基因工程技术在烟草研究中的应用现状与展望

介绍转基因、RAPD分子标记、基因芯片、mRNA差异显示以及蛋白质组学等基因工程技术在烟草中的应用,指出这些技术不仅在烟草遗传图谱建立、系统分析、物种及品系的鉴定、转基因烟草鉴定和检测等方面发挥着重要作用,而且在改善烟草品质和建立烟草基因组学方面也有广阔的应用前景,并从抗病性、抗虫性、抗旱性、抗除草剂等方面介绍了基因工程技术在烟草抗逆性中的研究现状,对转基因烟草的安全性问题进行了探讨。     

烟草扭脉病毒部分基因组特征及其分类地位分析

通过RT-PCR从烟草丛顶病发病烟株总RNA中获得烟草扭脉病毒（Tobacco vein distorting virus,TVDV）基因组部分序列。序列分析显示该片段全长1655bp,共包含TVDV的部分RdRp基因、完整的CP基因和完整的MP基因。其中RdRp基因与CP基因的间隔区（IR）长201nts,符合马铃薯卷叶病毒属病毒的归属依据;对RdRp、CP、MP基因以及IR序列的对比分析,显示了TVDV与黄症病毒科马铃薯卷叶病毒属病毒的较高同源性。根据三个ORF编码的氨基酸序列构建的分子同源树的分析,也都显示了TVDV与黄症病毒科马铃薯卷叶病毒属病毒的同源性最高,进一步证实了TVDV应该是黄症病毒科马铃薯卷叶病毒属的确定成员。     

RNA沉默介导的转基因烟草抗中国番茄黄化曲叶病毒研究

近年来,中国番茄黄化曲叶病毒(Tomato yellow leaf curl China virus,TYLCCNV)病在我国自南向北不断蔓延,发病地块减产甚至绝产,造成了巨大的经济损失.本研究应用RNA沉默(RNA silencing)防治病毒病原理构建TYLCCNV外壳蛋白(coat protein,CP)部分基因片段dsRNA(double-strand RNA)导入本氏烟(Nicotiana benthamiana)获得了抗TYLCCNV的转基因烟草.实验结果表明,目的基因已整合到转基因烟草植株的基因组中.用TYLCCNV侵染性克隆接种转基因烟草,症状观察和PCR检测发现,对TYLCCNV表现为免疫的转基因烟草占14.6％.Northern blot分析表明,在不同的抗病类型转基因植株中,目的基因mRNA的积累量存在明显的差异,其积累量与抗病型呈负相关.研究结果对利用RNA沉默防治TYLCCNV有一定的理论指导意义.     

烟草病毒病及其检测鉴定技术

简介了病毒及烟草病毒的分类,烟草病毒病的检测鉴定技术。重点叙述酶联免疫吸附反应（ELISA）在烟草病毒检测中的应用。     

从烟草上分离的中国番茄曲叶病毒及其卫星DNA全基因组结构特征

本研究从具有典型曲叶病症状的广西靖西烟草病植株上分离到病毒分离物JX-2,全基因组序列测定结果表明,JX-2DNA．A全长2738个核苷酸,共编码6个开放阅读框架（openreadingframes,ORFs）,其中病毒链编码AV1（CP）和AV2两个ORFs,互补链编码AC1、AC2、AC3和AC4共4个ORFs。BLAST结果表明,JX-2DNA—A与中国番茄曲叶病毒（Tomato leaf curl Chinavirus,ToLCCNV）各分离物的相似性在93．0％-99．7％之间,其中与ToLCCNV广西番茄分离物ToLCCNV．G32的相似性最高,达99．7％,而与其它双生病毒的同源性均在88．0％以下,表明Jx-2是ToLCCNV的一个分离物。基于Jx-2和已报道的双生病毒属代表种DNA-A全基因组核苷酸序列构建的系统进化树显示,JX-2与ToLCCNV-G32分离物的亲缘关系最近,并与ToLCCNV其它分离物形成一个分支,而与其它10种双生病毒的亲缘关系均相对较远。利用双生病毒卫星DNAβ的特异性引物β01／β02在Jx-2样品中扩增到DNAβ分子（JX-2β）,全长为1341个核苷酸,其互补链编码1个ORF（即βC1）,并包含一个富含A序列和一个卫星病毒保守序列。序列分析表明,JX-2β与ToLCCNV伴随的DNAβ的相似性在91．0％～96．1％之间,其中与ToLCCNV-G61DNAβ和ToLCCNV—G18DNAβ的相似性最高（96．1％）,与其它卫星DNAβ的相似性均低于61．8％。基于JX-2β全基因组核苷酸序列构建的系统进化关系树显示,JX-29与ToLCCNVG61分离物伴随的DNAβ亲缘关系最近,并形成一个独立的分支,再与ToLCCNV其余两个分离物伴随的DNAβ形成一个较大的分支。这是首次报道从烟草中分离到的中国番茄曲叶病毒及其伴随卫星DNA分子的全基因组结构特征。     

