Angiosperm seeds usually consist of two major parts： the embryo and the endosperm. However, the molec- ular mechanism（s） underlying embryo and endosperm development remains largely unknown, particularly in rice, th...Angiosperm seeds usually consist of two major parts： the embryo and the endosperm. However, the molec- ular mechanism（s） underlying embryo and endosperm development remains largely unknown, particularly in rice, the model cereal. Here, we report the identification and functional characterization of the rice GIANT EMBRYO （GE） gene. Mutation of GE resulted in a large embryo in the seed, which was caused by excessive expansion of scuteUum cells. Post-embryonic growth of ge seedling was severely inhibited due to defective shoot apical meristem （SAM） mainte- nance. Map-based cloning revealed that GE encodes a CYP78A subfamily P450 monooxygenase that is localized to the endoplasmic reticulum. GE is expressed predominantly in the scutellar epithelium, the interface region between embryo and endosperm. Overexpression of GE promoted cell proliferation and enhanced rice plant growth and grain yield, but reduced embryo size, suggesting that GE is critical for coordinating rice embryo and endosperm development. Moreover, transgenic Arabidopsis plants overexpressing AtCYP78AlO, a GE homolog, also produced bigger seeds, implying a con- served role for the CYP78A subfamily of P450s in regulating seed development. Taken together, our results indicate that GE plays critical roles in regulating embryo development and SAM maintenance.展开更多
缩节安(1,1-dimethyl piperidinium chloride, DPC)是棉花生产中广泛应用的植物生长延缓剂。增效DPC (DPC+,25%水剂)助剂中的成分能对植物幼嫩组织表面形成轻微伤害,实践证明其可实现棉花化学封顶、起到替代人工打顶的作用。为探究DPC+...缩节安(1,1-dimethyl piperidinium chloride, DPC)是棉花生产中广泛应用的植物生长延缓剂。增效DPC (DPC+,25%水剂)助剂中的成分能对植物幼嫩组织表面形成轻微伤害,实践证明其可实现棉花化学封顶、起到替代人工打顶的作用。为探究DPC+作用机制,本试验于2015年在田间条件下研究了棉花盛花期后(7月24日)应用DPC+(1125 mL hm–2)对棉花主茎生长和顶芽解剖结构、氧化还原状态及相关基因表达的影响。结果表明,与对照(同期喷施清水)相比, DPC+处理后棉花株高降低,白花以上节位(nodes above the last white flower, NAWF)更早降到5;处理后3 d即可观察到主茎生长点较对照扁平,生长点的纵横比显著低于对照;处理后6 h棉花顶芽的O2-、H2O2和MDA含量高于对照,而开花相关基因GhSPL3和GhV1及顶端分生组织相关基因GhREV3的表达量则低于对照。化学封顶剂DPC+可引起棉株顶芽的短期氧化应激反应,降低与主茎生长点发育和花芽分化相关基因的表达水平,从而延缓棉株生长和花芽的产生,实现化学封顶。展开更多
A subtracted cDNA library of rice (Oryza sativa L.) inflorescence meristem (IM) was constructed using the suppression subtractive hybridization (SSH) method. The cDNAs of the rice shoot apical meristem (SAM) were used...A subtracted cDNA library of rice (Oryza sativa L.) inflorescence meristem (IM) was constructed using the suppression subtractive hybridization (SSH) method. The cDNAs of the rice shoot apical meristem (SAM) were used as 'driver' and inflorescence meristem (IM) as 'tester' in the experiment, respectively. Forty of 250 randomly chosen cDNA clones were identified by differential screening, which were IM-specific or IM-highly expressed. Most of the rice IM cDNAs cloned by SSH appear to represent rare transcripts, 40% of which were derived from truly differentially expressed genes. Of all the forty sequenced cDNA inserts, eleven contain the regions with 60%-90% identity to their homolog in GenBank, eighteen are expected to be new genes, only two correspond to published rice genes.展开更多
