香蕉束顶病毒研究进展

香蕉束顶病毒（Bananabunchytopvirus,BBTV）引起的香蕉束顶病（Ban。bu。bytoPdisease）是香蕉一种严重的病毒病害。迄今此病已普遍分布在世界许多产区,诸如：亚洲、非洲、澳大利亚、南太平洋一些岛屿以及美国的夏威夷等地区［‘－’l。在我国广东、广西、福建、云南等省的部分产区的发病率约占5—25％左右,严重地块已发展到毁灭性程度卜］。1987年Dale曾对世界香蕉种植的地理分布和BBTV的流行范围之间的关系、病株症状、病毒病原学、流行病学、病毒诊断方法以及病害的控制作过全面的综述【门。然而由于BBTV存在于寄主植物的韧皮…     

香蕉束顶病毒研究进展

香蕉束顶病毒(Bananabunchytopvirus,BBTV)是引起香蕉束顶病害(Bananabunchytopdisease,BBTD)的病毒,它严重地危害了香蕉的生产。综述了近年来香蕉束顶病毒的分离提纯方法,株系划分以及分类地位,较为全面的介绍了BBTV病毒基因组分结构和各组分编码蛋白的功能等,并提出了目前需要进一步澄清的问题。     

香蕉离体茎尖超低温保存研究

以香蕉(Musaspp.)试管苗为试材,对其离体茎尖小滴玻璃化法超低温保存的影响因素进行了研究。小滴玻璃化法和玻璃化法超低温保存后再生率的差异表明,香蕉更适合用小滴玻璃化法进行超低温保存。香蕉小滴玻璃化法超低温保存的方案如下:试管苗在60g/L蔗糖的MS培养基上培养1~2个月,剥离带有1~2片叶原基的茎尖,室温下装载30m in(可延长至4h),0℃下PVS2处理40~50m in。6个基因型的14个品种的再生率平均为46.9%。通过SSR分子标记检测,再生植株的遗传稳定性没有发生改变。该结果为香蕉种质资源的长期保存提供了理论依据和技术支撑。     

香蕉束顶病毒研究新进展

介绍香蕉束顶病毒从发现到诊断和检测,从分子生物学研究到抗病毒基因工程,探究香蕉束顶病毒100多年的研究历程,为香蕉束顶病毒的深入研究和有效防治奠定了坚实的基础。     

香蕉束顶病毒基因克隆和序列分析

对香蕉束顶病毒（ＢＢＴＶ）中国分离株ＤＮＡ组份Ｉ（ＤＮＡ－１）、外壳蛋白（ＣＰ）和运转蛋白（ＭＰ）基因进行了克隆和序列分析。ＢＢＴＶＤＮＡ－１含有１１０３个核苷酸,与南太平洋和亚洲分离株分别有８７％－８８％ ９６．９－９８％的核苷酸序列同源性。由ＤＮＡ－１编码的复制酶含有１８６个在酸残基。与南太平洋和亚洲分离株分别有８４．４％－９５．８％和９７．６％、９８．０％的氨基酸序列同源性。外壳蛋白基因由５     

香蕉束顶病毒的纯化及理化特性

从具有典型香蕉束顶病(BBTD)症状的香蕉病组织中提纯了香蕉束顶病毒(Banana bunchy top virus,BBTV)。电镜下可观察到直径为18nm的球形病毒颗粒。最高紫外吸收在255nm,最低紫外吸收在240nm,A_(260)/A_(280)为1.30。用标准BBTV抗体通过ECL-Western转印法测定其外壳蛋白分子量为21kDa。其核酸经DNaseI、RNaseA和Mung Bean Nuclease分析,表明是约1kb的ssDNA。结果与国外文献报道一致。     

香蕉束顶病毒DNA组分6的克隆和序列分析

香蕉束顶病(banana bunchy top disease,BBTD)是香蕉生产上重要的病害之一,它威胁着世界约1/4香蕉产区的生产[1].到1998年7月,世界上报道发生该病害的国家和地区达20多个,遍及亚洲、南太平洋地区和少数非洲国家.     

