共查询到17条相似文献，搜索用时 180 毫秒
1.
植物根结线虫病对农业生产的危害连年加重,以轮作和化学农药为主的传统防治难以满足现代农业生产的需要。以常规的抗性育种和表达外源蛋白为主的抗线虫转基因育种主要受限于抗性基因的匮乏。而近来RNA干扰技术的应用为抗线虫基因工程带来新的突破,通过构建RNA干扰载体,在转基因植物中表达寄生线虫重要基因的dsRNA或siRNA,并经口针取食被导入线虫体内,并引发线虫的系统性RNA干扰反应,导致其出现寄生、发育、代谢、运动等障碍甚至致死,从而使转基因植物实现对寄生线虫的抗性。本文综述了RNAi介导的抗根结线虫基因工程方面的研究进展,分析探讨了这种新的策略的特点并展望了它的应用前景。 相似文献
2.
RNA干涉（RNA interference,RNAi）技术是一门新兴的基因阻断技术,可通过将外源双链RNA导入细胞介导同源靶基因mRNA序列的降解,使靶基因表达沉默,是一种转录后的基因沉默现象。目前,RNA干涉技术在植物研究中已经得到广泛应用。本文简介了植物的RNA干涉研究及RNAi表达载体的构建,综述了RNAi在棉花基因功能和功能基因组学研究、棉花品质性状的遗传改良和棉花的抗虫抗病研究中的应用进展及其在棉花研究中存在的主要问题和应用前景。 相似文献
3.
RNA干扰(RNA interference,RNAi)是近年来生物学领域研究的热点之一,本研究应用改进的重组PCR技术构建大豆脂肪氧化酶基因及玉米淀粉分支酶基因的RNA干扰构件,以探索一条简便快捷,适应范围广范的植物基因RNAi结构构建方法. 相似文献
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RNAi作为反向遗传学手段,以其序列特异性、高效性等特点,在植物基因功能验证、抗病和品种改良等方面发挥了积极作用,RNAi的系统性也同时受到研究者的广泛关注。系统性RNAi（systemic RNA interference）传统定义是指沉默信号从一个细胞或一种组织,传递到另外的细胞或同一个体的另外组织中去的现象。本文主要综述植物基因工程研究中应用系统性RNAi技术的研究现状,总结了植物系统性RNAi的特征及沉默效应的抑制。对植物系统性RNAi的研究方法与应用,特别是在植物抗性研究和遗传改良等方面作了重点介绍,并分析了技术存在的限制因素。 相似文献
6.
植物RNA沉默(RNAsilencing)是植物本身固有的一种抗病毒防御系统,是对病毒在复制过程中形成双链RNA(dsRNA)的特殊反应。RNA沉默介导的dsRNA干涉病毒侵染转基因抗病毒有其不足,几种体外生产dsRNA的抗病毒体系能弥补这一不足,它们与转基因表达病原RNA不同,但仍然依赖RNA沉默机制来获取病原抗性。综述了近年来发展起来的各种启动RNA沉默的dsRNA产生策略、抗病状况和存在的问题及发展前景 相似文献
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RNA沉默（RNAi）介导的植物抗病毒研究是近年来引起广泛关注的一项植物抗病毒基因工程策略。马铃薯Y病毒（PVY）在世界范围内引起马铃薯、烟草等重要经济作物的病害,并且造成严重的经济损失。本文以PVY的外壳蛋白（CP）基因为模板扩增300bp和354bp两个片段,正向和反向分别插入植物表达载体pROKⅡ的35S启动子下游,从而构建了以PVY的CP基因为靶标的RNAi植物表达载体pROKY300,转入农杆菌EHA105中,以农杆菌渗入法在本氏烟中瞬时表达与wyCP同源的hairpin RNA。结果表明,瞬时表达的hairpin RNA有效干涉了PVY侵染。 相似文献
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为了获得高抗番茄黄化曲叶病毒(TYLCV)番茄材料,本研究通过人工设计以TYLCV病毒基因V1、C1为靶标的双链RNA(dsRNA),通过农杆菌介导法转化番茄,探索RNAi技术在番茄抗TYLCV中的防御效果。结果表明,通过RNAi技术干扰TYLCVV1和C1基因可以延缓病毒症状的发生,提高番茄植株对TYLCV的抗性。田间试验结果发现,以TYLCV V1和C1为靶标的RNAi株系RNAi-CP-2和RNAi-Rep-12,不仅可以干扰病毒V1、C1的表达,而且可以干扰TYLCV其他4个基因V2、C2、C3和C4,表明RNAi技术可以在靶标基因附近传递,影响相邻其他基因的表达。本研究结果为番茄抗病毒研究奠定了理论基础。 相似文献
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RNA干扰(RNAi)技术是研究基因功能的一种常用方法,为了快捷高效地构建水稻(简易RNAi表达载体,本研究采用简易RNAi构建法,设计3'末端9个碱基互补的正向和反向寡聚核苷酸引物,通过聚合酶延伸成为具有反向重复序列的小干扰片段。以pCAMBIA1301-Gt13a为表达载体,将小干扰片段与表达载体经过一次双酶切与连接得到RNAi载体。用农杆菌(Agrobacterium tumefaciens)介导法得到水稻(Oryza sativa ssp.japonica)转基因株系后,用叶片GUS染色和qRT-PCR法,对RNAi转基因水稻和野生型日本晴叶片GUS组织活性和籽粒中目的基因表达量进行检测。水稻叶片GUS染色结果显示,有10株转基因水稻叶片切口处呈现蓝色,而野生型无显色反应,说明RNAi载体T-DNA区域的基因已整合到水稻基因组上,并表达。在mRNA水平上转基因水稻籽粒中目的基因相对表达量降低至18%~55%,差异极显著(P0.01),表明整合在水稻基因组上的小干扰片段能降低目的基因的表达水平。籽粒灌浆成熟后对10株转基因水稻及野生型日本晴籽粒的单粒重、粒长、粒宽和厚度分别进行测量。与野生型日本晴相比,转基因水稻籽粒单粒重发生显著性降低(P0.05),籽粒变小,长和宽都发生显著性变化(P0.05),说明简易RNAi载体对水稻目的基因的表达起到很好的沉默效果。本研究不仅为利用简易RNAi构建法研究水稻功能提供了依据,也为快捷高效地研究水稻基因功能提供了基础资料。 相似文献
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热激蛋白70（heatshockprotein70,Hsp70）是所有原核生物和真核生物在发育过程中为了适应不同环境而合成并起关键作用的蛋白质家族。多种植物寄生线虫编码的Hsp70基因序列己被克隆和检测,但其在应激反应中线虫与寄主植物的互作机制仍不是很清楚。本文对Hsp70家族的分类、Hsp70结构及其生物学功能进行了综述,从Hsp70基因的克隆、表达和系统进化介绍了植物寄生线虫Hsp70基因的研究进展,并就今后植物寄生线虫Hsp70的相关应用基础研究进行了展望。 相似文献
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《Applied soil ecology》2007,35(2):370-379
