玉米大斑病菌cDNA文库的构建及转录因子StMR1互作蛋白的筛选

【目的】筛选玉米大斑病菌(Setosphaeria turcica)转录因子的互作蛋白,解析黑色素调控转录因子StMR1调控玉米大斑病菌致病性的分子机制。为解析玉米大斑病菌侵染过程中转录因子的调控网络,阐明病菌的致病机理提供参考。【方法】收集玉米大斑病菌菌丝和孢子不同萌发阶段作为试验材料,采用Gateway方法构建玉米大斑病菌cDNA文库,使用同源重组的方法构建转录因子StMR1的诱饵载体,采用酵母双杂交技术筛选其互作蛋白并进行一对一验证。【结果】构建的玉米大斑病菌文库插入的平均片段长度大于1000 bp,初级文库及次级文库的库容量为1.2×107和1.04×107CFU,重组率为100%,可以用于酵母双杂交筛选。成功构建可以用于筛库的诱饵载体pGBKT7-StMR1,经初筛与复筛得到3个互作蛋白,一对一验证短链脱氢酶、糖基转移酶、富含亮氨酸重复序列蛋白均与转录因子StMR1存在互作。【结论】成功构建了丰富度高且质量好的玉米大斑病菌cDNA文库并筛选到了与转录因子StMR1互作的蛋白。

白菜种子cDNA酵母文库的构建及BrTTG1互作蛋白的筛选及分析

【目的】通过构建白菜种子的cDNA文库,筛选WDR 40蛋白TRANSPARENT TESTA GLABRA 1(TTG1)的互作蛋白,探究TTG1参与MBW三元复合体调控种皮原花青素形成的分子机制。【方法】以棕籽白菜自交系‘B147’的种子为材料,提取总RNA并建立cDNA文库,通过gateway技术构建诱饵载体pGBKT7-TTG1并进行酵母双杂交筛库。【结果】酵母文库库容为1.2×10^(7)CFU,文库滴度是5.0×10^(7)CFU/mL,插入片段平均长度大于1000 bp,诱饵载体在酵母中无自激活活性。通过构建的诱饵载体pGBKT7-TTG1与构建的cDNA文库杂交,共获得了38个阳性互作蛋白,功能预测显示其中一个蛋白注释为MYB转录因子,注释为MYB73,序列分析结果显示该基因含有R2R3-MYB型抑制子保守基序C1和C2,推测该基因为白菜中参与种皮颜色形成的R2R3-MYB型抑制子,暗示着白菜中可能存在不同MYB转录因子参与的调控网络,影响着原花青素的形成。【结论】本研究构建了白菜种子组织的酵母双杂交cDNA文库,获得了38个TTG1阳性互作蛋白,首次挖掘到了可能影响白菜种皮颜色原花青素形成的R2R3-MYB型抑制子MYB73,为后期探究白菜种皮原花青素的调控网络奠定良好的基础。

矢车菊不同颜色花瓣酵母cDNA文库的构建

【目的】矢车菊花瓣的蓝色呈色和品种间花色变异的分子调控机制尚不明晰。本研究采用Gateway技术构建了矢车菊6个不同花色品种花瓣的酵母cDNA文库,以期进一步通过酵母单杂交或双杂交技术筛选参与调控花瓣呈色的关键互作蛋白。【方法】本研究以白色、粉色、红色、蓝色、紫色和墨色矢车菊花瓣为材料,提取总RNA后分离和纯化mRNA,合成双链cDNA后依次进行BP重组反应和LR重组反应,分别获得初级和次级文库。最后将次级文库质粒转化酵母Y187,获得矢车菊不同颜色花瓣的酵母cDNA文库。【结果】质量鉴定结果显示:初级文库的库容量为1.3×10^(7) CFU,重组率为100%,且插入片段长度均在1000 bp以上;次级文库的库容量为1.6×10^(7) CFU,重组率为100%,且插入片段长度均在1000 bp以上。酵母文库的滴度为3.5×10^(7) CFU/mL,随机挑选的24个单克隆经PCR检测后均扩增出明亮条带,重组率为100%,插入片段长度均大于1000 bp。【结论】本研究构建的矢车菊不同颜色花瓣酵母cDNA文库的质量较高,能满足酵母文库筛选的试验要求,为后续探究矢车菊花瓣的蓝色呈色和品种间花色变异的分子调控机制提供了材料基础。

