作物遗传育种研究现状论文

基因工程技术的现状和前景发展 【摘要】从20世纪70年代初发展起来的基因工程技术，经过30多年来的进步与发展，已成为生物技术的核心内容。许多科学家预言，生物学将成为21世纪最重要的学科，基因工程及相关领域的产业将成为21世纪的主导产业之一。基因工程研究和应用范围涉及农业、工业、医药、能源、环保等许多领域。【关键词】基因工程技术；前景；现状一、基因工程应用于植物方面 农业领域是目前转基因技术应用最为广泛的领域之一。农作物生物技术的目的是提高作物产量，改善品质，增强作物抗逆性、抗病虫害的能力。基因工程在这些领域已取得了令人瞩目的成就。由于植物病毒分子生物学的发展，植物抗病基因工程也也已全面展开。自从发现烟草花叶病毒(TMV)的外壳蛋白基因导入烟草中，在转基因植株上明显延迟发病时间或减轻病害的症状，通过导入植物病毒外壳蛋白来提高植物抗病毒的能力，已用多种植物病毒进行了试验。在利用基因工程手段增强植物对细菌和真菌病的抗性方面，也已取得很大进展。植物对逆境的抗性一直是植物生物学家关心的问题。由于植物生理学家、遗传学家和分子生物学家协同作战，耐涝、耐盐碱、耐旱和耐冷的转基因作物新品种(系)也已获得成功。植物的抗寒性对其生长发育尤为重要。科学家发现极地的鱼体内有一些特殊蛋白可以抑制冰晶的增长，从而免受低温的冻害并正常地生活在寒冷的极地中。将这种抗冻蛋白基因从鱼基因组中分离出来，导入植物体可获得转基因植物，目前这种基因已被转入番茄和黄瓜中。随着生活水平的提高，人们越来越关注口味、口感、营养成分、欣赏价值等品质性状。实践证明，利用基因工程可以有效地改善植物的品质，而且越来越多的基因工程植物进入了商品化生产领域，近几年利用基因工程改良作物品质也取得了不少进展，如美国国际植物研究所的科学家们从大豆中获取蛋白质合成基因，成功地导入到马铃薯中，培育出高蛋白马铃薯品种，其蛋白质含量接近大豆，大大提高了营养价值，得到了农场主及消费者的普遍欢迎。在花色、花香、花姿等性状的改良上也作了大量的研究。二、基因工程应用于医药方面目前，以基因工程药物为主导的基因工程应用产业已成为全球发展最快的产业之一，发展前景非常广阔。基因工程药物主要包括细胞因子、抗体、疫苗、激素和寡核甘酸药物等。它们对预防人类的肿瘤、心血管疾病、遗传病、糖尿病、包括艾滋病在内的各种传染病、类风湿疾病等有重要作用。在很多领域特别是疑难病症上，基因工程工程药物起到了传统化学药物难以达到的作用。我们最为熟悉的干扰素(IFN)就是一类利用基因工程技术研制成的多功能细胞因子，在临床上已用于治疗白血病、乙肝、丙肝、多发性硬化症和类风湿关节炎等多种疾病。 目前，应用基因工程研制的艾滋病疫苗已完成中试，并进入临床验证阶段；专门用于治疗肿瘤的“肿瘤基因导弹”也将在不久完成研制，它可有目的地寻找并杀死肿瘤，将使癌症的治愈成为可能。由中国、美国、德国三国科学家及中外六家研究机构参与研制的专门用于治疗乙肝、慢迁肝、慢活肝、丙肝、肝硬化的体细胞基因生物注射剂，最终解决了从剪切、分离到吞食肝细胞内肝炎病毒，修复、促进肝细胞再生的全过程。经4年临床试验已在全国面向肝炎患者。此项基因学研究成果在国际治肝领域中，是继干扰素等药物之后的一项具有革命性转变的重大医学成果。三、基因工程应用于环保方面工业发展以及其它人为因素造成的环境污染已远远超出了自然界微生物的净化能力，已成为人们十分关注的问题。基因工程技术可提高微生物净化环境的能力。美国利用DNA重组技术把降解芳烃、萜烃、多环芳烃、脂肪烃的4种菌体基因链接，转移到某一菌体中构建出可同时降解4种有机物的“超级细菌”，用之清除石油污染，在数小时内可将水上浮油中的2/3烃类降解完，而天然菌株需1年之久。也有人把Bt蛋白基因、球形芽孢杆菌、且表达成功。它能钉死蚊虫与害虫，而对人畜无害，不污染环境。现已开发出的基因工程菌有净化农药的DDT的细菌、降解水中的染料、环境中有机氯苯类和氯酚类、多氯联苯的工程菌、降解土壤中的TNT炸药的工程菌及用于吸附无机有毒化合物(铅、汞、镉等)的基因工程菌及植物等。90年代后期问世的DNA改组技术可以创新基因，并赋予表达产物以新的功能，创造出全新的微生物，如可将降解某一污染物的不同细菌的基因通过PCR技术全部克隆出来，再利用基因重组技术在体外加工重组，最后导入合适的载体，就有可能产生一种或几种具有非凡降解能力的超级菌株，从而大大地提高降解效率。四、前景展望由于基因工程运用DNA分子重组技术，能够按照人们预先的设计创造出许多新的遗传结合体，具有新奇遗传性状的新型产物，增强了人们改造动植物的主观能动性、预见性。而且在人类疾病的诊断、治疗等方面具有革命性的推动作用，对人口素质、环境保护等作出具大贡献。所以，各国政府及一些大公司都十分重视基因工程技术的研究与开发应用，抢夺这一高科技制高点。其应用前景十分广阔。我国基因工程技术尚落后于发达国家，更应当加速发展，切不可坐失良机。但是，任何科学技术都是一把“双刃剑”，在给人类带来利益的同时，也会给人类带来一定的灾难。比如基因药物，它不仅能根治遗传性疾病、恶性肿瘤、心脑血管疾病等，甚至人的智力、体魄、性格、外表等亦可随意加以改造；还有，克隆技术如果不加限制，任其自由发展，最终有可能导致人类的毁灭。还有，尽管目前的转基因动植物还未发现对人类有什么危害，但不等于说转基因动植物就是十分安全的，毕竟这些东西还是新生事物，需要实践慢慢地检验。转基因生物和常规繁殖生长的品种一样，是在原有品种的基础上对其部分性状进行修饰或增加新性状，或消除原来的不利性状，但常规育种是通过自然选择，而且是近缘杂交，适者生存下来，不适者被淘汰掉。而转基因生物远远超出了近缘的范围，人们对可能出现的新组合、新性状会不会影响人类健康和环境，还缺乏知识和经验，按目前的科学水平还不能完全精确地预测。所以，我们要在抓住机遇，大力发展基因工程技术的同时，需要严格管理，充分重视转基因生物的安全性。【参考文献】[1]楼士林，杨盛昌，龙敏南，等.基因工程[M].北京：科学出版社，2002.[2]李庆军，董艳桐，施冰.植物抗虫基因的研究进展[J].林业科技，2002，27(2)：22 26. 这还有一篇

