中国野生大豆(Glycine soja)遗传资源主要形态、遗传变异和结构

介绍了我国野生大豆遗传资源主要的形态类型、物种内遗传关系和遗传结构。进化的瓶颈不仅发生在由野生大豆到栽培大豆,也以另一种方式"分化瓶颈"出现于同性状的不同表型类型之间。野生大豆种内种子大小类型是否存在遗传分化?野生和半野生大豆的边界在哪?半野生大豆如何产生的?半野生大豆遗传上密切于栽培种还是野生种?百粒重3～4g的小粒半野生大豆与百粒重8.5g以上的特大粒半野生大豆是否有遗传差异?百粒重8.5g以上的特大粒半野生大豆是否属于栽培大豆?野生大豆的种皮色和种子大小哪个更能反映进化程度?栽培大豆基因是否已经渗入到野生大豆?对这些在学术界常年存在的疑问本文介绍了我们的研究答案。我们认为"真"半野生大豆不存在于现在中国半野生资源收集品中;一些野生大豆中的白花、灰毛、无泥膜性状来源于栽培大豆的基因渗透。     

Sampling strategy for wild soybean (Glycine soja) populations based on their genetic diversity and fine-scale spatial genetic structure

A total of 892 individuals sampled from a wild soybean population in a natural reserve near the Yellow River estuary located in Kenli of Shandong Province (China) were investigated.Seventeen SSR (simple sequence repeat) primer pairs from cultivated soybeans were used to estimate the genetic diversity of the population and its variation pattern versus changes of the sample size (sub-samples),in addition to investigating the fine-scale spatial genetic structure within the population.The results showed relatively high genetic diversity of the population with the mean value of allele number (A) being 2.88,expected heterozygosity (He) 0.431,Shannon diversity index (/) 0.699,and percentage of polymorphic loci (P) 100%.Sub-samples of different sizes (ten groups) were randomly drawn from the population and their genetic diversity was calculated by computer simulation.The regression model of the four diversity indexes with the change of sample sizes was computed.As a result,27-52 individuals can reach 95% of total genetic variability of the population.Spatial autocorrelation analysis revealed that the genetic patch size of this wild soybean population is about 18 m.The study provided a scientific basis for the sampling strategy of wild soybean populations.     

Comparison of saponin composition and content in wild soybean (Glycine soja Sieb. and Zucc.) before and after germination

Eight wild soybean accessions with different saponin phenotypes were used to examine saponin composition and relative saponin quantity in various tissues of mature seeds and two-week-old seedlings by LC–PDA/MS/MS. Saponin composition and content were varied according to tissues and accessions. The average total saponin concentration in 1?g mature dry seeds of wild soybean was 16.08?±?3.13?μmol. In two-week-old seedlings, produced from 1?g mature seeds, it was 27.94?±?6.52?μmol. Group A saponins were highly concentrated in seed hypocotyl (4.04?±?0.71?μmol). High concentration of DDMP saponins (7.37?±?5.22?μmol) and Sg-6 saponins (2.19?±?0.59?μmol) was found in cotyledonary leaf. In seedlings, the amounts of group A and Sg-6 saponins reduced 2.3- and 1.3-folds, respectively, while DDMP?+?B?+?E saponins increased 2.5-fold than those of mature seeds. Our findings show that the group A and Sg-6 saponins in mature seeds were degraded and/or translocated by germination whereas DDMP saponins were newly synthesized.     

Genetic characterization of a leaf margin necrosis mutant in wild annual soybean (Glycine soja)

A leaf margin necrosis mutant was observed in a wild annual soybean (Glycine soja Sieb. & Zucc.) population from South Korea. Genetic studies showed that it was controlled by a single recessive nuclear gene, designatedlmn. TheLmn locus segregated independently of theAp, Dial, Dia3, Idh2, Pgi1 andTi isozyme loci.     

Population structure of the wild soybean (Glycine soja) in China: implications from microsatellite analyses

Background and Aims Wild soybean (Glycine soja), a native species of East Asia, is the closest wild relative of the cultivated soybean (G. max) and supplies valuable genetic resources for cultivar breeding. Analyses of the genetic variation and population structure of wild soybean are fundamental for effective conservation studies and utilization of this valuable genetic resource. Methods In this study, 40 wild soybean populations from China were genotyped with 20 microsatellites to investigate the natural population structure and genetic diversity. These results were integrated with previous microsatellite analyses for 231 representative individuals from East Asia to investigate the genetic relationships of wild soybeans from China. Key Results Analysis of molecular variance (AMOVA) revealed that 43·92 % of the molecular variance occurred within populations, although relatively low genetic diversity was detected for natural wild soybean populations. Most of the populations exhibited significant effects of a genetic bottleneck. Principal co-ordinate analysis, construction of a Neighbor-Joining tree and Bayesian clustering indicated two main genotypic clusters of wild soybean from China. The wild soybean populations, which are distributed in north-east and south China, separated by the Huang-Huai Valley, displayed similar genotypes, whereas those populations from the Huang-Huai Valley were different. Conclusions The previously unknown population structure of the natural populations of wild soybean distributed throughout China was determined. Two evolutionarily significant units were defined and further analysed by combining genetic diversity and structure analyses from Chinese populations with representative samples from Eastern Asia. The study suggests that during the glacial period there may have been an expansion route between south-east and north-east China, via the temperate forests in the East China Sea Land Bridge, which resulted in similar genotypes of wild soybean populations from these regions. Genetic diversity and bottleneck analysis supports that both extensive collection of germplasm resources and habitat management strategies should be undertaken for effective conservation studies of these important wild soybean resources.     

