烟草数量性状遗传距离与杂种优势关系的研究

利用8个数量性状计算了主成分遗传距离,对15个烟草品种进行了聚类,在4.37的阀值下可将15个亲本分为5大类,分类结果与品种地理来源无必然的联系,而与品种的血缘关系有一定的联系,可将烤烟和晒晾烟分开,在一定程度上反映了品种的遗传差异。F1产量杂种优势指数(F1/MP）与亲本间遗传距离（D2）相关系数不显著,二者呈抛物线关系。在D2<5.63的范围内,二者呈一直线关系,二者相关系数为0.511**,达极显著水平,在此范围内随D2增大,优势指数增大,杂种优势增大,当D2>5.63时,亲本间D2增大,优势指数呈下降趋势。建议在杂种优势利用中选择遗传距离中等偏小的品种做亲本。 Abstract:Fifteen tobacco parental cultivars of 24 hybrids were classified into five groups on 4.37 clustering level by the genetic distance calculated on 8 agronomic quantitative characters. The relative cultivars were clustered into the same group. The result of correlation analysis showed that there was a parabola relationship between genetic distance (D2)and yield heterosis (F1/Mp). WhenD2<5.63, the correlative coefficient was significant(r=0.511**), and the heterosis increased with the increasing of genetic distance. When D2>5.63, the heterosis decreased with the increasing of genetic distance. Therefore, in order to obtain higher heterosis of yield in tobacco, it might be better to choose cultivars with small to medium genetic distance as crossing parents.     

吉林爆玉米遗传距离与杂种优势关系的研究

根据吉林省80个爆玉米自交系数量性状的表现,估算了它们之间的遗传距离。又估算了这80个自交系间随机组配的67个杂交组合F1代小区产量、爆粒率和膨胀倍数的杂种优势。相关和回归分析表明,F1代产量的对照优势与其双亲之间的遗传距离呈显著的二次曲线关系,而F1代品质特性爆粒率和膨胀倍数的对照优势与其双亲之间的遗传距离无确定性关系。因此,可以根据亲本间数量性状的综合遗传差异——遗传距离来预测吉林省爆玉米杂种一代的产量优势。 An experiment was conducted in 1990 to 1991 at the university,to study the relationships between genetic distance,cluster analysis and heterosis in popcorn(Zea mays var.everta).Results showed that there is no sense in cludtering parental lines for prediction of yield heterosis,but blood pedigree can beidentifed from cluster analysis.The relation between genetic divergence or distance and yield heterosis of F1 hybrids can be predicted from the genetic distances of their parental lines according to this model,but no definite relation could be found between parental genetic divergence and the quality heterosis of F1 hybrids.     

小麦异交群体连续歧化选择的RAPD分析

利用太谷核不育基因构建的遗传变异丰富的基础群体DNS2,进行了连续5轮歧化选择。本论文从不同的世代中,选择了10个子群体进行RAPD分析。采用7个引物扩增出116个位点,从基因频率和表型带两个角度的分析都表明,群体具有丰富的遗传变异。整个群体总的多态位点百分率达88.79,总杂合度为0.3143。子群体内（间）遗传距离的结果显示：子群体内的遗传差异小于子群体间的遗传差异;各选择子群体与未选群体间都有较大的遗传距离;随着选择轮次的增加,株高选择子群体间的遗传距离逐渐增大;对同一性状进行选择的子群体间世代内（间）平均遗传距离小于对不同性状进行选择的子群体内（间）的遗传距离。RAPD分子聚类结果显示出对同一性状进行选择的子群体聚在一起,反映了对株高选高的选择效果比较明显。 Abstract:A base population was established through multi-parent random crossing by using Taigu dominant male-sterile wheat,and then five cycles of 2-way selection for four quantitative characters were conducted.The dynamic changes of genetic structures in the open-pollinated wheat population were examined by RAPD technique.Seven primers in RAPD analysis amplified 116 sites.The results of gene frequencies and phenotypic bands showed abundant genetic variations existed in the population.The percentage of polymorphic loci was 8879,and the average heterozygosity was 0.3143 in the whole population.The genetic distance of RAPD showed as follows :① The genetic distance within a subpopulation was lower than that between every two subpopulations.② Each subpopulation had considerable divergence compared with unselected population.③ The genetic distances between the subpopulations which were selected for plant height gradually increased accompanied with the selection.④The genetic distance between subpopulations which were selected for the same character was lower than that were selected for different characters both in the same generation and among different generations.The cluster results of RAPD genetic distance demonstrated that the subpopulations selected for the same character going to one cluster.It also showed that the selective effect of increasing plant height was obvious.     

