Rose has emerged as a model ornamental plant for studies of flower development, senescence, and morphology, as well as the metabolism of floral fragrances and colors.Virus-induced gene silencing(VIGS) has long been us...Rose has emerged as a model ornamental plant for studies of flower development, senescence, and morphology, as well as the metabolism of floral fragrances and colors.Virus-induced gene silencing(VIGS) has long been used in functional genomics studies of rose by vacuum infiltration of cuttings or seedlings with an Agrobacterium suspension carrying TRV-derived vectors. However, VIGS in rose flowers remains a challenge because of its low efficiency and long time to establish silencing. Here we present a novel and rapid VIGS method that can be used to analyze gene function in rose,called ‘graft-accelerated VIGS’, where axil ary sprouts are cut from the rose plant and vacuum infiltrated with Agrobacterium. The inoculated scions are then grafted back onto the plants to flower and silencing phenotypes can be observed within 5 weeks, post-infiltration. Using this new method, we successfully silenced expression of the RhDFR, RhA G, and RhNUDXin rose flowers, and affected their color, petal number, as well as fragrance, respectively. This grafting method will facilitate high-throughput functional analysis of genes in rose flowers. Importantly, it may also be applied to other woody species that are not currently amenable to VIGS by conventional leaf or plantlet/seedling infiltration methods.展开更多
Gene function analysis is challenging for Lilium due to the lack of an efficient method for stable genetic transformation. Virus-induced gene silencing(VIGS) is an attractive tool for determining gene function in plan...Gene function analysis is challenging for Lilium due to the lack of an efficient method for stable genetic transformation. Virus-induced gene silencing(VIGS) is an attractive tool for determining gene function in plants. This study reported that Tobacco rattle virus(TRV)-based VIGS of a PHYTOENE DESATURASE(PDS) ortholog(LhPDS) can be achieved in Lilium × formolongi seedlings, with a survival rate of 92%, using the inoculation method of rubbing plus injection. Compared with untreated and mock-treated seedlings, the photobleached leaf phenotype of silenced plants significantly correlates with down-regulation of endogenous LhPDS(P ≤ 0.05). In addition, the silencing phenomenon can be observed in the growing points of plants, indicating that systemic viral infection was achieved using the protocol. The results indicate that TRV-based VIGS can be used to characterize gene function in Lilium × formolongi. This work lays the foundation for gene function analysis and molecular breeding in Lilium spp.展开更多
500kV输电线路安装串联电抗器后,断路器开断短路电流时产生的暂态恢复电压(TRV)较高,可能会导致断路器重燃而无法正常开断。文中以江苏500kV电网为对象,建立了断路器TRV仿真计算模型,研究石牌-常熟南线安装串抗后,出现单相接地故障时断...500kV输电线路安装串联电抗器后,断路器开断短路电流时产生的暂态恢复电压(TRV)较高,可能会导致断路器重燃而无法正常开断。文中以江苏500kV电网为对象,建立了断路器TRV仿真计算模型,研究石牌-常熟南线安装串抗后,出现单相接地故障时断路器的TRV,分析断路器断口两端的TRV是否满足超出了其绝缘水平,提出了相应的抑制措施,并通过仿真计算验证了措施的有效性。计算结果表明,石牌侧安装串抗后,其断路器TRV不符合标准要求,可在串抗两端并联35 n F以上的电容器有效抑制TRV的上升率。文中成果可为串抗及TRV防护措施在工程中的实际应用提供理论参考。展开更多
为解决500 kV电网发展过程中短路电流过大的问题,提出了一种基于高耦合分裂电抗器的限流装置。该装置可有效限制短路电流并提高断路器的开断容量,但存在并联断路器同时开断不同时灭弧时瞬态恢复电压超标的问题。文中首先分析限流装置的...为解决500 kV电网发展过程中短路电流过大的问题,提出了一种基于高耦合分裂电抗器的限流装置。该装置可有效限制短路电流并提高断路器的开断容量,但存在并联断路器同时开断不同时灭弧时瞬态恢复电压超标的问题。文中首先分析限流装置的结构和开断过程,并利用EMTP仿真软件计算不同条件下后灭弧断路器的瞬态恢复电压,得出限流装置参数对瞬态恢复电压的影响。然后在500 k V工程实例中搭建限流装置的仿真模型,分别在不同故障类型下验证限流装置的可行性。仿真结果表明,选择合适的电抗值和并联电容值可有效降低瞬态恢复电压幅值和上升率,且能够达到预期的短路电流限制效果。展开更多
