在丝瓜和黄瓜发育过程中肌动蛋白基因的表达

对肌动蛋白基因在丝瓜（Ｌｕｆｆａ ｃｙｌｉｎｄｒｉｃａ Ｌ．）和黄瓜（Ｃｕｃｕｍ ｉｓ ｓａｔｉｖｕｍ Ｌ．）各器官的表达进行了研究．Ｎｏｒｔｈｅｒｎ ｂｌｏｔ和Ｄｏｔｂｌｏｔ结果表明,肌动蛋白基因在丝瓜和黄瓜中表现出器官特异性表达． 首先,肌动蛋白基因在丝瓜幼苗发育过程中表现明显的发育阶段特异性． ３０ ｄ 苗茎的ｍ ＲＮＡ 水平为８ ｄ 苗的根、子叶和１５ ｄ 苗的根、下胚轴的４～６ 倍, 同时为开花植株茎和叶片的ｍ ＲＮＡ 水平的１０～１２ 倍． 其次,肌动蛋白基因在黄瓜中表现器官特异性表达,它们倾向于在黄瓜幼嫩果实中（开花后１５ ｄ）特异表达     

国兰肌动蛋白基因片段的克隆与表达分析

根据兰科植物(Orchidaceae)蝴蝶兰(Phdaenopsis)的肌动蛋白基因(Actin)序列设计跨内含子引物,分别以cDNA第一链和基因组DNA为模板,采用RT-PCR和PCR方法从墨兰(Cymbidium sinense)、春兰(C.goeringii)中分离出Actin基因的同源片段.序列分析结果表明:墨...     

箭筈豌豆两个肌动蛋白基因片段的克隆及序列分析

通过同源克隆获得了箭筈豌豆两个不同的Actin基因片段,为研究该箭筈豌豆其它基因的表达状况提供了内标参照。根据近缘物种Actin基因序列设计一对引物,通过RT-PCR技术分别从叶片和果实材料中克隆获得了两条不同的Actin基因片段。生物信息学分析表明,叶片中克隆的片段长度604 bp,编码201个氨基酸;果实中克隆的片段长度677 bp,编码225个氨基酸。两条序列与其它物种Actin基因的碱基序列相似度高于80%,氨基酸序列相似度高于93%。将来自叶片和果实的两条序列分别命名为VsACT7和VsACT11,并在GenBank注册,登录号分别为HM004434和GU946218。     

枣树肌动蛋白基因cDNA片段的克隆及其表达分析

根据GenBank中登录的植物肌动蛋白基因同源核苷酸保守序列设计引物,以壶瓶枣(Ziziphus jujuba Mill.Hupingzao)刚萌发结果枝构建的cDNA文库为模板,利用PCR技术得到了一个478 bp的cDNA片段.与其它植物同源序列进行分析表明,其核苷酸序列的同源性在70%以上,氨基酸序列的同源性在85%以上,证明它是肌动蛋白基因在枣树中的同源cDNA片段,命名为ZjAT1(Ziziphus jujuba actin1),GenBank登录号为EU251882.DNA印迹分析结果表明,ZjAT1在枣树基因组中以单拷贝的形式存在.对不同发育阶段的不同器官组织进行了RT-PCR分析,结果显示ZjAT1基因只在花和幼果中有明显表达,在毛根、幼茎、叶片、成熟茎尖、成熟茎段以及成熟果实的果肉和种仁中都没有检测到表达.     

白沙蒿肌动蛋白基因核心片段的克隆和序列分析

本研究以荒漠植物白沙蒿总RNA为模板,运用RT-PCR方法扩增出肌动蛋白基因核心序列.将获得的片段克隆到T载体后进行测序,序列分析表明:白沙蒿肌动蛋白基因核心片段长599 bp,编码198个氨基酸.将该序列在GenBank中注册,并与多种植物肌动蛋白序列进行同源性比较,发现该片段的核酸序列同源性在75%以上,氨基酸序列同源性在85%以上,具有高度保守性.     