Predatory nematodes feed on soil microorganisms including plant parasitic nematodes. They reduce populations of plant parasitic nematodes in virtually all soils because of their constant association with plant parasitic nematodes in the rhizosphere, and also release nutrients in plant-available forms, which may enable plants to better withstand nematode burden on their roots. Predation by nematodes of the orders Mononchida, Diplogasterida, Dorylaimida and Aphelenchida, has been studied but the data available in field/natural conditions are insufficient to conclude whether they are effective biocontrol agents of plant parasitic nematodes. However, among the different types of predators, diplogasterids are the most suited for biocontrol of nematodes, because of their short life cycles, easy culture, prey-specificity, chemotaxis sense and resistance to adverse conditions. This article summarizes progress to date and suggests ways to encourage the use of predatory nematodes as biocontrol agents in the management of plant parasitic nematodes. 相似文献
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土壤线虫和微生物群落结构与作物健康密切相关。采用田间试验，利用传统分类和高通量测序技术，研究了水稻–番茄轮作(FS)、番茄连作(FF)和休耕(CK)3种种植制度土壤线虫及微生物群落结构差异。结果表明，水旱轮作土壤中线虫种类少，自由生活线虫占比高。土壤中植物寄生线虫属的检出率，轮作最少，仅有5个，连作最多，共13个，且大部分为常见属；水旱轮作同时能降低土壤中植物寄生线虫的种类，包括主要危害番茄的根结线虫属，占比仅2.1%，而连作为29.7%。不同种植制度下真菌和细菌类群OUTs和群落结构差异明显；与连作相比，轮作和休耕真菌、细菌种群丰富度更高，共享占比更多，群落构成更相近；水旱轮作Alpha多样性指数显著高于连作；轮作土壤中植物寄生线虫拮抗微生物类群Chaetomium,Talaromyces,Anaerolineaceae和Acidobacteria相对丰度高于连作。水稻–番茄轮作能大幅减少植物寄生线虫种类，增加微生物群落多样性，改善土壤质量，是番茄生产中防控线虫病害的理想措施。 相似文献
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In this paper, the possible role of plant parasitic nematodes as a driving force of change in natural vegetation is analysed using the succession at coastal foredunes as a model. In pot trials, when grown in natural substrates from mature stands, seedlings of dominant foredune plants showed poor growth when compared to sterilised substrates. In natural substrates from preceding stages, growth reduction was far less, or even non-significant. Chemical soil treatment with nematicides resulted in enhanced growth of the seedlings. Inoculation of ectoparasitic nematodes reduced plant growth, but only at densities much higher than those occurring in control pots with unsterilised field soil. Identification at species level showed that endoparasitic nematodes are specifically associated with particular plant species. Therefore, it is hypothesised that the distribution of endoparasitic nematodes may be an important factor leading to the specific nature of soil pathogen complexes in coastal foredunes. We discuss the role of endoparasitic nematodes as possible key species in soil communities and compare the possible effects of specific vs. generalistic plant parasitic nematodes in soil communities on vegetation processes. 相似文献
