【目的】研究水稻防御反应和叶片早衰相关基因的分子机理。【方法】从粳稻武运粳7号诱变库中筛选出一个类病变早衰突变体lmes7(lesion mimic and early senescence 7)。调查统计了该突变体的主要农艺性状,对其叶片中的光合色素含量进行...【目的】研究水稻防御反应和叶片早衰相关基因的分子机理。【方法】从粳稻武运粳7号诱变库中筛选出一个类病变早衰突变体lmes7(lesion mimic and early senescence 7)。调查统计了该突变体的主要农艺性状,对其叶片中的光合色素含量进行测定,利用图位克隆技术对目的基因进行精细定位和测序鉴定,并对其编码蛋白进行分析与序列比对。【结果】突变体叶片中的光合色素含量比WT极显著降低,且细胞中存在活性氧(reactive oxygen species,ROS)的过量积累;突变体植株的生长发育受到严重影响,有效分蘖数、株高、剑叶长、剑叶宽、穗长、每穗粒数、结实率及单株产量等均显著下降,但粒厚显著增加;遗传分析表明,lmes7的突变表型受单隐性核基因控制;利用图位克隆技术将目的基因精细定位在水稻12号染色体上RM28486和RM28489之间的90 kb区域内;PCR测序分析表明,lmes7突变体中一个编码ATP-柠檬酸裂解酶的目标基因Os ACL-A2发生了7个碱基缺失,导致该基因发生移码突变,蛋白翻译提前终止;对水稻OsACL-A2蛋白的进化分析与序列比对可知,lmes7突变位点发生在琥珀酰辅酶A合成酶结构域,lmes7是OsACL-A2新的等位变异。展开更多
植物类病变与早衰的发生受激素、代谢、环境信号等多重因素影响,其分子机制尚未完全清楚。从水稻辐射诱变库中筛选到一个类病变早衰突变体lmes6(lesion mimic and early senescence 6),与野生型相比,lmes6突变体叶片从分蘖期开始出现类...植物类病变与早衰的发生受激素、代谢、环境信号等多重因素影响,其分子机制尚未完全清楚。从水稻辐射诱变库中筛选到一个类病变早衰突变体lmes6(lesion mimic and early senescence 6),与野生型相比,lmes6突变体叶片从分蘖期开始出现类病变、叶色发黄、叶绿素含量显著降低,其穗长、每穗粒数、粒长及单株产量显著降低;组织染色显示该突变体的叶片出现细胞程序性死亡及活性氧过量积累;且该突变体增强了对水稻白叶枯病与细菌性条斑病的抗性。遗传分析表明lmes6的突变表型受单隐性核基因控制。利用图位克隆技术将目的基因精细定位在水稻7号染色体53 kb区间内,经候选基因预测与PCR测序分析,发现在lmes6突变体中一个编码Fd-GOGAT1(依赖于铁氧还蛋白的谷氨酸合酶)的基因LOC_Os07g46460发生了一个碱基替换,导致苯丙氨酸(F)变为亮氨酸(L),是该基因的一个新的复等位基因,与其他已报道的lc7、abc1、spl32等位突变相比,lmes6对水稻的生长发育、产量等方面抑制较小。对Fd-GOGAT1进行系统发育树分析及同源蛋白序列比对,结果表明Fd-GOGAT1蛋白在单子叶植物中高度保守。展开更多
Retained austenite plays a significant role in third-generation advanced high-strength steels (AHSS 3. Gen.), renowned for their excellent combination of strength and ductility. Silicon (Si) is a key element in stabil...Retained austenite plays a significant role in third-generation advanced high-strength steels (AHSS 3. Gen.), renowned for their excellent combination of strength and ductility. Silicon (Si) is a key element in stabilizing retained austenite. However, it introduces challenges in galvannealing and welding processes in Zn-coated steels, such as inhibited Fe-Zn alloying and increased susceptibility to liquid metal embrittlement (LME). This study investigated the mechanism of Si enrichment at the Zn/steel interface and its role in suppressing Fe-Zn interdiffusion during annealing. Using advanced techniques such as high-resolution transmission electron microscopy and atomic probe tomography, and Thermo-Calc DICTRA simulations, we analyzed the diffusion behavior and microstructural evolution in Zn-coated steels with varying Si contents. Si, driven by its low solubility in liquid Zn and Fe-Zn intermetallic phases, accumulates at the interface, forming a Si-enriched region that significantly suppresses Zn diffusion while permitting limited Fe diffusion. Numerical simulations revealed that the Si-enriched layer forms via the drag effect of the Fe-Zn reaction line, progressively concentrating Si at the interface as Zn diffuses. As annealing progresses, the morphology of the Si-enriched region evolves from layered, cloud-like structures to droplets and elongated dendritic forms, driven by Zn penetration and Fe consumption. These findings provide novel insights into the role of Si enrichment in mitigating LME and optimizing the Zn-coated AHSS 3. Gen., paving the way for advancements in automotive material design.展开更多
Using VAR-DCC-GARCH model,the literature on commodity price was extended by exploring the co-movement between Chinese nonferrous metal prices and global nonferrous metal prices represented by the nonferrous metal pric...Using VAR-DCC-GARCH model,the literature on commodity price was extended by exploring the co-movement between Chinese nonferrous metal prices and global nonferrous metal prices represented by the nonferrous metal prices from London Metal Exchange(LME).The results show that LME nonferrous metals prices still have a greater impact on Chinese nonferrous metals prices.However,the impact of Chinese nonferrous metals prices on LME nonferrous metals prices is still weak except for lead price.The co-movement of nonferrous metal prices between LME and China presents hysteretic nature,and it lasts for 7-8trading days.Furthermore,the co-movement between LME nonferrous metals prices and Chinese nonferrous metals prices has the characteristics of time-varying,and the correlation of lead prices between LME and China is the more stable than all other nonferrous metals prices.展开更多
