Polycomb group proteins （PcG） play important roles in epigenetic regulation of gene expression. Some core PeG proteins, such as Enhancer of Zeste （E（z））, Suppressor of Zeste （12） （Su（z）12）, and Extra Sex C...Polycomb group proteins （PcG） play important roles in epigenetic regulation of gene expression. Some core PeG proteins, such as Enhancer of Zeste （E（z））, Suppressor of Zeste （12） （Su（z）12）, and Extra Sex Combs （ESC）, are conserved in plants. The rice genome contains two E（z）-Iike genes, OsiEZ1 and OsCLF, two homologs of Su（z）12, OsEMF2a and OsEMF2b, and two ESC-like genes, OsFIE1 and OsFIE2. OsFIE1 is expressed only in endosperm; the maternal copy is expressed while the paternal copy is not active. Other rice PcG genes are expressed in a wide range of tissues and are not imprinted in the endosperm. The two E（z）-Iike genes appear to have duplicated before the separation of the dicots and monocots; the two homologs of Su（z）12 possibly duplicated during the evolution of the Gramineae and the two ESC- like genes are likely to have duplicated in the ancestor of the grasses. No homologs of the Arabidopsis seed-expressed PcG genes MEA and FIS2 were identified in the rice genome. We have isolated T-DNA insertion lines in the rice homologs of three PcG genes. There is no autonomous endosperm development in these T-DNA insertion lines. One line with a T-DNA insertion in OsEMF2b displays pleiotropic phenotypes including altered flowering time and abnormal flower organs, suggesting important roles in rice development for this gene.展开更多
Two rice genotypes Huanghuazhan(HHZ, heat-resistant) and IR36(heat-susceptible) were subjected to high-temperature(HT, 40℃) and normal-temperature(NT, 32℃) treatments at the spikelet differentiation stage. HT treatm...Two rice genotypes Huanghuazhan(HHZ, heat-resistant) and IR36(heat-susceptible) were subjected to high-temperature(HT, 40℃) and normal-temperature(NT, 32℃) treatments at the spikelet differentiation stage. HT treatment inhibited spikelet differentiation, aggravated spikelet degeneration, reduced spikelet size, and disordered carbohydrate allocation. Meanwhile, HT treatment increased nonstructural carbohydrate content in leaves, but decreased that in stems and young panicles, and the same tendencies of sucrose and starch contents were observed in leaves and stem. However, HT treatment significantly increased the sucrose content and sharply decreased the glucose and fructose contents in young panicles. Lower activity levels of soluble acid invertase(EC3.2.1.26) and sucrose synthase(EC2.4.1.13) were observed under HT treatment. Moreover, HT treatment reduced the activities of key enzymes associated with glycolysis and the tricarboxylic acid cycle, which indicated sucrose consumption was inhibited in young panicles under HT treatment. Exogenous glucose and fructose applied under HT treatment increased the spikelet number more than exogenous sucrose. In conclusion, the results demonstrated that the reduction of spikelet number under high temperature was more affected by the decrease in sugar consumption than the blocking of sucrose transport. The impairment of sucrose hydrolysis was the main reason for the inhibition of sugar utilization.展开更多
In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internod...In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internodes （UPIs）. To elucidate the underlying molecular mechanisms, we cloned the rice gene NECK LEAF 1 （NL1）, which when mutated results in delays in flowering time, smaller panicles with overgrown bracts and abnormal UPI elongation patterns. The NL1 gene encodes a GATA-type transcription factor with a single zinc finger domain, and its transcripts are de- tected predominantly in the bract primordia, which normally degenerate in the wild-type plants. Overexpression of NL1 in transgenic plants often gives rise to severe growth retardation, less vegetative phytomers and smaller leaves, suggesting that NL1 plays an important role in organ differentiation. A novel mutant allele of PLASTOCHRON1 （PLAD, a gene known to play a key role in regulating leaf initiation, was identified in this study. Genetic analysis demonstrated an interaction between nil and plal, with NL1 acting upstream of PLA1. The expression level and spatial pattern of PLA1 were found to be altered in the nil mutant. Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nil mutant. On the basis of these findings, we propose that NL1 is an intrinsic factor that modulates and coordinates organogenesis through regulating the expression of PLA1 and other regulatory genes during reproductive development in rice.展开更多
As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important ag...As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important agronomic traits in rice by manipulating the expression of OscZOG1 gene, encoding a putative zeatin O-glucosyltransferase. We found that OscZOG~ was preferentially expressed in shoot and root meristematic tissues and nascent organs. The growth of lateral roots was stimulated in the overexpression lines, but inhibited in RNA interference lines. In shoots, knockdown of OscZOG1 expression by RNA interference significantly im- proved tillering, panicle branching, grain number per panicle and seed size, which are important agronomic traits for grain yield. In contrast, constitutive expression of OscZOG1 leads to negative effects on the formation of the grain-yielding traits with a marked increase in the accumulation levels of cis-zeatin O-glucoside （cZOG） in the transgenic rice plants. In this study,our findings demonstrate the feasibility of improving the critical yield-determinant agronomic traits, including tiller number, panicle branches, total grain number per panicle and grain weight by downregulating the expression level of OscZOG1. Our results suggest that modulating the levels of cytokinin glucosylation can function as a fine-tuning switch in regulating the formation of agronomic traits in rice.展开更多
A rice （Oryza sativa L.） mutant displaying defects in panicle development was identified among transformants in a transgenic mutagenlzed experiment using an antlsense cDNA library prepared from young rice panicles. ...A rice （Oryza sativa L.） mutant displaying defects in panicle development was identified among transformants in a transgenic mutagenlzed experiment using an antlsense cDNA library prepared from young rice panicles. In the mutant, the average splkelet number was reduced to 59.8 compared with 104.3 in wild-type plants. In addition, the seed-setting rate of the mutant was low （39.3%） owing to abnormal female development. Genetic analysis of T1 and T2 progeny showed that the traits segregated In a 3 （mutant） ： 1 （wild type） ratio and the mutation was cosegregated with the transgene. Southern blot and thermal asymmetric interlaced polymerase chain reaction analyses showed that the mutant had a single T-DNA insertion on chromosome 5, where no gene was tagged. Sequencing analysis found that the transgenic antisense cDNA was derived from a gene encoding an F-box protein in chromosome 7 with unidentified function. This and another four homologous genes encoding putative F-box proteins form a gene cluster. These results indicate that the phenotyplc mutations were most likely due to the silencing effect of the expressed transgenic antisense construct on the member（s） of the F-box gene cluster.展开更多
水稻穗发育是产量形成的基础。从粳稻品种‘武香粳9号’组织培养后代中筛选获得一份幼穗发育异常的突变体pdf1(panicle development failure 1)。突变体pdf1能正常从营养生长向生殖生长转换,穗分化能正常起始,但随后穗轴基部细胞出现程...水稻穗发育是产量形成的基础。从粳稻品种‘武香粳9号’组织培养后代中筛选获得一份幼穗发育异常的突变体pdf1(panicle development failure 1)。突变体pdf1能正常从营养生长向生殖生长转换,穗分化能正常起始,但随后穗轴基部细胞出现程序性死亡,引起穗发育停止。不同生长条件处理试验表明,pdf1突变性状受温度调控。转录组测序显示,差异表达基因主要参与DNA代谢过程、信号转导等生物过程,并定位于质膜和过氧化物酶体,其可能与信号刺激和过氧化物酶体等细胞通路的改变有关。展开更多
