籼粳交新种质康丰A对稻瘟病抗性的遗传

康丰A是利用带有广亲和基因的籼粳亚种间杂交育成恢复系97gk419与恢复系明恢70杂交(恢复系×恢复系),所形成的胞质正常、雄性可育,而无恢复性的特殊变异新种质,再与野败胞质不育系连续回交转育成的具有特殊核遗传背景的新型水稻三系不育系。本研究通过接种不同地区的53个稻瘟病菌系,发现康丰A对华南稻区尤其是福建稻区的稻瘟病菌系具有广谱抗性。以康丰A(同型保持系康丰B)与普感品种丽江新团黑谷(LTH)杂交,获得杂交F1和F2,分别接种稻瘟病菌系81278、Guy11、FJ2009-66和98013A。接种鉴定和遗传分析表明,康丰A对4个菌系的抗性均由1对显性抗病基因控制。等位性测定表明,康丰A抗菌系81278的基因与已知抗病基因Pi-1、Pi-2、Pi-ta和Pi-3呈非等位关系,与Pi-ta(Pi-?)呈现连锁遗传,暂命名为Pi-kf1(t)。     

分子标记辅助选择改良水稻不育系臻达A及其杂交种的稻瘟病抗性

水稻抗稻瘟病基因Pi25是一个遗传传递能力强的广谱抗性基因。本研究以携带抗稻瘟病基因Pi25的BL27为抗源供体,与优质、配合力强、感稻瘟病的水稻保持系臻达B为受体亲本进行杂交、回交创制水稻抗病保持系新种质,再与臻达A测交和回交进行不育系转育,结合分子标记辅助选择和农艺性状筛选,获得3个抗性基因纯合、农艺性状和开花习性均与臻达A相似的改良不育系株系。利用福建省近年来致病性代表的22个稻瘟病菌株对3个改良不育系及其15个杂交种进行抗性鉴定,3个改良不育系的抗性频率为95.45%~100%,15个杂交种的抗性频率均达75%以上,而原始对照臻达A及其杂交种的抗性频率仅为54.55%和40.91%~63.64%。自然病圃诱发鉴定表明,3个改良不育系的叶瘟和穗颈瘟均为0级,表现高抗,而对照臻达A的叶瘟为5级,穗颈瘟为7级,表现感病;15个杂交种均表现良好的稻瘟病抗性。进一步分析比较15个杂交种的产量、农艺性状和稻米品质表现,结果表明臻达A-Pi25-3改良不育系的综合性状表现最优,继续回交转育,于2015年育成了稻瘟病抗性强、配合力好、群体整齐和性状稳定的不育系,命名为157A。研究表明,抗稻瘟病基因Pi25不仅在水稻不育系臻达A的遗传背景下的抗性表达完全,且在不同水稻恢复系测交种的背景下同样表现出较高水平的抗性,说明抗性基因Pi25对不育系稻瘟病改良的效果明显。创制的新不育系157A的稻瘟病抗性显著提高,还基本保留了原来不育系高配合力等优良特性,为选育高产、优质、抗病杂交稻新品种提供了不育系新种质。     

杂交水稻抗病性遗传研究初报

二年间,对大量的杂交水稻组合进行了抗病性遗传分析。结果表明,杂交水稻对稻瘟病和白叶枯病 的抗性受细胞核基因控制。抗病性在F：中的表现是：抗性显性、抗性隐性、中间类型（部分显性）,以及 出现双亲所没有的新类型。为了获得更多的抗病的杂交水稻F：,我们认为有必要将抗病性导入不育系 中去,以克服当前不育系抗性较差的缺点。     

体细胞突变体HX-3抗水稻白叶枯病基因的鉴定

以感病杂交稻恢复系明恢63的成熟胚为外植体,利用离体筛选技术获得了抗水稻白叶枯病细胞突变体HX-3。连续8年以我国长江流域白叶枯病代表菌析浙173（IV型）对HX-3的R1到R9代进行抗性鉴定,HX-3的抗病性可以稳定遗传。抗性遗传分析表明HX-3的抗性由1对显性核基因控制。1999～2000年连续两年利用我国、菲律宾和日本的32个水稻白叶枯病菌株,测定HX-3及IRBB1等13个具不同显性抗病基因的近等基因系抗性,HX-3抗谱广,且与已知显性抗病基因的抗谱不同。在此基础上,以抗白叶枯病近等基因系IRBB4、IRBB7、CBB12和IRBB21和HX-3杂交,进行等位性分析,4个杂交组合的F2代均出现抗、感分离,说明HX-3与这4个基因不等位。综合以上研究结果,HX-3具有1个新的抗白叶枯病基因,暂命名为Xa-25(t）。     

