农作物抗除草剂遗传工程研究进展

控制杂草提高农作物产量是农业生产中共同面临的问题,发展抗除草剂农作物将是最经济最方便控制杂草的技术。由于对除草剂的作用模式和除草剂代谢途径的了解,弄清了除草剂的关键靶酶及其基因,因此分离除草剂靶酶基因,克隆能解毒除草剂的酶基因,通过转化技术可获得抗除草剂农作物,大量的抗除草剂转基因农作物大田试验表明,将最有希望在２０００年进入市场。     

作物抗除草剂转基因研究进展

综述了抗除草剂基因研究的意义、研究机理及国内外研究现状,分析了各种转基因方法的优缺点,展望了除草剂抗性育种的发展方向。     

农作物抗除草剂基因工程

概述抗除草剂作物基因工程抗性基因的来源,产生抗性的机理,抗除草剂外源基因的导入方法,并对目前普遍关注的抗除草剂作物的安全性问题进行了讨论,提出了抗除草剂作物研究及开发中应注意的问题。     

制备遗传工程小鼠的技术改进

遗传工程小鼠是当今生命科学领域集成度最高的研究体系之一。特别在“人类基因组计划和小鼠基因组计划”完成后,遗传工程小鼠在制备人类疾病模型、药物开发和评价、基因功能分析以及比较基因组学中发挥着越来越重要的作用。由此,也推动了遗传工程小鼠相关技术的快速发展。就遗传工程小鼠制备的现况、存在的问题以及新策略等相关问题进行了总结。     

转基因抗除草剂油菜对十字花科杂草的基因漂移

以转基因抗除草剂油菜Q3为花粉供体材料,油菜远缘杂草为花粉受体材料,在自然传粉和人工辅助授粉条件下研究甘蓝型油菜与十字花科杂草间的基因漂移频率。结果表明,以转基因油菜为父本,十字花科杂草荠菜、碎米荠、播娘蒿、诸葛菜、风花菜、遏蓝菜和菜为母本,杂交高度不亲和,基因漂移率为0 % ,无生态风险,但对野芥菜的基因漂移率高达0 .885 %。野芥菜是我国大部分地区的常见杂草,种类繁多,分布范围广,大面积种植转基因抗除草剂油菜对野生芥菜的基因污染应引起高度重视。     

抗除草剂转基因植物的研究现状

主要对目前在农业上广泛采用的除草剂以及抗除草剂转基因植物的研究现状进行了阐述．介绍了非选择性除草剂和选择性除草剂的分类及其作用机理。并对杂草产生除草剂抗药性的机理进行了分析,此外还介绍了抗除草剂基因的作用机理和对转基因植物所产生的生理作用,另外对抗除草剂转基因植物的生物安全性问题,如对基因飘移和生物多样性的影响进行了讨论,并对新型除草剂的发展方向提出思考。     

转基因抗除草剂油菜对近缘作物的基因漂移

以转基因抗除草剂油菜 Q3和 HCN- 19为花粉供体材料 ,油菜近缘作物为花粉受体材料 ,在自然授粉条件下研究甘蓝型油菜与芸薹属近缘作物间的基因漂移频率。结果表明 ,油菜对芸薹属 6个种甘蓝、黑芥、埃芥、芥菜型油菜、白菜型油菜和甘蓝型油菜的基因漂移率分别为 0、0 .0 2 4 %～ 0 .2 4 3%、 0 .0 2 8%～ 0 .0 92 %、 0 .10 9%～ 0 .95 1%、 0 .4 79%～ 0 .879%、 1.2 5 2 %～2 .191%。且基因漂移频率受多种因素影响 ,其中与杂交亲和性、花期同步率、种植面积等高度相关。通过花粉将抗除草剂基因漂移给近缘作物 ,油菜是需要特别关注的作物     

抗除草剂作物对未来化学农药发展的影响

近年来,转基因抗除草剂植物已取得重大进展,在２１世纪,迅速发展的转基因抗除草剂植物将对传统的农药工业产生重大的影响,除草剂在农药中的比重将继续增加,高效、灭生性除草剂的开发将成为除草剂开发的主流,并由此带来新除草剂问世速度加快,开发费用下降。本文讨论了转基因植物对未来除草剂发展的影响,同时就转基因抗除草剂的有关问题展开了讨论。     

除草剂与抗除草剂作物

从本世纪40年代发展用2,4-D作除草剂以来,使世界农业传统的耕作制度发生了根本的变革。杂草及其防除科学走在“绿色革命”的最前沿。50年来,化学除草剂的发展为世界农业收成作出了重要贡献。除草剂在农药中所占的比重也越     

除草剂抗性基因的研究进展

概述了除草剂抗性基因的种类,主要来源以及抗除草剂基因的应用。并对新的抗除草剂基因的发掘、既有的抗除草剂基因的改良、除草剂抗性机理研究以及新的抗除草剂作物的培育等方面的进一步研究进行了探讨。     

