Eggplant Mottled Dwarf Virus Associated with Vein Yellowing of Honeysuckle

A rhabdovirus isolated in Tunisia by mechanical inoculation from honeysuckle (Lonicera sp.) plants with vein yellowing, was compared with a Tunisian isolate of eggplant mottled dwarf virus (EMDV). The two viruses had similar host ranges and caused the same symptoms in artificially infected hosts. The honeysuckle virus induced in eggplant a syndrome indistinguishable from that typical of EMDV. The two viruses could not be differentiated serologically, had particles of the same size and elicited identical cytopathological alterations in naturally and artificially infected hosts. Honeysuckle is the first host, besides eggplant, found to be naturally infected with EMDV.     

Complete Genome Sequence and Genome Analysis of Eggplant mottled dwarf virus‐Iranian Isolate

The full‐length nucleotide sequence of the Iranian isolate of Eggplant mottled dwarf virus (EMDV), a phytorhabdovirus, was determined using the random polymerase chain reaction method (rPCR) followed by PCR with specific primers to fill in the gaps. The negative‐sense RNA genome of the Iranian isolate of EMDV contains 13154 nucleotides and seven open‐reading frames (ORFs) in the order 3′‐leader‐N‐X‐P‐Y‐M‐G‐L‐trailer‐5′. These ORFs encode the nucleocapsid, X protein (of unknown function), phosphoprotein, Y protein (putative movement protein), matrix protein, glycoprotein and RNA‐dependent RNA polymerase, respectively. EMDV has a 199 nt 3′ leader RNA and a 151 nt 5′ trailer, and the ORFs are separated by conserved intergenic sequences. Phylogenetic analyses indicate that EMDV is most closely related to Potato yellow dwarf virus, which has a distinctly different geographical distribution.     

Comparison of Three Plant Rhabdovirus Isolates by Two Different Serological Techniques

Three different rhabdovirus isolates, eggplant mottled dwarf virus (EMDV), tomato veinyellowing virus (TVYV) and a hitherto undefined isolate from tomato in Portugal (Tom-P) were compared by two different serological techniques, immunosorbent electron microscopy (ISEM) and electro-blot-immunoassay (EBIA). Antisera were prepared either against purified virus or against partially purified virus preparations extracted by a one-step procedure. Even the partially purified virus preparations yielded antisera that allowed unequivocal identification of two of the five structural virus proteins, G and N, in EBIA and were suitable for specific trapping of complete virus particles on electron microscope grids. With both serological techniques identical results were obtained indicating a close serological relationship between the three isolates tested. Cross-reactions between the G proteins could be deduced from heterologous trapping of complete virus particles in ISEM. The cross-reactions for the G proteins were substantiated by the EBIA-results which indicated in addition cross-reactions between the remaining three major structural virus proteins, N, M₁, and M₂, but also revealed significant differences in the molecular weights of the G and M₁ proteins between TVYV and the other two isolates. The results obtained indicate that Tom-P is serologically closely related and in respect of protein molecular weights identical to EMDV, and that TVYV is not a separate virus but rather a strain of EMDV.     

烟草害虫天敌及其自然控制作用

介绍了云南省烟草主要害虫天敌资源和天敌昆虫的自然控制作用。在云南省烟田内 ,控制烟草害虫发生的生物因子大致可归纳为寄生性和捕食性两大类。充分发挥自然因素的生态调控作用 ,对保护利用天敌、维护烟田生态平衡、提高害虫综合治理效果、保护生态环境都有重要意义     

口蹄疫病毒和猪肠道病毒基因重组获得的c731重组株的进一步研究

对不同属间小RNA病毒基因重组株c731,进行了病毒与细胞亲和力、毒蛋白的PAGE,病毒的乳鼠毒力和免疫原性试验,进一步证实,c731是口蹄疫病毒和猪肠道病毒通过基因重组产生的新病毒株。     

Mutagenicity in the Salmonella/microsome assay of tobacco condensates formed during pipe smoking

The condensates collected after pipe smoking of a natural tobacco and a cavendish type tobacco, either unwrapped or wrapped in a paper "saver" bag, were tested for mutagenicity in the Salmonella/mammalian microsome assay with strains TA100 and TA98. The number of revertants induced with cavendish type tobacco in the presence of metabolic activation (mouse-liver S9) was higher in both strains compared to the natural tobacco. Further increase in the number of revertants (approx. 3 times) was consistently seen when the tobacco was smoked after paper wrapping "savers".     

Myosmine in different organs of tobacco plant

Myosmine was found to be present in different organs of tobacco plant by TLC. Myosmine is a natural minor alkaloid of tobacco plant; it is not a decomposition product nor a 'smoke' alkaloid.     

Neutral Aroma Constituents in Burley Tobacco

The constituents of the neutral volatiles from air-cured Burley tobacco were studied using distillation, silicic acid column chromatography, preparative gas chromatography and GC–MS. The isolation and identification of 84 compounds are reported of which 27 are newly identified as tobacco constituents and 4 are new natural products.     