香蕉束顶病毒DNA组分4的克隆与序列分析

香蕉束顶病毒(banana bunchy top virus,BBTV)基因组中至少含有6个DNA组分,我们实验室已经对BBTV广东两个株系(NS和NSP)基因组中的DNA组分1、3、6进行了测序和报道.现又对NS和NSP的DNA组分4分别进行了克隆和序列分析.     

菊花茎尖的玻璃化超低温保存研究

本文建立了适合中国菊花种质资源长期保存的玻璃化超低温保存技术体系.在4℃下,把1～2mm的菊花茎尖放在含0.4mol/L蔗糖的MS培养基上暗培养2～3d,用预处理液在25℃下处理30min,再用玻璃化试剂PVS2在冰浴条件下处理15min,换新鲜的PVS2试剂并迅速投入液氮.液氮保存24h后,40℃水浴解冻2min,用含蔗糖1.2mol/L的MS液体培养基洗涤20min,滤纸吸干后接种到恢复培养基中,在25℃条件下弱光培养1～3d转入正常光照培养条件下培养,2周后成活率可达86%以上,成活的茎尖均可再生.     

Purification and Characterization of Banana Bunchy Top Virus

Abstract Banana bunchy top virus (BBTV) was successfully purified by a procedure which included pulverizing diseased tissues frozen in liquid nitrogen, clarification of the extract with chloroformbutanol, concentration of the virus by cycles of differential centrifugation, stirring and incubating at 4°C followed by a second cycle of differential centrifugation and sucrose density gradient centrifugation. The concentrations of BBTV obtained from leaf blades and midribs plus petioles were up to 0.34 and 0.56mg/kg tissue, respectively. The virus concentration was highest in diseased leaves collected from October to December, and lowest in those collected from June to September. BBTV is a luteovirus (particles 20– 22 nm in diameter), preparations of which have maximum absorbance at 257 nm, minimum absorbance at 240 nm and a A260/280 ratio of 1.46. The relative molecular mass (M_r) of BBTV coat protein subunit is 21,000, and that of its ssRNA is 2.0 × 10⁶.     

香蕉束顶病毒基因Ⅰ的克隆及序列分析

以中国漳州地区感染ＢＢＴＶ的香蕉组织总ＤＮＡ为模板,根据我国台湾地区ＢＢＴＶ分离物基因组Ⅰ序列,设计并合成了一对引物,通过ＰＣＲ扩增出约５００ｂｐ的片段。利用ｐＢｌｕｅｓｃｒｉｐｔⅡＳＫ Ｔ－载体获得此片段的克隆,经测序表明为ＢＢＴＶ组分Ⅰ的部分序列。由已测知的ＢＢＴＶ基因组Ⅰ序列设计一对相邻引物,以我国漳州的感染ＢＢＴＶ香蕉组织总ＤＮＡ为模板,通过ＰＣＲ坟增出约１．１ｋｂ的片段。利用ｐＢｌｕｅｓ     

香蕉束顶病毒海口分离物核穿梭蛋白(NSP)的纯化及抗血清制备

本研究以本实验室保存的含重组载体pDEST17-NSP的原核表达菌株E.coli BL21(DE3)为材料,于25℃、0.1 mmol/L IPTG条件下诱导4 h,集菌后超声波破碎,获得以包涵体形式表达的约20 kD的融合蛋白.实验结果表明,将沉淀的融合蛋白溶于含6 mol/L尿素的Binding Buffer中,再经Ni2+-NTA亲和层析纯化后,可获得高纯度的融合蛋白.将纯化融合蛋白经12%SDS-PAGE电泳,切胶回收目的带,液氮研磨并按1:1(W/V)混合佐剂,4次免疫家兔,获得BBTV病毒核穿梭蛋白的特异性抗血清.以融合蛋白作抗原,间接ELISA法测定其抗血清效价为1:5 000.田间检测样品的最佳抗血清工作浓度为1:500.Western Blot鉴定结果表明抗血清能与目的蛋白特异性结合.本研究的结果将为下一步NSP基因转录调控和蛋白功能研究奠定一定基础.     