文摘【目的】研究水稻防御反应和叶片早衰相关基因的分子机理。【方法】从粳稻武运粳7号诱变库中筛选出一个类病变早衰突变体lmes7(lesion mimic and early senescence 7)。调查统计了该突变体的主要农艺性状,对其叶片中的光合色素含量进行测定,利用图位克隆技术对目的基因进行精细定位和测序鉴定,并对其编码蛋白进行分析与序列比对。【结果】突变体叶片中的光合色素含量比WT极显著降低,且细胞中存在活性氧(reactive oxygen species,ROS)的过量积累;突变体植株的生长发育受到严重影响,有效分蘖数、株高、剑叶长、剑叶宽、穗长、每穗粒数、结实率及单株产量等均显著下降,但粒厚显著增加;遗传分析表明,lmes7的突变表型受单隐性核基因控制;利用图位克隆技术将目的基因精细定位在水稻12号染色体上RM28486和RM28489之间的90 kb区域内;PCR测序分析表明,lmes7突变体中一个编码ATP-柠檬酸裂解酶的目标基因Os ACL-A2发生了7个碱基缺失,导致该基因发生移码突变,蛋白翻译提前终止;对水稻OsACL-A2蛋白的进化分析与序列比对可知,lmes7突变位点发生在琥珀酰辅酶A合成酶结构域,lmes7是OsACL-A2新的等位变异。
文摘植物类病变与早衰的发生受激素、代谢、环境信号等多重因素影响,其分子机制尚未完全清楚。从水稻辐射诱变库中筛选到一个类病变早衰突变体lmes6(lesion mimic and early senescence 6),与野生型相比,lmes6突变体叶片从分蘖期开始出现类病变、叶色发黄、叶绿素含量显著降低,其穗长、每穗粒数、粒长及单株产量显著降低;组织染色显示该突变体的叶片出现细胞程序性死亡及活性氧过量积累;且该突变体增强了对水稻白叶枯病与细菌性条斑病的抗性。遗传分析表明lmes6的突变表型受单隐性核基因控制。利用图位克隆技术将目的基因精细定位在水稻7号染色体53 kb区间内,经候选基因预测与PCR测序分析,发现在lmes6突变体中一个编码Fd-GOGAT1(依赖于铁氧还蛋白的谷氨酸合酶)的基因LOC_Os07g46460发生了一个碱基替换,导致苯丙氨酸(F)变为亮氨酸(L),是该基因的一个新的复等位基因,与其他已报道的lc7、abc1、spl32等位突变相比,lmes6对水稻的生长发育、产量等方面抑制较小。对Fd-GOGAT1进行系统发育树分析及同源蛋白序列比对,结果表明Fd-GOGAT1蛋白在单子叶植物中高度保守。
基金supported by the Fundamental Research Program of the Korea Institute of Materials Science(No.PNK9820).
文摘Retained austenite plays a significant role in third-generation advanced high-strength steels (AHSS 3. Gen.), renowned for their excellent combination of strength and ductility. Silicon (Si) is a key element in stabilizing retained austenite. However, it introduces challenges in galvannealing and welding processes in Zn-coated steels, such as inhibited Fe-Zn alloying and increased susceptibility to liquid metal embrittlement (LME). This study investigated the mechanism of Si enrichment at the Zn/steel interface and its role in suppressing Fe-Zn interdiffusion during annealing. Using advanced techniques such as high-resolution transmission electron microscopy and atomic probe tomography, and Thermo-Calc DICTRA simulations, we analyzed the diffusion behavior and microstructural evolution in Zn-coated steels with varying Si contents. Si, driven by its low solubility in liquid Zn and Fe-Zn intermetallic phases, accumulates at the interface, forming a Si-enriched region that significantly suppresses Zn diffusion while permitting limited Fe diffusion. Numerical simulations revealed that the Si-enriched layer forms via the drag effect of the Fe-Zn reaction line, progressively concentrating Si at the interface as Zn diffuses. As annealing progresses, the morphology of the Si-enriched region evolves from layered, cloud-like structures to droplets and elongated dendritic forms, driven by Zn penetration and Fe consumption. These findings provide novel insights into the role of Si enrichment in mitigating LME and optimizing the Zn-coated AHSS 3. Gen., paving the way for advancements in automotive material design.
基金Project(71073177)supported by the National Natural Science Foundation of ChinaProject(12JJ4077)supported by the Natural Science Foundation of Hunan Province of ChinaProject(2012zzts002)supported by the Fundamental Research Funds of Central South University,China
文摘Using VAR-DCC-GARCH model,the literature on commodity price was extended by exploring the co-movement between Chinese nonferrous metal prices and global nonferrous metal prices represented by the nonferrous metal prices from London Metal Exchange(LME).The results show that LME nonferrous metals prices still have a greater impact on Chinese nonferrous metals prices.However,the impact of Chinese nonferrous metals prices on LME nonferrous metals prices is still weak except for lead price.The co-movement of nonferrous metal prices between LME and China presents hysteretic nature,and it lasts for 7-8trading days.Furthermore,the co-movement between LME nonferrous metals prices and Chinese nonferrous metals prices has the characteristics of time-varying,and the correlation of lead prices between LME and China is the more stable than all other nonferrous metals prices.