转基因耐除草剂作物的环境风险及管理

自1996年第1例转基因作物在美国商业化种植, 其在全球的种植面积一直处于持续、快速增长的趋势。2010年, 全球转基因作物种植总面积达1.48×10⁸ hm², 所种植的转基因作物主要是耐除草剂和抗虫作物, 其中耐除草剂作物占种植总面积的81%。耐除草剂作物的种植为杂草的高效控制提供了新的手段, 但其可能带来的生态环境风险也引起了全世界各国的广泛关注和争议。该文在总结归纳前人研究的基础上, 针对耐除草剂作物的基因漂移、杂草化及对生物多样性的影响等当前人们普遍关注的环境风险问题, 系统讨论了相关的风险评价程序和方法, 概括和分析了当前耐除草剂作物的环境风险研究进展和管理措施, 以期为我国转基因耐除草剂作物的开发、风险评价及管理提供依据。     

Use of Genetically Improved Nitrogen-Fixing Cyanobacteria in Rice Paddy Fields: Prospects as a Source Material for Engineering Herbicide Sensitivity and Resistance in Plants

Cyanobacteria are the largest and most widely distributed group of photosynthetic prokaryotes on Earth, forming a prominent component of microbial populations in wetland soils, especially in rice paddy fields, and significantly contributing to fertility as a natural biofertilizer. Modern agricultural fields are generally treated with high doses of synthetic nitrogenous fertilizers and pesticides having adverse effects on the soil microflora of naturally occurring N₂-fixing cyanobacteria. This review deals with some of the advances made during the last few decades in the areas of developing ammonia derepressible pesticide-resistant cyanobacterial mutants for algalization of the wet agricultural fields as a viable and efficient N-photobiofertilizer.     

微生物除草剂的研究进展与展望

综述了国内外微生物除草剂的研究进展,介绍5种已经商品化的微生物除草剂和包括真菌、根际细菌、病毒、放线菌4种具有除草潜能的微生物类型的除草剂,并对我国微生物除草剂的研究开发提出了建议。     

Herbicide resistance in a mutant of the microalga Bumilleriopsis filiformis

A DCMU* (diuron)-resistant algal mutant was selected and characterized. Chlorophyll content, growth, and photosystem-I activity are as in the wild-type. Growth in liquid medium with 3 M DCMU present is half of the control. Apparently only the herbicide-binding site is affected within the redox chain. In contrast to the wild-type, trypsin treatment of isolated chloroplast material completely abolishes photosynthetic electron transport inhibition by DCMU or atrazine.DCMU resistance of chloroplasts is accompanies by tolerance to triazinones and phenylpyridazinones, but not to symmetric triazines. Sensitivity to diphenylethers, DBMIB or o-phenanthroline is not altered.Data on this algal mutant combined with those from triazine-resistant mutants of higher plants give direct evidence of overlapping binding sites at a (hypothetical) binding protein located at the reducing side of photosytem II.     

除草剂对杂草微观进化及多样性的影响

本文归纳了除草剂作用下杂草种下分化的机理及影响这一过程的内外因素,指出除草剂作用下农田杂草多样性的特点及杂草遗传和多样性变化研究的理论意义。     

盐藻对除草剂草丁膦的抗性研究

对分离出的单藻落盐藻进行除草剂草丁膦的抗性实验,液体培养结果显示,野生盐藻对除草剂草丁膦敏感,3.0mg/L剂量的草丁膦能完全抑制盐藻的生长和增殖。     

Somatic mutation-mediated evolution of herbicide resistance in the nonindigenous invasive plant hydrilla (Hydrilla verticillata)

Hydrilla (Hydrilla verticillata L.f. Royle) was introduced to the surface water of Florida in the 1950s and is today one of the most serious aquatic weed problems in the USA. As a result of concerns associated with the applications of pesticides to aquatic systems, fluridone is the only USEPA-approved chemical that provides systemic control of hydrilla. After a decrease in fluridone's efficacy at controlling hydrilla, 200 Florida water bodies were sampled to determine the extent of the problem and the biological basis for the reduced efficacy. Our studies revealed that hydrilla phenotypes with two- to six-fold higher fluridone resistance were present in 20 water bodies. Since fluridone is an inhibitor of the enzyme phytoene desaturase (PDS), the gene for PDS (pds) was cloned from herbicide-susceptible and -resistant hydrilla plants. We report for the first time in higher plants three independent herbicide-resistant hydrilla biotypes arising from the selection of somatic mutations at the arginine 304 codon of pds. The three PDS variants had specific activities similar to the wild-type enzyme but were two to five times less sensitive to fluridone. In vitro activity levels of the enzymes correlated with in vivo resistance of the corresponding biotypes. As hydrilla spread rapidly to lakes across the southern United States in the past, the expansion of resistant biotypes is likely to pose significant environmental challenges in the future.     

Herbicide resistance-endowing ACCase gene mutations in hexaploid wild oat (Avena fatua): insights into resistance evolution in a hexaploid species

Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids.