During the course of their life cycles, plants undergo various morphological and physiological changes un- derlying juvenile-to-adult and adult-to-flowering phase transitions. To flower or not to flower is a key step ...During the course of their life cycles, plants undergo various morphological and physiological changes un- derlying juvenile-to-adult and adult-to-flowering phase transitions. To flower or not to flower is a key step of plasticity of a plant toward the start of its new life cycle. In addition to the previously revealed intrinsic genetic programs, exogenous cues, and endogenous cues, a class of small non-coding RNAs, microRNAs （miRNAs）, plays a key role in plants making the decision to flower by integrating into the known flowering pathways. This review highlights the age-dependent flowering pathway with a focus on a number of timing miRNAs in determining such a key process. The contributions of other miRNAs which exist mainly outside the age pathway are also discussed. Approaches to study the flowering-determining miRNAs, their inter- actions, and applications are presented.展开更多
Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and...Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and year. The circadian clock regulates a number of central plant activities, including growth, develop- ment, and reproduction, primarily through controlling a substantial proportion of transcriptional activity and protein function. This review examines the roles that alleles of circadian clock genes have played in domestication and improvement of crop plants. The focus here is on three groups of circadian clock genes essential to clock function in Arabidopsis thaliana： PSEUDO-RESPONSE REGULATORs, GIGANTEA, and the evening complex genes EARL Y FLOWERING 3, EARLY FLOWERING 4, and LUX ARRHYTHMO. Homol- ogous genes from each group underlie quantitative trait loci that have beneficial influences on key agricul- tural traits, especially flowering time but also yield, biomass, and biennial growth habit. Emerging insights into circadian clock regulation of other fundamental plant processes, including responses to abiotic and biotic stresses, are discussed to highlight promising avenues for further crop improvement.展开更多
植物花器官的发育和开花是植物生殖发育中最重要的过程,植物在长期的进化过程中产生了春化(低温)途径、自主途径、光周期途径以及不依赖于光温环境条件的赤霉素信号途径来适应多变的环境和调控植物开花过程。本文综述了模式植物拟南芥中...植物花器官的发育和开花是植物生殖发育中最重要的过程,植物在长期的进化过程中产生了春化(低温)途径、自主途径、光周期途径以及不依赖于光温环境条件的赤霉素信号途径来适应多变的环境和调控植物开花过程。本文综述了模式植物拟南芥中由LEAFY(LFY)、CONSTANS(CO)、FLOWERING LOCUSC(FLC)、FLOW ERING LOCUS T(FT)和SUPPRESSOR OF OVEREXPRESSION OF CO1(SOC1)等基因构成的双子叶植物响应光温条件变化的开花调控网络;以及大麦、小麦中由VERNALIZATION1(VRN1)、VRN2、ODD-SOC2(OS2)和拟南芥CO、FT同源基因构成的禾本科植物开花调控网络。其中最重要的是转录调控因子MADS-box基因FLC、SOC1、VRN1和OS2,并发现组蛋白的乙酰化/脱乙酰化,赖氨酸的甲基化/脱甲基化在调控FLC、VRN1染色质活性状态及基因表达,从而产生开花控制的机理。这些研究发现将有助于对具有重要经济价值的单双子叶植物,通过生物技术手段改良其品种特性以应对非生物逆境,特别是低温胁迫的指导。展开更多
The timing of floral transition is critical to reproductive success in angiosperms and is genetically controlled by a network of flowering genes. In Arabidopsis, expression of certain flowering genes is regulated by v...The timing of floral transition is critical to reproductive success in angiosperms and is genetically controlled by a network of flowering genes. In Arabidopsis, expression of certain flowering genes is regulated by various chromatin modifications, among which are two central regulators of flowering, namely FLOWERING LOCUS C （FLC） and FLOWERING LOCUS T（FT）. Recent studies have revealed that a number of chromatin-modifying components are involved in activation or repression of FLC expression. Activation of FLC expression is associated with various ＇active＇ chromatln modifications including acetylation of core histone tails, histone H3 lysine-4 （H3K4） methylation, H2B monoubiquitination, H3 lysine-36 （H3K36） di- and tri-methylation and deposition of the histone variant H2A.Z, whereas various ＇repressive＇ histone mod- ifications are associated with FLC repression, including histone deacetylation, H3K4 demethylation, histone H3 lysine-9 （H3K9） and H3 lysine-27 （H3K27） methylation, and histone arginine methylation. In addition, recent studies have revealed that Polycomb group gene-mediated transcriptional-silencing mechanism not only represses FLC expression, but also directly represses FTexpression. Regulation of FLC expression provides a paradigm for control of the expression of other developmental genes in plants through chromatin mechanisms.展开更多
文摘During the course of their life cycles, plants undergo various morphological and physiological changes un- derlying juvenile-to-adult and adult-to-flowering phase transitions. To flower or not to flower is a key step of plasticity of a plant toward the start of its new life cycle. In addition to the previously revealed intrinsic genetic programs, exogenous cues, and endogenous cues, a class of small non-coding RNAs, microRNAs （miRNAs）, plays a key role in plants making the decision to flower by integrating into the known flowering pathways. This review highlights the age-dependent flowering pathway with a focus on a number of timing miRNAs in determining such a key process. The contributions of other miRNAs which exist mainly outside the age pathway are also discussed. Approaches to study the flowering-determining miRNAs, their inter- actions, and applications are presented.