Flowering at the most appropriate times of the year requires careful monitoring of environmental conditions and correct integration of such information with an endogenous molecular network. Rice （Oryza sativa） is a ...Flowering at the most appropriate times of the year requires careful monitoring of environmental conditions and correct integration of such information with an endogenous molecular network. Rice （Oryza sativa） is a facultative short day plant, and flowers quickly under short day lengths, as opposed to Arabidopsis thaliana whose flowering is accelerated by longer days. Despite these physiological differences, several genes controlling flowering in response to day length （or photoperiod） are conserved between rice and Arabidopsis, and the molecular mechanisms involved are similar. Inductive day lengths trigger expression of florigenic proteins in leaves that can move to the shoot apical meristem to induce reproductivedevelopment. As compared to Arabidopsis, rice also possesses unique factors that regulate expression of florigenic genes. Here, we discuss recent advances in understanding the molecular mechanisms involved in day length perception, production of florigenic signals, and molecular responses of the shoot apical meristem to florigenic proteins.展开更多
LATERAL ORGAN BOUNDARIES DOMAIN(LBD)基因家族是在拟南芥中发现的高等植物所特有的一类基因,编码的蛋白中含有LATERAL ORGAN BOUNDARIES(LOB)结构域。LBD基因一般在侧生器官与茎尖分生组织的边界处、侧生器官的近轴面一侧的基部表达,...LATERAL ORGAN BOUNDARIES DOMAIN(LBD)基因家族是在拟南芥中发现的高等植物所特有的一类基因,编码的蛋白中含有LATERAL ORGAN BOUNDARIES(LOB)结构域。LBD基因一般在侧生器官与茎尖分生组织的边界处、侧生器官的近轴面一侧的基部表达,并呈现出在多种组织内特异性表达的特征,暗示该类基因可能在植物的多种发育过程中发挥功能。LBD蛋白结构中除含有上述LOB结构域以外,尚未发现其它已知功能的结构域的存在。目前,已经在拟南芥中发现43个LBD基因,而在玉米和水稻中各有35和43个LBD基因。根据LBD蛋白结构中是否含有亮氨酸拉链类似基序,将LBD基因分为两类:第一类(class I)LBD蛋白结构域中包含完整亮氨酸拉链基序;第二类(class II)LBD蛋白结构域中不含亮氨酸拉链基序。本文就LBD基因的结构以及它们对高等植物生长发育的影响、LBD基因和植物激素的关系、LBD基因与miRNA的关系进行了系统的总结。展开更多
基金Natural Science Foundation of China grants，by the CAS International Partnership Program for Creative Research Teams
文摘Angiosperm seeds usually consist of two major parts： the embryo and the endosperm. However, the molec- ular mechanism（s） underlying embryo and endosperm development remains largely unknown, particularly in rice, the model cereal. Here, we report the identification and functional characterization of the rice GIANT EMBRYO （GE） gene. Mutation of GE resulted in a large embryo in the seed, which was caused by excessive expansion of scuteUum cells. Post-embryonic growth of ge seedling was severely inhibited due to defective shoot apical meristem （SAM） mainte- nance. Map-based cloning revealed that GE encodes a CYP78A subfamily P450 monooxygenase that is localized to the endoplasmic reticulum. GE is expressed predominantly in the scutellar epithelium, the interface region between embryo and endosperm. Overexpression of GE promoted cell proliferation and enhanced rice plant growth and grain yield, but reduced embryo size, suggesting that GE is critical for coordinating rice embryo and endosperm development. Moreover, transgenic Arabidopsis plants overexpressing AtCYP78AlO, a GE homolog, also produced bigger seeds, implying a con- served role for the CYP78A subfamily of P450s in regulating seed development. Taken together, our results indicate that GE plays critical roles in regulating embryo development and SAM maintenance.