香港土壤研究 Ⅰ.研究现状与展望

对近半个世纪以来香港地区的土壤分类、农业和园林绿地土壤的肥力以及土壤环境保护等研究工作进行了系统的回顾和介绍,为中国香港地区及其他社会经济快速发展地区的土壤资源合理利用、生态环境保护与社会可持续发展提供了科学信息。认为,高度城市化和国际化的香港地区可以结合香港高科技及新产业的发展目标,合理利用和开发土地资源,定向培育中草药产地土壤环境与教育基地;需要进一步系统研究香港地区土壤发生与系统分类、性状与特征、空间分布与变异规律,建立香港土壤基础数据库、土壤图和土壤信息与服务系统;进一步探明污染元素和有益元素的土壤地球化学背景以及持久性有机污染物的环境生物地球化学过程及其生态与健康风险,建立长期的土壤环境质量动态观测点与研究平台,以及区域尺度的土壤环境质量信息系统和定量可视化预测预警系统;研究与发展适合香港地区的有问题土壤的风险评估与修复技术体系     

农业微生物基因工程研究与展望

摘要：介绍了我国农业微生物基因工程研究现状，特别是饲料、肥料和农药用重组微生物制剂的研究成果。为争取5～10年内使我国农业微生物成为新兴的高技术支柱产业，建议进一步加强基础研究，重视资源开发利用，适时开展功能基因组学研究，从高起点切入，以加快源头创新。另建议将微生物农药、饲料和食品加工用酶制剂列为近期研究开发重点。同时也要不断革新生产工艺，改进加工剂型，调整研发结构，促进产业发展。     

茶叶香气成分研究现状与展望

茶叶香气是形成茶叶风味特征、决定茶叶价值的重要指标。文章综述了目前茶叶香气的成分、形成机理、检测分析和数据处理方法的研究进展,并作了展望。     

Decomposition in soil of soluble, insoluble and lignin-rich fractions of plant material from tobacco with genetic modifications to lignin biosynthesis

The decomposition in soil of pieces of stem and different fractions of stems from uniformly-grown tobacco plants with genetic modifications to lignin biosynthesis was investigated by measuring CO₂ production over 74 d. The fractions used were intact stems, the insoluble fraction obtained by washing the stems with water, the lignin-rich fraction obtained by dissecting away the epidermis and cortex from the stems to leave a fraction in which the vascular tissue was concentrated, and the lignin-rich, insoluble fraction obtained by washing the lignin-rich fraction in water. The genetic modifications were the introduction of partial or antisense transgenes for cinnamyl alcohol dehydrogenase (CAD), caffeic acid O-methyl transferase (COMT) and cinnamoyl CoA reductase (CCR), which are all enzymes that catalyse key steps in the monolignol pathway. The total CO₂ produced during decomposition declined in the following order: intact stem>insoluble stem fraction>lignin-rich fraction>lignin-rich, insoluble fraction, for all plant lines except the lignin-rich fraction from the reduced CCR plants. There was an initial flush of CO₂ production that peaked between 2 and 4 d and which subsided within 20 d for both the intact stems and the lignin-rich fractions from all lines. There was no such flushes of CO₂ release from the corresponding insoluble fractions. For the intact stems, the amount of CO₂ released during the initial 20 d was significantly greater for the reduced COMT plants, than for the reduced CAD or reduced CCR plants, both of which released significantly more CO₂ than the unmodified plants. Liquid-state ¹³C nuclear magnetic resonance spectroscopy of the water-soluble material from all lines showed that it was dominated by soluble sugars, but that there were no clear differences in the composition of the soluble fractions between the different lines of plants. Furthermore, the timing of the initial flush of CO₂ release from the intact plant materials corresponded to that from glucose when incubated in the same soil indicating that sugars probably fuelled the initial flush of CO₂ from the intact stems. Over 74 d, significantly more CO₂ was released from the reduced CCR plant stems than from the reduced CAD and reduced COMT plants, which did not differ significantly from each other, but which were significantly greater than the unmodified stems. The total CO₂ production from the lignin-rich fractions did not differ significantly between the unmodified, the reduced CAD and the reduced COMT plants, but the total CO₂ production from the lignin-rich fraction from the reduced CCR plants was substantially greater than that from the other lines.We have shown significant effects of targeted lignin modification on decomposition in laboratory studies over a relatively short period (<74 d). The effects of genetic modification can be explained in part at least by alterations in the amount, composition and conformation of the lignin and the effect it has on other, more labile, components. However, longer-term and more detailed field-based investigations are needed before the wider ecological significance of the differences in decomposition can be properly assessed.     