文摘Circadian clocks are endogenous timers that enable plants to synchronize biological processes with daily and seasonal environmental conditions in order to allocate resources during the most beneficial times of day and year. The circadian clock regulates a number of central plant activities, including growth, develop- ment, and reproduction, primarily through controlling a substantial proportion of transcriptional activity and protein function. This review examines the roles that alleles of circadian clock genes have played in domestication and improvement of crop plants. The focus here is on three groups of circadian clock genes essential to clock function in Arabidopsis thaliana： PSEUDO-RESPONSE REGULATORs, GIGANTEA, and the evening complex genes EARL Y FLOWERING 3, EARLY FLOWERING 4, and LUX ARRHYTHMO. Homol- ogous genes from each group underlie quantitative trait loci that have beneficial influences on key agricul- tural traits, especially flowering time but also yield, biomass, and biennial growth habit. Emerging insights into circadian clock regulation of other fundamental plant processes, including responses to abiotic and biotic stresses, are discussed to highlight promising avenues for further crop improvement.
文摘植物花器官的发育和开花是植物生殖发育中最重要的过程,植物在长期的进化过程中产生了春化(低温)途径、自主途径、光周期途径以及不依赖于光温环境条件的赤霉素信号途径来适应多变的环境和调控植物开花过程。本文综述了模式植物拟南芥中由LEAFY(LFY)、CONSTANS(CO)、FLOWERING LOCUSC(FLC)、FLOW ERING LOCUS T(FT)和SUPPRESSOR OF OVEREXPRESSION OF CO1(SOC1)等基因构成的双子叶植物响应光温条件变化的开花调控网络;以及大麦、小麦中由VERNALIZATION1(VRN1)、VRN2、ODD-SOC2(OS2)和拟南芥CO、FT同源基因构成的禾本科植物开花调控网络。其中最重要的是转录调控因子MADS-box基因FLC、SOC1、VRN1和OS2,并发现组蛋白的乙酰化/脱乙酰化,赖氨酸的甲基化/脱甲基化在调控FLC、VRN1染色质活性状态及基因表达,从而产生开花控制的机理。这些研究发现将有助于对具有重要经济价值的单双子叶植物,通过生物技术手段改良其品种特性以应对非生物逆境,特别是低温胁迫的指导。
文摘The timing of floral transition is critical to reproductive success in angiosperms and is genetically controlled by a network of flowering genes. In Arabidopsis, expression of certain flowering genes is regulated by various chromatin modifications, among which are two central regulators of flowering, namely FLOWERING LOCUS C （FLC） and FLOWERING LOCUS T（FT）. Recent studies have revealed that a number of chromatin-modifying components are involved in activation or repression of FLC expression. Activation of FLC expression is associated with various ＇active＇ chromatln modifications including acetylation of core histone tails, histone H3 lysine-4 （H3K4） methylation, H2B monoubiquitination, H3 lysine-36 （H3K36） di- and tri-methylation and deposition of the histone variant H2A.Z, whereas various ＇repressive＇ histone mod- ifications are associated with FLC repression, including histone deacetylation, H3K4 demethylation, histone H3 lysine-9 （H3K9） and H3 lysine-27 （H3K27） methylation, and histone arginine methylation. In addition, recent studies have revealed that Polycomb group gene-mediated transcriptional-silencing mechanism not only represses FLC expression, but also directly represses FTexpression. Regulation of FLC expression provides a paradigm for control of the expression of other developmental genes in plants through chromatin mechanisms.