麦根腐平脐蠕孢cDNA文库的构建及BsTup1互作蛋白筛选

【目的】深入探究麦根腐平脐蠕孢(Bipolaris sorokiniana)生长发育及致病力的分子作用机制,并鉴定BsTup1的互作蛋白。【方法】利用麦根腐平脐蠕孢(B.sorokiniana)孢子和不同时期的菌丝体为材料,构建酵母双杂交cDNA文库,以BsTup1基因为诱饵来筛选酵母双杂交文库,确定与BsTup1相互作用的蛋白。【结果】1)利用SMART(switching mechanism at 5′end of the RNA transcript)技术首次成功构建了麦根腐平脐蠕孢(B.sorokini-ana)分生孢子和菌丝体的混合cDNA文库。文库鉴定结果表明,构建的cDNA文库库容为4.8×10^(7) cfu·mL^(-1),文库插入片段重组率达100%且平均大小为1000 bp。2)构建了pGBKT7-BsTup1诱饵载体,无自激活活性。3)使用诱饵蛋白载体pGBKT7-BsTup1对麦根腐平脐蠕孢(B.sorokiniana)酵母双杂交cDNA文库进行筛选,经测序、序列比对和酵母回转验证,获得38个与BsTup1相互作用的候选蛋白。【结论】成功构建了麦根腐平脐蠕孢(B.sorokiniana)的cDNA文库,并鉴定出38个与BsTup1相互作用的候选蛋白。

橡胶树膜系统酵母双杂交cDNA文库构建及HbSRPP7互作蛋白筛选

橡胶树橡胶粒子上的蛋白质在橡胶生物合成一系列反应过程中起着关键作用,它们直接决定着橡胶烃分子的数量和大小,影响天然橡胶的产量和质量。小橡胶粒子蛋白(small rubber particle protein,SRPP)是丰度仅次于橡胶延伸因子(rubber elongation factor,REF)的橡胶粒子蛋白组分,与橡胶粒子发育和橡胶生物合成密切相关。目前已知橡胶粒子上存在多种SRPP家族蛋白,但大部分成员的功能尚不清楚。SRPP可能通过与其他橡胶粒子蛋白相互作用发挥功能。为了筛选SRPP蛋白家族成员之一Hb SRPP7的互作蛋白,本研究利用位点特异性重组技术构建了原始库容为1.5×10^(7)CFU的均一化橡胶树胶乳膜蛋白酵母双杂交系统(membrane yeast two-hybrid system,MYTH)cDNA文库,该文库插入片段平均长度大于1500 bp,重组率约为100%。构建了用于MYTH系统筛选HbSRPP7互作蛋白的pBT3STE-SRPP7和pBT3SUC-SRPP7诱饵载体并确认其能在NMY32酵母菌株中正确表达,无自激活活性。使用pBT3STE-SRPP7诱饵质粒对胶乳MYTHcDNA文库进行筛选,获得21个HbSRPP7候选互作的蛋白,包括3个REF家族蛋白(HbREF1、HbREF3和HbREF8)、2个SRPP家族蛋白(HbSRPP1、HbSRPP2)、2个活性氧清除相关蛋白(thioredoxin H-type-like、L-ascorbate peroxidase 2)以及5个胁迫相关蛋白(high mobility group Bprotein 2-like、RPM1-interacting protein 4-like、stress-related protein-like、salt stress-induced hydrophobic peptide ESI3-like和F-box/kelch-repeat protein)。结果显示HbSRPP7除了可能通过与橡胶生物合成相关的橡胶粒子蛋白互作参与橡胶生物合成,也可能通过与生物和非生物逆境胁迫相关蛋白互作,响应橡胶树乳管生物和非生物逆境胁迫系统信号,参与橡胶粒子上的橡胶生物合成调控。该研究结果有助于了解SRPP家族蛋白的功能,为揭示橡胶粒子上参与橡胶生物合成的蛋白复合体组成,阐明橡胶生物合成及其调控的分子机制奠定基础。

