南方玉米锈病抗病基因的定位及不同遗传背景对基因标记的比较分析

玉米自交系齐319高抗南方玉米锈病。利用SSR标记技术和BSA分析对齐319抗南方玉米锈病基因进行了标记分析,结果表明SSR标记phi041和phi118与齐319抗南方锈病基因连锁,其遗传距离分别为7.69cM和8.55cM。因此南方玉米锈病抗病基因定位于玉米10号染色体短臂上。本研究进行的抗病基因标记,选择使用了两个杂交组合的3个分离群体,标记结果显示同一杂交组合的不同分离群体其标记结果是一致的,而不同组分分离群体的标记结果有显著差异,这可能与基因的遗传背景相关。因此,在进行基因标记分析时,选择合适的分离群体是至关重要的。     

玉米P25自交系抗锈病基因的遗传分析及SSR分子标记定位

以玉米南方型锈病免疫自交系P2 5和感病自交系F3 4 9及F1、F2 、B1和B2 为材料 ,采用主基因 多基因混合遗传模型研究了P2 5的抗病遗传规律。结果表明 :自交系P2 5的抗病基因为一主基因 ,表现为加性效应 ,没有检测出多基因 ,其在F2 、B1和B2 群体的遗传率分别为 81 88%、38 14 %和 5 5 1%。利用SSR分子标记技术 ,以组合P2 5×F3 4 9的F2 :3 家系作为构图群体 ,构建了玉米SSR遗传连锁图谱 ,并将玉米抗南方型锈病基因定位于 10号染色体上 ,与phi0 5 9标记的遗传距离为 5 8cM。     

基于混池测序的抗玉米灰斑病QTL定位

玉米灰斑病是由玉米尾孢菌(Cercospora zeine)和玉蜀黍尾孢菌(Cercospora zeae-maydis)引起的真菌性病害,是世界范围内重要的玉米叶部病害之一。以玉米灰斑病抗病自交系Suwan1和感病自交系HM01构建的BC1F1群体为研究材料,在自然发病条件下通过对BC1F1群体中玉米灰斑病的抗性鉴定,选择30株抗病材料和30株感病材料分别构建DNA抗、感混池。在对两个混池进行高通量测序后,通过质量控制和数据分析得到两个极端混池中的变异信息。利用高质量SNP标记对应的两个混池中测序深度差异进行统计检验,成功鉴定了29个玉米灰斑病抗性QTL(quantitative trait loci)。利用Maize GDB网站在29个抗病QTL内共搜索到2 768个基因,通过Phytozome网站与拟南芥和水稻基因组进行同源比对,在1号、5号和10号染色体上分别确定了1个基因作为抗玉米灰斑病的候选基因。     

番茄对细菌性斑点病的抗性遗传规律研究

利用细菌性斑点病的抗病番茄品种(红珍珠和美味樱桃)和感病品种(中蔬四号、美国大红樱桃和MR),通过常规田间抗感杂交、回交,接种病原菌鉴定子代的抗病性分离情况,统计分析的结果表明,杂交F2代全部抗病,F2代和BC1代的抗感分离比分别符合3：1和1：1的理论分离比,说明了红珍珠和美味樱桃对番茄细菌性斑点病的抗病性为单基因显性遗传。     

玉米种质资源抗南方锈病鉴定

玉米南方锈病已成为近几年我国夏玉米生产区间歇性暴发流行的病害,对玉米生产构成严重威胁,病害流行年份可造成10%以上的产量损失。目前,已确认的抗病自交系非常有限,而抗病育种急需不同抗性控制背景的自交系。为发掘和丰富可利用的南方锈病抗源,于2008～2012年,在广西南宁采用田间人工接种方法对1589份玉米种质资源进行抗南方锈病鉴定。通过高病害压力和连续多年的鉴定,从1589份玉米种质中鉴定出高抗（HR）材料26份,占鉴定总数的1.64%;抗病（R）材料137份,占鉴定总数的8.62%;中抗（MR）水平的材料382份,占鉴定总数的24.04%;感病（S）材料489份,占鉴定总数的30.77%;高感（HS）材料555份,占鉴定总数的34.93%。总体上抗南方锈病种质较少,引进种质中抗病类型材料的比例略高。经重复鉴定,筛选出赤556等18份自交系、老来秕等3份地方品种、A69等4份来自津巴布韦的材料、引自CIMMYT的Dr11表现稳定高抗南方锈病,为今后我国玉米抗南方锈病育种提供了新的抗性资源。     

玉米自交系CML470抗南方锈病基因的定位

南方锈病是我国玉米产区的主要病害,玉米抗病品种的利用是控制其为害的一条最为安全和经济的途径。但是,在我国当前的玉米育种中,所利用的玉米南方锈病基因多来自美国杂交种78599等。为寻找新的南方锈病抗病基因,本研究对CIMMYT自交系CML470的抗性进行了遗传分析。结果发现CML470的抗性由一个显性抗病基因（定名为RppC）控制,该抗病基因被定位于10号染色体短臂端部,位于SSR标记umc1380和umc1291之间,分别与两标记相距3.5 cM和8.8 cM。通过回交,并利用分子标记辅助选择,RppC被转移到了优良自交系昌7-2中。     

