贝类非整倍体研究进展

近年来,在贝类多倍体育种研究中,人们发现了成活的非整倍体胚胎和成体,并就此开展了相关的研究.对此研究进行了综述,对非整倍体的类型、产生原因、生长发育、鉴定方法等进行探讨,并展望了非整倍体研究的前景和应用价值.     

我国沿海主要经济贝类中典型人类肠道病毒的污染分布

【目的】了解我国沿海主要经济贝类中肠道病毒的污染分布对保障贝类食用安全具有重要作用。【方法】通过建立5种典型人类肠道病毒的特异、灵敏、高通量的基因芯片检测技术,开展全国范围内沿海主要海水增养殖区经济贝类体内肠道病毒的污染调查。【结果】采集的162份经济贝类中肠道病毒的阳性检出率分别为:甲肝病毒4.3%;诺如病毒14.8%;轮状病毒6.2%;星状病毒5.6%;腺病毒9.9%,其中诺如病毒污染居于首位,该检测结果与PCR结果高度一致。我国沿海省市主要养殖区内贝类均受到了肠道病毒不同程度的污染,且不同省市之间差异不显著。在选取的6类经济贝类中,牡蛎中肠道病毒阳性检出率最高,其次是毛蚶和泥蚶。【结论】本研究表明,在我国,沿海主要经济贝类受到肠道病毒污染是一种较普遍的现象,给人类健康带来了潜在的危害,本研究为贝类食品的安全监控提供了基础数据资料。     

厦门海域贝类养殖环境中有机氯农药的积累和降解

利用气相色谱法(GC-ECD)对厦门海域贝类养殖环境(海水、底质和养殖贝类)中有机氯农药六六六(HCH)和滴滴涕(DDT)的含量进行了调查分析,初步探讨了贝类养殖环境中HCH和DDT的积累和降解规律.结果表明:厦门海域不同种贝类养殖环境中HCH和DDT的积累和降解存在明显差异,主要与各种贝类的栖息环境和生理生活习性有关.贝类养殖环境中处于积累状态(Rx＞1)的主要为p-HCH、δ-HCH和γ-HCH;处于降解状态(Rx＜1)的主要为α-HCH.α-HCH/γ-HCH的比值≤1.0,贝类养殖环境中的HCH来源于工业品HCH和林丹,大部分HCH为长时间残留,但尚有少量林丹输入.贝类养殖区海水中DDT主要为好氧降解,底质中主要为厌氧降解.海水中的降解产物主要为DDE,(DDD+ DDE )/DDTs(p,p-DDE+p,p-DDD+o,p-DDT+p,p-DDT)的比值＜0.5;底质和养殖贝类体中的降解产物主要为DDD,(DDD+DDE)/DDTs的比值＞0.5,贝类养殖区底质和养殖贝类体中的DDT大部分已降解为DDD和DDE,海水中尚有少量新的DDT输入.贝类养殖环境中HCH异构体降解率的高低顺序存在一定差异,其在贝类养殖生态系中的迁移、转化过程发生了构象变化.     

药用植物多倍体育种的研究进展

药用植物多倍体具有营养器官的巨大性、抗逆性强、药用成份含量高等特性,在药用植物多倍体育种中有很重要的作用。本文对植物多倍体育种技术,包括人工诱导染色体加倍的原理和诱导、鉴定方法进行了介绍,总结了药用植物多倍体的应用优势,并提出了在药用植物多倍体育种中存在的问题及发展前景。     

海产贝类尼氏单抱子虫病害的研究进展

目前,我国形成规模养殖的经济贝类有近20种,贝类增养殖已经成为沿海海水养殖业的支柱产业。资料显示,2004年全国海水贝类产量为1024万吨,占海水养殖总产量的77．82％。但是目前,由于气候变化、海洋环境污染、外来生物入侵等因素导致我国海产贝类病害越来越重,寄生虫就是主要病原之一,其中尼氏单孢子虫就是其中的一种原生动物寄生虫,寄生于很多种海产贝类体内。这种病害在很多地区都有暴发,国外对其研究较多,国内梁玉波等时这一病害进行了研究。因此,系统阐述国外贝类尼氏单孢子虫病害的研究现状与进展,对我国海产贝类病害的研究具有现实意义。本文时尼氏单孢子虫的分类、病害的流行情况、尼氏单孢子虫的形态学,病害的主要症状。尼氏单孢子虫的检测方法,尼氏单孢子虫与寄主之间的交互作用,环境因素时病害流行的影响等方面进行了论述,为我国贝类病害的研究和防治提供参考。     