几种小麦雄性不育系育性恢复性的比较研究

以三种小麦胞质雄性不育系(Q型不育系、T型不育系和 AL型不育系)与 13 个 Q型胞质恢复系进行杂交,以花粉碘染率为指标,比较研究了不同恢复系对不同不育系的恢复度。研究发现,尽管 Q型胞质恢复系本身育性正常,但它与Q型不育系杂交后所得 F1 代,育性有较大变幅,花粉碘染率 0.177 7~0.774 7。有些恢复系如QR3、QR3 37、QR30207等对AL型不育系、恢复系 QR2 143 对 T型不育系的恢复度(杂种花粉碘染率)较高,达0.85以上。在对供试恢复系对不同不育系的恢复度进行 t检验后发现,这三种不育系在恢复程度上无显著差别,说明它们可能是同类不育系,或者可能是所涉及的恢复系具有广泛恢复能力。在上述三种类型不育系中,QA92 8的可恢复程度偏低,其原因可能是其核遗传背景不同。     

太湖流域粳稻地方品种黑壳子粳对稻瘟病抗性的遗传分析

太湖流域粳稻地方品种黑壳子粳对稻瘟病菌表现抗谱广,抗性强的特点,利用黑壳子粳与感病的云南稻地方品种丽江新团黑谷杂交获得的F1、F2和RIL群体,在苗期喷雾接种研54-04和北1两个日本稻瘟病鉴别菌系,根据抗感反应分析亲本的抗病基因组成,结果表明,黑壳子粳对菌系北1的抗性由一对显性基因控制,对菌系研54-04的抗性由两对互为独立遗传的显性基因控制,等位性测定结果和重组自交系的抗感反应表明：黑壳子粳对菌系北1的抗病基因兼抗菌系研54-04,该抗病基因与Pi-k,Pi-z,Pi-ta,Pi-b,Pi-t等5个已知抗病基因座呈非等位关系。也不是Pi-i和Pi-a基因,推断是一个未知的新基因;另一个抗病基因抗菌系研54-04,感菌系北1。     

红莲型杂交稻(红莲2号)及其骨干亲本的RAPD分析与鉴定

利用RAPD技术,从248个随机寡核苷酸引物（10－mer）中筛出18个引物对红莲型杂交稻组合红莲2号及其亲本（T－07A、T－07B、YD6－05）,另6个红莲型胞质不育系的骨干恢复和汕优63及其亲本共14份水稻材料进行分析。共检测到173个多态性标记。聚类分析结果表明：不育系与保持系间因核背景相似,遗传差异很小;杂种（F1）的基因型更倾向于恢复系;恢复系与保持系间遗传距离的相对较大,但各恢复系之间的遗传距离较小。利用这些标记能有效地地区交组合中不育系,保持系、恢复系和杂种（F1）。     

杂交水稻谷粒性状三种不育胞质遗传效应的分析

利用K型、D型和W型三种不育胞质与三个保持系培育成的9个（三套）同质异核或同核异质不育系,以其与5个恢复系按p×q交配模式设计,研究三种不育胞质对F1粒长、粒宽、千粒重和长／宽等谷粒性状的遗传效应．结果表明：各性状均以不育胞质一般配合力效应最重要,随性状而异,还有与保持系、恢复系及二者的一、二级特殊配合力效应;三种不育胞质各性状的一般配合力效应均表现显著或极显著差异,K胞质在千粒重方面、D胞质在粒长和长／宽方面、W胞质在粒宽方面有加性促进作用．因此,注意选择不育胞质源和对质核组合的评价,可进一步改良杂交水稻谷粒性状.     

BT型细胞质雄性不育水稻及其三系的线粒体DNA研究

用RAPD技术对BT型水稻胞质雄性不育系秀A及其保持系秀B、恢复系湘晴以及杂种F1代的线粒体DNA进行了比较分析。结果表明不育系与其保持系间存在显著差异;不育系与其F1之间mtDNA也存在差异。在引物OPJ－08的扩增产物中,秀A扩增出一条分子量为800bp的多态性片段,在引物OPK－10的扩增产物中,杂种F1扩增出一条分子量为900bp的片段。把这两片段回收、克隆并制备探针,OPJ－08800的Southern杂交结果显示不育系与其F1杂交图谱存在多态性;OPK－10900的Suthern杂交结果显示不育系与其保持系同存在差异。推测这两片段与育性可能有一定的联系。     

抗南方水稻黑条矮缩病水稻光温敏核不育系的筛选和鉴定

对东乡野生稻(Oryza rufipogon Griff.)3个生态群落株系及协青早B//协青早B/东乡野生稻的BC1F6株系进行了南方水稻黑条矮缩病抗性鉴定,筛选出抗性较好的种质资源。利用筛选到的协青早B//协青早B/东乡野生稻抗性株系,与光温敏核不育系C47S杂交转育,鉴定筛选到6份抗性较好的光温敏核不育系,为选育抗南方水稻黑条矮缩病的两系杂交稻组合奠定了材料基础;同时研究发现,来源于东乡野生稻的对南方水稻黑条矮缩病的抗性可能由数量性状基因控制。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.