Lumbricus terrestris counteract the effects of modified lignin biosynthesis on the decomposition of tobacco plant residues

The C and N transformations during decomposition over 26 d of root material from two lines of tobacco plants (Nicotiana tabacum L.) were compared in soil with or without earthworms (Lumbricus terrestris L.). The tobacco plants were either unmodified or genetically modified to reduce the activity of caffeic acid O-methyl transferase (COMT), which leads to plants with altered lignin structure and composition. In the absence of earthworms, C mineralization and net N immobilization were greater for the soil amended with reduced COMT roots than with the unmodified roots. In the presence of earthworms, C mineralization was still significantly greater for reduced COMT roots than for unmodified roots, but the difference was smaller, and the net N immobilization did not differ significantly between the two lines of plants.     

Isolation and identification of potassium-solubilizing bacteria from tobacco rhizospheric soil and their effect on tobacco plants

Soil potassium supplementation relies heavily on the use of chemical fertilizer, which has a considerable negative impact on the environment. Potassium-solubilizing bacteria (KSB) could serve as inoculants. They convert insoluble potassium in the soil into a form that plants can access. This is a promising strategy for the improvement of plant absorption of potassium and so reducing the use of chemical fertilizer. The objectives of this study were to isolate and characterize tobacco KSB and to evaluate the effects of inoculation with selected KSB strains on tobacco seedlings. Twenty-seven KSB strains were isolated and identified through the comparison of the 16S ribosomal DNA. Among them, 17 strains belonged to Klebsiella variicola, 2 strains belonged to Enterobacter cloacae, 2 strains belonged to Enterobacter asburiae, and the remaining 6 strains belonged to Enterobacter aerogenes, Pantoea agglomerans, Agrobacterium tumefaciens, Microbacterium foliorum, Myroides odoratimimus, and Burkholderia cepacia, respectively. All isolated KSB strains were capable of solubilizing K-feldspar powder in solid and liquid media. K. variicola occurred at the highest frequency with 18 strains. Four isolates, GL7, JM3, XF4, and XF11, were selected for a greenhouse pot experiment because of their pronounced K-solubilizing capabilities. After being treated with the four KSB strains, plant dry weight and uptake of both K and nitrogen (N) by tobacco seedlings increased significantly. These increases were higher with the combination of KSB inoculation and K-feldspar powder addition. Isolate XF11 showed the most pronounced beneficial effect on plant growth and nutrient uptake by tobacco seedlings. Combining the inoculation of KSB and the addition of K-feldspar powder could be a promising alternative to commercial K fertilizer and may help maintain the availability of soil nutrients. Further studies are necessary to determine the effects of these bacterial strains on mobilization of potassium-bearing minerals under field conditions.     

气候变化对我国烟草生产及其适生地选择的影响研究

简析了气候变化对我国烟草生长发育、产量和品质、烟草适生地选择以及烟草病虫害的发生等影响 ,并提出适应对策     

烟草配方肥增效剂对烤烟根系内源激素和多胺含量的影响

本试验研究了烟草配方肥增效剂对进入成熟期后烟株根系内源激素含量和多胺含量以及烟叶产量和产值的影响.结果表明,施用配方肥增效剂可提高烟株根系内赤霉素(GA3)、生长素(IAA)和精胺含量,降低脱落酸(ABA)和腐胺含量,其中精胺含量随着肥料用量的减少而增加.前期,配方肥增效剂对根系内亚精胺含量的影响很小,但后期会导致亚精胺含量迅速增高.增效剂对根系内源激素含量和多胺含量的影响以每株施用45.45g配方肥和0.4545g增效剂处理效果最好.施用增效剂能提高烟叶的产量和产值,减少肥料用量的增效剂处理虽降低了烟叶产量,但因改善了烟叶品质而提高其产值,增效剂对烟叶产量和产值的影响以每株施用36.36g配方肥和0.4545g增效剂处理效果最好.     