利用生物技术向小麦导入冰草优异基因的研究 摘 要 小麦是世界上种植面积最大和最重要的粮食作物。利用生物技术向栽培作物转移向外源优异基因来拓宽小麦育种的遗传基础，是现代作物遗传育种学科中的一个非常重要的研究领域。 栽培小麦(Triticum aestivum L., 2n=4x-42, AABBDD)与冰草属(Agropyron Gaertn., P genome )(这儿所说的冰草属是现代小麦族植物分类学上的概念，而非传统的广义冰草属概念，即与一些小麦遗传育种学家将长穗偃麦草(Elytrigia elongata)和中间偃麦草(Elytrigia intermedia)等偃麦草属种也称为冰草的传统概念截然不同)植物间的杂交，可追溯到本世纪30年代(White, 1940; Smith, 1942; Dewey , 1984), 但直到90年代一些学者才先后报道了小麦与冰草属植物间的成功杂交(李立会等， 1990， 1995；Li & Dong, 1991; Chen et al., 1990; Limin & Fowler, 1990; Ahmad & Comeau , 1992; Jauhar, 1992)。 尽管这儿所列出的国外一些科学家也曾获得了小麦与冰草属植物间的杂种，但由于外源种选择的盲然性，即对要从冰草属植物向小麦转移哪些基因不明确(Chen et al., 1990; Jauhar, 1992), 或杂种F1的高度不育性(Ahmad & Comear, 1992), 或要转移的目标基因难以在小麦背景下表达(Limin & Fowler, 1990 )等原因，未见进一步的报道，而是基本上放弃了该领域的研究工作(私人通信，1997)。 在本项研究工作中，我们以普通小麦品种Fukuho (春性，具3对可杂交性基因，农艺性状良好，原产于日本)为母本，以分别采自新疆和内蒙古的3份冰草(Agropyron cristatum Gaertn., 2n=4x=28, PPPP)为父本进行杂交，并对杂种后代进行了研究。主要结果包括： 1、科学选择远缘杂交亲本，为杂交和外源优异基因转移的成功奠定了坚实的基础。在选择外源供体种的过程中，本项研究首先由中国农业科学院作物品种资源研究所和植物保护研究所、澳大利亚Division of Plant Industry, CSIRO, 加拿大Cytogenetics Section, Ottawa Research Station, Agriculture Canada 等单位对上千份小麦野生近缘植物的农艺性状、抗逆性和抗病性进行了联合鉴定，然后根据综合鉴定结果才精选出本项研究所利用的3份冰草－最佳外源供体种。因为这3份冰草不仅具有其它外源种难以比拟的众多优异基因（性状），包括小麦超高产育种所需的合理株型结构(株高小于60cm且穗下茎长度约占株高的2/3、有效分蘖>50、叶片窄短上挺)、大穗多粒（每穗结实在150粒以上）、黑粒且蛋白质含量极高、极强的抗旱和抗寒性、适度的耐盐性、对三种锈病、白粉病和黄矮病免疫、高抗赤霉病等，而且更为重要的是上述优异基因都是当前小麦育种迫切需要的。 2、利用现代远缘杂交方法和幼胚拯救技术，在国际上首次获得了具部分自交可育性的普通小麦与冰草间的杂种，并发现以不同来源的冰草为父本，不仅杂交结实率不同，而且杂种F1的表现型亦不同。这一结果，一方面突破了前人(Dewey, 1984)所认为的“冰草属P染色体组在小麦族中具有独立的遗传地位，与小麦之间不可能杂交”的论断；另一方面杂种F1具部分自交可育性，为实现外源基因的成功转移 奠定了坚实的物质基础。 3、以杂种F1幼穗为外植体，通过诱导愈伤组织产生体细胞无性系变异，首次发现杂种F1在无染色体数量变异情况下，其自交可育性或从无到有(0Õ ),或显著提高(10倍)。这一发现之所以重要，是因为它向人们展示了通过这一技术有可能在杂种F1就实现外源基因转移的美好前景。 4、通过精细分析，首次阐明了一些遗传学机理：一是杂种F1自交可育性是由于2条P染色体含有控制减数分裂过程中染色体分离的基因，从而能够形成有功能的近等2n或未减数配子；二是另外1条P染色体上具有抑制小麦Ph基因的遗传因子，能够诱发冰草P染色体组和小麦A、B、D染色体组间的染色体相互配对；三是证实了通过染色体间的自发易位可实现小麦－冰草间的基因交流。这些发现，一方面彻底突破了国际权威所认为的“小麦－冰草间不可能进行基因交流”的论断，另一方面为更加有目的、更加高效率地转移冰草优异基因提供了重要的理论指导。 5、利用回交、选择和形态学、细胞学、等位酶以及基因组原位杂交检测等综合技术，首次育成了11个遗传稳定的小麦－冰草异源二体附加系，并提出了有效产生异源二体附加系（列）的可行做法。异源二体附加系的产生，是研究每条P染色体上的基因在小麦背景下的遗传效应及其有效利用的重要工具。 6、首次创造了一批携带冰草优异基因、遗传稳定(2n=42, 21II ,异源易位系或代换系)且能为育种和生产利用的新种质。其普遍的特点是：有效分蘖多(15~82穗/株)；株高70～95cm且穗下茎约占株高的1/2；旗叶上挺；大穗(55～112粒/穗)；籽粒外观白色或黑色、蛋白质含量高(); 千粒重>38g; 综合抗病性（白粉病、条锈病、黄矮病和赤霉病)、抗寒性和抗旱性良好，特别是一些新种质具超高产潜力(理论产量高于600 kg/亩)。目前，这批新种质已为我国小麦主产区的9省15家育种单位利用，其中在陕西、山西有5个新种质正参加产量比较试验。 7、对获得的遗传稳定(2n=42, 21II ,异源易位系)的黑色籽粒和对白粉病免疫新种质中的黑色籽粒基因和抗白粉病基因(均来自冰草)进行了初步遗传分析，证明二者皆为显性单基因遗传。关键词：普通小麦(Triticum aestivum, L., 2n=6x=42, AABBDD); 冰草(Agropyron cristatum Gaertn., 2n=4x=28, PPPP)；属间杂种；自交可育性；异源二体附加系；遗传分析；新种质Introduction of Desirable Genes from Agropyron cristatum (L.) Gaertn. to Triticum aestivum L. Using BiotechnologyDoctoral student : Li-Hui LiSupervisor: Professor Yu-Shen Dong (Institute of Crop Germplasm Resources, Chinese Academy of Agriculture Sciences, Beijing, 100081)AbstractAs in most other crops, the genetic variation of cultivated wheat has been greatly eroded under modern agricultural systems. Genetic erosion not only limits the further improvement of yield and quality but also makes wheat increasingly vulnerable to biological and environmental stresses. A large amount of genetic variation exists in the wild relatives of cultivated wheat. The introduction of genetic variation from