3种外源诱导剂预处理对甜瓜抗病特征及其Fom 2和CHT基因表达的影响

该研究选用水杨酸(SA)、茉莉酸甲酯(MeJA)、Ca~(2+)、无菌水(对照)作为外源预处理诱导剂,以抗、感枯萎病甜瓜品种为材料,分别于诱导预处理2d后接种甜瓜枯萎菌,并于接种5、7、9d时观察发病情况,进行病情调查;在接种后1、3、5、7、9d取甜瓜叶片,分析抗病甜瓜(MR-1)和感病甜瓜(M1-15)叶片中甜瓜抗枯萎病基因(Fom-2)、几丁质酶基因(CHT)的表达变化,以探寻提高防治甜瓜枯萎病菌侵染的技术途径。结果显示:(1)外源MeJA和SA预处理接种后2品种的病情指数显著低于对照,但Ca~(2+)处理后的病情指数与对照无显著差异。(2)经外源诱导预处理接种后,MR-1和M1-15品种叶片的Fom-2和CHT基因均出现差异表达,但Ca~(2+)诱导其上调表达的效果微弱。(3)经SA、MeJA诱导预处理接种后,2品种叶片的Fom-2和CHT基因表达总体均显著高于对照;Fom-2基因的表达抗病甜瓜MR-1分别在接种后5d、7d时达到峰值,而感病甜瓜M1-15则均在接种9d时达到峰值;CHT基因的表达抗病甜瓜MR-1则均在接种后7d时达到峰值,而感病甜瓜M1-15分别在接种后7d、9d时达到峰值。(4)Ca~(2+)处理对抗、感甜瓜叶片的Fom-2和CHT基因的表达均无显著影响。(5)相关分析表明,经SA、MeJA诱导预处理接种后,甜瓜枯萎病病情指数与Fom-2和CHT基因表达量有显著的相关性;而Ca~(2+)处理效果不显著。研究表明:SA、MeJA通过诱导Fom-2、CHT基因上调表达,进而使甜瓜的抗病性提高,而Ca~(2+)处理对两基因表达和甜瓜抗病性均无显著影响。     

菘蓝CYP83A1基因的克隆、表达特性及原核表达分析

本研究对菘蓝CYP83A1基因进行了克隆、表达特性及原核表达研究。结果表明,IiCYP83A1基因组DNA全长为1 622 bp,包含2个外显子和1个内含子;cDNA全长为1 512 bp,编码503个氨基酸。IiCYP83A1编码的蛋白包含2个跨膜结构域,无信号肽,主要定位于内质网膜,属于亲水性蛋白,二级结构主要由α-螺旋和无规则卷曲组成,与萝卜、欧洲油菜、西兰花和芜菁等植物的CYP83A1蛋白具有较高的同源性。qRT-PCR结果表明,IiCYP83A1在不同组织中的表达具有显著性差异,表现为茎叶果花和根;在幼苗期、生长期和花期的表达量显著高于萌芽期;茉莉酸甲酯(MeJA)和伤害处理能够显著促进该基因的表达,而低温(4℃)和水杨酸(SA)处理则对其表达具有一定的抑制作用。将克隆到的IiCYP83A1基因连接到表达载体pET-28a上,构建原核表达载体pET-28a-IiCYP83A1并对其进行原核表达。SDS-PAGE结果显示,在E.coli BL21中成功诱导表达了CYP83A1蛋白,与预期蛋白分子量大小一致。本研究结果可为进一步研究IiCYP83A1的功能提供实验依据。     

百脉根小G蛋白Rac1基因的克隆与功能分析

小G蛋白Rop在植物细胞信号转导中发挥着重要的分子开关功能。该实验通过RT-PCR方法克隆了百脉根的一个Rop编码基因LjRac1,并对LjRac1基因序列进行生物信息学分析,然后采用半定量RT-PCR检测LjRac1基因在百脉根不同组织中的表达,用荧光实时定量PCR方法检测百脉根接种根瘤菌后LjRac1基因在不同阶段根系中的表达,构建过表达重组质粒,利用发根农杆菌介导的遗传转化法对LjRac1基因功能进行分析。结果表明:(1)序列分析显示,LjRac1完整编码区的cDNA序列长度为594bp,编码197个氨基酸,其编码蛋白具有典型的Rop家族保守结构域;同源分析显示,百脉根LjRac1与大豆GmRac1、野大豆GsRac1的一致性最高(94.42%)。(2)LjRac1基因在百脉根的根、茎、叶、根瘤和花中均有表达,且在根和根瘤中的表达水平较高;接种根瘤菌0.5h后,LjRac1基因在根系中的表达量呈显著升高趋势。(3)过表达转基因植株中LjRac1mRNA的表达水平为对照植株的14.3倍,且过表达植株的结瘤数目较对照明显增加。研究认为,LjRac1基因是一个受根瘤菌诱导增强表达的基因,过表达LjRac1基因可以引起植株结瘤数目的增加,说明LjRac1基因可能参与早期结瘤信号转导途径,从而在根瘤的发育中发挥一定作用。     