柠条锦鸡儿肌动蛋白基因的克隆和表达稳定性分析

以几种豆科植物中肌动蛋白的氨基酸保守序列设计简并引物,采用RT—PCR结合RACE扩增技术,从柠条锦鸡儿叶片中克隆到一个编码肌动蛋白的基因,命名为CkACT。该基因cDNA全长为1655bp,开放阅读框1134bp,编码377个氨基酸。氨基酸比对分析表明,该基因编码的氨基酸与其他植物肌动蛋白基因具有较高的同源性。不同组织中的表达基本上一致,不同发育时期的基因表达相似,低温、NaCl、干旱和ABA处理后的表达强度没有明显差异,说明CkACT基因表达稳定。     

山药Actin基因片段的克隆及表达分析北大核心CSCD

通过山药Actin基因的克隆和表达分析,为研究山药生长发育中肌动蛋白的作用及其他基因的表达和调控奠定基础。根据Gen Bank中已经公布的其他植物肌动蛋白基因(Actin)的保守序列设计一对简并引物,采用RT-PCR技术从山药块茎中分离出1个Actin基因cDNA片段,命名为DoActin。片段长度为1 091 bp,编码357个氨基酸,并提交Gen Bank(登录号:KU669295)。与NCBI核酸和蛋白质数据库序列比对,该序列与其他植物Actin基因核苷酸序列的同源性均在83%以上,氨基酸序列的同源性均在97%以上。进化分析结果显示,DoActin与海枣Actin-2、木本棉Actin-7的亲缘关系最近。实时定量PCR结果显示,DoActin在山药叶片、地上茎和地下块茎以及不同发育期的块茎和叶片中表达量相对稳定,表明其适宜作为山药的内参基因。     

多浆旱生植物霸王Actin基因片段的克隆及序列分析

根据其他植物Actin基因的保守序列设计一对简并性引物,以霸王叶片总RNA为模板,采用RT-PCR的方法扩增出Actin基因片段并克隆到PUCm-T载体.阳性克隆经PCR鉴定后进行测序,序列分析结果表明:该片段长598bp,编码198个氨基酸;所得序列与GenBank中注册的Actin基因序列的同源性均在82%以上,与其他肌动蛋白的氨基酸序列的同源性达91%以上.     

春兰CgSEP3基因的克隆和表达分析

该研究采用RT-PCR和RACE技术从春兰(Cymbidium goeringii)中分离到1个SEPALLATA3(SEP3)基因。序列分析表明,该基因含有1个732bp的开放阅读框(ORF),共编码243个氨基酸。系统进化树分析显示,该基因是MADS-box基因家族AP1/AGL9组SEP的同源基因,其编码蛋白与其它植物SEP3类蛋白具有较高的一致性,命名为CgSEP3(登录号为KF924272)。实时荧光定量分析表明,CgSEP3在春兰花器官中均有表达,其中在唇瓣、侧瓣和萼片中的表达量较高,在子房和蕊柱中的表达量较低;而且CgSEP3在花发育各个时期都有表达,在1~2cm的花芽中表达量最高,在盛开的花中的表达量最低。研究认为,CgSEP3基因可能在春兰花瓣和萼片的形成过程中具有重要作用。     

青杨脊虎天牛CYP4G2基因片段的克隆、序列分析与表达

根据报道的十几种昆虫CYP4家族基因的氨基酸序列保守区域设计一对引物,利用RT-PCR技术扩增编码青杨脊虎天牛Xylotechus rusticus中肠细胞色素氧化酶CYP4G2蛋白的cDNA片段,构建原核表达载体pET-CYP4G2,将其转化入大肠杆菌Escherichia coli JM109中表达。序列分析结果表明,该基因(CYP4G2,GenBank登录号为EF429250)保守区域阅读框全长387 bp,编码129个氨基酸残基,预测分子量和等电点分别为16.9 kD和5.75;推导的氨基酸序列与已报道的昆虫CYP4家族氨基酸序列一致性较高（63%～86%）,且具有细胞色素氧化酶的典型特征。IPTG诱导后,SDS-PAGE电泳检测到一条22 kD大小的外源蛋白,与预测融合蛋白的分子量大小相应。CO差光谱分析证明重组菌表达了有活性的pET-CYP4G2。     

