杨树基因工程研究进展

运用现代分子生物学技术进行林木遗传改良研究具有重要的现实意义。介绍了杨树基因工程方面的研究进展，综述了杨树遗传图谱构建、基因克隆及转基因应用研究方面的状况，并对杨树基因工程研究存在的问题和前景进行了讨论。总结了杨树基因工程研究的规律，以促进林木基因工程研究的发展。     

植物转基因技术及其在林木遗传改良中的应用

转基因技术不断进步为基因的功能解析和生物的定向改良提供了最为有效的途径。林木基因工程育种也随着转基因技术的成熟而步入快速发展时期,但目前国内对林木基因工程育种中处于关键地位的转基因技术进行系统论述的还比较少。文中从原理、过程和优缺点等几个方面系统介绍了几种应用于植物基因工程的转基因技术,评述了转基因技术在林木中的应用现状,并对其在林木遗传改良中的应用前景进行展望,以期为后续的林木基因工程研究及应用提供参考。     

林木基因工程研究现状与展望

本文概述了植物遗传转化的方法,论述了林木抗病、抗虫、抗除草剂、生殖发育调控、抗逆境和木材品质改良转基因研究进展。并对现阶段林木基因工程中存在的主要问题和应用前景进行了讨论。     

转基因林木研究进展

着重论述了林木抗虫,抗菌,抗除草剂,生殖发育调控,抗逆境,材性改良等转基因林木的研究进展,简述了转基因林木的应用现状,提出了林木基因工程现存的问题,并对该领域进行了展望。     

转基因林木生态安全性评价研究现状

近年来林木基因工程育种技术日益成熟,而转基因林木生态安全性评价相对滞后,其中转基因林木基因漂移研究尚处于空白。花粉传播是转基因植物外源基因发生转移的主要途径。文章对转基因植物基因漂移、林木开花散粉规律的研究现状进行综述,讨论了目前转基因植物基因漂移研究中存在的问题和发展前景,以期为转基因林木生态安全性评价研究提供依据。     

派间杂种110杨再生系统的建立

杨树(Populus spp.)是我国北方地区重要的造林绿化树种之一,因其速生丰产、防风固沙能力强、无性繁殖容易,且基因组较少,而成为林木遗传改良的理想模式植物[1].随着分子生物学的发展和杨树组织培养技术的日趋成熟,人们纷纷把目光转向基因工程,希望在短期内达到改良杨树品种的目的[2].     

杨树基因工程研究的现状及展望

杨树是重要的栽培树种,具有广泛的用途,同时也是最早开展基因工程研究的树种。迄今为止,杨树基因工程取得了许多重要进展,有近二十个杨属种或杂种获得了转基因植株,一些重要的基因如抗虫基因、抗病基因、降低木质素基因、抗除草剂基因、不育基因等被转入杨树细胞基因组中。通过基因工程育种,有可能获得用常规育种方法很难或需要很长时间才能选育出的具有重要经济价值的杨树新品种。随着杨树基因工程的进一步发展,不仅在理论上推动林木基因工程的研究,也必将为林业生产的可持续发展发挥重要作用。     

白桦转基因遗传改良研究进展

随着科学技术深入发展, 转基因技术已经成为林木定向遗传改良的重要途径之一, 林木基因工程也随着转基因技术的成熟而步入快速发展时期。目前国内对白桦(Betula platyphylla)的研究处于常规育种向分子育种的过渡阶段, 转基因技术在白桦定向培育过程中的应用才刚刚起步。文中从白桦开花、抗虫、木材改良、抗非生物胁迫等方面总结了国内外白桦转基因研究现状, 对转基因技术在白桦遗传改良种应用中存在的问题进行探讨, 展望了转基因技术在白桦遗传改良中的应用前景, 以期为白桦基因工程研究提供参考。     

我国转基因杨树的研究及应用现状

综述了我国转基因杨树研究的主要进展,以及在我国人工林建设中的应用现状和潜力。指出我国抗虫转基因杨树的培育已经取得重大突破并处于世界领先地位,将为人工林建设不断提供抗虫新品种;耐盐碱、纸浆材的转基因研究取得了较大进展,经过进一步田间试验,将进入商品化应用;杨树基因组全序列的完成,将促进木材形成过程的认识,为杨树木材品质的基因工程改良及商品林的定向培育奠定基础。     

林木基因工程风险评估和安全管理现状

综述了国内外林木基因工程的研究发展以及国内外现有的对转基因植物的安全评估和管理概况,强调了对转基因林木的评估标准和管理措施应结合林木自身特点逐一进行,以减少其可能造成的基因污染为重点。对我国转基因林木生物安全的评估和管理提出了一些建设。     