Cryopreservation of Shoot Tips of Tetraploid Potato (Solanum tuberosumL.) Clones by Vitrification

In vitro-grown shoot tips of five tetraploid potato (SolanumtuberosumL.) clones were cryopreserved by vitrification. Excisedshoot tips (0.5–0.7 mm) were pre-cultured on filter paperdiscs over half strength liquid Murashige and Skoog (MS) mediumsupplemented with 8.7 µMGA₃and different combinationsof sucrose (0.3, 0.5 and 0.7M) plus mannitol (0, 0.2 and 0.4M)for 2 d under a 16 h photoperiod at 24 °C. The pre-culturedshoot tips were either successively loaded with 20 and 60% PVS2 solutions or directly exposed to concentrated vitrificationsolution before physical vitrification during liquid nitrogentreatment. The vitrified shoot tips were warmed rapidly andtreated with dilution mixture (MS+1.2Msucrose) for 30 min beforeplating on regrowth medium. Addition of mannitol to the pre-culturemedium improved survival of vitrified shoot tips. Direct dehydrationof pre-cultured shoot tips with concentrated PVS 2 was detrimentalto survival of vitrified shoot tips. Shoot tips pre-culturedon medium containing 0.3Msucrose plus 0.2Mmannitol, and loadedwith 20% PVS 2 for 30 min followed by 15 min incubation in 60%PVS 2 and 5 min incubation in 100% PVS 2 at 0 °C resultedin up to 54% survival after vitrification. About 50% of vitrifiedand warmed shoot tips formed shoots directly. Post-thaw culturingof vitrified shoot tips on medium containing an elevated levelof sucrose (0.2M) under diffuse light for the first week enhancedthe survival rate. Continuous culturing of vitrified shoot tipson high-sucrose medium induced multiple shoot formation.Copyright1998 Annals of Botany Company Solanum tuberosumL., potato, cryopreservation, germplasm conservation,in vitroconservation, meristems, shoot tips, tissue culture, vitrification.     

切花百合离体茎尖玻璃化法超低温保存研究

以切花百合西伯利亚试管苗离体茎尖为试材,通过正交设计试验对预培养培养基中蔗糖浓度、预培养时间和PVS2处理时间等影响超低温保存存活率的主要因素进行了分析,初步建立了切花百合种质玻璃化法超低温保存的技术方案。通过形态观察、可溶性蛋白和同工酶检测,冻存前后材料的遗传稳定性没有发生改变,表明该方法对切花百合的种质保存具有较强的实用意义。     

Silicon Isotopic Fractionation by Banana (Musa spp.) Grown in a Continuous Nutrient Flow Device

The determination of the plant-induced Si-isotopic fractionation is a promising tool to better quantify their role in the continental Si cycle. Si-isotopic signatures of the different banana plant parts and Si source were measured, providing the isotopic fractionation factor between plant and source. Banana plantlets (Musa acuminata Colla, cv Grande Naine) were grown in hydroponics at variable Si supplies (0.08, 0.42, 0.83 and 1.66 mM Si). Si-isotopic compositions were determined on a multicollector plasma source mass spectrometer (MC-ICP-MS) operating in dry plasma mode. Results are expressed as δ²⁹Si relative to the NBS28 standard, with an average precision of ± 0.08‰ (±2σ_D). The fractionation factor ²⁹ε between bulk banana plantlets and source solution is −0.40 ± 0.11‰. This confirms that plants fractionate Si isotopes by depleting the source solution in ²⁸Si. The intra-plant fractionation Δ²⁹Si between roots and shoots amounts to −0.21 ± 0.08‰. Si-isotopic compositions of the various plant parts indicate that heavy isotopes discrimination occurs at three levels in the plant (at the root epidermis, for xylem loading and for xylem unloading). At each step, preferential crossing of light isotopes leaves a heavier solution, and produces a lighter solution. Si-isotopic fractionation processes are further discussed in relation with Si uptake and transport in plants. These findings have important implications on the study of continental Si cycle.