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Plant–parasitic nematodes are injurious crop pests that have been managed mainly by chemical nematicides. However, safe and alternative methods such as those based on organic materials need to be developed. Our study has evaluated (i) the effects of four organic amendments with different biochemical compositions that are abundantly produced in the study area (Guadeloupe, French West Indies) on soil nematode communities and (ii) some of the suppression mechanisms of banana parasitic nematodes, especially those involving the soil food web. This study is based on a microcosm experiment comparing sugarcane bagasse, sugarcane sludge, plant residues and sewage sludge. All amendments except sewage sludge decreased the root abundances of plant–parasitic nematodes, by 96% in the case of sugarcane bagasse. For this treatment, soil densities of carnivorous nematodes were six times higher than the treatments without organic amendment. Plant residues and bagasse were mainly composed of materials that are difficult to decompose, namely cellulose and lignins. These organic materials favored a fungal decomposition pathway and permitted development of carnivorous nematode populations and increased the Channel Index (CI). Pratylenchus coffeae control after sugarcane refinery sludge application remains unexplained. Lastly, sewage sludge, composed mainly of easily degradable compounds, did not permit nematode control, and only bacterivorous nematode populations were enhanced by this treatment. 相似文献
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Actinomycetes, Bacillus subtilis, and Bacillus thuringiensis were isolated from municipal–solid waste (MSW) compost, and different microbial liquid filtrates (MLF) were prepared. Sterile culture media with no microbes were used as their controls. The effects of MLF on soil nematode communities were examined in pot‐grown Festuca arundinacea Schreb. Fifteen genera of nematodes in background soil were identified, of which Helicotylenchus and Rotylenchus were dominant. The inoculation of MLF strongly affected the abundance and community structure of soil nematodes. Compared with their controls, lower total nematode numbers following MLF incorporation were found. Actinomycetes inoculation changed community structure of soil nematodes, transforming the dominant genera from Helicotylenchus and Rotylenchus into Cephalobus, Chiloplacus, and Aphelenchus. Actinomycetes incorporation resulted in a significant decrease of plant‐parasitic nematodes relative to control pots. Only plant‐parasitic and omnivorous‐predatory nematodes were found in treatments following B. subtilis inoculation, and Helicotylenchus, Rotylenchus were dominant genera with relative abundance of 76.2% and 14.3%, respectively. Although the dominant genera were still Helicotylenchus and Rotylenchus, B. thuringiensis inoculation led to a marked decrease in populations of plant‐parasitic nematodes and an increase in populations of fungivorous and bacterivorous nematodes relative to control. Shannon's diversity index (H′), evenness index (J′), richness index (SR), and Wasilewska index (WI) in pots treated with actinomycetes and B. thuringiensis filtrates were significantly higher than those of their controls, whereas significant lower dominance index (λ) in actinomycetes and B. thuringiensis treatments was observed than their controls. Plant growth was improved in the treatments inoculated with three microbes. The findings highlight that actinomycetes can most effectively suppress plant‐parasitic nematodes, increase community diversity, evenness, and richness, thus improving soil environment for turf growth. 相似文献
