参与植物次生代谢调控的转录因子及其在植物次生代谢遗传改良中的应用

转录因子与结构基因的结合,激活合成基因的表达是次生代谢物合成途径启动前的重要分子事件,对植物次生代谢起着十分重要的调节作用。转录因了可激活次牛代谢物合成途径中多个基因协同表达,从而有效启动次生代谢途径。因此,转录因子为揭示植物次生代谢调控机制提供重要工具,转录因子的基因工程可为植物次生代谢的遗传改良提供有效的手段。     

基于转录组测序的花烟草低温胁迫响应转录因子挖掘

为了鉴定参与花烟草低温胁迫的转录因子,对花烟草幼苗进行了4℃低温处理,并在处理后12 h采集其幼苗样本,提取总RNA后,采用高通量测序技术,进行了转录组测序。在对差异表达基因进行GO及KEGG分析的基础上,对参与其中的转录因子进行了挖掘,并采用qRT-PCR的方法,对转录组测序的结果进行了验证。结果表明,低温处理后,花烟草基因表达量变化在2倍以上的基因有8388个(P<0.01),其中,上调表达4229个,下调表达4159个。这些差异表达基因的功能归类于生物过程、细胞组分及分子功能3大类69个GO条目,并显著富集在40条KEGG代谢通路中。同时,在低温胁迫下,花烟草有118个转录因子的表达发生了显著改变,其中,上调表达82个,下调表达36个。这些转录因子属于28个家族,其中,数量最多的为NAC家族19个,其次为ERF家族16个、MYB家族15个、WRKY家族15个。本研究的结果为花烟草低温响应分子机制的研究提供了借鉴。     

植物WRKY转录因子结构及功能研究进展

WRKY蛋白是植物所特有的转录因子家族.因WRKY结构域中的N-端均含有高度保守的WRJKYGQK氨基酸序列而得名.它能够与(T)TGACC(A/T)序列(W*box)发生特异性作用,调节启动子中含W-box元件的调节基因或功能基因的表达,从而参与植物的各种防卫反应,调节植物的发育和代谢等.近些年来.有关WRKY转录因子的研究很多,如模式生物中的拟南芥和水稻基因组中拥有大量的WRKY成员.主要介绍WRKY转录因子的结构特点及生物学功能.     

光诱导香菇菌丝转色阶段的转录因子表达分析

转录因子在真菌环境响应及生理过程中发挥重要的调节作用。本文利用转录组测序（RNA-Seq）技术研究光诱导香菇菌丝转色过程中的转录因子表达变化。转录组测序结果表明,在光照条件下转色的菌丝（313C）与黑暗条件下未转色的菌丝（313W）相比,香菇菌丝中共有68个转录因子基因表达发生变化（48个转录因子上调表达,20个转录因子下调表达）;转色的菌丝（313C）与初始未转色的菌丝（118）相比,香菇菌丝中有80个转录因子基因表达发生变化（49个转录因子上调表达,31个转录因子下调表达）。这些差异表达的转录因子包括WD40、MADS-box、MYB和GATA等家族。另外,样品的两两比较中差异表达的转录因子既存在部分重叠,也表现特异性。其中,313C/313W中有14个特异性差异表达转录因子,313C/118中有26个特异差异表达的转录因子。重叠的转录因子有64个,其中有39个表达水平上调,15个表达水平下调。采用实时荧光定量PCR对几个转录因子进行了表达检测,其中部分转录因子的表达趋势与转录组分析基本相同。这些数据为进一步研究香菇转色的转录调控奠定了一定的基础。     

植物WRKY转录因子家族研究进展

WRKY是植物特有的一类转录因子家族,因含有由WRKYGQK 7个氨基酸组成的保守序列而得名,在拟南芥(Arabidopsis thaliana)中共发现了74个成员.WRKY蛋白能与TTGAC序列(又称W-box)专一结合调节基因转录,其表达主要受病原菌、损伤和信号分子SA的诱导.除主要与植物的抗逆反应和衰老有关外,WRKY也参与植物其他发育和代谢的调控.在植物的抗逆反应过程中,WRKY的表达通常发生在诱导的早期,且不需要蛋白质的重新合成.     