基金supported by the National Natural Science Foundation of China (31501791, 31660579, and 31360492)Leading talents in science and technology (2016HA005)funded in part by Beijing Natural Science Foundation (6162017)
文摘Rose has emerged as a model ornamental plant for studies of flower development, senescence, and morphology, as well as the metabolism of floral fragrances and colors.Virus-induced gene silencing(VIGS) has long been used in functional genomics studies of rose by vacuum infiltration of cuttings or seedlings with an Agrobacterium suspension carrying TRV-derived vectors. However, VIGS in rose flowers remains a challenge because of its low efficiency and long time to establish silencing. Here we present a novel and rapid VIGS method that can be used to analyze gene function in rose,called ‘graft-accelerated VIGS’, where axil ary sprouts are cut from the rose plant and vacuum infiltrated with Agrobacterium. The inoculated scions are then grafted back onto the plants to flower and silencing phenotypes can be observed within 5 weeks, post-infiltration. Using this new method, we successfully silenced expression of the RhDFR, RhA G, and RhNUDXin rose flowers, and affected their color, petal number, as well as fragrance, respectively. This grafting method will facilitate high-throughput functional analysis of genes in rose flowers. Importantly, it may also be applied to other woody species that are not currently amenable to VIGS by conventional leaf or plantlet/seedling infiltration methods.
基金supported by the National Natural Science Foundation of China (31272205, 31672196)the Fundamental Research Funds for Central Non-profit Scientific Institutionsthe Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences
文摘Gene function analysis is challenging for Lilium due to the lack of an efficient method for stable genetic transformation. Virus-induced gene silencing(VIGS) is an attractive tool for determining gene function in plants. This study reported that Tobacco rattle virus(TRV)-based VIGS of a PHYTOENE DESATURASE(PDS) ortholog(LhPDS) can be achieved in Lilium × formolongi seedlings, with a survival rate of 92%, using the inoculation method of rubbing plus injection. Compared with untreated and mock-treated seedlings, the photobleached leaf phenotype of silenced plants significantly correlates with down-regulation of endogenous LhPDS(P ≤ 0.05). In addition, the silencing phenomenon can be observed in the growing points of plants, indicating that systemic viral infection was achieved using the protocol. The results indicate that TRV-based VIGS can be used to characterize gene function in Lilium × formolongi. This work lays the foundation for gene function analysis and molecular breeding in Lilium spp.
文摘500kV输电线路安装串联电抗器后,断路器开断短路电流时产生的暂态恢复电压(TRV)较高,可能会导致断路器重燃而无法正常开断。文中以江苏500kV电网为对象,建立了断路器TRV仿真计算模型,研究石牌-常熟南线安装串抗后,出现单相接地故障时断路器的TRV,分析断路器断口两端的TRV是否满足超出了其绝缘水平,提出了相应的抑制措施,并通过仿真计算验证了措施的有效性。计算结果表明,石牌侧安装串抗后,其断路器TRV不符合标准要求,可在串抗两端并联35 n F以上的电容器有效抑制TRV的上升率。文中成果可为串抗及TRV防护措施在工程中的实际应用提供理论参考。
文摘为解决500 kV电网发展过程中短路电流过大的问题,提出了一种基于高耦合分裂电抗器的限流装置。该装置可有效限制短路电流并提高断路器的开断容量,但存在并联断路器同时开断不同时灭弧时瞬态恢复电压超标的问题。文中首先分析限流装置的结构和开断过程,并利用EMTP仿真软件计算不同条件下后灭弧断路器的瞬态恢复电压,得出限流装置参数对瞬态恢复电压的影响。然后在500 k V工程实例中搭建限流装置的仿真模型,分别在不同故障类型下验证限流装置的可行性。仿真结果表明,选择合适的电抗值和并联电容值可有效降低瞬态恢复电压幅值和上升率,且能够达到预期的短路电流限制效果。