alien species has been a valuable method for increasing the amount of genetic diversity available to wheat this experiment, intergeneric hybrids of Triticum aestivum cv Fukuho (2n=6x=42, AABBDD) with three accessions of tetraploid A. cristatum (2n=4x=28, PPPP) were synthesized through immature embryo rescued in artificial medium. These hybrids can be used to: (1) transfer the desirable traits from A. cristatum into common wheat; (2) identify the effects of the P genome on self-fertility in intergeneric hybrids; and (3) produce disomic addition lines of wheat-A. cristatum. Through study of the intergeneric hybrids and their derivatives, the following results were obtained:1. A. cristatum may be one of the best potential alien donors in the Triticeae for wheat improvement. Agropyron Gaertn. is a small genus of no more than ten species, which constitute what is known as the “crested wheatgrass complex” with the P genome, in accordance with the terminology of many modern botanists. A. cristatum (L.) Gaertn. is the type species of this genus. All species of the genus are very valuable; they are cultivated as predominantly pasture-fodder plants, distinguished by their high level of drought and cold tolerance; some species have be successfully used for fixing drifting sands. In addition, A. cristatum has also been found to possess the other desirable traits that are potentially valuable for wheat improvement through evaluation of all Triticeae collections from the northern part of China; these include shorter stem (usually less than 60 cm), more tillers and florets, immunity to wheat diseases such as rusts, powdery mildew, and barley yellow dwarf virus (BYDV) as well as resistance to wheat scab. 2. In the three hybridization combinations, seed set () and plant development were different. Each one plant obtained from Fukuho with A. cristatum accession No. Z540 and Z602 respective developed poorly. The former died before heading. Although the later produced two spikes, neither selfed nor backcross seed was obtained from these two spikes. The two plants obtained from the Fukuho×A. cristatum Z559 showed vigorous tillering. This result indicated that the three accessions of A. cristatum used in this experiment are different in crossability with the Fukuho. The root-tips of all hybrid seedlings were observed, and revealed that somatic chromosome number of each was 2n=35 as . A self-fertile intergeneric hybrids between Triticum aestivum cv Fukuho (2n=6x=42, AABBDD) and tetraploid A. cristatum (2n=4x=28, PPPP) were obtained for the first contrast with the reports that either no BC1 derivatives from wheat-Agropyron hybrids was obtained or BC1 derivatives obtained were very difficult, in the Fukuho×A. cristatum Z559 hybrids, however, they not only had a high seed set () of backcrossing with common wheat, but also were partially self-fertile. The mean configurations at meiotic