Genetic diversity and conservation and utilization of plant genetic resources

Biodiversity refers to variation within the living world, while genetic diversity represents the heritable variation within and between populations of organisms, and in the context of this paper, among plant species. This pool of genetic variation within an inter-mating population is the basis for selection as well as for plant improvement. Thus, conservation of this plant genetic diversity is essential for present and future human well-being. During recent years, there has been increasing awareness of the importance of adopting a holistic view of biodiversity, including agricultural biodiversity, conservation for sustainable utilization and development. These principles have been enshrined in the Convention on Biological Diversity and the Global Plan of Action of the Food and Agriculture Organization of the United Nations. The emphasis is now to understand the distribution and extent of genetic diversity available to humans in plant species, so that the genetic diversity can be safely conserved and efficiently used. It is generally recognized that plant genetic diversity changes in time and space. The extent and distribution of genetic diversity in a plant species depends on its evolution and breeding system, ecological and geographical factors, past bottlenecks, and often by many human factors. Much of the large amount of diversity of a species may be found within individual populations, or partitioned among a number of different populations.A better understanding of genetic diversity and its distribution is essential for its conservation and use. It will help us in determining what to conserve as well as where to conserve, and will improve our understanding of the taxonomy and origin and evolution of plant species of interest. Knowledge of both these topics is essential for collecting and use of any plant species and its wild relatives. In order to mange conserved germplasm better, there is also a need to understand the genetic diversity that is present in collections. This will help us to rationalize collections and develop and adopt better protocols for regeneration of germplasm seed. Through improved characterization and development of core collections based on genetic diversity information, it will be possible to exploit the available resources in more valuable ways.     

Population genetic structure of Japanese wild soybean (Glycine soja) based on microsatellite variation

The research objectives were to determine aspects of the population dynamics relevant to effective monitoring of gene flow in the soybean crop complex in Japan. Using 20 microsatellite primers, 616 individuals from 77 wild soybean (Glycine soja) populations were analysed. All samples were of small seed size (< 0.03 g), were directly collected in the field and came from all parts of Japan where wild soybeans grow, except Hokkaido. Japanese wild soybean showed significant reduction in observed heterozygosity, low outcrossing rate (mean 3.4%) and strong genetic differentiation among populations. However, the individual assignment test revealed evidence of rare long-distance seed dispersal (> 10 km) events among populations, and spatial autocorrelation analysis revealed that populations within a radius of 100 km showed a close genetic relationship to one another. When analysis of graphical ordination was applied to compare the microsatellite variation of wild soybean with that of 53 widely grown Japanese varieties of cultivated soybean (Glycine max), the primary factor of genetic differentiation was based on differences between wild and cultivated soybeans and the secondary factor was geographical differentiation of wild soybean populations. Admixture analysis revealed that 6.8% of individuals appear to show introgression from cultivated soybeans. These results indicated that population genetic structure of Japanese wild soybean is (i) strongly affected by the founder effect due to seed dispersal and inbreeding strategy, (ii) generally well differentiated from cultivated soybean, but (iii) introgression from cultivated soybean occurs. The implications of the results for the release of transgenic soybeans where wild soybeans grow are discussed.     

国家基因库野生大豆（Glycine soja）资源最近十年考察与研究

总结了国家种质库最近10年野生大豆搜集进展和研究概况。我国野生大豆资源在1979-1982年间搜集并保存在国家基因库的为5939份;1996-2000年搜集了600份;2001-2010最近10年补充搜集了全国17个省(市、区)、318个县(市、旗)、930个乡镇(农场)。其中新搜集县市178个,共收集典型野生大豆资源1979份,野生大豆收集样品新增资源33.3%。     

