Panicle number per plant,grain number per panicle,and grain weight are three key factors influencing rice grain yield.Gn1a,a major QTL for grain number per panicle,encodes the cytokinin oxidase/dehydrogenase(CKX)OsCKX...Panicle number per plant,grain number per panicle,and grain weight are three key factors influencing rice grain yield.Gn1a,a major QTL for grain number per panicle,encodes the cytokinin oxidase/dehydrogenase(CKX)OsCKX2.While the use of elite Gn1a alleles has been well documented in indica rice cultivars,their potential in japonica rice remains largely unexplored.In this study,we characterized three suppressor mutants of the rice cytokinin receptor mutant pal1/ohk4 and found that all causal genes were novel alleles of Gn1a identified through the MutMap approach.These three suppressor mutants caused single amino acid substitutions in the FAD-binding domain(G556D and G156D)and the cytokinin-binding domain(Y357C),resulting in significantly reduced enzymatic activity of OsCKX2 and elevated cytokinin levels in the panicle.Haplotype analysis of Gn1a using a natural population from the 3K Rice Genomes Project showed that G556D,G156D,and Y357C were novel alleles of Gn1a.G556,G156,and Y357 were highly conserved,whereas four natural variants G54A,A105V,H116R,and N535K identified in different haplotypes of Gn1a showed extremely low conservation.By backcrossing the suppressor mutants with their original wild-type Huaidao 5,an elite japonica rice variety,we developed improved lines carrying only the gn1a mutation.The improved lines showed a significant increase in grain number per panicle,grain weight,panicle number per plant,plant height,and stem thickness,leading to a 25.7%-28.7%increase in grain yield per plot compared with Huaidao 5.This study provides valuable Gn1a alleles for synergistic improvement of the three key yield factors and offers germplasm resources for high-yielding breeding in japonica rice.展开更多
目的鉴定裂谷热病毒(Rift Valley fever virus,RVFV)囊膜蛋白Gn与受体结合的关键位点,以期为针对RVFV感染抑制剂的研发奠定基础。方法采用真核细胞表达系统表达RVFV囊膜蛋白Gn、RVFV阳性抗体(抗体140、144、268、R12、R17)、低密度脂蛋...目的鉴定裂谷热病毒(Rift Valley fever virus,RVFV)囊膜蛋白Gn与受体结合的关键位点,以期为针对RVFV感染抑制剂的研发奠定基础。方法采用真核细胞表达系统表达RVFV囊膜蛋白Gn、RVFV阳性抗体(抗体140、144、268、R12、R17)、低密度脂蛋白相关受体1(low density lipoprotein receptor-related protein 1,LRP1)受体结构域(ClusterⅡ-Fc和ClusterⅣ-Fc)和6种Gn突变体(T173A、Q174A、D176A、K180A、S291A、K294A)。ELISA法或竞争性ELISA法检测LRP1受体结构域与RVFV Gn的结合活性、RVFV阳性抗体对LRP1受体结构域与RVFV Gn结合能力的影响及Gn点突变对其与RVFV阳性抗体和LRP1受体结构域结合能力的影响。通过假病毒中和试验检测LRP1结构域对RVFV感染的抑制作用。结果LRP1受体结构域ClusterⅡ-Fc和ClusterⅣ-Fc可与RVFV Gn蛋白发生特异性结合。抗体268、R12和R17与Gn蛋白的结合能力呈剂量依赖性,抗体140和144均未检测到显著结合活性;抗体268、R12和R17对ClusterⅡ-Fc与Gn蛋白的结合能力存在一定的竞争抑制作用,其中抗体268的竞争效果最显著;仅有抗体268对ClusterⅣ-Fc展现出竞争效果。Gn突变体与RVFV阳性抗体的结合活性均低于Gn。除Q174A外,其他Gn突变体与ClusterⅡ-Fc和ClusterⅣ-Fc的结合活性均低于Gn,其中T173A、K180A、S291A和K294A与ClusterⅡ-Fc的结合能力显著低于Gn(F=15.83,P<0.05),K180A、S291A和K294A与ClusterⅣ-Fc的结合能力显著低于Gn(F=8.75,P<0.05)。结论K180、S291和K294是RVFV Gn蛋白介导与宿主受体LRP1相互作用的关键氨基酸位点,揭示了Gn与LRP1结合的部分分子基础,为开发靶向病毒吸附的抑制剂奠定了基础。展开更多
Chitosan-montmorillonite(CS-MMT) hybrid was prepared and characterized by XRD,FTIR and TG.The results showed that chitosan was intercalated into the layer structure of Na+-montmorillonite.The ability of CS-MMT hybrid ...Chitosan-montmorillonite(CS-MMT) hybrid was prepared and characterized by XRD,FTIR and TG.The results showed that chitosan was intercalated into the layer structure of Na+-montmorillonite.The ability of CS-MMT hybrid as an adsorbent for the removal of reactive orange X-GN from aqueous solution has been studied.The effects of various parameters such as initial concentration and temperature were also studied.The Langmuir and Freundlich adsorption isotherms have been used to fit the experimental data,and the former giving the higher correlation.Thermodynamic parameters of the adsorption process,ΔG°,ΔH° and ΔS° were determined to be-24.90 kJ·mol-1(at 20℃),10.58 kJ·mol-1 and 121.0 J·mol-1·K-1,respectively.The results indicated that the adsorption of reactive orange X-GN on CS-MMT hybrid was spontaneous.展开更多
基金supported by the Biological Breeding-National Science and Technology Major Project,China(Grant No.2023ZD0406801)the National Natural Science Foundation of China(Grant No.32300278)+2 种基金the Key R&D Plan of Shandong Province,China(Grant No.2024LZGC009)the Innovation Program of Chinese Academy of Agricultural Sciences(Grant No.CAAS-CSCB-202402)the Science and Technology Innovation Project of Shandong Academy of Agricultural Sciences,China(Grant No.CXGC2025B09).