Synthesis and accumulation of pea plastocyanin in transgenic tobacco plants

The pea plastocyanin gene in a 3.5 kbp Eco RI fragment of pea nuclear DNA was introduced into tobacco by Agrobacterium-mediated transformation. Regenerated plants contained pea plastocyanin located within the chloroplast thylakoid membrane system. Analysis of seedlings from a self-pollinated transgenic plant containing a single copy of the pea plastocyanin gene indicated that seedlings homozygous for the pea gene contained almost twice as much pea plastocyanin as seedlings hemizygous for the pea gene. Homozygous seedlings contained approximately equal amounts of pea and tobacco plastocyanins. The amount of tobacco plastocyanin in leaves of transgenic plants was unaffected by the expression of the pea plastocyanin gene. The mRNA from the pea gene in tobacco was indistinguishable by northern blotting and S1 nuclease protection from the mRNA found in pea. In both pea and transgenic tobacco, expression of the pea plastocyanin gene was induced by light in leaves but was suppressed in roots. Pea plastocyanin free of contaminating tobacco plastocyanin was purified from transgenic tobacco plants and shown to be indistinguishable from natural pea plastocyanin by N-terminal protein sequencing and ¹H NMR spectroscopy.     

烟蚜自然种群聚集与扩散趋势的初步研究

本文采用空间格局分析方法,从烟草移载到烟叶采收,对烟蚜Ｍｙｚｕｓ ｐｅｒｓｉｃａｅ在烟株和烟株上,中,下三个部位的聚集和扩散趋势,采用Ｍｏｎｔ Ｌｏｌｙｄ给出的方法,并结合Ｉｗａｏ的ｍ－ｍ回归分析法和ｍ－ｍ的改进模型进行判断分析。结果表明,六月下旬和七月中旬是烟蚜在烟株上的两个聚集高峰期。烟蚜在烟株不同部位的聚集和扩散趋势有所不同。整株烟株和上,中,下部烟蚜都呈聚集分布。分析结果对指导烟蚜防治有一     

转基因烟草的大田抗病性分析

为了尽快地将抗病转基因烟草品种应用于生产,在选育抗病优良株系的同时,进行了转基因株系的大田抗病性鉴定。结果表明：（１）在田间自然发病情况下,转基因烟草的ＮＣ８９各株系的发病率及病情指数显著低于对照ＮＣ８９,对ＣＭＶ的相对防治效果为５５％－７０％,表现较强的抗病性;同时对ＴＭＶ也有一定的抗病力;（２）转基因烟草的产量、产值也明显高于对照。     

烟草和香芋上斜纹夜蛾的自然种群生命表

应用作用因子生命表方法,组建烟草和香芋上第2、3代斜纹夜蛾Spodoptera litura（Fabricius）自然种群生命表,分析作用因子对斜纹夜蛾种群数量的控制作用。结果表明,2005和2006年烟草和香芋上第2、3代斜纹夜蛾种群的增长倍数均以香芋高于烟草。无论烟草还是香芋上第2、3代斜纹夜蛾,均以“捕食及其它”的排除作用控制指数最大。如排除所有天敌等作用因子的作用,2005年烟草上第2、3代斜纹夜蛾自然种群趋势指数将分别增长31．2029和50．0371倍,香芋上第2、3代斜纹夜蛾自然种群趋势指数将分别增长29．3492和41．2873倍;2006年烟草上第2、3代斜纹夜蛾自然种群趋势指数将分别增长33．1421和75．4167倍,香芋上第2、3代斜纹夜蛾自然种群趋势指数将分别增长31．5357和70．5355倍。说明天敌等自然作用因子对斜纹夜蛾种群数量有较为明显的控制作用,而烟草上的自然作用因子的作用要强于香芋上的自然作用因子。     

Artificial cleavage site recognized by plum pox potyvirus protease in Escherichia coli.

A synthetic plum pox virus (PPV) NIb-CP cleavage site was recognized by a PPV protease in an in vivo Escherichia coli expression system. The presence of the natural NIb-CP cleavage site did not affect processing at the artificial one. However, although both the proteases and the cleavage sites of PPV and tobacco etch virus show high sequence homology, a similar cassette from the tobacco etch virus NIb-CP junction was not efficiently recognized by the PPV protease.     

Engineering photoassimilate partitioning in tobacco plants improves growth and productivity and provides pathogen resistance

Expression of pathogenesis-related (PR) genes is part of the plant's natural defense response against pathogen attack. To study the in vivo role and function of the maize PRms protein, tobacco plants were transformed with the PRms cDNA under the control of the CaMV35S promoter. Transgenic tobacco plants grow faster and yield more leaf and seed biomass. By using immunoelectron microscopy, we found that PRms is associated with plasmodesmata in leaves of transgenic tobacco plants. Furthermore, we found that activation of sucrose efflux from photosynthetically active leaves and accumulation of higher levels of sucrose in leaf tissues are characteristic features of PRms tobacco plants. This, in turn, results in the constitutive expression of endogenous tobacco PR genes and resistance to phytopathogens. The expression of multiple plant defense genes can then be achieved by using a single transgene. These data provide a new approach for engineering disease-resistant plants while simultaneously improving plant yield and productivity through the modification of photoassimilate partitioning.     