盐碱胁迫诱导的猴樟酵母cDNA文库构建及CbP5CS上游调控因子筛选

盐碱土壤环境是限制猴樟引种推广的主要因素,脯氨酸是植物适应盐碱胁迫过程中主要的渗透调节物质,筛选并鉴定出调控脯氨酸合成的转录因子对于猴樟耐盐碱分子机理研究具有重要意义。以猴樟实生苗为材料,在水培培养基础上,采用0 mmol/L和10 mmol/L的Na_(2)CO_(3)溶液分别进行处理,选取处理6 h、48 h的根系组织,提取总RNA,构建盐碱胁迫诱导的猴樟根系酵母c DNA文库;以猴樟根系总DNA为模板,克隆CbP5CS启动子序列,采用Y1H酵母单杂交技术筛选出与CbP5CS启动子存在互作的蛋白,并通过高通量测序技术鉴定出调控猴樟脯氨酸合成的转录因子。结果表明,所构建的cDNA文库库容为4.88×10^(7)CFU/mL,总克隆数为9.76×10^(7)CFU,文库插入片段平均长度在1000 bp左右,cDNA片段重组率为100%,符合酵母杂交试验的要求。克隆出的CbP5CS启动子序列长2012 bp,成功构建出诱饵质粒pHIS2-CbP5CS,利用共转化方法从文库中筛选到31个与CbP5CS互作的EST序列。经酵母回转验证,31个EST序列均与CbP5CS存在互作。经NGS测序和BLAST比对搜索,获得6个转录因子基因,分别为锌指CCCH结构域蛋白25异构体x1、AtbHLH104、转录因子TFIIIC、RING/FYVE/PHD锌指超家族蛋白、GATA型锌指转录因子家族蛋白、AtbHLH96。以上结果为进一步研究植物脯氨酸代谢响应盐碱胁迫的分子机制奠定基础。

甘蓝型油菜-核盘菌酵母双杂交cDNA文库构建及BnJar1互作蛋白筛选

油菜与核盘菌相互作用的过程中,JA(茉莉酸)合成相关基因表达量升高,但是JA信号传递却受到了抑制,推测核盘菌分泌的效应蛋白可能直接或间接作用于JAR1蛋白,使其活性降低,从而抑制依赖JA途径的油菜防御系统。前期通过转录组测序获得了差异表达基因BnJar1全长序列,为进一步揭示BnJar1基因参与油菜-核盘菌相互作用过程的机理,本研究对BnJAR1蛋白进行生物信息学分析和预测,构建了核盘菌-油菜互作表达基因酵母文库,并以BnJar1作为诱饵蛋白对文库进行酵母双杂交筛选,获得了5个来自油菜的互作蛋白:丙二烯氧化物环化酶2(BnAOC2)、COP9信号复合物(BnCOP9)、4a-羟基四氢生物蝶呤脱水酶(BnDcoH)、腈水解酶2(BnNIT2)和茎特异性蛋白(BnTSJT1);2个来自核盘菌的互作蛋白:MFS结构域蛋白(SsMFS)和Rho3 GTP酶(SsRho3)。相关结果为研究油菜-核盘菌的相互作用,挖掘致病或抗病相关基因,进一步解析其机理奠定了基础。

Construction of a Normalized Full-Length cDNA Library of Sesame Developing Seed by DSN and SMART^(TM)

Sesame （Sesamue indicum L.） is one of the most important oilseed crops with high oil yield. Here, we described a simple and efficient method for constructing a normalized cDNA library from a high oil content cultivar of sesame Zhongzhi 14, during its oil accumulation stages. It combined switching mechanism at 5？end of RNA transcript （SMART） technique and duplex-specific nuclease （DSN） normalization methods. Double-stranded cDNAs were synthesized from mRNAs, processed by normalization and Sfi I restriction endonuclease, and finally the cDNAs were ligated to pDNR-LIB vector. The ligation mixture was transformed into Escherichia coli DH10B by electroporation. The capacity of the library was 1.0？06 clones in this library. Gel electrophoresis results indicated the fragments ranged from 700 to 2 000 bp, with the average size of 1 800 bp. Random picking clones showed that the recombination rate was 100%. The results showed that the cDNA library constructed successfully was a full-length library with high quality, and could be used to screen the genes related to development of oil synthesis.