酸性土壤施石灰对土壤性质与烤烟品质的影响

试验研究酸性土壤施石灰对土壤生物化学性质、烤烟生长和品质的影响结果表明,施用适量石灰可增加土壤细菌、放线菌、好气性纤维素分解菌数量,增强脲酶、酸性磷酸酶、过氧化氢酶和纤维素酶活性。pH值5.2的土壤石灰施用量以750～1125kg/hm~2为宜,可促进烤烟根系生长,提高烤烟产量和品质。     

稻壳掺播对土壤质地及烟叶生产的影响

皖南烟区土壤主要为水稻土,质地偏黏,不利于烟叶生长,为此,在宣城烟区耕作层土壤中掺播一定体积比例的稻壳,探讨其对土壤质地和烟叶生产的影响。结果表明:①随着掺播稻壳比例的增加,0.02～2mm的土壤颗粒和土壤有机质含量增加,土壤体积质量(容重)、含水量和pH降低,但这种趋势随着时间推移而逐渐减缓。②烟田耕作层土壤掺播稻壳总体上有利于烤烟生长,能够提高烟叶产量和品质,经济效益也明显提高。其中以掺播20%～30%的稻壳(稻壳体积/土壤体积)时烤烟的农艺性状、经济性状及工艺评价结果最佳。     

硒和硫相互作用对烟草硫吸收与积累的影响

以第四纪红色粘土为母质的红壤和下蜀黄土为母质的黄褐土为供试土壤 ,进行盆栽试验 .结果表明 ,施硫可提高烟草各部位硫含量 ,烟叶硫含量高于根部 .施硒对烟草中硫含量影响不明显 ,但对硫积累量的影响比较明显 .红壤施低硒 (Se<3.71 μg/ g)时烟草地上部积累增加 ,高硒 (Se >3.71 μg/ g)时有降低趋势 ;黄褐土上则随施硒增加而下降     

外源抗坏血酸与谷胱甘肽对打顶后烟草氧化 还原平衡及烟碱的影响

烟碱含量偏高是我国烤烟的现状。如何有效降低烟叶烟碱含量,提高烤烟工业可用性是烟叶生产中的一个难题。根据烟草打顶导致烟碱含量急剧上升和机械损伤造成细胞氧化迸发的的现象,本试验从打顶创伤引起的一系列生理变化入手,采取打顶后在伤口涂抹抗氧化剂抗坏血酸+谷胱甘肽(As A+GSH)和抗坏血酸(As A)两种方法来抑制活性氧含量的上升,探究茉莉酸刺激烟碱含量上升和活性氧含量之间的关系,并比较两种方法在抑制活性氧及烟碱上升的效果。结果发现,涂抹As A+GSH和As A处理对烟草叶片超氧阴离子、过氧化氢、丙二醛的上升有抑制效果,过氧化氢降解速度慢于超氧阴离子,在烟草内有积累现象。涂抹As A+GSH和As A处理在打顶6 h时茉莉酸含量低于常规打顶,对茉莉酸的产生有抑制效果。其中处理96 h后,打顶后涂抹As A+GSH的处理叶片烟碱含量比常规打顶低21.5%,打顶后涂抹As A的处理叶片烟碱含量比常规打顶低17.5%。且各检测指标之间存在显著或极显著的相关性。另外,打顶后24 h,各处理的活性氧含量回到对照(不打顶)的水平。试验表明,抗氧化型物质(As A+GSH)涂抹打顶后烟草的伤口能有效抑制活性氧、茉莉酸和烟碱含量的上升,且活性氧、茉莉酸、烟碱之间存在着密切联系。As A+GSH比As A有更强的抗氧化性,能更好地抑制打顶后烟碱的上升。     

控释肥料性质及其对烟草生长影响的研究

该文以自然资源“桐油”为包膜材料(从油桐果实中提取),生产包膜肥料,采用盆栽试验,对控释尿素养分释放动态进行研究。养分的测定采用“质量法”进行。结果表明：在红壤中,以桐油为原料的控释尿素初期溶出率为12.6%,比普通尿素初期溶出率下降69.5%,并且较好地满足烟草生长对养分需求特点。施包膜尿素比施普通尿素烟草叶片干物质产量增加5.5 g/株。