野生稻基因导入系W6023对白叶枯菌的抗谱及转录组差异表达基因分析

水稻白叶枯病是世界性水稻病害,严重威胁水稻的高产和稳产。为了挖掘水稻抗白叶枯病新基因,本研究对一个野生稻基因导入系W6023进行了白叶枯病多菌系接种鉴定及抗谱分析,发现W6023具有广谱抗病性。用强致病菌PXO99诱导W6023及其感病轮回亲本IR24后进行转录组测序,分别获得105644962和91022599条序列,通过GO注释及KEGG富集分析,发现差异表达基因主要富集在次生代谢产物的生物合成、植物激素信号转导及糖代谢途径等方面。在这些差异表达基因中,发现203个基因的表达有显著差异,其中在W6023中上调表达的基因有114个(56.2%),下调表达的有89个(43.8%),而且35.9%分布在第11染色体上。生物信息学分析发现在203个差异表达基因中有16个属于类抗病基因,如NBS-LRR等;14个直接或间接与水稻体内过氧化物的代谢相关,如编码过氧化物酶和金属硫蛋白等;6个编码抗病相关转录因子,如WRKY和NAC等;18个为信号传导相关基因,编码钙调素结合蛋白和萜类合成酶等。随机选择6个W6023中上调表达和3个IR24中上调表达的基因进行RT-PCR及qRT-PCR分析,结果与转录组测序结果一致,表明本研究获得的转录组测序数据结果是可靠的,为以后更深入挖掘W6023的抗病基因及分子机理研究提供了基础。     

WRKY转录因子功能研究进展

植物各种诱导型基因的表达主要受特定的转录因子在转录水平上的调控.转录因子结构和功能的研究近年来成为植物分子生物学、细胞分子生物学和分子遗传学研究领域的重要内容.WRKY转录因子在拟南芥中有74个成员,水稻中有100多个成员,在生物胁迫及非生物胁迫方面发挥着非常重要的作用.该文就近年来国内外关于WRKY转录因子家族的结构与起源进化和在植物损伤、衰老、发育及代谢等过程中参与的调控功能,以及在植物防御反应中对防御相关基因表达的调控及参与的植物激素类信号途径等方面的研究进展进行了综述,为全面解析WRKY转录因子家族的结构与功能提供了新的视点.     

植物WRKY 转录因子家族研究进展

WRKY是植物特有的一类转录因子家族,因含有由WRKYGQK 7个氨基酸组成的保守序列而得名,在拟南芥(Arabidopsis thaliana)中共发现了74个成员。WRKY蛋白能与TTGAC序列（又称W-box）专一结合调节基因转录,其表达主要受病原菌、损伤和信号分子SA的诱导。除主要与植物的抗逆反应和衰老有关外,WRKY也参与植物其他发育和代谢的调控。在植物的抗逆反应过程中,WRKY的表达通常发生在诱导的早期,且不需要蛋白质的重新合成。     

白化菠萝蜜茎2个蛋白激酶和4个转录因子家族分析

为探究蛋白激酶(PKs)和转录因子(TFs)在白化菠萝蜜(Artocarpus heterophyllus)幼苗茎次生生长中的表达变化,基于转录组数据对其差异表达基因(DEGs)进行预测及分类,并对挑选出的2个PKs和4个TFs家族构建系统进化树。结果表明,胞质类受体激酶(RLCK)-VIII家族的DEGs上下调表达各4个,亮氨酸富集重复类受体激酶(LRR-RLK)-X家族Xa和Xb-2分支中的DEGs均下调表达,Xb-1中的均上调,TCP家族的20个DEGs中有15个上调表达,zf-HD和GRF家族中的大多数DEGs上调表达,Alfin-like家族中的DEGs均下调表达。因此,这表明6个家族可能在菠萝蜜茎的次生生长过程和应对非生物胁迫中发挥重要作用。     