To understand the reallocation of organic nitrogen from leaf to the flower head of rice, the role of glutamine synthetase （GS） was investigated by characterizing GS1 RNAi transgenic rice, which revealed a significa...To understand the reallocation of organic nitrogen from leaf to the flower head of rice, the role of glutamine synthetase （GS） was investigated by characterizing GS1 RNAi transgenic rice, which revealed a significant reduction in panicle number and number of seeds per panicle. We observed the expression of GS isotypes at transcriptional and protein levels in flag leaves, leaf sheaths and panicles at three different flower development stages. The mRNA expression of GS1;1 was clearly suppressed in flag leaves, especially at the flowering stage. GS1 protein was barely detectable in flag leaves until the flowering stage, while GS1 protein was compromised in the leaf sheath and panicle, with transient expression of GS2 protein at the flowering stage. The glutamine level in transgenic plants was significantly reduced in both flag leaves and panicles, but ammonium was highly accumulated. The level of other amino acids, including aspartate and asparagine, tended to be higher in RNAi transgenic plants than the wild type plants during the reproductive stage. In addition, accumulation of toxic ammonium in panicles with low glutamine level might have caused low seed-setting in the transgenic rice. These results indicated that nitrogen reallocation was critical for panicle development, and that multiple GS isotypes functioned cooperatively to complete the rice life cycle when leaf nitrogen was remobilized to the developing reproductive organs.展开更多
Boron(B) is an essential micronutrient for vascular plant growth. Both B deficiency and toxicity can impair tissue development in diverse plant species, but little is known about the effect of B on reproductive panicl...Boron(B) is an essential micronutrient for vascular plant growth. Both B deficiency and toxicity can impair tissue development in diverse plant species, but little is known about the effect of B on reproductive panicle development and grain yield. In this study, a mutant of Setaria italica exhibiting necrotic panicle apices was identified and designated as sibor1. Sequencing revealed a candidate gene, Si BOR1, with a G-to-A alteration at the seventh exon. Knockout transgenic lines generated by clustered regularly interspaced short palindromic repeats and their associated protein-9 also had necrotic panicles, verifying the function of Si BOR1. Si BOR1 encoded a membrane-localized B efflux transporter, co-orthologous to the rice BOR1 protein. Si BOR1 was dominantly expressed in panicles and displayed a distinct expression pattern from those of its orthologs in other species. The induced mutation in Si BOR1 caused a reduction in the B content of panicle primary branches, and B deficiency-associated phenotypes such as thicker cell walls and higher cell porosity compared with Yugu 1. Transcriptome analysis indicated that differentially expressed genes involved in cell wall biogenesis, jasmonic acid synthesis, and programmed cell death response pathways were enriched in sibor1. q PCR analysis identified several key genes, including phenylalanine ammonia-lyase(Si PAL) and jasmonate-ZIM-domain(Si JAZ) genes, responsive to B-deficient conditions. These results indicate that Si BOR1 helps to regulate panicle primary branch development to maintain grain yield in S. italica. Our findings shed light on molecular mechanisms underlying the relationship between B transport and plant development in S. italica.展开更多