硝酸银对雌性黄瓜植株三种氧化酶同工酶的影响

雌性黄瓜植株经硝酸银处理后其茎尖和真叶过氧化物酶活性极显著地增加,茎尖24小时、真叶36小时酶活性达到最大值,分别增加了178.2%和284.6%,随后酶活性逐渐下降,但酶活性仍然较对照植株高。多酚氧化酶和超氧化物歧化酶的同工酶活性也增加。同时硝酸银能诱发黄瓜植株过氧化物酶、多酚氧化酶和超氧化物歧化酶产生新的同工酶, 用等电聚焦更能有效地观察新产生的同工酶。     

硝酸银对雌性黄瓜植株三种氧化酶同工酶的影响

雌性黄瓜植株经硝酸银处理后其茎尖和真叶过氧化物酶活性极显著地增加,茎尖２４小时、真叶３６小时酶活性达到最大值,分别增加１７８．２％和２８４．６％,随后酶活性逐渐下降,但酶活性仍然较对照植株高。多酚氧化酶和超氧化物歧化酶的同工酶活性也增加。同时硝酸银能诱发黄瓜植株过氧化物酶、多酚氧化酶和超氧化物歧化酶产生新的同工酶。用等电聚焦更能有效地观察新产生的同工酶。     

Photochlorophyll Biosynthesis in Cucumber (Cucumis sativus, L.) Cotyledons

The formation of protochlorophyllide and protochlorophyllide phytyl ester was investigated during etioplast biogenesis in order to study the biosynthetic relation of these two compounds. Protochlorophyllide accumulates slowly during the first 2 days of germination, its rate of formation increases sharply during the 3rd day, and then it decreases. Protochlorophyllide phytyl ester starts accumulating a day later; its formation coincides with the initiation of xanthophyll biosynthesis. Kinetic analysis of specific radioactivities after ¹⁴C labeling of the protochlorophyll pools does not support the currently accepted conversion of protochlorophyllide into protochlorophyllide phytyl ester, but suggests that both compounds originate simultaneously from a common precursor pool.     

Genetic Diversity and Population Structure of Cucumber (Cucumis sativus L.)

Knowing the extent and structure of genetic variation in germplasm collections is essential for the conservation and utilization of biodiversity in cultivated plants. Cucumber is the fourth most important vegetable crop worldwide and is a model system for other Cucurbitaceae, a family that also includes melon, watermelon, pumpkin and squash. Previous isozyme studies revealed a low genetic diversity in cucumber, but detailed insights into the crop''s genetic structure and diversity are largely missing. We have fingerprinted 3,342 accessions from the Chinese, Dutch and U.S. cucumber collections with 23 highly polymorphic Simple Sequence Repeat (SSR) markers evenly distributed in the genome. The data reveal three distinct populations, largely corresponding to three geographic regions. Population 1 corresponds to germplasm from China, except for the unique semi-wild landraces found in Xishuangbanna in Southwest China and East Asia; population 2 to Europe, America, and Central and West Asia; and population 3 to India and Xishuangbanna. Admixtures were also detected, reflecting hybridization and migration events between the populations. The genetic background of the Indian germplasm is heterogeneous, indicating that the Indian cucumbers maintain a large proportion of the genetic diversity and that only a small fraction was introduced to other parts of the world. Subsequently, we defined a core collection consisting of 115 accessions and capturing over 77% of the SSR alleles. Insight into the genetic structure of cucumber will help developing appropriate conservation strategies and provides a basis for population-level genome sequencing in cucumber.     

Identification and Expression Analysis of D-type Cyclin Genes in Early Developing Fruit of Cucumber (Cucumis sativus L.)