文摘缩节安(1,1-dimethyl piperidinium chloride, DPC)是棉花生产中广泛应用的植物生长延缓剂。增效DPC (DPC+,25%水剂)助剂中的成分能对植物幼嫩组织表面形成轻微伤害,实践证明其可实现棉花化学封顶、起到替代人工打顶的作用。为探究DPC+作用机制,本试验于2015年在田间条件下研究了棉花盛花期后(7月24日)应用DPC+(1125 mL hm–2)对棉花主茎生长和顶芽解剖结构、氧化还原状态及相关基因表达的影响。结果表明,与对照(同期喷施清水)相比, DPC+处理后棉花株高降低,白花以上节位(nodes above the last white flower, NAWF)更早降到5;处理后3 d即可观察到主茎生长点较对照扁平,生长点的纵横比显著低于对照;处理后6 h棉花顶芽的O2-、H2O2和MDA含量高于对照,而开花相关基因GhSPL3和GhV1及顶端分生组织相关基因GhREV3的表达量则低于对照。化学封顶剂DPC+可引起棉株顶芽的短期氧化应激反应,降低与主茎生长点发育和花芽分化相关基因的表达水平,从而延缓棉株生长和花芽的产生,实现化学封顶。
基金the National Natural Science Foundation of China (Grant No. 39770047).
文摘A subtracted cDNA library of rice (Oryza sativa L.) inflorescence meristem (IM) was constructed using the suppression subtractive hybridization (SSH) method. The cDNAs of the rice shoot apical meristem (SAM) were used as 'driver' and inflorescence meristem (IM) as 'tester' in the experiment, respectively. Forty of 250 randomly chosen cDNA clones were identified by differential screening, which were IM-specific or IM-highly expressed. Most of the rice IM cDNAs cloned by SSH appear to represent rare transcripts, 40% of which were derived from truly differentially expressed genes. Of all the forty sequenced cDNA inserts, eleven contain the regions with 60%-90% identity to their homolog in GenBank, eighteen are expected to be new genes, only two correspond to published rice genes.
基金supported by an ERC Starting Grant(No.260963) to F.F
文摘Flowering at the most appropriate times of the year requires careful monitoring of environmental conditions and correct integration of such information with an endogenous molecular network. Rice （Oryza sativa） is a facultative short day plant, and flowers quickly under short day lengths, as opposed to Arabidopsis thaliana whose flowering is accelerated by longer days. Despite these physiological differences, several genes controlling flowering in response to day length （or photoperiod） are conserved between rice and Arabidopsis, and the molecular mechanisms involved are similar. Inductive day lengths trigger expression of florigenic proteins in leaves that can move to the shoot apical meristem to induce reproductivedevelopment. As compared to Arabidopsis, rice also possesses unique factors that regulate expression of florigenic genes. Here, we discuss recent advances in understanding the molecular mechanisms involved in day length perception, production of florigenic signals, and molecular responses of the shoot apical meristem to florigenic proteins.
文摘LATERAL ORGAN BOUNDARIES DOMAIN(LBD)基因家族是在拟南芥中发现的高等植物所特有的一类基因,编码的蛋白中含有LATERAL ORGAN BOUNDARIES(LOB)结构域。LBD基因一般在侧生器官与茎尖分生组织的边界处、侧生器官的近轴面一侧的基部表达,并呈现出在多种组织内特异性表达的特征,暗示该类基因可能在植物的多种发育过程中发挥功能。LBD蛋白结构中除含有上述LOB结构域以外,尚未发现其它已知功能的结构域的存在。目前,已经在拟南芥中发现43个LBD基因,而在玉米和水稻中各有35和43个LBD基因。根据LBD蛋白结构中是否含有亮氨酸拉链类似基序,将LBD基因分为两类:第一类(class I)LBD蛋白结构域中包含完整亮氨酸拉链基序;第二类(class II)LBD蛋白结构域中不含亮氨酸拉链基序。本文就LBD基因的结构以及它们对高等植物生长发育的影响、LBD基因和植物激素的关系、LBD基因与miRNA的关系进行了系统的总结。