metaphase I of the hybrids were I + rod Ⅱ + ring Ⅱ + Ⅲ + Ⅳ. Some of bivalents per cell were clearly heteromorphic on the basis of various chromosome size, indicating that these bivalents were heterogenetic pairing. At anaphase I, chromosome separation was mainly the most (16~30 chromosomes) of 35 chromosomes to assemble at one pole, resulting in that the bigger daughter cells receiving most of 35 chromosomes might develop the functional . In order to induce somaclonal variation, the immature inflorescences of the hybrids between Triticum aestivum cv Fukuho and A. cristatum Z559 were cultured. Although the regenerants did not exhibit variation in chromosome number, they did show a higher degree of meiotic instability than the initial hybrids. Especially, the selfed seed set could be increased greatly in the regenerated plants, being from to . As a result, a total of 61 selfed seeds were obtained. Obtaining of so more selfed seeds from the Fukuho×A. cristatum Z559 is rare in the intergeneric hybrids involving wheat, and makes a substantial foundation for transferring the desirable genes from A. cristatum into common wheat. 5. Using methods such as morphology, cytology, isozymes and genomic in situ hybridization, the selfed and backcross derivatives were analysed. The results showed that all plants with the alien characters carried the genetic materials of the P genome. Meanwhile, a total of 11 disomic alien addtion lines were obtained. 6. After all cytological data obtained from this experiment were summed up and analysed, some conclusions could be obtained. They were: (1) the A. cristatum Z559 used in this experiment carried a genetic system suppressing Ph activity, and this genetic system might be mainly involved one of the P genome; (2) the P genome contained genes controlling chromosomes segregation at meiotic anaphase, and the genes might be mainly involved two of the P chromosomes; and (3) the spontaneous wheat-A. cristatum translocations can occur in the selfed and backcross . In this experiment, the other very important result is that some new germplasm with the desirable alien genes were obtained. They showed more effective tillerings (15-82 spikes per plant), plant height ranged from 70 to 95 cm, 55-112 grains per spike, a higher content of protein (), resistance to wheat diseases such as powdery mildew, stripe rust, BYDV and wheat scab, and tolerance to drought and cold. So far, all new germplasm obtained from this experiment have been utilized by the 15 institutions for wheat breeding in . The new germplasm with black-grain in color and immunity to powdery mildew were analyzed. Genetic analysis revealed that these two characters were from A. cristatum Z559 and were controlled by a dominant gene respectively. Key Words: Triticum aestivum L., Agropyron cristatum, Intergeneric hybrids, Self-fertility, Alien addition and translocation lines, Genetic analysis.