龙眼体胚发生过程中DlAGO4基因的克隆及表达分析

该研究基于龙眼基因组数据库,采用RT-PCR技术,以‘红核子’品种龙眼松散型胚性愈伤组织cDNA为模板,进行龙眼胚性愈伤组织DlAGO4基因的克隆和生物信息学分析,并采用实时荧光定量技术分析其在龙眼体细胞胚胎发生不同阶段、不同组织部位、激素和非生物胁迫处理以及5-氮胞苷(5-azac)处理的表达模式。结果表明:(1)DlAGO4基因cDNA全长为3 425 bp,包含开放阅读框长度为2 781 bp,编码926个氨基酸。(2)生物信息学分析表明,DlAGO4蛋白为碱性亲水非分泌蛋白,含有AGO经典的保守结构域PAZ和Piwi,与克莱门柚CcAGO4的同源性最近,含有85个磷酸化位点和2个糖基化位点;亚细胞定位预测其最可能定位于细胞核;MicroRNA预测显示,DlAGO4基因受到4个miRNA靶向调控。(3)qRT-PCR结果表明,DlAGO4在龙眼球形胚阶段和种子中相对表达量最高;激动素、水杨酸、NaCl、甘露醇、PEG-4000和ABA处理均能促进DlAGO4基因的表达,而2,4-D和MeJA处理抑制其表达;不同浓度的5-azac处理1 d和3 d抑制DlAGO4的表达,但从处理第6天开始该基因呈上调表达,并于处理第12天相对表达量最高。研究认为,DlAGO4基因可能参与龙眼球形胚和种子的转录调控,且可能参与KT、SA的激素信号转导途径和NaCl、甘露醇、PEG-4000、ABA的逆境胁迫响应途径以及DNA甲基化调控机制。     

青花菜BoSCL3基因的克隆和渍水胁迫下的表达特征分析

为了解SCL3 (scarecrow-like 3)基因的功能,从青花菜(Brassica olreacea var. italica)中克隆得到1个SCL3基因,命名为BoSCL3,其cDNA全长1 355 bp,编码446个氨基酸。BoSCL3分子量为49.96 kD,为疏水性蛋白,与油菜(B. napus)、芜菁(B. rapa)中SCL3蛋白的亲缘关系最近,同科植物的SCL3具有较高的同源性。荧光定量PCR分析结果表明,青花菜BoSCL3基因表达量随渍水胁迫时间延长先下降后上升,推测其可能参与渍水胁迫响应。这为探讨青花菜BoSCL3基因响应渍水胁迫的分子机制提供理论依据。     

菘蓝IiCYP79F1基因的克隆与表达分析

该研究以菘蓝叶片为材料,采用RT PCR方法克隆菘蓝IiCYP79F1基因,并对其进行生物信息学与表达模式分析。结果表明：（1）成功获得IiCYP79F1基因的gDNA全长（2 109 bp）,包含3个外显子及2个内含子,ORF全长为1 626 bp,编码541个氨基酸（GenBank登录号为KY774689.1）;生物信息学分析显示,IiCYP79F1蛋白的二级结构主要由α 螺旋（43.81%）、无规则卷曲（35.49%）、延伸链（13.68%）和β 转角（7.02%）组成;其氨基酸序列与西兰花、欧洲油菜、芜菁和芝麻菜的相似性较高,其蛋白与芝麻菜的亲缘关系最近。（2）qRT PCR分析显示,IiCYP79F1基因呈时空特异性表达,且在茎中与幼苗期高表达;MeJA、Ag⁺、葡萄糖和机械损伤处理均能有效促进IiCYP79F1基因的表达,而SA和低温处理则具有明显的抑制作用。该研究结果为进一步探讨IiCYP79F1在菘蓝芥子油苷生物合成中的作用奠定了基础,也为培育高芥子油苷含量的菘蓝新种质提供了新思路。     