拟南芥WRKY68转录调控因子的表达谱分析

WRKY基因家族是主要存在于植物中的转录因子,拟南芥中至少有74个成员。根据锌指结构特征和WRKY结构域的数目,可以将WRKY转录因子分为三大类。拟南芥WRKY68属于第Ⅱ类WRKY蛋白。通过GUS染色和qRT PCR分析各组织部位的表达情况,发现WRKY68在根中的表达量是最高的,其次是幼嫩的叶片和老的荚果中。各种处理条件下的表达水平显示,IAA和高温处理后,WRKY68的表达明显上调,PstDC3000、JA、SA、NAA轻微诱导WRKY68的表达,而Botrytis、NaCl、甘露醇、PEG、脱水、ACC、ABA抑制WRKY68的表达,根据以上实验结果,我们推测WRKY68可能参与生长素和温度调控的植物形态建成及发育过程。     

Characterization of SSEA-1 glycolipids from the brain of a patient with fucosidosis

Neutral glycolipids from the brain of a patient with Fucosidosis were analyzed and two complex glycolipids containing five and eight sugars were isolated from the cortical grey matter. These two glycolipids reacted with antibodies recognizing the SSEA-1 [Le^x(X)] carbohydrate determinant. SSEA-1 glycolipids are normally expressed in human embryonic brain but are found in only small amounts in postnatal human brain. The accumulation of the two SSEA-1 glycolipids in Fucosidosis brain thus represents a defect which affects the normal developmentally regulated decrease in postnatal, expression of these glycolipids, and may be a contributing factor in the abnormal brain development associated with the disease. Chemical characterization of the two isolated glycolipids by gas chromatographic and mass spectrometric analyses has identified the two glycolipids as lacto-N-fucopentaosylceramide (III) and difucosyl-neolactonorhexaosylceramide.Abbreviations DCl direct chemical ionization - FAB tastatiom bombardment - GC gas chromatography - GSLs glycosphingolipids - MS mass spectrometry - SSEA-1 stage specific embryonic antigen-1 - TLC thin layer chromatographys     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

1H and13C-NMR analysis of four pentasaccharides from urine of blood-group A and B,Leb adults. Confirmation of the structure of two new oligosaccharides: Fuc(α1–2)[GalNAc(α1–3)]Gal(β1–3)[Fuc(α1–4)]Glc and Fuc(α1–2)[Gal(α1–3)]Gal(β1–3)[Fuc(α1–4)]Glc

The major pentasaccharides Fuc(1-2)[GalNAc(1-3)]Gal(1-4)[Fuc(1-3)]Glc and Fuc(1-2) [Gal(1-3)]Gal(1-4)[Fuc(1-3)]Glc, which are normally present in the urine of bloodgroup A Le^b and B Le^b healthy subjects, were each found to be contaminated by a minor component when analysed by¹H-NMR. The determination of these structures, Fuc(1-2) [GalNAc(1-3)]Gal(1-3)[Fuc(1-4)]Glc and Fuc(1-2) [Gal(1-3)]Gal(1-3)[Fuc(1-4)]Glc, was based on the results of methylation analysis and¹H/¹³C-NMR spectroscopy.Abbreviations HPLC high performance liquid chromatography - GLC gas liquid chromatography - NMR nuclear magnetic resonance - COSY correlation spectroscopy - Gal d-galactopyranose - GalNAc 2-acetamido-2-deoxy-d-galactopyranose - Glc d-glucopyranose - Fuc l-fucopyranose - LNDFH I lacto-N-difucohexaose I (Le^b determinant     

Genome Analysis inNeurospora crassa;Cloning of Four Lociarginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) and Associated Chromosome Walking

We have cloned fourNeurospora crassagenes by complementation analysis. Cloned genes include thearginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) loci. Chromosome walks were initiated in ordered cosmid libraries from the cloned loci. A total of about 700 kb of theNeurosporagenome is covered in these walks.     

“HAIRY CANOLA” – Arabidopsis GL3 Induces a Dense Covering of Trichomes on Brassica napus Seedlings

Transformation with the Arabidopsis bHLH gene 35S:GLABRA3 (GL3) produced novel B. napus plants with an extremely dense coverage of trichomes on seedling tissues (stems and young leaves). In contrast, trichomes were strongly induced in seedling stems and moderately induced in leaves of a hairy, purple phenotype transformed with a 2.2 kb allele of the maize anthocyanin regulator LEAF COLOUR (Lc), but only weakly induced by BOOSTER (B-Peru), the maize Lc 2.4 kb allele, or the Arabidopsis trichome MYB gene GLABRA1 (GL1). B. napus plants containing only the GL3 transgene had a greater proportion of trichomes on the adaxial leaf surface, whereas all other plant types had a greater proportion on the abaxial surface. Progeny of crosses between GL3⁺ and GL1⁺ plants resulted in trichome densities intermediate between a single-insertion GL3⁺ plant and a double-insertion GL3⁺ plant. None of the transformations stimulated trichomes on Brassica cotyledons or on non-seedling tissues. A small portion of bHLH gene-induced trichomes had a swollen terminal structure. The results suggest that trichome development in B. napus may be regulated differently from Arabidopsis. They also imply that insertion of GL3 into Brassica species under a tissue-specific promoter has strong potential for developing insect-resistant crop plants. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Validation of the <Emphasis Type="Italic">VRN-H2</Emphasis>/<Emphasis Type="Italic">VRN-H1</Emphasis> epistatic model in barley reveals that intron length variation in <Emphasis Type="Italic">VRN-H1</Emphasis> may account for a continuum of vernalization sensitivity

The epistatic interaction of alleles at the VRN-H1 and VRN-H2 loci determines vernalization sensitivity in barley. To validate the current molecular model for the two-locus epistasis, we crossed homozygous vernalization-insensitive plants harboring a predicted “winter type” allele at either VRN-H1 (Dicktoo) or VRN-H2 (Oregon Wolfe Barley Dominant), or at both VRN-H (Calicuchima-sib) loci and measured the flowering time of unvernalized F₂ progeny under long-day photoperiod. We assessed whether the spring growth habit of Calicuchima-sib is an exception to the two-locus epistatic model or contains novel “spring” alleles at VRN-H1 (HvBM5A) and/or VRN-H2 (ZCCT-H) by determining allele sequence variants at these loci and their effects relative to growth habit. We found that (a) progeny with predicted “winter type” alleles at both VRN-H1 and VRN-H2 alleles exhibited an extremely delayed flowering (i.e. vernalization-sensitive) phenotype in two out of the three F₂ populations, (b) sequence flanking the vernalization critical region of HvBM5A intron 1 likely influences degree of vernalization sensitivity, (c) a winter habit is retained when ZCCT-Ha has been deleted, and (d) the ZCCT-H genes have higher levels of allelic polymorphism than other winterhardiness regulatory genes. Our results validate the model explaining the epistatic interaction of VRN-H2 and VRN-H1 under long-day conditions, demonstrate recovery of vernalization-sensitive progeny from crosses of vernalization-insensitive genotypes, show that intron length variation in VRN-H1 may account for a continuum of vernalization sensitivity, and provide molecular markers that are accurate predictors of “winter vs spring type” alleles at the VRN-H loci.     

N-andO-glycosylation of glycoprotein C synthesized by Herpes simplex virus type 1-infected ricin resistant cells

The progeny of Herpes simplex virus type 1 (HSV-1) grown in ricin-resistant 14 cells (Ric^R14) lackingN-acetylglucosaminyltransferase I was released in the extracellular medium at a very low rate. By using a monoclonal antibody immobilized on Sepharose we purified from HSV-1-infected Ric^R14 cells a viral glycoprotein (gC), which carries bothN-andO-linked oligosaccharides. Glycopeptides obtained from [³H]mannoselabeled gC by Pronase digestion were entirely susceptible to endo--N-acetylglucosaminidase H, and the major oligosaccharide released was Man₄GlcNAc. The accumulation of this high-mannose species was related to the enzymic defect of the host cells and to the long retention of the viral glycoprotein within the cells. The extent ofO-glycosylation evaluated in [¹⁴C]glucosamine-labeled gC from Ric^R14 cells as compared to that of gC from wild type cells did not appear to be significantly modified.Abbreviations Con A concanavalin A - BHK cells baby hamster kidney cells - HSV Herpes simplex virus     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.