破坏ARF8基因降低拟南芥对红光的敏感性

通过ARF8基因的突变体arf8-1以及arf8-1与红光受体突变体phyB-5所组成的双突变体在红光条件下的表型鉴定,探讨ARF8参与拟南芥对红光的反应以及PhyB与ARF8在红光信号转导中的关系.结果表明,在红光条件下,arf8-1和phyB-5幼苗下胚轴的长度比相应野生型的长,倒伏度比相应野生型的低,而双突变体arf8-1 phyB-5的下胚轴的长度和倒伏度均比两个单突变体的更长和更低.上述结果说明,破坏ARF8基因降低了拟南芥对红光的敏感性,即ARF8参与了拟南芥对红光的反应,但没有介导PhyB所接收的红光信号转导.     

一个新的拟南芥雄性不育突变体的鉴定

前期研究表明,高度不育的infer1含有arf8-1和fer1-1.利用TAIL-PCR,研究组已经证实fer1-1为一个T-DNA插在At4g33050基因(鳊码Fer1蛋白)的突变体.于是,研究组从ABRC(the Ambidopsis Biological Re-souce Center)购买了At4g33050的另一个T-DNA插入突变体fer1-2.在fer1-2与arf8-1的杂交后代F2中,得到了一个与infer1明显不同的部分雄性不育突变体,命名为infer2,该不育株的所有后代均为部分不育.表型鉴定表明infer2在花发育、花的形态结构、角果的形态结构、植株的营养生长和植株的育性等方面与infer1比较存在明显差异.分子标记分析表明infer2仅含有arf8-1的分子标记而不含有fer1-2的分子标记.因此,可以确定infer2是一个不同于infer1的新的拟南芥雄性不育突变体.infer1和infer2均可作为植物雄性不育分子机制研究的良好材料.     

激素对甘蓝型油菜(Brassica napus L)矮化突变体幼苗生长及内源GA3含量的影响

以甘蓝型油菜矮化突变体“DDF-1”为材料，研究了赤霉素（GA3）、生长素（IAA）和油菜素内酯（BR）3种激素对突变体幼苗的影响，并用石蜡切片观察其细胞形态，用酶联免疫吸附技术(ELISA) 检测下胚轴内源激素GA3含量.结果表明，外加一定浓度的GA3（7 mg/L）对矮化突变体“DDF-1”的下胚轴伸长作用显著，但不能使之恢复到野生型的长度；萌发早期，BR有明显的促进伸长作用，萌发后期效果不明显；突变体对IAA敏感性较弱.三种激素交互作用对矮秆下胚轴伸长的影响也不显著.施加外源GA3的矮化突变体“DD     

水稻突变体B1-24的细胞学观察及其激素调控

以半矮化水稻突变体B1-24及其野生型惠阳珍珠早(Hyz)幼苗为材料,探究其细胞学特征及其对激素的响应.在光下生长的B1-24幼苗比Hyz矮14.62%,第一真叶长度短11.18%,黄化苗植株的中胚轴长度增长41.89%,但Hyz的胚芽鞘长度比之长28.71%.细胞学观察发现,与野生型相比,突变体第一真叶叶片细胞长度和宽度都无显著差异.B1-24黄化苗的胚芽鞘细胞长度仅为Hyz的45.95%,而中胚轴细胞长度是其118.28%.B1-24对激素GA3(600 μg/ml)和IAA(7 μg/ml)的处理敏感,其细胞长度显著增长,植株表型更接近Hyz.而50 μg/mL PAC处理使其严重缩短.推测B1-24的半矮化突变可能与激素合成或响应有关     

拟南芥18srRNA参与隐花色素介导的信号传导途径的研究

通过筛选以拟南芥蓝光受体隐花色素双突变体cry1cry2为遗传背景的激活标签突变体库,得到一株SCC98-D株系,该突变体具有早开花,下胚轴变短,并具有花瓣数目增加等表型,彻底恢复了cry1cry2的晚开花和长下胚轴表型.通过Tail-PCR的方法克隆得到SCC98-D突变体中激活标签插入位点的侧翼序列,通过对该侧翼序列测序发现插入位点在18srRNA的1751bp处,运用RT-PCR方法分析插入位点周围基因的表达,发现只有18srRNA的表达被激活,由此证实了18srRNA参与隐花色素介导的信号传导途径.     