中国野生稻遗传资源的保护及其在育种中的利用

我国有三种野生稻,即普通野生稻(Oryza rufipogon)、药用野生稻(O.officinalis)和瘤粒野生稻(O.meyeriana)。这三种野生稻均被列为国家二级保护植物(渐危种)。调查结果表明,野生稻由于其自然群落大量丧失而濒危,濒危程度为普通野生稻>药用野生稻>瘤粒野生稻。造成濒危的主要原因是人为的破坏活动。人类的经济活动导致了野生稻生境丧失、生境质量不断恶化、栖息地越来越少;人类的活动也导致了外来种的入侵。目前,对野生稻的保护措施主要有就地保护(原地保护或原位保护)和迁地保护(易地保护或异位保护)。易地保护包括以种子保存的种质厍、以种茎保存的种质圃和以器官培养物作为材料的超低温保存。野生稻具有许多优良特性,如特强的耐寒性、高的抗病虫性、优质蛋白质含量高、功能叶片耐衰老的特异性、特强的再生性、良好的繁茂性及生长优势等等,这些优良特性已被广泛用于水稻常规育种和杂交育种中,并取得了巨大的社会效益和经济效益。有关野生稻生物技术方面的研究,如花药培养、原生质培养、体细胞杂交和基因工程等方面已取得了较大的进展。野生稻将在水稻育种中发挥越来越重要的作用。     

植物的繁育系统、遗传结构和遗传多样性保护

达尔文和最早的群体遗传学理论,都认为繁育系统对生物的遗传多样性和进化起重要作用。本文首先介绍用蛋白质电泳检测植物繁育系统的优点,然后讨论中外学者的实验结果,表明在植物众多特征中,如生活型、是有性繁殖还是无性繁殖等都能影响群体遗传结构,但最显著的是繁育系统和群体遗传分化两者间的关系。因此我们能从植物的繁育系统推测群体遗传结构,进而提出监测遗传多样性的取样策略,这对就地保护和移地保护都是十分重要的     

Sampling strategy for wild soybean ( Glycine soja ) populations based on their genetic diversity and fine-scale spatial genetic structure

A total of 892 individuals sampled from a wild soybean population in a natural reserve near the Yellow River estuary located in Kenli of Shandong Province (China) were investigated. Seventeen SSR (simple sequence repeat) primer pairs from cultivated soybeans were used to estimate the genetic diversity of the population and its variation pattern versus changes of the sample size (sub-samples), in addition to investigating the fine-scale spatial genetic structure within the population. The results showed relatively high genetic diversity of the population with the mean value of allele number (A) being 2.88, expected heterozygosity (He) 0.431, Shannon diversity index (I) 0.699, and percentage of polymorphic loci (P) 100%. Sub-samples of different sizes (ten groups) were randomly drawn from the population and their genetic diversity was calculated by computer simulation. The regression model of the four diversity indexes with the change of sample sizes was computed. As a result, 27–52 individuals can reach 95% of total genetic variability of the population. Spatial autocorrelation analysis revealed that the genetic patch size of this wild soybean population is about 18 m. The study provided a scientific basis for the sampling strategy of wild soybean populations. __________ Translated from Journal of Fudan University (Natural Science), 2006, 45(3): 322–327 [译自: 复旦学报 (自然科学版)]     

北京地区野生大豆种群SSR标记的遗传多样性评价

 使用40对SSR引物分析了北京地区野生大豆(Glycine soja)天然种群的遗传结构与遗传多样性。10个种群共检测到526个等位变异, 平均每对引物等位基因数为13.15个, 种群平均Shannon指数(I)为0.658, 群体平均位点预期杂合度(H_e)为0.369, 群体平均位点杂合度(H_o)为1.29 %。平均种群内遗传多样度(H_s)为0.362, 平均种群间遗传多样度(D_ST)为0.446, 基因分化程度(G_ST)为0.544。该研究显示, 中-西部生态区种群比北部和东部山区种群有较高的遗传多样性。在地理上, 环绕北京地区的太行山和燕山两大余脉区域野生大豆种群遗传分化表现出地理差异。可能是经过干旱选择而形成的有抗旱潜力的种群在遗传上表现单一化。期待该种群提供耐旱基因。     

渤海湾津唐沿海野生大豆(Glycine soja)种群高盐碱胁迫反应

以渤海湾津唐沿海地带895份野生大豆种群在高盐碱(3%)环境下的全生育期鉴定试验,分析不同种群(株系)的生长发育动态以及对盐碱土壤生态适应性的分化。结果表明,出苗阶段存在3种耐盐碱能力类型:耐高盐碱胁迫发芽出苗;耐低盐碱胁迫发芽出苗;盐胁迫不能发芽出苗。在高盐胁迫下营养生长早期阶段种群死亡率最高,中期以后相对降低,成熟期死亡率较低。种群植株形态建成和生殖生长受到高盐胁迫的强烈抑制,表现早期严重而后期较轻。植株和产量性状的受害程度由大到小依次为:单株的地上干物质重、单株产量、种子数、百粒重和收获指数。株系间变异系数从大到小依次为:单株产量、种子数、荚数、收获指数、地上干物质重、百粒重。研究揭示该地域种群内对盐碱土壤有很高的适应性分化,存在高耐盐碱生态型。     