虹鳟二倍体与人工四倍体核型的比较

多倍体鱼由于生长快,适应性强,经济价值高等特点,而可能成为鱼类增殖高产的优良品种。研究它们的核型可为遗传育种提供基础资料。 虹鳟(Salmo gairdneri R.)是世界上优势养殖鱼类之一。近年来,许多研究者对其进行了人工多倍体的诱导国内尚未见有关     

齿瓣石斛多倍体的诱导初报

采用多倍体育种技术,对云南的野生热带兰花齿瓣石斛(Dendrobium devonianum)进行多倍体诱导试验。利用秋水仙素作为诱导剂,对二倍体试管苗进行诱导,在短期内培育出多倍体植株。用0.03%的秋水仙素处理齿瓣石斛丛生芽24h,其诱导效果最好。观察结果显示:多倍体齿瓣石斛材料在形态、气孔直径、染色体数目上都有变化。DNA指纹图谱等方面都发生了显著的改变。多倍体齿瓣石斛试管苗出现了植株粗壮、叶片增厚等优良性状。此研究是多倍体育种技术在我国热带兰花育种中的一次成功尝试。     

海洋生物技术在海水养殖动植物品种培育和病害防治中的应用

海水养殖是我国沿海地区发展经济的重要支柱产业。目前影响我国海水养殖业持续、稳定、健康发展的主要制约因素是苗种和病害问题。本文就海洋生物技术在海水养殖物植物品种培育和病害防治中的应用及有关问题进行了探讨,分别就应用海洋生物技术在群体和个体水平、细胞和染色体水平以及基因和分子水平培育新品种的工作,包括ＳＰＦ和ＳＰＲ苗种的培育、性别控制和杂交育种、多倍体育种、雌核发育、藻类细胞工程育种、转基因技术等进行     

贝类人工育苗产业化的科学发展

世界上养殖生产很多贝类,我国有世界上历史最为悠久的贝类养殖产业,可是贝类人工育苗产业化才只有半个世纪的时间,我国在这一科学和生产领域起到了带头和领先的作用。现在需要建设生态环境优美而又科学合理的贝苗工厂,在贝类人工育苗产业化的基础上,进行选种育种和品种培育,促使贝类养殖的科学和生产再有重大的进步和发展。介绍了我国贝类人工育苗产业化的由来,以及贝类人工育苗的发展方向。     

6-DMAP抑制栉孔扇贝（♀）×虾夷扇贝（♂）受精卵第一极体释放后染色体的分离状况

三倍体贝类因其具有生长快、个体大、肉质佳和成活率高等优良的经济性状而存水产养殖业中具有重要的应用价值。获得100％三倍体贝类的最佳途径是通过四倍体贝类与二倍体贝类杂交来获得。目前已经发展出多种诱导四倍体的方法,包括抑制受精卵第一极体的释放、抑制受精卯的卵裂、细胞融合和利用人工雌核发育等方法。人工诱导四倍体技术已经在多种鱼类上获得成功。     

Genome editing of polyploid crops: prospects,achievements and bottlenecks

Plant breeding aims to develop improved crop varieties. Many crops have a polyploid and often highly heterozygous genome, which may make breeding of polyploid crops a real challenge. The efficiency of traditional breeding based on crossing and selection has been improved by using marker-assisted selection (MAS), and MAS is also being applied in polyploid crops, which helps e.g. for introgression breeding. However, methods such as random mutation breeding are difficult to apply in polyploid crops because there are multiple homoeologous copies (alleles) of each gene. Genome editing technology has revolutionized mutagenesis as it enables precisely selecting targets. The genome editing tool CRISPR/Cas is especially valuable for targeted mutagenesis in polyploids, as all alleles and/or copies of a gene can be targeted at once. Even multiple genes, each with multiple alleles, may be targeted simultaneously. In addition to targeted mutagenesis, targeted replacement of undesirable alleles by desired ones may become a promising application of genome editing for the improvement of polyploid crops, in the near future. Several examples of the application of genome editing for targeted mutagenesis are described here for a range of polyploid crops, and achievements and bottlenecks are highlighted.