矮牵牛PhUGT74E2基因的克隆及对逆境胁迫的响应

糖基化转移酶(UGTs)能够维持植物体内的激素平衡,广泛参与植物的生长发育及逆境胁迫应答。该研究从矮牵牛(Petunia hybrida var. Mitchel diploid)中克隆了UGT74E2的同源基因PhUGT74E2及其启动子序列,并分析了序列特征和蛋白结构特点,同时采用qRT-PCR对该基因在不同组织、不同逆境胁迫下的转录水平进行了检测,以探讨矮牵牛UGT74E2基因的功能,为揭示其调控矮牵牛抗逆性的分子机制奠定基础。结果显示:(1)成功克隆获得矮牵牛UGT74E2基因全长序列,命名为PhUGT74E2。(2)PhUGT74E2基因cDNA全长1 986 bp,包含一个1 347 bp开放阅读框,编码448个氨基酸;其蛋白分子式为C_(2278)H_(3544)N_(586)O_(676)S_(18),分子量为50.53 kDa,等电点为5.18;PhUGT74E2无信号肽和跨膜域,主要定位于叶绿体;同时克隆了PhUGT74E2基因上游2 083 bp启动子序列,该序列中含有脱落酸、赤霉素、光及逆境等响应元件。(3)系统进化树分析显示,PhUGT74E2与其他物种UGT74E2起源相同,而与烟草NtUGT74E2的亲缘关系最近。(4)荧光定量PCR分析表明,PhUGT74E2基因在叶片、茎、根、叶腋和顶端5个组织中均有表达,其中叶腋中的表达量最高,而茎和根中的表达量最低;PEG6000模拟干旱处理及NaCl处理均引起了PhUGT74E2表达水平的显著上调,且随着时间的延长表达水平相应增加,说明PhUGT74E2能够参与矮牵牛对干旱及盐胁迫的响应。     

甘菊ClHSP70与ClHSP90基因的克隆及表达分析

该研究以甘菊(Chrysanthemum lavandulifolium)为实验材料,通过RT-PCR方法从甘菊转录组数据中分离出热激蛋白合成相关基因,命名为ClHSP70和ClHSP90。序列分析表明,ClHSP70基因ORF全长为2 559bp,编码852个氨基酸,蛋白功能区预测表明含有典型的HSP70蛋白NBD和SBD保守结构域;ClHSP90基因ORF全长为2 094bp,编码697个氨基酸,含有HATPase结构域和HSP90保守结构域。生物信息学分析表明,甘菊ClHSP70与大豆(Glycine max)和烟草(Nicotiana tomentosiformis)HSP70蛋白有较高的一致性,ClHSP90基因编码的氨基酸序列与紫茎泽兰(Ageratina adenophora)HSP90高度相似;实时荧光定量表达分析表明,在42℃处理不同时间,甘菊叶片中ClHSP70和ClHSP90基因表达均在0.5h时显著增加,1h达到最大值,2h后缓慢下降;不同组织表达分析表明,甘菊在42℃处理1h后,ClHSP70在成熟叶中的表达量显著高于嫩叶和根等其他组织;ClHSP90在成熟茎中的表达量最高。研究说明,ClHSP70和ClHSP90基因具有热激蛋白特征,参与了甘菊热胁迫应答过程,该研究结果为以后深入研究其基因功能奠定了基础。     

小麦TaLEC1基因的克隆及其表达特性分析

为了探讨LEC1基因在小麦(Triticum aestivum L)非生物胁迫应答中的功能,该研究通过RT-PCR结合RACE技术克隆小麦TaLEC1基因,并采用qRT-PCR方法分析了该基因在小麦不同组织以及不同处理下的表达模式,为深入研究小麦LEC1基因在干旱、高温和高盐胁迫下的响应机制奠定基础。结果表明:(1)成功克隆到小麦TaLEC1基因,该基因cDNA序列全长为1 074 bp,其中5′端非编码区23 bp,开放阅读框为741 bp,3′端非编码区310 bp,编码246个氨基酸,具有典型的CBFD_NFYB结构域。(2)实时荧光定量分析显示,TaLEC1在不同组织间表达差异显著,10 d龄幼苗的叶中表达量最高。(3)TaLEC1基因可被植物激素ABA诱导而上调表达,属于ABA依赖型的表达调控通路。(4)PEG模拟干旱胁迫处理后的0.5～1 h,TaLEC1基因呈上调表达;42℃胁迫处理过程中,TaLEC1基因呈稳定上调表达趋势,并在胁迫处理后12 h和48 h时表达急剧上调,分别为对照的52.8倍和34.5倍;NaCl胁迫处理0.5 h时TaLEC1基因迅速上调表达。研究表明,小麦TaLEC1基因参与ABA依赖的胁迫响应,推测可能在小麦耐受高温胁迫和渗透胁迫过程中发挥着重要的脱水保护功能。     

海岛棉GbRLCK10基因克隆及表达分析

该研究以拟南芥抗逆基因At1g67520为探针,利用海岛棉ESTs数据库,通过电子克隆获得海岛棉RLCK家族基因GbRLCK10,解析该基因组结构,并结合qRT-PCR技术分析该基因mRNA的组织表达特征以及在不同胁迫诱导下的表达模式,为揭示RLCK家族基因在海岛棉中的表达调控及作用机制提供理论依据。结果显示:(1)获得海岛棉类受体胞质激酶(RLCK)基因,其开放阅读框(ORF)为1 179bp,编码392个氨基酸,具有典型的Serine/Threonine结构域,属于RLCK家族,与GaRLCK10(XP_017604046.1)亲缘关系较近,命名为GbRLCK10(登录号2022184),且该基因由5个外显子和4个内含子组成。(2)实时荧光定量(qRT-PCR)检测显示,GbRLCK10基因在抗病品种‘新海21’和感病品种‘新海14’的根、茎、叶中均有表达;当黄萎病菌诱导后,GbRLCK10基因在抗病品种中对于病原菌的响应时间早于感病品种,且对黄萎病菌响应更强烈,推测该基因参与棉花对黄萎病的响应;盐(NaCl)、干旱(PEG-6000)处理‘新海21’后,GbRLCK10基因在NaCl处理下响应时间要早于PEG-6000处理,但对PEG-6000处理响应更强烈;分别用4种激素处理‘新海21’后,GbRLCK10均能被诱导表达,且在水杨酸(SA)处理后表现为先增加后下降再增加趋势,在乙烯(ET)处理后表达量为持续上升趋势,在茉莉酸甲酯(MeJA)处理后呈先升高然后下降的趋势,但GbRLCK10基因对赤霉素(GA3)响应不明显。研究表明,GbRLCK10基因具有RLCK基因家族典型特征,该基因随黄萎病菌、NaCl、干旱、激素处理时间推移而发生变化,推测GbRLCK10基因可能参与了棉花对黄萎病菌、NaCl、干旱、激素胁迫的应答反应,但其功能仍需进一步研究。     

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.     

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.     

Structural Peculiarities of Na+,K+-ATPase Isozymes from the Calf Brain

Functionally active preparations of Na⁺,K⁺-ATPase isozymes from calf brain that contain catalytic subunits of three types (1, 2, and 3) were obtained using two approaches: a selective removal of contaminating proteins by the Jorgensen method and a selective solubilization of the enzyme with subsequent reconstitution of their membrane structure by the Esmann method. The ouabain inhibition constants were determined for the isozymes. The real isozyme composition of the Na⁺ pump from the grey matter containing glial cells and the brain stem containing neurons was determined. The plasma membranes of glial cells were shown to contain mainly Na⁺,K⁺-ATPase of the 11 type and minor amounts of isozymes of the 22(1) and the 31(2) type. The axolemma contains 21 and 31 isozymes. A carbohydrate analysis indicated that 11 enzyme preparations from the brain grey matter substantially differ from the renal enzymes of the same composition in the glycosylation of the 1 isoform. An enhanced sensitivity of the 3 catalytic subunit of Na⁺,K⁺-ATPase from neurons to endogenous proteolysis was found. A point of specific proteolysis in the amino acid sequence PNDNR⁴⁹² Y⁴⁹³ was localized (residue numbering is that of the human 3 subunit). This sequence corresponds to one of the regions of the greatest variability in 1-, 2-, 3-, and 4-subunits, but at the same time, it is characteristic of the 3 isoforms of various species. The presence of the 3 isoform of tubulin (cytoskeletal protein) was found for the first time in the high-molecular-mass Na⁺,K⁺-ATPase 31 isozyme complex isolated from the axolemma of brain stem neurons, and its binding to the 3 catalytic subunit was shown.     

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     

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     

“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.