文摘Panicle number per plant,grain number per panicle,and grain weight are three key factors influencing rice grain yield.Gn1a,a major QTL for grain number per panicle,encodes the cytokinin oxidase/dehydrogenase(CKX)OsCKX2.While the use of elite Gn1a alleles has been well documented in indica rice cultivars,their potential in japonica rice remains largely unexplored.In this study,we characterized three suppressor mutants of the rice cytokinin receptor mutant pal1/ohk4 and found that all causal genes were novel alleles of Gn1a identified through the MutMap approach.These three suppressor mutants caused single amino acid substitutions in the FAD-binding domain(G556D and G156D)and the cytokinin-binding domain(Y357C),resulting in significantly reduced enzymatic activity of OsCKX2 and elevated cytokinin levels in the panicle.Haplotype analysis of Gn1a using a natural population from the 3K Rice Genomes Project showed that G556D,G156D,and Y357C were novel alleles of Gn1a.G556,G156,and Y357 were highly conserved,whereas four natural variants G54A,A105V,H116R,and N535K identified in different haplotypes of Gn1a showed extremely low conservation.By backcrossing the suppressor mutants with their original wild-type Huaidao 5,an elite japonica rice variety,we developed improved lines carrying only the gn1a mutation.The improved lines showed a significant increase in grain number per panicle,grain weight,panicle number per plant,plant height,and stem thickness,leading to a 25.7%-28.7%increase in grain yield per plot compared with Huaidao 5.This study provides valuable Gn1a alleles for synergistic improvement of the three key yield factors and offers germplasm resources for high-yielding breeding in japonica rice.
文摘目的鉴定裂谷热病毒(Rift Valley fever virus,RVFV)囊膜蛋白Gn与受体结合的关键位点,以期为针对RVFV感染抑制剂的研发奠定基础。方法采用真核细胞表达系统表达RVFV囊膜蛋白Gn、RVFV阳性抗体(抗体140、144、268、R12、R17)、低密度脂蛋白相关受体1(low density lipoprotein receptor-related protein 1,LRP1)受体结构域(ClusterⅡ-Fc和ClusterⅣ-Fc)和6种Gn突变体(T173A、Q174A、D176A、K180A、S291A、K294A)。ELISA法或竞争性ELISA法检测LRP1受体结构域与RVFV Gn的结合活性、RVFV阳性抗体对LRP1受体结构域与RVFV Gn结合能力的影响及Gn点突变对其与RVFV阳性抗体和LRP1受体结构域结合能力的影响。通过假病毒中和试验检测LRP1结构域对RVFV感染的抑制作用。结果LRP1受体结构域ClusterⅡ-Fc和ClusterⅣ-Fc可与RVFV Gn蛋白发生特异性结合。抗体268、R12和R17与Gn蛋白的结合能力呈剂量依赖性,抗体140和144均未检测到显著结合活性;抗体268、R12和R17对ClusterⅡ-Fc与Gn蛋白的结合能力存在一定的竞争抑制作用,其中抗体268的竞争效果最显著;仅有抗体268对ClusterⅣ-Fc展现出竞争效果。Gn突变体与RVFV阳性抗体的结合活性均低于Gn。除Q174A外,其他Gn突变体与ClusterⅡ-Fc和ClusterⅣ-Fc的结合活性均低于Gn,其中T173A、K180A、S291A和K294A与ClusterⅡ-Fc的结合能力显著低于Gn(F=15.83,P<0.05),K180A、S291A和K294A与ClusterⅣ-Fc的结合能力显著低于Gn(F=8.75,P<0.05)。结论K180、S291和K294是RVFV Gn蛋白介导与宿主受体LRP1相互作用的关键氨基酸位点,揭示了Gn与LRP1结合的部分分子基础,为开发靶向病毒吸附的抑制剂奠定了基础。
文摘Chitosan-montmorillonite(CS-MMT) hybrid was prepared and characterized by XRD,FTIR and TG.The results showed that chitosan was intercalated into the layer structure of Na+-montmorillonite.The ability of CS-MMT hybrid as an adsorbent for the removal of reactive orange X-GN from aqueous solution has been studied.The effects of various parameters such as initial concentration and temperature were also studied.The Langmuir and Freundlich adsorption isotherms have been used to fit the experimental data,and the former giving the higher correlation.Thermodynamic parameters of the adsorption process,ΔG°,ΔH° and ΔS° were determined to be-24.90 kJ·mol-1(at 20℃),10.58 kJ·mol-1 and 121.0 J·mol-1·K-1,respectively.The results indicated that the adsorption of reactive orange X-GN on CS-MMT hybrid was spontaneous.
基金国家自然科学基金(the National Natural Science Foundation of China under Grant No.10771092)国家重点基础研究发展规划(973)(the National Grand Fundamental Research973Program of China under Grant No.2004CB318000)