穗是谷子(Setaria italica)产量和品质形成的基础,理想的穗型是谷子遗传改良的重要目标。以新型C4禾谷类模式植物超早熟小型谷子突变体xiaomi为对象,利用RNA测序(RNA-Seq)技术分析了抽穗期、开花期和灌浆期3个发育时期穗中基因表达动态...穗是谷子(Setaria italica)产量和品质形成的基础,理想的穗型是谷子遗传改良的重要目标。以新型C4禾谷类模式植物超早熟小型谷子突变体xiaomi为对象,利用RNA测序(RNA-Seq)技术分析了抽穗期、开花期和灌浆期3个发育时期穗中基因表达动态。结果表明,开花期/抽穗期、灌浆期/开花期和灌浆期/抽穗期差异表达基因数分别为4159、4254和9243个。其中,光敏色素基因(PHYTOCHROME)、光周期枢纽基因(CONSTANS,CO)以及成花素基因(FLOWERING LOCUS T,FT)等在上述3个穗发育时期表达量差异显著,而一些与淀粉合成和代谢相关的基因在谷子穗发育过程中表达量逐渐升高。此外,还发现大量未知功能基因,这些基因在不同穗发育时期表达量差异显著。这些基因主要涉及次生代谢物生物合成、苯丙素类化合物生物合成、植物病原菌互作、植物激素信号转导、脂肪酸合成、糖类物质合成和蜡质合成等代谢通路。本研究揭示了谷子穗发育的基因表达动态,拟为深入解析穗发育调控的分子机制奠定基础。展开更多
Physiological processes governing rice plant light capture and subsequent crop growth and development are intimately tied to canopy architecture. Conversely, the production and spatial orientation of organs are depend...Physiological processes governing rice plant light capture and subsequent crop growth and development are intimately tied to canopy architecture. Conversely, the production and spatial orientation of organs are dependent on the underlying physiological processes. An integrated functional-architectural modeling system would allow greater refinement of intra- and inter-plant interactions, facilitate the incorporation of additional mechanistic processes, allow greater integration of processes across multiple structural scales, and improve the accuracy of predictions. The objective of this study is to quantify the physiological bases for organ morphological development of 3 rice cultivars （Banks, IR68886B, and their hybrid Banks × IR68886A）. Detailed organ morphological data were obtained through repeated field observations and destructive samplings over the growing season, including leaf length, width, area, mass, and leaf phyllochron; sheath length, diameter and mass; internode length, diameter and mass; panicle length; stem and tiller number. The result showed that the plant age （GDD, 〉 10 ℃ d） at the first full leaf initiation （node = 2） was 147.92, 154.35, 166.23 for Banks, IR68886B, and Banks × IR68886A respectively. Banks × IR68886A produced 18 nodes, while IR68886B produced 17 nodes, and Banks 16 nodes. The Specific Leaf Weight （SLW, mg cm2） was fairly constant （about 6 mg cm2） during the growing season for the 3 cultivars, and appears to slowly increase for the latter nodes. The leaf length and SLW of Banks × IR68886A was more than Banks and IR68886B. Specific internodes weight of Banks x IR68886A was higher than IR68886B ×and Banks. Growing duration for Banks × IR68886A is longer than Banks and IR68886B. Banks × IR68886A shows positive heterosis,, and the mid-parent heterosis （MPH） for panicle length was 26.74% and that for stem and tiller number was 135.00%. Results from the experiments were used to parameterize a rice functional-architectural model that simulates organ d展开更多
文摘Polycomb group proteins （PcG） play important roles in epigenetic regulation of gene expression. Some core PeG proteins, such as Enhancer of Zeste （E（z））, Suppressor of Zeste （12） （Su（z）12）, and Extra Sex Combs （ESC）, are conserved in plants. The rice genome contains two E（z）-Iike genes, OsiEZ1 and OsCLF, two homologs of Su（z）12, OsEMF2a and OsEMF2b, and two ESC-like genes, OsFIE1 and OsFIE2. OsFIE1 is expressed only in endosperm; the maternal copy is expressed while the paternal copy is not active. Other rice PcG genes are expressed in a wide range of tissues and are not imprinted in the endosperm. The two E（z）-Iike genes appear to have duplicated before the separation of the dicots and monocots; the two homologs of Su（z）12 possibly duplicated during the evolution of the Gramineae and the two ESC- like genes are likely to have duplicated in the ancestor of the grasses. No homologs of the Arabidopsis seed-expressed PcG genes MEA and FIS2 were identified in the rice genome. We have isolated T-DNA insertion lines in the rice homologs of three PcG genes. There is no autonomous endosperm development in these T-DNA insertion lines. One line with a T-DNA insertion in OsEMF2b displays pleiotropic phenotypes including altered flowering time and abnormal flower organs, suggesting important roles in rice development for this gene.