Transgenic poplar with enhanced growth by introduction of the ugt and acb genes

The transgenic poplar (Populus tremula L.) was obtained by transfer of the ugt and acb genes via triparental mating, which was employed to deliver large fragments of TDNA as a cluster. Freshly harvested seeds of local poplar were placed on MS agar medium and plantlets were obtained. After 1 year of subcultivation, plantlets were infected with a transconjugant of triparental mating with target ugt and acb genes into axillary buds. The transformed sprouts so obtained were cut and subcultivated on agar medium with an addition of 0.6 mg/l indole-3-butyric acid as an auxin source. The transformed sprouts showed GUS activity and resistance to gentamycin and kanamycin. The integrity of the target ugt and acb genes into poplar genome was demonstrated via PCR and Southern blot hybridisation. The transgenic poplar plants revealed a higher growth energy, corresponding to a higher content of IAA as opposed to control plants. Both transgenic and non-transformed plants were potted into soil for outdoor acclimatisation and subsequently transferred to earth in beds. Growing outside during 3 years, the transgenic poplar demonstrated a higher growth rate with fast bud and branch development.     

Survival and development of immature Harmonia axyridis (Pallas) feeding on Chaitophorus populeti (Panzer) propagated on transgenic Populus alba × P. glandulosa

Laboratory feeding experiments with the poplar aphid, Chaitophorus populeti (Panzer), feeding on transgenic poplar (P. alba × P. glandulosa) varieties C13-5 and C013-5, were carried out to study the effect of transgenic poplar on the ladybird Harmonia axyridis (Pallas). The mortality and development time of the immature stages, the eclosion rate and body mass of H. axyridis were measured. The results indicated that C. populeti feeding on different varieties of transgenic plants had no statistically significant effect on the mortality of H. axyridis larvae. The development time of larval and pupal stages were not significantly different between the two transgenic poplars and a non-transgenic poplar. Furthermore, the body mass and eclosion rate did not show any difference between the H. axyridis feeding on aphids reared on transgenic plants and those from non-transgenic plants. It is suggested that transgenic plants have no deleterious effect on the predatory ladybird.     

Over-expression of Tryptophan Decarboxylase Gene in Poplar and its Possible Role in Resistance Against Malacosoma disstria

Amines and their derivatives are known to influence insect behavior involved in feeding and reproduction. In order to examine the feasibility of improving the resistance of poplar to insect pests by the introduction of a plant-derived amine-generating transgene, explants from the hybrid poplar clone ‘INRA 717 1B4’ (P. tremula ×P. albo) were transformed with a Camptotheca acuminata tryptophan decarboxylase (TDC, EC 4.1.1.28) cDNA driven by the CaMV 35S promoter. The enzyme TDC catalyzes the decarboxylation of tryptophan to tryptamine, which, in addition to being a bioactive amine itself, is known to act as a precursor of various other indole derivatives. Putative transgenic lines were confirmed by PCR for the TDC1 gene sequence and by the expression analysis of the transgene mRNA and encoded protein. No visible phenotypic changes were associated with ectopic TDC1 expression. Chemical and radiotracer analyses of the transgenic plants revealed tryptamine accumulation as high as 4 mM in leaf tissue, and suggested that the tryptamine produced by ectopically expressed TDC was not further metabolized. Insect bioassays with the TDC transgenic plants showed that the tryptamine accumulation was consistently associated with adverse effects on feeding potential and physiology of Malacosoma disstria (forest tent caterpillar).     

Antisense expression of a caffeic acidO-methyltransferase ofStylosanthes humilis in transgenic poplar: Effect of expression onO-methyltransferase activity and lignin composition

Poplar (Populus tremula) was transformed with a construct carrying an antisense caffeic acidO-methyltransferase (COMT) cDNA (pOMT8) from a tropical pasture legume,Stylosanthes humilis. pOMT8 shows 83% overall homology to the corresponding COMT gene (pPCLA) of poplar. Of the 200 putatively-transformed plants regenerated on selective media after co-cultivation of poplar stem explants withAgrobacterium tumefaciens harbouring a CaMV 35S-antisensepOMT8 construct, a subset of 20 plants were randomly chosen for further analysis. PCR and Southern blot analysis demonstrated the stable integration of T-DNA into the genome of these plants. Antisense expression ofpOMT8 resulted in reductions in total COMT activity in the majority of the transgenic plants with the lowest total COMT activities (61–70% of untransformed control plants) being observed in four transgenic plants. The composition of lignin in transgenic plants was also changed, as detected by reductions in the content of syringyl units using infrared spectroscopy. However, no changes were found in the amount of insoluble lignin in transgenic plants as compared to untransformed control plants. These results indicate the potential of thepOMT8 gene to partially suppress COMT activity and modify the composition of lignin in transgenic poplar. This work was partly supported by General Management of Turkish Pulp and Paper Mills.     