烟草生产废弃物提取烟碱的研究

从烟草生产废弃物中提取的烟碱是重要的医药和化工原料,本研究分析了不同烟草类型的废弃物烟碱含量,论述了烟碱在医药、农药和卷烟添加剂方面的用途,作为废物利用,开发天然产物具有十分重要的经济价值。     

不同寄主来源的马铃薯Y病毒群体遗传结构的比较分析

文章以马铃薯Y病毒(Potato virus Y, PVY) P3和pipo基因为分子标记,比较分析烟草和马铃薯两个寄主的PVY遗传多样性和群体分化,并评估突变、选择、基因流等遗传力所起的作用。通过P3和pipo基因计算获得的烟草和马铃薯群体分化指数F_ST分别为0.116和0.120,且统计检验差异显著,表明烟草和马铃薯寄主的PVY之间中度分化。变异分析结果显示,烟草分离物P3和pipo基因的核苷酸序列一致性分别为85.2%~100%和76.5%~100%,而马铃薯分离物的P3和pipo基因的核苷酸序列一致性分别为95.7%~100%和93.0%~100%,表明烟草PVY变异程度高于马铃薯。同时,P3基因内检测到大量的净化选择位点,表明该基因大部分位点的变异为有害突变,在进化过程中被剔除。此外,P3基因内还检测到两个显著正向选择位点,表明这两个位点的变异为有益突变,有利于病毒的生存竞争。在pipo基因中未检测到显著的选择位点,表明该基因上的变异基本不受自然选择影响。通过P3和pipo基因计算烟草和马铃薯群体间的基因流Nm值分别为1.91和1.83,表明这两个群体间存在较强的基因交流。以上结果表明,来源于烟草和马铃薯寄主的PVY遗传差异显著,突变、自然选择以及基因流都影响两者的遗传多样性及遗传分化程度。     

Nuclear expression of an environmentally friendly synthetic protein based polymer gene in tobacco cells

Summary We report here expression of a protein based polymer gene (Gly-Val-Gly-Val-Pro)₁₂₁, coding for three amino acids in a pentamer sequence repeated 121 times via the nuclear genome of tobacco cells. Transformed tobacco cells were obtained by particle bombardment. Stably transformed cells show the presence of the polymer gene in the tobacco nuclear genome (2–5 copies); introduced polymer gene is transcribed efficiently as revealed by Northern blots; Western blots show the presence of the polymer protein. To the best of our knowledge, this report represents the first demonstration of expression of a synthetic gene (with no natural analog) in higher plants.     

Transgenic Tobacco with αα Mutant Gene Has Higher Tolerance to Heavy Metals

Metallothionein (MT) has two domains, α and β domain. α domain preferred to bind Cd2+and Hg2+. Mouse metallothionein mutant αα has been constructed and expressed in E.coli, which has the same stability as the nature one but has stronger affinity to heavy metals. To testify the result in vivo, αα mutant gene was cloned into plant expression vector pE3 under the CaMV 35S promoter. A transgenic tobacco was obtained by using leaf discs of tobacco (Nicotiana tabacum L. cv. NC89) to Agrobacterium-mediated ααgene transfer. Southern blotting analysis indicated that the αα mutant gene was indeed integrated into the tobacco genome; Western blot indicated that the αα mutant gene was expressed in transgenic tobacco. It was also demonstrated that the transgenic tobacco with αα mutant gene have a little higher tolerance to heavy metals than that with natural MT gene. Moreover, the transgenic tobacco can accumulate more Cd2+ in its roots than natural, so that, it can decrease the concentration of Cd2+ in its leaves.     

beta]-1,3-Glucanase Is Cryoprotective in Vitro and Is Accumulated in Leaves during Cold Acclimation

We have used isolated spinach (Spinacea oleracea L.) thylakoid membranes to investigate the possible cryoprotective properties of class I [beta]-1,3-glucanase (1,3-[beta]-D-glucan 3-glucanohydrolase; EC 3.2.1.39) and chitinase. Class I [beta]-1,3-glucanase that was purified from tobacco (Nicotiana tabacum L.) protected thylakoids against freeze-thaw injury in our in vitro assays, whereas class I chitinase from tobacco had no effect under the same conditions. The [beta]-1,3-glucanase acted by reducing the influx of solutes into the membrane vesicles during freezing and thereby reduced osmotic stress and vesicle rupture during thawing. Western blots probed with antibodies directed against tobacco class I [beta]-1,3-glucanase showed that in spinach and cabbage (Brassica oleracea L.) leaves an isoform of 41 kD was accumulated during frost hardening under natural conditions.