Construction and analysis of a subtracted cDNA library of Betula platyphylla female inflorescence

Female inflorescence of Betula platyphylla was sampled at an interval of eachtwo days to analyze the background of gene expression in floral phase. On the basis of SMARTstrategy, the driver cDNA was obtained from total RNA of the last sample and the tester cDNA wasfrom that of the others by RT-PCR which were subsequently used to construct a subtracted cDNAlibrary. The result of the ESTs (expression sequence tags) blastX showed that the genes in thesubtracted cDNA library could be mainly clustered into 5 groups related to metabolism,transportation and signal transduction, cell cycle, stress response, and regulation. Therelationship between gene expression and development was also discussed.

Construction of SMART cDNA Library of Sheep Ovary and Identification of Candidate Gene by Homologous Cloning

The cDNA library of an ovary from Small Tail Han sheep before estrus was constructed by switching mechanism at 5＇ end of RNA transcript （SMART） approach. This library had a plaque titer of 1 x 109 pfu mL-1 and a 96% recombinant ratio of which the fragment length of inserted average cDNA sequences was 1.0 kb. Based on bioinformatics analysis of the sequences, we obtained 338 expressed sequence tags （ESTs） from 380 cDNA clones which indicated 191 contigs. These contigs consist of 89 unmatched ESTs, 9 homologous known genes in sheep, and 93 homologous sequences in species of mouse, bovine, and human beings, including 19 sequences expressed in the ovary or follicle and 14 unknown sequences. Several candidate genes associated with sheep reproduction trait such as epidermal growth factor （EGF）, estrogen receptor （ESR）, Inhibin, follicle stimulating hormone receptor （FSHR）, prostaglandin （PG）, and transforming growth factor-β （TGF-β） were identified and the homologous were cloned from this library, which will contribute to compile expression profiles and find the major genes of prolificacy of Small Tail Han sheep.

The EST Analysis of A Suppressive Subtraction cDNA Library of Chinese Wild Vitis pseudoreticulata Inoculated with Uncinula necator

Uncinula necator is a worldwide serious fungus disease causing annual heavy lost on grapevine production. In order to get more informations on defense related EST sequences and help breeding program, we constructed and characterized a suppression subtractive hybridization cDNA library with artificially inoculated leaves and control Chinese wild Vitis pseudoreticulata clone Baihe-35-1, which is highly resistant to powdery mildew. In the library, the length of 58 EST fragments known as putative functions varied from 130 to 800 bp, and 60% of the ESTs exhibited high similarity to known sequences in database of GenBank with BLASTX analysis. These genes were involved in stress/defense response, detoxification, signal transduction, disease defense, and etc., and 14 ESTs remained unknown or hypothetical proteins, which may be new genes. The experiment provided an important basis for studying the disease-resistance mechanism and obtaining the genes for the aim of improving grapevine powdery mildew resistance.

Generation and Analysis of Expressed Sequence Tags(ESTs) from Muscle Full-Length cDNA Library of Wujin Pig

Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Construction of a full-length cDNA library is an effective way to understand the expression of functional genes in muscle tissues. In addition, novel genes for further research could be identified in the library. In this study, we constructed a full-length cDNA library from porcine muscle tissue. The estimated average size of the cDNA inserts was 1 076 bp, and the cDNA fullness ratio was 86.2%. A total of 1 058 unique sequences with 342 contigs （32.3%） and 716 singleton （67.7%） expressed sequence tags （EST） were obtained by clustering and assembling. Meanwhile, 826 （78.1%） ESTs were categorized as known genes, and 232 （21.9%） ESTs were categorized as unknown genes. 65 novel porcine genes that exhibit no identity in the TIGR gene index of Sus scrofa and 124 full-length sequences with unknown functions were deposited in the dbEST division of GenBank （accession numbers： EU650784-EU650788, GE843306, GH228978-GH229100）. The abundantly expressed genes in porcine muscle tissue were related to muscle fiber development, energy metabolism and protein synthesis. Gene ontology analysis showed that sequences expressed in porcine muscle tissue contained a high percentage of binding activity, catalytic activity, structural molecule activity and motor activity, which involved mainly in metabolic, cellular and developmental process, distributed mainly in intracellular region. The sequence data generated in this study would provide valuable information for identifying porcine genes expressed in muscle tissue and help to advance the study on the structure and function of genes in pigs.

Construction and Characterization of a cDNA Expression Library for the North American Ginseng Root Tissues

The root of Panax ginseng plant undergoes a specific developmental process to become a biosynthesis and accumulation tissue for ginsenosides. To identify and analyze genes involved in the biosynthesis of ginsenoside, we constructed and characterized a full-length cDNA library for 6-year-old North American ginseng. The titer of primary cDNA library is 1.2 × 10^6 pfu/mL, the titer of amplified library is 2. 6 × 10^10 pfu/mL and the rate of recombinant is above 86%. The insert size ranges from 0. 3 to 2.0 kb. Sequencing results show that 18 of 58 genes are high homologous to the genes （GBRS, GBR3 and GBR1 ） known in GenBank, which are involved in biosynthesis of ginsenoside in North American ginseng plant; 16 of 58 genes are novel genes. The full-length cDNA library of North American ginseng root tissues is essential for the cloning of genes known and it is also an initial key for the screening and cloning of new genes.

Representative appressorium stage cDNA library of Magnaporthe grisea

A mature appressorium cDNA library of rice blast fungus, Magnaporthegrisea, was constructed in a λ TriplEx2 vector by SMARTTM cDNA library containing 2.37×10^6 independent clones about 100% of which harbor foreign cDNA inserts with average size of 660 bp. Of 9 randomly selected clones, 2 expressed sequence tags (ESTs) sequences did not have homologous EST sequences of M. grisea in Gen Bank. The appressorium cDNA library is suitable for gene expression analysis and function analysis of the late stages of appressorium formation and the early stages of penetration of M. grisea.

Construction of a Full-Length cDNA Library of Solen grandis Dunker and Identification of Defense- and Immune-Related Genes

The basic genetic characteristics, important functional genes, and entire transcriptome of Solen grandis Dunker were investigated by constructing a full-length cDNA library with the ‘switching mechanism at the 5'-end of the RNA transcript'(SMART) technique. Total RNA was isolated from the immune-relevant tissues, gills and hemocytes, using the Trizol reagent, and cDNA fragments were digested with Sfi I before being ligated to the pBluescript II SK* vector. The cDNA library had a titer of 1048 cfu μL-1 and a storage capacity of 1.05×106 cfu. Approximately 98% of the clones in the library were recombinants, and the fragment lengths of insert cDNA ranged from 0.8 kb to 3.0 kb. A total of 2038 expressed sequence tags were successfully sequenced and clustered into 965 unigenes. BLASTN analysis showed that 240 sequences were highly similar to the known genes(E-value < 1e-5; percent identity >80%), accounting for 25% of the total unigenes. According to the Gene Ontology, these unigenes were related to several biological processes, including cell structure, signal transport, protein synthesis, transcription, energy metabolism, and immunity. Fifteen of the identified sequences were related to defense and immunity. The full-length cDNA sequence of HSC70 was obtained. The cDNA library of S. grandis provided a useful resource for future researches of functional genomics related to stress tolerance, immunity, and other physiological activities.