     

The breeding of two polyploid rice lines with the characteristic of polyploid meiosis stability

Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice.Because low seed set rates in polyploid rice usually makes it difficult to breed, the selection of Ph-liked gene lines was emphasized. After progenies of indica-japonica were identified and selected, two polyploid lines, PMeS-1 and PMeS-2 with Polyploid Meiosis Stability (PMeS) genes were bred. The procedure included seven steps: selecting parents, crossing or multiple crossing, back-crossing, doubling chromosomes, identifying the polyploid, and choosing plants with high seed set rates that can breed themselves into stable lines. The characteristics of PMeS were determined by observing meiotic behaviors and by cross-identification of seed sets. PMeS-1 and PMeS-2, (japonica rice), have several characteristics different from other polyploid rice lines, including a higher rate of seed set (more than 65%, increasing to more than 70% in their F1 offspring); and stable meiotic behaviors (pairing with bivalents and quarivalents nearly without over-quarivalent in prophase, nearly without lagging chromosomes in metaphase and without micronuclei in anaphase and telophase). The latter was obviously different from control polyploid line Dure-4X, which displayed abnormal meiotic behaviors including a higher rate of multivalents, univalents and trivalents in prophase, lagging chromosomes in metaphase and micronuclei in anaphase and telophase. There were also three differences of the breeding method between PMeS lines and normal diploid lines: chromosomes doubling, polyploidism identifying and higher seed set testing. The selection of PMeS lines is the first step in polyploid rice breeding; their use will advance the progress of polyploid rice breeding, which will in turn offer a new way to breed super rice.     

Climatic variation and the distribution of an amphibian polyploid complex

The establishment of polyploid populations involves the persistence and growth of the polyploid in the presence of the progenitor species. Although there have been a number of animal polyploid species documented, relatively few inquiries have been made into the large-scale mechanisms of polyploid establishment in animal groups. Herein we investigate the influence of regional climatic conditions on the distributional patterns of a diploid-tetraploid species pair of gray treefrogs, Hyla chrysoscelis and H. versicolor (Anura: Hylidae) in the mid-Atlantic region of eastern North America. Calling surveys at breeding sites were used to document the distribution of each species. Twelve climatic models and one elevation model were generated to predict climatic and elevation values for gray treefrog breeding sites. A canonical analysis of discriminants was used to describe relationships between climatic variables, elevation and the distribution of H. chrysoscelis and H. versicolor. There was a strong correlation between several climatic variables, elevation and the distribution of the gray treefrog complex. Specifically, the tetraploid species almost exclusively occupied areas of higher elevation, where climatic conditions were relatively severe (colder, drier, greater annual variation). In contrast, the diploid species was restricted to lower elevations, where climatic conditions were warmer, wetter and exhibited less annual variation. Clusters of syntopic sites were associated with areas of high variation in annual temperature and precipitation during the breeding season. Our data suggest that large-scale climatic conditions have played a role in the establishment of the polyploid H. versicolor in at least some portions of its range. The occurrence of the polyploid and absence of the progenitor in colder, drier and more varied environments suggests the polyploid may possess a tolerance of severe environmental conditions that is not possessed by the diploid progenitor. Our findings support the hypothesis that increased tolerance to severe environmental conditions is a plausible mechanism of polyploid establishment.     

The breeding of two polyploid rice lines with the characteristic of polyploid meiosis stability

Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice. Because low seed set rates in polyploid rice usually makes it difficult to breed, the selection of Ph-liked gene lines was emphasized. After progenies of indica-japonica were identified and selected, two polyploid lines, PMeS-1 and PMeS-2 with Polyploid Meiosis Stability (PMeS) genes were bred. The procedure included seven steps: selecting parents, crossing or multiple crossing, back-crossing, doubling chromosomes, identifying the polyploid, and choosing plants with high seed set rates that can breed themselves into stable lines. The characteristics of PMeS were determined by observing meiotic behaviors and by cross-identification of seed sets. PMeS-1 and PMeS-2, (japonica rice), have several characteristics different from other polyploid rice lines, including a higher rate of seed set (more than 65%, increasing to more than 70% in their F1 offspring); and stable meiotic behaviors (pairing with bivalents and quarivalents nearly without over-quarivalent in prophase, nearly without lagging chromosomes in metaphase and without micronuclei in anaphase and telophase). The latter was obviously different from control polyploid line Dure-4X, which displayed abnormal meiotic behaviors including a higher rate of multivalents, univalents and trivalents in prophase, lagging chromosomes in metaphase and micronuclei in anaphase and telophase. There were also three differences of the breeding method between PMeS lines and normal diploid lines: chromosomes doubling, polyploidism identifying and higher seed set testing. The selection of PMeS lines is the first step in polyploid rice breeding; their use will advance the progress of polyploid rice breeding, which will in turn offer a new way to breed super rice. Supported by the National Natural Science Foundation of China (Grant Nos. 39970447, 30240090, 30471063 and 30650002), the High Technology Research and Development Program of China (Grant No. SZ-01-02-02), the Chenguang Youth Science and Technology Project of Wuhan City (Grant No. 20045006071-31), and the Educational Commission of Hubei Province of China (Grant No. 2004D004)     