Plant D-type cyclin genes (CYCDs) are important regulators of cell division. However, little is known on their participation during the early developmental stage of cucumber fruit. In this study, cucumber CYCD genes were identified and characterized. The expression levels of these genes during early fruit development were assessed from 0 to 8 days after anthesis (DAA). The results revealed the presence of 13 different CYCD genes, which were named according to identity percentages of the corresponding orthologs in Arabidopsis thaliana and poplar. The genomic organization of each subgroup CYCD was similar to their orthologs in A. thaliana and poplar. The expression levels of CsCYCD genes were analyzed in cucumber fruits under different treatments including natural parthenocarpic fruit, pollinated fruit, and N-(2-chloro-4-pyidyl)-N′-phenyurea (CPPU)-induced parthenocarpic fruit. The highest expression levels of most CsCYCDs genes were at four DAA in natural parthenocarpic and pollinated fruits. Interestingly, the expression patterns of 8 of 13 CsCYCD genes in natural parthenocarpic fruit were similar to those in pollinated fruit, but different from those in CPPU-induced parthenocarpic fruit. Collectively, the results of this study provide insights on the CYCDs involved in cucumber parthenocarpic fruit development.     

Characteristics of Radial Solution Flow in Roots of Cucumber (Cucumis sativus L.)

Low salt roots of Cucumis sativus L. cv. Burpeeana Hybrid weresubjected to iso-ionic treatments in which the external solutionconcentration of K⁺ was maintained at 14 mM. Solution concentrationof varied from 0 to 14 mM, other anions compensating. When Cl^– was the compensating ion, its concentrationin the exudate increased during the first 4 h and thereafterwas nearly the same as that of the external solution in alltreatments containing I mM or more. After 8 h of equilibration the concentration in the exudate increased almost exactly as its concentrationin the external solution. Rates of exudation and K⁺ transportwere almost constant between I and 14 mM KNO₂. More Cl^–was transported from solutions of similar Cl– concentrationwhen was also present. When water transport was inhibited with mannitol in treatments containing both KNO₃and KCI, exudate concentrations of K⁺ and were increased, but exudate concentration of Cl^– was notsignificantly affected except at the highest Cl     

Estimation and Analysis of Cucumber (Cucumis sativus L.) Leaf Cellular Heat Sensitivity

Triphenyl tetrazolium chloride (TTC) reduction by cucumber (Cucumis sativus L. cv Poinsett 76 and cv Ashley) leaf discs was used as a viability assay to examine the effect of temperature pretreatment on the tissue response to acute hyperthermia. Semi-logarithmic plots of TTC reduction as a function of incubation time at different temperatures from 40 to 60[deg]C resembled the heat survival curves of animal cells. Heat inactivation rates were obtained and subjected to "quasi" Arrhenius analyses by analytical methods derived from the animal studies. The Arrhenius plots of TTC reduction rates for cv Ashley leaf discs preincubated at 25 or 37[deg]C and for cv Poinsett 76 preincubated at 37[deg]C were linear with the same activation energy (Ea) of about 80 kcal mol-1. The Arrhenius plot of cv Poinsett 76 preincubated at 25[deg]C was nonlinear with an Ea of about 80 kcal mol-1 at temperatures below 46[deg]C and an Ea of about 27.5 kcal mol-1 at temperatures above 47[deg]C. The significance of these differences is discussed in terms of the role of protein denaturation in the thermal sensitivity of cucumber disc reduction of TTC and the applicability of these methods to the analysis of plant cellular heat sensitivity.     

Flower Formation In vitro by Hypocotyl Explants of Cucumber (Cucumis sativus L.)

Hypocotyl explants of cucumber (Cucumis sativus L.) producedcallus when grown in Murashige and Skoog medium with 0.5 or1.0 µM benzyladenine and 1.5 or 5.0 µm 2, 4-D. Somaticembryos and adventitious buds were formed when callus was transferredto medium without growth regulators. Flowers that were formedin vitro were either staminate or pistillate. Cucumis sativus L, cucumber, embryogenesis, organogenesis, flowering in vitro