植物数量性状遗传体系检测中回交或自交家系重复试验数据的分析方法

为提高主基因+多基因混合遗传分析的精度,降低试验误差,采用重复内分组随机区组设计,对低遗传力性状的B1:2和B2:2或F2:3家系平均数资料进行遗传分析.通过AIC准则和适合性检验比较无主基因(A-0)、1对主基因(A)、2对主基因(B)、多基因(C)、1对主基因+多基因(D)和2对主基因+多基因(E)模型以鉴定其遗传模式.采用IECM算法估计混合模型参数.通过油菜HSTC14×宁油7号初花期F2:3家系平均数资料阐明该方法。 abstract:To improve the precision in the genetic analysis of quantitative traits,the B1:2 and 132:2,or F2:3 families in a randomized blocks design were used to identify the mixed major gene plus polygene inheritance model while error variance was estimated from the analysis of variance.Five kinds of genetic models were established,including:one-major-gene model,two-major-gene model,polygene model,mixed one-major-gene plus polygene model,and mixed two-major-gene plus polygene model.The AIC value and a set of tests of goodness-of-fit were used to identify the most fitted model among the possible ones.The iterated ECM (IECM) algorithm was used to obtain maximum likelihood estimates of the parameters in sample likelihood function.An example of the genetic analysis of days from planting to flowering of a rape cross was used to illuminate the above procedure.     

小麦异交群体选择分化的RAPD分析

用RAPD分子标记技术及数量遗传分析手段对小麦异交群体趋异选择4代得到的各子群体的遗传关系进行了分析,并对两种结果进行了相关分析。采用11个引物扩增出134个位点,RAPD分析结果表明,群体具有丰富的遗传变异,整个群体的多态位点百分率达0.8134,杂合度达0.3006;子群体间遗传分化较小,相对基因分化系数Gst为0.2310,固定指数平均0.2120,标准遗传距离为0.1044±0.048,表明遗传变异多数来自群体之内。而数量遗传分析发现,选择性状进展都与预期方向相符,主成分遗传距离大部分达显著水平,说明选择使群体发生了相当程度的分化。对两种遗传距离进行聚类分析表明,二种信息间关系各类群成员多不一致。其原因可能在于：数量性状是人工选择的目标,RAPD是基因组随机序列的扩增,二者之间的相关与引物选择有关。 Abstract：The genetic relations of some subpopulations in the fourth generation of selection in outbreeding population of winter wheat were examined by RAPD techniques and quantitative analysis. The correlations of the two results were examined.For RAPD analysis, 11 primers were adopted, and 134 sites were amplified. The results showed that abundant genetic variations existed in the populations. In the whole population, the percentage of polymorphic sites (P) is 0.8134, and the averaged heterozygosity is 0.3006. However,genetic differentiation among subpopulations is small. The relative gene differentiation (Gst) is 0.2310,fixed index averages 0.2120, and the standard genetic distance between subpopulations is 0.1044±0.048.All above shows that most of the genetic variations existed within populations.The cluster results from RAPD analysis and principal component distances showed that similarity relations were only found in small part of the subpopulations. The reason for the results may be that the genes concerned for quantitative traits are selected directly,while the genes involved in RAPD analysis are only random samples of the whole genomes.     

栓皮栎天然群体SSR遗传多样性研究

利用微卫星(SSR)标记对我国4个省内的5个栓皮栎（Quercus variabilis Bl.）天然群体的遗传多样性进行了研究。16对SSR标记揭示了栓皮栎丰富的遗传多样性：等位基因数（A）平均8.4375个,有效等位基因数(Ne)平均为5.9512个,平均期望杂合度(He)0.8059,Nei多样性指数(h)为0.8041。栓皮栎自然分布区中心地带的群体具有较高的遗传多样性,而人为对森林的破坏将降低林木群体的遗传多样性。栓皮栎群体的变异主要来源于群体内,群体间分化较小,遗传分化系数仅为0.0455。此外,栓皮栎群体间的遗传距离与地理距离之间存在显著的正相关。这些遗传信息为栓皮栎遗传多样性的保护和利用提供了一定依据。Abstract: Genetic diversity of five Quercus variabilis natural populations in four provinces of China was studied with microsatellite (SSR) markers. A relatively high level of genetic diversity was detected in Q. variabilis species with 16 polymorphic microsatellite loci. Average number of alleles (A) and effective number of alleles (Ne) were 8.4375 and 5.9512 respectively. The mean expected heterozygosity (He) was 0.8059 and Nei diversity index (h) was 0.8041. Higher diversity was found with the populations from the central range of the species in contrast to those from peripheral areas and human activities might decrease the genetic diversity of populations. The majority of genetic variation occurred within populations, which could be concluded from the low coefficient of genetic differentiation (Fst=0.0455). In addition, significant correlation was found between geographical distance and genetic distance. All these results present a basis to the conservation and utilization of genetic diversity of Quercus variabilis.     