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Populations of plant parasitic nematodes and their effects on symbiotic nitrogen (N) fixation in herbaceous legumes and on
some selected characteristics of other plant species associated with such cover crops were studied. Two legume species [mucuna,
Mucuna pruriens (L) DC. var. utilis (Wright) Bruck and lablab, Lablab purpureus L. Sweet], one grass/weed species [imperata, Imperata cylindrica (L.) Rauschel] and a cereal (maize, Zea mays L.) were used. There were three soil treatments (fumigation, fumigation plus inoculation with Meloidogyne species, and an untreated control). Plant parasitic nematode populations in soil, roots and nodules were determined at 4,
8 and 12 weeks after planting. The response of the phytoparasitic nematodes to soil treatments varied according to the plant
species present. The predominant nematodes in soils, roots and nodules of legumes were of the genus Meloidogyne, whereas other genera of parasitic nematodes dominated the fauna in soils and roots of maize and imperata. Biomass yield
of mucuna was not significantly affected by either Meloidogyne spp. or the other genera of phytoparasitic nematodes. In contrast, the dry matter yield of lablab measured at 12 weeks was
reduced by 16% in inoculated compared with fumigated soils. Similarly, the biomass yields of maize and imperata were reduced
by 10% and 29%, respectively, in unfumigated rather than fumigated soils. The amounts of N accumulated in mucuna, maize and
imperata were not significantly affected by the two groups of plant parasitic nematodes. However, at 12 weeks, lablab grown
on inoculated soils accumulated only 69% of the N found in plants grown on fumigated soils. Inoculation of soil with Meloidogyne spp. significantly increased the number of nodules on lablab roots compared with the non-inoculated treatments, whereas nodulation
in mucuna was not affected by soil treatment. After 12 weeks, the quantity of N2 derived from symbiotic fixation in mucuna was not significantly affected by soil treatments whereas the amount of fixed N
in lablab was 32% lower in inoculated than in fumigated soils. Possible mechanisms for the non-suppressive effect of plant
parasitic nematodes on mucuna are discussed.
Received: 12 March 1999 相似文献
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通过2种化肥用量、5种翻压绿肥量组成的10个处理田间小区试验,研究云南红壤翻压绿肥量对烟草农艺性状及线虫危害的影响。结果表明,烟草叶片大小、株高、茎粗与翻压绿肥量呈显著或极显著正相关;烟草采收末期,红壤寄生性线虫和非寄生性线虫数量随着翻压绿肥数量的增加而趋于增加,烟草根结线虫危害级别与翻压绿肥量呈极显著负相关。因此,翻压绿肥改善了烟草养分供给,促进了烟草生长,增强了烟草抗御线虫危害的能力,对烟草根结线虫危害起到了防治作用。生产上通常翻压绿肥15 000 kg/hm2,以达优质适产。 相似文献