An improved transformation system for Lombardy poplar (Populus nigra var. italica)

We report an improved transformation system for Lombardy poplar (Populus nigra var. italica). A new binary vector, pBF2, with 11 unique restriction enzyme sites and the normal neomycin phosphotransferase II (NPTII) gene was constructed for the transformation of Lombardy poplar. Genetically transformed adventitious shoots were directly regenerated after cocultivation of stem segments with Agrobacterium tumefaciens EHA105 that harbored a binary vector with genes for the NPTII and enhanced green fluorescent protein. Successful transformation was confirmed by fluorescence microscopy, immunoblotting and Southern blotting analyses, and resistance to kanamycin and geneticin. This transformation system requires less time than our previous method for the regeneration of transgenic shoots. When explants were incubated on a smedium containing dithiothreitol, the transformation frequency increased to approximately 20%.     

杨树抗性转基因研究进展

本文重点介绍了杨树基因工程中采用的抗虫基因、抗病基因、抗除草剂基因和抗逆境基因类型及研究现状 ,并对杨树抗性转基因研究存在的问题及解决途径作了探讨     

Identification of <Emphasis Type="Italic">CpTI</Emphasis> gene integration for 2-year-old transgenic poplars at DNA level

The putative transgenic hybrid triploid poplars [(P. tomentosa × P. bolleana) × P. tomentosa] with CpTI gene have been outplanted in test field for 2 years. Although the authors’ previous studies have proved that they are highly resistant to 3 species of poplar-threatening insect pests and contain high content of CpTI protein in foliage, incorporation status of foreign CpTI gene in poplar genome is uncertain. In this present study, the incorporation of foreign CpTI gene in genome of 5 transgenic poplars was confirmed by PCR and Southern blotting analysis. DNA amplification showed that there were clear DNA bands of about 450bp specific to CpTI gene in transgenic lanes, while no corresponding band in non-transgenic lane was observed. Correspondingly, clear DNA hybridization signals and no signal were exhibited on film for DNA Southern blotting analysis in transgenic lanes and non-transgenic lane, respectively, which further confirmed the stable integration of foreign CpTI gene in genome of 2-year-old transgenic poplar.     

Relationship between trophic component of different poplar strains and occurrence ofSaperda poplnea

An experimental area of poplar was established in Songyuan of Jilin Province in 1999 for testing the resistance of different poplar stains toSaperda poplnea. Incidence ofS. poplnea on ten poplar strains were investigated, and the main trophic component of branches of these poplar trees were measured and analyzed in April 2001. The results showed that there existed significant difference in population size ofS. poplnea on different poplar strains, and the branches of these poplar strains have significant difference in nutrient component and content of amino acids. The population size of this pest had a significantly positive correlation with dissolvable total sugar and water content but had no significant correlation with content of total nitrogen and protein nitrogen. Foundation Item: This paper is part of the subject of integrated control of longicorn of poplar for mainly focusing on pest resistance, which was supported by Jilin Provincial Forestry Department (96-010). Biography: Gao Chang-qi (1949-), Research Fellow, Doctorate Tutor, Jilin Provincial Academy of Forestry Science, Changehun 139931, P. R. China. Responsible editor: Chai Ruihai     

超量表达FBL1对84K杨根系和生长量影响研究

生长素及其信号转导系统对植物的生长发育具有重要的影响。本研究从银腺杨'84K'(Populus alba × P. glandulosa cl. '84K')中分离了生长素受体基因PtrFBL1,利用PMDC32构建了PMDC32-PtrFBL1超量表达载体,并通过遗传转化获得了超量表达植株17个。对温室定植的3个转基因株系和对照植株的根系、生长量和光合指标等性状分析结果显示:转基因株系总根长和总根面积达到显著或极显著差异,而根系干质量、平均不定根系长度、平均不定根直径差异不显著;株高、平均节间长、地径和高径比皆高于对照,且大多数转基因株系达到显著差异;除气孔限制值(Ls)低于对照外,气孔导度(Cd)、水分利用效率(WUE)、光能利用效率(LUE)和叶绿素相对含量皆高于对照,且大多数转基因株系达到显著或极显著差异。以上结果表明,可能是FBL1超表达增加了转基因株系根系面积,提高了水分和养分的吸收利用,进而导致转基因株系光能吸收和转化效率提高,引起转基因株系生长加快。