Development of Oryza rufipogon and O. sativa Introgression Lines and Assessment for Yield-related Quantitative Trait Loci

Introgression lines population was effectively used in mapping quantitative trait loci （QTLs）, identifying favorable genes, discovering hidden genetic variation, evaluating the action or interaction of QTLs in multiple conditions and providing the favorable experimental materials for plant breeding and genetic research. In this study, an advanced backcross and consecutive selfing strategy was used to develop introgression lines （ILs）, which derived from an accession of Oryza rufipogon Griff. collected from Yuanjiang County, Yunnan Province of China, as the donor, and an elite indica cultivar Teqing （O. sativa L.）, as the recipient. Introgression segments from O. rufipogon were screened using 179 polymorphic simple sequence repeats （SSR） markers in the genome of each IL. Introgressed segments carried by the introgression lines population contained 120 ILs covering the whole O. rufipogon genome. The mean number of homozygous O. rufipogon segments per introgression line was about 3.88. The average length of introgressed segments was approximate 25.5 cM, and about 20.8% of these segments had sizes less than 10 cM. The genome of each IL harbored the chromosomal fragments of O. rufipogon ranging from 0.54% to 23.7%, with an overall average of 5.79%. At each locus, the ratio of substitution of O. rufipogon alleles had a range of 1.67-9.33, with an average of 5.50. A wide range of alterations in morphological and yield-related traits were also found in the introgression lines population. Using single-point analysis, a total of 37 putative QTLs for yield and yield components were detected at two sites with 7%-20% explaining the phenotypic variance. Nineteen QTLs （51.4%） were detected at both sites, and the alleles from O. rufipogon at fifteen loci （40.5%） improved the yield and yield components in the Teqing background. These O. rufipogon-O, sativa introgression lines will serve as genetic materials for identifying and using favorable genes from common wild rice.     

The construction of a genetic linkage map of non-heading Chinese cabbage （Brassica campestris ssp. chinensis Makino）

Non-heading Chinese cabbage （Brassica carnpestris ssp. chinensis Makino） is one of the most important vegetables in eastern China. A genetic linkage map was constructed using 127 doubled haploid （DH） lines, and the DH population was derived from a commercial hybrid ＂Hanxiao＂ （lines SW-13 x L-118）. Out of the 614 polyrnorphic markers, 43.49% were not assigned to any of the linkage groups （LGs）. Chi-square tests showed that 42.67% markers were distorted from expected Mendelian segregation ratios, and the direction of distorted segregation was mainly toward the paternal parent L-118. After sequentially removing the markers that had an interval distance smaller than 1 cM from the upper marker, the overall quality of the linkage map was increased. Two hundred and sixty-eight molecular markers were mapped into 10 LGs, which were anchored to the corresponding chromosome of the B. rapa reference map based on com- mon simple sequence repeat （SSR） markers. The map covers 973.38 cM of the genome and the average interval distance between markers was 3.63 cM. The number of markers on each LG ranged from 18 （R08） to 64 （R07）, with an average interval distance within a single LG from 1.70 cM （R07） to 6.71 cM （R06）. Among these mapped markers, 169 were sequence-related amplified polymorphism （SRAP） molecular markers, 50 were SSR markers and 49 were random amplification polymorphic DNA （RAPD） markers. With further saturation to the LG9 the current map offers a genetic tool for loci analysis for important agronomic traits.     