基金funded by the National Key Research and Development Program of China (Grant No. 2017YFD0300409)the Special Fund for China Agricultural Research System (Grant No. CARS-01-07B)+2 种基金Agricultural Sciences and Technologies Innovation Program of Chinese Academy of Agricultural Sciences, National Natural Science Foundation (Grant No. 31701374)Zhejiang Provincial Natural Science Foundation (Grant No. LY16C130006)Basic Research Foundation of National Commonweal Research Institute (Grant No. 2017RG004-4) in China
文摘Two rice genotypes Huanghuazhan(HHZ, heat-resistant) and IR36(heat-susceptible) were subjected to high-temperature(HT, 40℃) and normal-temperature(NT, 32℃) treatments at the spikelet differentiation stage. HT treatment inhibited spikelet differentiation, aggravated spikelet degeneration, reduced spikelet size, and disordered carbohydrate allocation. Meanwhile, HT treatment increased nonstructural carbohydrate content in leaves, but decreased that in stems and young panicles, and the same tendencies of sucrose and starch contents were observed in leaves and stem. However, HT treatment significantly increased the sucrose content and sharply decreased the glucose and fructose contents in young panicles. Lower activity levels of soluble acid invertase(EC3.2.1.26) and sucrose synthase(EC2.4.1.13) were observed under HT treatment. Moreover, HT treatment reduced the activities of key enzymes associated with glycolysis and the tricarboxylic acid cycle, which indicated sucrose consumption was inhibited in young panicles under HT treatment. Exogenous glucose and fructose applied under HT treatment increased the spikelet number more than exogenous sucrose. In conclusion, the results demonstrated that the reduction of spikelet number under high temperature was more affected by the decrease in sugar consumption than the blocking of sucrose transport. The impairment of sucrose hydrolysis was the main reason for the inhibition of sugar utilization.
文摘In the monocot rice species Oryza sativa L., one of the most striking morphological processes during reproductive development is the concurrence of panicle development with the sequential elongation of upper internodes （UPIs）. To elucidate the underlying molecular mechanisms, we cloned the rice gene NECK LEAF 1 （NL1）, which when mutated results in delays in flowering time, smaller panicles with overgrown bracts and abnormal UPI elongation patterns. The NL1 gene encodes a GATA-type transcription factor with a single zinc finger domain, and its transcripts are de- tected predominantly in the bract primordia, which normally degenerate in the wild-type plants. Overexpression of NL1 in transgenic plants often gives rise to severe growth retardation, less vegetative phytomers and smaller leaves, suggesting that NL1 plays an important role in organ differentiation. A novel mutant allele of PLASTOCHRON1 （PLAD, a gene known to play a key role in regulating leaf initiation, was identified in this study. Genetic analysis demonstrated an interaction between nil and plal, with NL1 acting upstream of PLA1. The expression level and spatial pattern of PLA1 were found to be altered in the nil mutant. Furthermore, the expression of two regulators of flowering, Hd3a and OsMADS1, was also affected in the nil mutant. On the basis of these findings, we propose that NL1 is an intrinsic factor that modulates and coordinates organogenesis through regulating the expression of PLA1 and other regulatory genes during reproductive development in rice.
基金supported in parts by the Ministry of Science and Technology of China(2012CB944802 and 2012AA101103)the National Natural Science Foundation of China(91317305)the Ministry of Agriculture of China(2014ZX08009-003)
文摘As a ubiquitous reaction, glucosylation controls the bioactivity of cytokinins in plant growth and development. Here we show that genetic manipulation of zeatin-O- glucosylation regulates the formation of important agronomic traits in rice by manipulating the expression of OscZOG1 gene, encoding a putative zeatin O-glucosyltransferase. We found that OscZOG~ was preferentially expressed in shoot and root meristematic tissues and nascent organs. The growth of lateral roots was stimulated in the overexpression lines, but inhibited in RNA interference lines. In shoots, knockdown of OscZOG1 expression by RNA interference significantly im- proved tillering, panicle branching, grain number per panicle and seed size, which are important agronomic traits for grain yield. In contrast, constitutive expression of OscZOG1 leads to negative effects on the formation of the grain-yielding traits with a marked increase in the accumulation levels of cis-zeatin O-glucoside （cZOG） in the transgenic rice plants. In this study,our findings demonstrate the feasibility of improving the critical yield-determinant agronomic traits, including tiller number, panicle branches, total grain number per panicle and grain weight by downregulating the expression level of OscZOG1. Our results suggest that modulating the levels of cytokinin glucosylation can function as a fine-tuning switch in regulating the formation of agronomic traits in rice.