基于染色体片段导入系发掘抗玉米丝黑穗病主效QTL

选用抗玉米丝黑穗病自交系Mo17和SH15为供体,与受体感病自交系黄早四和昌7-2构建回交群体(BC3F1\BC4F2),通过田间人工接种玉米丝黑穗病原菌鉴定抗病性表现,评价群体抗病性。研究结果显示黄早四×(黄早四×Mo17)BC4F2群体发病率明显高于BC3F1群体;两个BC4F2黄早四×(黄早四×Mo17)和昌7-2×(昌7-2×SH15)群体的发病率差异较大。采用SSR标记分析抗病株的供体染色体导入片段,发现随着回交次数的增多,导入片段数量减少,但不同回交群体中供体导入片段数目明显不同。通过连锁不平衡分析,在染色体2.09和3.04区段发掘和验证2个抗玉米丝黑穗病主效QTL,连锁标记分别为umc2077和phio53或bnlg1965。本文研究结果为抗丝黑穗病基因精细定位和分子聚合育种提供了信息和材料。     

玉米抗南方锈病基因的QTL定位

为发掘新的抗南方锈病基因资源,本研究以感病自交系黄早四为母本、抗病自交系W456为父本,构建F2群体并开展抗病基因定位研究。采用人工接种鉴定的方法对两个亲本、F1、F2群体及对照材料进行表型鉴定和遗传分析。利用均匀覆盖10条染色体的200个SSR标记,分析240个F2单株的基因型并构建含有200个SSR位点的遗传连锁图,连锁图总长度3331 cM,标记间平均距离16.6 cM。使用QTL IciMapping V4.1软件中的完备区间作图法对抗病QTL进行分析,共检测到6个控制南方锈病的QTL:qSCR3、qSCR7、qSCR8-1、qSCR8-2、qSCR9和qSCR10,邻近标记分别为umc2105和umc1729、umc1066和bnlg2271、umc1904和umc1984、umc1984和bnlg1651、umc1957和bnlg1401、umc2034和umc1291,分别位于3、7、8、9和10号染色体上,其中8号染色体上有两个位点,标记区间长度在5～19 cM之间。单个QTL的表型贡献率在2.61%～24.19%之间,可以解释表型总变异的62.3%,其中3个QTL贡献率大于10%,位于10号染色体上的qSCR10贡献率最大,可解释表型变异的24.19%。通过对目标区间标记加密,将该位点的定位区间进一步缩小到2.51 cM内,与两侧标记的距离分别是2.15 cM和0.36 cM。初步定位得到10号染色体上存在抗南方锈病的主效QTL,可为抗病品种的培育提供参考。     

玉米抗南方锈病种质资源初步鉴定及遗传多样性分析

南方锈病是玉米生产上的重要病害。2013-2015年在广西南宁和北京昌平对903份玉米种质资源进行了抗南方锈病的初步鉴定与评价,并利用SSR标记对筛选出的部分抗性材料进行了遗传多样性分析。结果表明,在903份种质中,8份自交系在广西南宁和北京昌平均对南方锈病表现高抗(HR),占总鉴定种质的0.9%;29份材料表现为抗病(R),占比3.2%,包括27份自交系和2份农家种;中抗种质(MR)100份,占比11.1%;感病(S)和高感(HS)种质分别为181和585份,占鉴定材料的20.0%和64.8%。由此可见,玉米资源中高抗南方锈病的种质较为匮乏,在不同地点均表现高抗的材料是难得的抗源。不同地理来源的玉米种质对南方锈病的抗性水平存在较大差异,其中抗性资源较为丰富的是源自内蒙古和山西的种质。42对多态性SSR引物在50份抗锈病材料中,共扩增出141个条带,多态性条带139个,多态位点百分率(PPB)为98.58%。平均等位基因数(Na)1.98,平均有效等位基因数(Ne)1.59,平均Nei's基因多样性(H)0.34,平均多态性信息含量(PIC)0.78,平均Shannon's信息指数(I)0.51;通过UPGMA聚类分析,50份抗病材料被划分为2个类群,其中,第Ⅰ类群又可划分为5个亚类,表现出较高的遗传多样性,为抗病育种中抗源的选择和利用提供参考信息。     

甜瓜抗蔓枯病基因Gsb-3的ISSR分子标记

以甜瓜抗病资源PI511890和感病自交系‘白皮脆’及其F1、BC1P1、BC1P2、F2群体为材料,苗期接种蔓枯病菌(Did ymella bryoniae)进行遗传分析.结果表明:(1)对甜瓜苗期蔓枯病菌接种鉴定结果显示,抗源PI511890的抗病基因Gsb-3由显性单基因控制.(2)利用集团分离分析及ISSR分析技术,引物ISSR-100扩增出的多态性条带与Gsb-3表现连锁关系,该多态性片段大小为900 bp.(3)统计ISSR-100在182个F2单株上的多态性,并用JoinMap 4.0软件分析结果显示,ISSR-100与Gsb-3遗传连锁距离为8.3 cM,定名为ISSR-100900.研究认为,ISSR100900可作为甜瓜抗蔓枯病分子育种的备选分子标记.     

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.