAT3 pathway(P<0.05).In HSCs,TGF-β1 reduced anti-fibrotic gene massage RNA(mRNA)and increased fibrotic mRNA(P<0.05),whereas zebularine had the opposite effects(P<0.01,P<0.05).CCl4-treated mice exhibited increases in various fibrosis-related indices,all of which were reversed by zebularine treatment(P<0.05).CONCLUSION Zebularine may reduce LX-2 activation and extracellular matrix deposition via RCAN1.4 and CaN/NFAT3 path-ways.Multiparametric MRI can assess its efficacy,suggesting zebularine’s potential as a liver fibrosis treatment.