基金Supported by the State Key Basic Research and Development Plan of China （G 1999011603-2005CB120802） and the National Natural Science Foundation of China （30570969）.
文摘A rice （Oryza sativa L.） mutant displaying defects in panicle development was identified among transformants in a transgenic mutagenlzed experiment using an antlsense cDNA library prepared from young rice panicles. In the mutant, the average splkelet number was reduced to 59.8 compared with 104.3 in wild-type plants. In addition, the seed-setting rate of the mutant was low （39.3%） owing to abnormal female development. Genetic analysis of T1 and T2 progeny showed that the traits segregated In a 3 （mutant） ： 1 （wild type） ratio and the mutation was cosegregated with the transgene. Southern blot and thermal asymmetric interlaced polymerase chain reaction analyses showed that the mutant had a single T-DNA insertion on chromosome 5, where no gene was tagged. Sequencing analysis found that the transgenic antisense cDNA was derived from a gene encoding an F-box protein in chromosome 7 with unidentified function. This and another four homologous genes encoding putative F-box proteins form a gene cluster. These results indicate that the phenotyplc mutations were most likely due to the silencing effect of the expressed transgenic antisense construct on the member（s） of the F-box gene cluster.
文摘水稻穗发育是产量形成的基础。从粳稻品种‘武香粳9号’组织培养后代中筛选获得一份幼穗发育异常的突变体pdf1(panicle development failure 1)。突变体pdf1能正常从营养生长向生殖生长转换,穗分化能正常起始,但随后穗轴基部细胞出现程序性死亡,引起穗发育停止。不同生长条件处理试验表明,pdf1突变性状受温度调控。转录组测序显示,差异表达基因主要参与DNA代谢过程、信号转导等生物过程,并定位于质膜和过氧化物酶体,其可能与信号刺激和过氧化物酶体等细胞通路的改变有关。
基金supported by by research fund from Chosun University(Grant No.2017-2017)
文摘To understand the reallocation of organic nitrogen from leaf to the flower head of rice, the role of glutamine synthetase （GS） was investigated by characterizing GS1 RNAi transgenic rice, which revealed a significant reduction in panicle number and number of seeds per panicle. We observed the expression of GS isotypes at transcriptional and protein levels in flag leaves, leaf sheaths and panicles at three different flower development stages. The mRNA expression of GS1;1 was clearly suppressed in flag leaves, especially at the flowering stage. GS1 protein was barely detectable in flag leaves until the flowering stage, while GS1 protein was compromised in the leaf sheath and panicle, with transient expression of GS2 protein at the flowering stage. The glutamine level in transgenic plants was significantly reduced in both flag leaves and panicles, but ammonium was highly accumulated. The level of other amino acids, including aspartate and asparagine, tended to be higher in RNAi transgenic plants than the wild type plants during the reproductive stage. In addition, accumulation of toxic ammonium in panicles with low glutamine level might have caused low seed-setting in the transgenic rice. These results indicated that nitrogen reallocation was critical for panicle development, and that multiple GS isotypes functioned cooperatively to complete the rice life cycle when leaf nitrogen was remobilized to the developing reproductive organs.