HD2基因调控拟南芥下胚轴发育的功能研究

为探究组蛋白去乙酰化酶HD2基因在拟南芥下胚轴发育中的调控作用,本研究采用野生型（Col-0）、HD2突变体以及过表达植株为材料,研究其在1/2MS以及1/2MS+100 mmol/L甘露醇培养中下胚轴的表型特征,并结合转录组测序数据进一步分析. 实验结果显示,四种过表达株系下胚轴长度较Col-0长,伸长百分比为7.1%～19.5%,差异显著;甘露醇处理后,过表达植株下胚轴较Col-0更长,伸长百分比为14.6%～32.8%,差异更加显著,缩短幅度也更小. hd2a/hd2b和hd2a/hd2c双基因突变体植株在有无甘露醇时,下胚轴长度均显著短于Col-0,但干旱胁迫后变短幅度无明显增加. 转录组数据揭示,HD2基因调控光合系统响应基因影响植株暗形态建成反应,从而影响下胚轴发育. 甘露醇处理后,HD2基因诱导产生非生物刺激响应因子,帮助下胚轴抵抗不良环境. 综上所述,HD2基因在拟南芥下胚轴发育中承担重要调控作用.     

过表达转录因子AhAREB1对拟南芥生长素分布的影响

本课题组前期研究表明,过表达AhAREB1(花生AREB转录因子基因)植株矮小,叶片卷曲,抗旱能力增强,体内IAA含量升高,推测AhAREB1可能影响植株体内IAA分布.该文采用携带3个重复IAA化学诱导启动子元件的pDR5::GUS植株与AhAREB1过表达拟南芥植株的杂交纯合后代,通过GUS组织化学染色方法,探讨AhAREB1转录因子对植株体内IAA分布的影响.结果表明,过表达AhAREB1植株体内IAA增加,主要分布在幼苗的根尖和成苗的叶片边缘;在过表达植株IAA响应基因IAA29和IAA运输蛋白基因LAX3表达均显著下调,而IAA响应蛋白基因ARF2和ARF9显著上调.过表达AhAREB1植株体内IAA分布不均衡是引起表型变化的原因之一.     

CONSTANS-LIKE 7基因对拟南芥开花的调控分析

为研究CONSTANS-LIKE 7(COL7)在调控植物开花方面的功能,以定量PCR,GUS染色等方法,研究光及生物钟对COL7表达的影响,以及COL7对拟南芥开花的影响.实验结果显示:光及生物钟参与调控COL7的表达;过表达COL7在长日照条件下抑制CONSTANS(CO)以及FLOWERING LOCUS T(FT)的表达,进而抑制拟南芥开花;col7突变体不论是在长日照下还是短日照下都没有明显的开花表型,说明COL7在调控拟南芥开化方面可能与其家族基因中的其它成员存在功能冗余.     

拟南芥ch1-4的图位克隆以及参与光形态建成分析

拟南芥通过光受体对外界光信号进行感知并将信号进一步传递,通过影响相关基因的表达,进而调控其生长发育.通过正向遗传筛选分离到一株在蓝光下发育缺陷的突变体,随后对其进行了图位克隆,发现是由CH1蛋白267位半胱氨酸突变为精氨酸引起的发育缺陷.通过等位突变体分析证实,ch1突变体在蓝光和红光下分别表现为下胚轴缩短和伸长的表型,说明CH1影响拟南芥的光形态建成.文章不仅揭示了叶绿素酸酯加氧酶CH1参与光形态建成,也为光信号网络的完善提供了重要信息.     

水稻突变体B1-24的细胞学观察及其激素响应

以半矮化水稻突变体B1-24及其野生型惠阳珍珠早(Hyz)幼苗为材料,探究其细胞学特征及其对激素的响应.在光下生长的B1-24幼苗比Hyz矮14.62%,第一真叶长度短11.18%,黄化苗植株的中胚轴长度增长41.89%.B1-24黄化苗的胚芽鞘细胞长度仅为Hyz的45.95%,而中胚轴细胞长度是其118.28%.B1-24分别经激素GA3(600μg/mL)和IAA(7μg/mL)处理,其细胞长度显著增长,50μg/mL PAC处理使其严重缩短.推测B1-24的半矮化突变可能与激素合成或响应有关.     

Fine mapping and cloning of MT1,a novel allele of D10

Rice tillering is an important determinant for grain production.To investigate the mechanism of tillering,we characterized a multiple tillering mutant (mt1) identified from the japonica variety,Zhonghua 11,treated with EMS.This mutant exhibits advanced tillering development and dwarfed compared with wild-type plants.Genetic analysis and fine gene mapping indicated that the mt1 mutant was controlled by a recessive gene,residing on a 29-kb window on AP003376 of chromosome 1.One putative gene in this region,encoding a carotenoid cleavage dioxygenase 8 (CCD8),was allelic to D10.The mt1 mutant phenotype was complemented by introduction of wild-type MT1,and knockdown of MT1 in wild-type rice mimicked the mutant phenotype.Real-time PCR analysis indicated that the MT1 gene is expressed highly in stems and at a low level in axillary buds,panicles,leaves,and roots.In addition,MT1 expression is clearly under feedback regulation.     