Development and application of biological technologies in fish genetic breeding

Fish genetic breeding is a process that remolds heritable traits to obtain neotype and improved varieties.For the purpose of genetic improvement,researchers can select for desirable genetic traits,integrate a suite of traits from different donors,or alter the innate genetic traits of a species.These improved varieties have,in many cases,facilitated the development of the aquaculture industry by lowering costs and increasing both quality and yield.In this review,we present the pertinent literatures and summarize the biological bases and application of selection breeding technologies(containing traditional selective breeding,molecular marker-assisted breeding,genome-wide selective breeding and breeding by controlling single-sex groups),integration breeding technologies(containing cross breeding,nuclear transplantation,germline stem cells and germ cells transplantation,artificial gynogenesis,artificial androgenesis and polyploid breeding)and modification breeding technologies(represented by transgenic breeding)in fish genetic breeding.Additionally,we discuss the progress our laboratory has made in the field of chromosomal ploidy breeding of fish,including distant hybridization,gynogenesis,and androgenesis.Finally,we systematically summarize the research status and known problems associated with each technology.     

植物多倍体中的基因组印记

植物多倍体在自然界中广泛存在,这说明拥有多套遗传物质使得多倍体的适应进化具有优势。新多倍体形成后,一些基因组范围的变化较迅速地发生在多倍体形成开端,另一些在长期进化中发生。由于受到遗传、表观等因素的影响,亲本对于新形成多倍体基因组的贡献不均衡。这种偏向于某个亲本基因组的显性优势,称为基因组印记。植物多倍体中的基因组印记表现为基因组偏向性的序列消除、不均衡基因表达、基因沉默,这些受到基因组合并及DNA甲基化、核仁显性等表观因素影响。本文旨在为多倍体基因组进化及育种的相关研究提供参考。     

Comparison of Leaf Proteomes of Cassava (Manihot esculenta Crantz) Cultivar NZ199 Diploid and Autotetraploid Genotypes

Cassava polyploid breeding has drastically improved our knowledge on increasing root yield and its significant tolerance to stresses. In polyploid cassava plants, increases in DNA content highly affect cell volumes and anatomical structures. However, the mechanism of this effect is poorly understood. The purpose of the present study was to compare and validate the changes between cassava cultivar NZ199 diploid and autotetraploid at proteomic levels. The results showed that leaf proteome of cassava cultivar NZ199 diploid was clearly differentiated from its autotetraploid genotype using 2-DE combined MS technique. Sixty-five differential protein spots were seen in 2-DE image of autotetraploid genotype in comparison with that of diploid. Fifty-two proteins were identified by MALDI-TOF-MS/MS, of which 47 were up-regulated and 5 were down-regulated in autotetraploid genotype compared with diploid genotype. The classified functions of 32 up-regulated proteins were associated with photosynthesis, defense system, hydrocyanic acid (HCN) metabolism, protein biosynthesis, chaperones, amino acid metabolism and signal transduction. The remarkable variation in photosynthetic activity, HCN content and resistance to salt stress between diploid and autotetraploid genotypes is closely linked with expression levels of proteomic profiles. The analysis of protein interaction networks indicated there are direct interactions between the 15 up-regulation proteins involved in the pathways described above. This work provides an insight into understanding the protein regulation mechanism of cassava polyploid genotype, and gives a clue to improve cassava polyploidy breeding in increasing photosynthesis and resistance efficiencies.     

植物同源多倍体耐盐性研究进展

多倍化是高等植物进化最重要的动力之一,多倍体植物由于基因组组成以及基因表达方面的变化,通常会表现出不同的生理现象,多倍体的抗性优于其同源二倍体祖先。土壤盐碱化和次生盐渍化是影响农作物生产的重要因素,严重制约着我国农业的可持续发展。同源多倍体植物耐盐能力较强,是作物遗传改良的重要种质资源,了解其耐盐机理对培育耐盐品种具有重要意义。本文从与盐胁迫相关的耐盐性进化、生理生化水平、细胞结构和分子层面等多角度总结了植物同源多倍体盐胁迫研究进展,并以作者所在研究团队培育出的多倍体西瓜为例讨论了多倍体抗逆性研究存在的问题及未来的发展方向,以期为多倍体抗逆优势机理研究提供参考。