基金supported by the National Key Research and Development Program of China(2019YFD1000700 and 2019YFD1000704)the National Natural Science Foundation of China(31871692)+1 种基金the China Agricultural Research System(CARS06-13.5-A04)the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences。
文摘Boron(B) is an essential micronutrient for vascular plant growth. Both B deficiency and toxicity can impair tissue development in diverse plant species, but little is known about the effect of B on reproductive panicle development and grain yield. In this study, a mutant of Setaria italica exhibiting necrotic panicle apices was identified and designated as sibor1. Sequencing revealed a candidate gene, Si BOR1, with a G-to-A alteration at the seventh exon. Knockout transgenic lines generated by clustered regularly interspaced short palindromic repeats and their associated protein-9 also had necrotic panicles, verifying the function of Si BOR1. Si BOR1 encoded a membrane-localized B efflux transporter, co-orthologous to the rice BOR1 protein. Si BOR1 was dominantly expressed in panicles and displayed a distinct expression pattern from those of its orthologs in other species. The induced mutation in Si BOR1 caused a reduction in the B content of panicle primary branches, and B deficiency-associated phenotypes such as thicker cell walls and higher cell porosity compared with Yugu 1. Transcriptome analysis indicated that differentially expressed genes involved in cell wall biogenesis, jasmonic acid synthesis, and programmed cell death response pathways were enriched in sibor1. q PCR analysis identified several key genes, including phenylalanine ammonia-lyase(Si PAL) and jasmonate-ZIM-domain(Si JAZ) genes, responsive to B-deficient conditions. These results indicate that Si BOR1 helps to regulate panicle primary branch development to maintain grain yield in S. italica. Our findings shed light on molecular mechanisms underlying the relationship between B transport and plant development in S. italica.
文摘穗是谷子(Setaria italica)产量和品质形成的基础,理想的穗型是谷子遗传改良的重要目标。以新型C4禾谷类模式植物超早熟小型谷子突变体xiaomi为对象,利用RNA测序(RNA-Seq)技术分析了抽穗期、开花期和灌浆期3个发育时期穗中基因表达动态。结果表明,开花期/抽穗期、灌浆期/开花期和灌浆期/抽穗期差异表达基因数分别为4159、4254和9243个。其中,光敏色素基因(PHYTOCHROME)、光周期枢纽基因(CONSTANS,CO)以及成花素基因(FLOWERING LOCUS T,FT)等在上述3个穗发育时期表达量差异显著,而一些与淀粉合成和代谢相关的基因在谷子穗发育过程中表达量逐渐升高。此外,还发现大量未知功能基因,这些基因在不同穗发育时期表达量差异显著。这些基因主要涉及次生代谢物生物合成、苯丙素类化合物生物合成、植物病原菌互作、植物激素信号转导、脂肪酸合成、糖类物质合成和蜡质合成等代谢通路。本研究揭示了谷子穗发育的基因表达动态,拟为深入解析穗发育调控的分子机制奠定基础。
基金Acknowledgments The authors acknowledge the help of Kade and Gary and the financial support of National Natural Science Foundation of China （31101084） and Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.
文摘Physiological processes governing rice plant light capture and subsequent crop growth and development are intimately tied to canopy architecture. Conversely, the production and spatial orientation of organs are dependent on the underlying physiological processes. An integrated functional-architectural modeling system would allow greater refinement of intra- and inter-plant interactions, facilitate the incorporation of additional mechanistic processes, allow greater integration of processes across multiple structural scales, and improve the accuracy of predictions. The objective of this study is to quantify the physiological bases for organ morphological development of 3 rice cultivars （Banks, IR68886B, and their hybrid Banks × IR68886A）. Detailed organ morphological data were obtained through repeated field observations and destructive samplings over the growing season, including leaf length, width, area, mass, and leaf phyllochron; sheath length, diameter and mass; internode length, diameter and mass; panicle length; stem and tiller number. The result showed that the plant age （GDD, 〉 10 ℃ d） at the first full leaf initiation （node = 2） was 147.92, 154.35, 166.23 for Banks, IR68886B, and Banks × IR68886A respectively. Banks × IR68886A produced 18 nodes, while IR68886B produced 17 nodes, and Banks 16 nodes. The Specific Leaf Weight （SLW, mg cm2） was fairly constant （about 6 mg cm2） during the growing season for the 3 cultivars, and appears to slowly increase for the latter nodes. The leaf length and SLW of Banks × IR68886A was more than Banks and IR68886B. Specific internodes weight of Banks x IR68886A was higher than IR68886B ×and Banks. Growing duration for Banks × IR68886A is longer than Banks and IR68886B. Banks × IR68886A shows positive heterosis,, and the mid-parent heterosis （MPH） for panicle length was 26.74% and that for stem and tiller number was 135.00%. Results from the experiments were used to parameterize a rice functional-architectural model that simulates organ d