两类猪ADP-核糖基化因子的克隆分析与原核表达载体构建

哺乳动物小G结合蛋白——二磷酸腺苷-核糖基化因子(ADP-ribosylation factors,Arfs)除在囊泡运输、细胞骨架重排和调节细胞吞噬等方面起重要作用外,还与病毒的感染有关.前期研究发现猪繁殖与呼吸综合征病毒(Porcine reproductive and respiratory syndrome virus,PRRSV)感染早期ARFs基因表达明显上调,然而在猪只中ARFs与PRRSV的感染至今知之甚少.本研究中,猪ARF1和ARF4分别被克隆,序列分析发现:ARF1包含一个长度为546bp的开放阅读框(Open reading frame,ORF),预测编码181个氨基酸,理论分子质量为20.70kDa,pI为6.62;ARF4包含一个长度为543bp的开放阅读框,预测编码180个氨基酸,理论分子质量为20.50kDa,pI为5.46.蛋白序列结构分析显示猪ARF1和ARF4蛋白含有典型的p loop,switch区,interswitch区和N端疏水区的Hasp,在第二位都含有可被肉豆蔻酰基化的甘氨酸.猪ARF1和ARF4的原核表达载体也被构建,为进一步研究其在PRRSV感染过程中的调控提供基础.     

Effect of internal deletion of Myosin Ⅱ on growth and development of Dictyostelium discoideum

Four deletion mutant Dictyostelium myosin Ⅱ heavy chain genes, MyΔ824-941 (Δ1/ 3S2), MyΔ934-1454 (ΔS2), MyΔ934-1194 (ΔS2-1) and MyΔ1157-1454 (ΔS2-2), were transformed by standard electroporation into mhcA- cells (T-null), a mutant Dictyostelium cell devoid of endogenous myosin Ⅱ heavy chain gene. The growth, development and formation of fruiting bodies of cells expressing those mutant myosin Ⅱ s under suspension culture were investigated by comparison with the wild type cell. The results indicate that internal deletion of myosin Ⅱ affects the growth and development of Dictyostelium. Furthermore, the longer the length of deletion , the more serious the defect in phenotype.     

8-羟基喹啉-7-醛的合成改进及其光谱性质

目的改进Reimer—Tiemann反应合成8-羟基喹啉-7-醛的实验方法,使其操作更方便,并提高产率。方法32mLCHCl3（0．4mol）滴加到100g35％～40％NaOH（1mol）水溶液和8-羟基喹啉（0．1mol）CH3CH2OH溶液体系中,65～70℃回流4h后,用0．1mol／LHCl酸化至PH5．0～5．5,可得到粗产物。再采用硅胶色谱柱分离,以V石油醚：V乙酸乙酯=40：1的混合溶剂作为洗脱剂,得橙红色结晶,然后用CHCl3重结晶得淡橙色针状晶体,真空干燥,可得产品3．1g。结果采用优化的实验方法合成了8-羟基喹啉-7-醛,产率为18％,熔点178℃,并利用红外光谱、质谱和核磁共振波谱对目标产物进行了结构表征,而且报道了其紫外和荧光光谱性质。结论改进了8-羟基喹啉-7-醛的合成方法,得到了目标产物,使实验操作方便易行,且提高了产率。     

Isolation and characterization of rice lesion mimic mutants from a T-DNA tagged population

A rice ( Oryza sativa L. ssp. japonica cv. Nipponbare) T-DNA tagged population consisting of about 7000 individual lines was generated and screened for rice lesion mimic mutants in the T1 generation. Ten lines were found to develop spontaneous lesions in the absence of pathogen infection and displayed distinct lesion phenotypes. These mutants were tentatively designated as lm1 -lm10 (for lesion mimic), respectively. Lesion formation of lm mutants was developmentally regulated, and all the mutants showed stunted growth and reduced fertility. Genetic analysis demonstrated that all the mutations were recessive, and five partially fertile mutants (lm4-lm8) were derived from different loci. Mimic lesions occurring on the leaves of lm mutants resulted from cell death as revealed by trypan blue staining. Six of them ( lm3 -lm8 ) exhibited enhanced resistance to five bacterial blight isolates, indicating their wide-spectrum resistance to this pathogen. These results imply that some lesion mimic mutations of rice might be involved in disease resistance signaling pathways,and that isolation of these mutated genes may be useful for elucidating molecular mechanisms of plant disease resistance. Among the mutants, only one mutant, lm6, was preliminarily shown to cosegregate with the inserted T-DNA in its T1 generation, making it feasible to isolate the gene responsible for the phenotype of this mutant.     

Reduced sleep in Drosophila Shaker mutants

Most of us sleep 7-8 h per night, and if we are deprived of sleep our performance suffers greatly; however, a few do well with just 3-4 h of sleep-a trait that seems to run in families. Determining which genes underlie this phenotype could shed light on the mechanisms and functions of sleep. To do so, we performed mutagenesis in Drosophila melanogaster, because flies also sleep for many hours and, when sleep deprived, show sleep rebound and performance impairments. By screening 9,000 mutant lines, we found minisleep (mns), a line that sleeps for one-third of the wild-type amount. We show that mns flies perform normally in a number of tasks, have preserved sleep homeostasis, but are not impaired by sleep deprivation. We then show that mns flies carry a point mutation in a conserved domain of the Shaker gene. Moreover, after crossing out genetic modifiers accumulated over many generations, other Shaker alleles also become short sleepers and fail to complement the mns phenotype. Finally, we show that short-sleeping Shaker flies have a reduced lifespan. Shaker, which encodes a voltage-dependent potassium channel controlling membrane repolarization and transmitter release, may thus regulate sleep need or efficiency.     

Partial inhibition of CDK4 gene expression leads to the extension of G1 phase of V79-8 cells

V79-8 is an abnormal cell line which does not have detectable G1 and G2 phases in its cell cycle. This cell line is derived from V79 cell line which has Gl phase but lacks G2 phase. By using an anti-sense approach, CDK4 gene expression was partially inhibited to find whether CDK4 might contribute to the lack of Gl phase in V79-8 cells. Anti-CDK4 anti-sense plasmid was constructed and used to transfect V79-8 cells. Clones of transfected cells (V79-8-asCDK4) were examined, in comparison with V79-8 cells, to determine its growth curve, cell doubling-time (GT), the level of CDK4 gene expression and the levels of expression of some other growth related genes. V79-8-asCDK4 cells showed a slower growth rate with a doubling time 2.5-h longer than that of V79-8 cells. A flow cytometry (FCM) analysis demonstrated that the 2.5 h increase of the doubling time of V79-8-asCDK4 cells was mainly due to the appearance of Gl phase because its G2 + M phase was not significantly different from that of V79-8 cells. The decrease of CDK4 gene expression in V79-8-asCDK4 cells was shown by Northern-blot. Changes in the expression levels of the growth-related genes TGF-β, cyclin D1 and Rb were also detected in V79-8-asCDK4 cells. CDK4 functions mainly in G1 and at the transition between G1 and S phases. Expression of an anti-sense CDK4 gene fragment reduces the levels of endogenous CDK4, CDK4/cyclinD kinase activity and the phosphorylation of Rb. These events may postpone the inactivation of the check-point leading to the delay of entry into S phase and the reappearance of G1 phase in V79-8-asCDK4 cells.     

拟南芥一氧化氮相关突变体在干旱胁迫下抗旱相关基因表达的研究

据报道,拟南芥一氧化氮（nitric oxide,NO）合成缺陷突变体noa1较野生型Col-0抗旱,而个别抗旱相关基因表达的增强是其抗旱机理之一.为了证实该结果及研究NO信号分子在抗旱中的作用,系统地对8种共12个不同类型的抗旱相关基因在干旱处理不同时间的拟南芥野生型和noa1及亚硝基谷胱甘肽还原酶功能缺失突变体gsnor1-3间的表达情况进行了反转录PCR分析.研究结果表明,抗旱相关基因的表达在拟南芥不同基因型间无明显差异,noa1的耐旱性与抗旱相关基因的表达无显著相关性.     

Genetic analysis and gene mapping of leafy head （lhd）, a mutant blocking the differen-tiation of rachis branches in rice （Oryza sativa L.）

Flowers, fruits and seeds are products of plant re- productive development and provide the important sources of foods for humans. Therefore, the moleculargenetic mechanisms of floral development have been ahotspot of research of plant developmental biology[1]. Rice is one of the most important staple food crops. Theoutcome of its reproductive development would determine the yield and quality of grains. Rice is also a model plantof cereals. Hence, the study of rice reproductivedevelopment, esp…