云南纵坑切梢小蠹四个地理种群同工酶比较研究

采用不连续聚丙烯酰胺凝胶电泳技术研究了纵坑切梢小蠹(Tomicus piniperda L.)4个自然种群的9个同工酶基因座。4个种群均在Es-1、Es-2、Es-4、Mdh-1、Mdh-2及AAT-1基因座上存在遗传多态现象。路南长湖、楚雄、蒙自3种群间的遗传距离为0.0036～0.0173, 平均值为0.0105, 表明其遗传结构基本相似。丽江种群与上述3种群之间的遗传距离为0.1421～0.2035, 平均值为0.1765,表明丽江种群与上述三种群已有了遗传分化。丽江种群近交系数较大,近亲繁殖程度较高。种群遗传结构的差异可能与不同蠹害程度之间存在一定的内在联系。 Abstract:　Using uncontinued polycrylamide gel electrophoresis, comparative studies of isozymes between the four geographical populations of Tomicus piniperda L. in Yunnan province were carried out in this paper. Among 9 loci, loci Es-1、Es-2 、Es-4、Mdh-1、Mdh-2 and AAT-1 exhibited the genetic polymorphs. The Nei's genetic distance (D) among Lunan's, Chuxiong's and Mengzi's populations was 0.0036 and 0.0173 with an average of 0.0105, indicating the similar genetic structure among them. The genetic distance between Lijiang population and other three populations was 0.1421～0.2035 with 0.1765 on average, which implied a certain degree of genetic differentiation between them. Investigation indicated the forest damages by the beetle were high in Lunan, Chuxiong and Mengzi, and was low in other population in Lijiang; whereas inbreeding coefficient was bigger and inbreeding degree was higher in Lijiang, but all low in other three districts. It is so proposed that the differentiation of population in genetic structure is related to the damage levels of Tomicus piniperda L.     

Analysis of the genetic diversity of Bemisia tabaci populations in Shanxi province, China

Five different primer combinations were used for the analysis of 152 B biotype Bemisia tabaci (Gennadius) individuals and five Trialeurodes vaporairiorum individuals collected from 19 counties and seven host plants in Shanxi province in China, respectively. The main objective of the present study was to use AFLP markers to determine the genetic diversity of B. tabaci populations collected from Shanxi Province. The use of these primer combinations allowed the identification of 127 polymorphic bands (52.26%) from 60 to 500 bp. The average number of polymorphic bands per primer was 25.4 while the range for the five primers was 20–32. The average degree of heterozygosity was 0.251, while the range for the five primers was 0.204–0.289. The results suggested definite genetic diversity among different B. tabaci populations. Cluster analysis showed that B. tabaci populations were firstly scattered to three genetic groups according to the regions, then every genetic group was scattered to several subgroups according to the host plants, which revealed the genetic variability of B biotype B. tabaci populations has been not only among different regions, but also among different host plants in Shanxi Province.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV     

Mink Circovirus Can Infect Minks,Foxes and Raccoon Dogs

正Dear Editor,Mink circovirus (MiCV), which is clustered in the genus Circovirus of the family Circoviridae, was first described in minks from farms in Dalian, China in 2013 (Lian et al.2014). The complete single-stranded circular genome of the virus is 1,753 nucleotides long and contains two major open reading frames (ORFs), designated ORF1 (Rep gene)and ORF2 (Cap gene)(Lian et al. 2014; Ge et al. 2018).Sequence analysis has shown that MiCV is most closely     

CypA Regulates AIP4-Mediated M1 Ubiquitination of Influenza A Virus

Cyclophilin A (CypA) is a peptidyl-prolyl cis/trans isomerase that interacts with the matrix protein (M1) of influenza A virus (IAV) and restricts virus replication by regulating the ubiquitin–proteasome-mediated degradation of M1. However,the mechanism by which CypA regulates M1 ubiquitination remains unknown. In this study, we reported that E3 ubiquitin ligase AIP4 promoted K48-linked ubiquitination of M1 at K102 and K104, and accelerated ubiquitin–proteasome-mediated degradation of M1. The recombinant IAV with mutant M1 (K102 R/K104 R) could not be rescued, suggesting that the ubiquitination of M1 at K102/K104 was essential for IAV replication. Furthermore, CypA inhibited AIP4-mediated M1 ubiquitination by impairing the interaction between AIP4 and M1. More importantly, both the mutations of M1 (K102 R/K104 R) and CypA inhibited the nuclear export of M1, indicating that CypA regulates the cellular localization of M1 via inhibition of AIP4-mediated M1 ubiquitination at K102 and K104, which results in the reduced replication of IAV.Collectively, our findings reveal a novel ubiquitination-based mechanism by which CypA regulates the replication of IAV.