Construction and characterization of a full-lengh cDNA library from non-fresh Giardia lamblia

Objective:To construct rapidly a full-length cDNA library from nanogram amounts total RIMA of Giardia lamblia(G.lamblia) trophozoites stocked in RNA stabilization reagent.Methods:Total RNA of Giardia was extracted using Trizol reagent.A full-length cDNA library of G.lamblia trophozoites was constructed by a long-distance PCR(LD-PCR) method.The recombinant rate and the coverage rate of full-length clones of the library were evaluated.The inserted fragments were identified and sequenced by PCR amplification.Results:The titer of cDNA library was 3.85×10~7 pfu/mL.The length of inserted fragments ranged from 0.4 to 2.5 kb,and the recombination efficiency accounted for 100%(20/20).The coverage rate of full-length clones is high(17/20). Conclusions:The RNA stabilization reagent may be used to fix the cells and prevent the RNA in cells even though delivered under normal atmospheric temperature.The long-distance PCR can be used to construct a full-length cDNA library rapidly and it needs less RNA than the traditional method from mRNA.

Construction of a Full-Length cDNA Library of Gossypium hirsutum L. and Identification of Two MADS-Box Genes

A full-length normalized cDNA library for the flower development stages of short-season cotton （Gossypium hirsutum L.） （CCRI36） was constructed. A total of 3 421 clones were randomly selected for sequencing, with a total of 3 175 effective sequences obtained after removal of empty-carriers and low-quality sequences. Clustering the 3 175 high-quality expressed sequence tags （ESTs） resulted in a set of 2 906 non-redundant sequences comprised of 233 contigs and 2 673 singletons. Comparative analyses indicated that 913 （43.6%） of the unigenes had homologues with function-known genes or functionassumed genes in the National Center for Biotechnology Information. In addition, 763 （36.4%） of the unigenes were functionally classified using Gene Ontology hierarchy. Through EST alignment and the screening method, the full-length cDNA of two MADS-box genes viz., GhMADSll and GhMADS12 were acquired. These genes may play a role in flower development. Phylogenetie analysis indicated that GhMADS11 and GhMADS12 had high homology and close evolutionary relationship with AGL2/SEP-type and PI-type genes, respectively. The expression of both GhMADSll and GhMADS12, genes was high in reproductive organs. In floral organs, GhMADSll expression was high in petals （whor12） and ovules, while GhMADS12 expression was high in petals （whor12） and stamens （whor13）. Results show that the EST strategy based on a normalized cDNA library is an effective method for gene identification. The study provides more insights for future molecular research on the regulation mechanism of cotton flower development.

Construction and Characterization of a cDNA Library from the Pulp of Coconut (Cocos nucifera L.)

To investigate the gene expression profile of endosperm development, a cDNA library was constructed and characterized from the pulp of coconut at different developmental stages. The constructed cDNA library incorporated approximately 1 × 10^7 clones in total, and the size of the insertion fragments ranged from 800 to 2 000 bp. Sequencing results of 100 randomly picked clones showed that the recombination rate was 96%. In subsequent sequence analysis, 41 clones （41%） were homologous to known function proteins, and 23 clones showed high amino acid identity （more than 80%） with the corresponding genes of different plants. Semi-quantitative RT-PCR indicated that oleosin and globulin genes are pulpspecific expression, and have differential expression level in different developmental stage. Clone 29, recognized as homologous to KIAA1239 protein （Homo sapiens）, was observed to occur nine times, indicating that this gene may be over-expressed during the endosperm development stage. However, the homologous protein was found only in mammals, and the detailed function is still unknown. Elucidation of the functional characterization of these genes will be carried out immediately.

Construction of cDNA Library from the Antenna of Chrysopa pallens(Rambur)

A full-length cDNA library from the antenna of Chrysopa pallens （Rambur） was constructed based on switching mechanism at 5＇ end of RNA transcript （SMART） system. The purified double-stranded cDNA was ligated to vector SMART2IFD, and transformed into gscherichia coli DHSa by electroporation. The li-brary constructed for female and male reached high titers of 2.1 × 106^ and 1.8 × 106^ pfu/mL, respectively. PCR results showed that the inserts varied from 400 bp to 2 000 bp with the average size larger than 500 bp and the recombination rate over 93.0%. FuRher studies on those genes and large scale sequencing of the library may be helpful in screening new olfactory related genes in C. pallens.