Genetic diversity and population structure of Korean wild soybean (Glycine soja Sieb. and Zucc.) inferred from microsatellite markers

Korea is considered one of the centers of genetic diversity for cultivated as well as wild soybeans. Natural habitats of wild soybeans are distributed across the Korean mainland and the islands surrounding the Korean peninsula. In this study, the genetic diversity of 100 mainland Korean wild soybean accessions was evaluated by using 42 simple sequence repeat markers covering 17 soybean chromosomes. All analyzed loci were polymorphic and a total of 114 alleles were found. The observed average genetic diversity was low (0.4). The results showed that the 100 selected accessions did not exactly follow the geographical distribution. These results were further confirmed by the phylogeny inferred from five morphological characteristics (i.e., leaf shape, leaf area, plant shape, seed area, and 100-seed weight). Together, the genetic and morphological evaluations suggested conclusively that the selected population did not follow the geographical distribution pattern. The present study could provide useful information for the ex situ conservation and exploitation of wild soybean accessions in soybean improvement stratagems, and will aid in further understanding about the phylogeography of the species in the Korean center of diversity.     

野生大豆种子cDNA文库的构建与分析

为了分离与鉴定野生大豆优良基因,以双高型优质野生大豆的近成熟种子为材料,采用裂解法提取了总RNA;以Oligo（dT）为引物,经SA—PMPS法分离出mRNA,反转录酶催化合成cDNA,并以cDNA第一链为模板在DNA聚合酶Ⅰ的作用下合成cDNA第二链,双链cDNA经加接头等步骤,成功构建了野生大豆cDNA文库。文库的重组率约为93．7％,PCR检测重组克隆的插入片段平均大于1000bp,测序片断大于500bp,表明构建的近成熟种子cDNA文库质量较高,为进一步进行EST测序和全长克隆打下了基础。     

半野生大豆种质资源SSR位点遗传多样性分析

利用12对SSR引物对67份半野生大豆种质进行了遗传多样性的检测分析,结果表明,12个位点共检测到184个等位基因变异,平均每个位点等位基因数目为15．41个,平均多态性信息量,平均遗传多样性指数,平均遗传距离分别为0．849,0．706,0．118,根据SSR分析结果,按欧式距离将67份半野生大豆种质聚类并划分为5个组群。     

Cloning and functional characterization of an O-acetylserine(thiol)lyase-encoding gene in wild soybean (Glycine soja)

The terminal step of soybean cysteine synthesis is catalyzed by O-acetylserine(thiol)lyase (OAS-TL, EC 2.5.1.47). In this study, we isolated and characterized an OAS-TL gene from a wild soybean material (designated as GsOAS-TL1). GsOAS-TL1 cDNA sequence showed strict conservation at both nucleotide and amino acid levels compared with that from cultivated soybean. Genomic structure analysis of GsOAS-TL1 indicated that it contained 10 exons and 9 introns in the coding region with conserved exon sizes and intron locations compared with Arabidopsis thaliana OAS-TL-like genes. Among the complete GsOAS-TL1 cDNA and three part-deletion fragments, only expression of the full-length cDNA could rescue the NK3 cys⁻ Escherichia coli auxotroph, which was coherent with the assayed enzyme activity of purified fusion proteins. For RT-PCR analysis in different wild soybean tissues, GsOAS-TL1 showed lower expression in roots and developing seeds, whereas total OAS-TL activity of corresponding tissues showed significantly higher level in seeds than other tissues. To our knowledge, this is the first report on cloning and characterization of an OAS-TL gene from wild soybean. Our results are informative to further elucidate the function and evolution of OAS-TL in soybean.     

Microsatellite markers reveal genetic diversity of wild soybean in different habitats and implications for conservation strategies (Glycine soja) in China

Wild soybean individuals were sampled from ten habitat sites in Beijing region, China and were assessed using 36 SSR markers for the genetic variation among the habitat subpopulations. AMOVA analysis showed 57.46 % inter-population and 42.54 % intrapopulation genetic variation. The genetic variation had geographical regionality. The drought-stressed and founder subpopulations intensively reduced genetic diversity, and along-river system habitats appeared to have closer genetic similarity. The bottleneck impact of drought stress appeared to be inferior to the founding effect on subpopulation genetic diversity but superior on genetically geographical grouping. Here, all the subpopulations were found to contain unique alleles. The phenotypic and genetic diversities had similarly fluctuated patterns across the subpopulations. These results here suggest that a conservation strategy should be taken: theoretically as many as possible populations are sampled to maximize the genetic diversity in ex situ conservation of wild soybean within an area in China. Spatial distance should be considered for isolating wild soybean populations when genetically modified soybeans are cultivated in China.