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.     

分子标记辅助选择聚合Xa23,Pi9和Bt基因

利用分子标记辅助选择将高抗水稻白叶枯病的Xa23基因、广谱高抗稻瘟病的Pi9基因、抗水稻螟虫和稻纵卷叶螟的Bt基因聚合到同一株系中,获得了三基因聚合的纯合株系。病、虫抗性鉴定结果显示：聚合了Xa23、Pi9和Bt基因的株系HB1471、HB1473能同时抗白叶枯病、稻瘟病和稻纵卷叶螟;与Xa23、Pi9基因的供体材料L10相比,对白叶枯病和稻瘟病的抗谱相同、抗性水平相当;对稻纵卷叶螟抗性与Bt基因的供体亲本MH63-Bt水平相当。Xa23、Pi9和Bt三基因纯合株系可以作为水稻育种的多抗供体材料。     

宁夏水稻代表性种质及后代抗稻瘟病基因型分析北大核心CSCD

以96份宁夏水稻代表性种质资源和47份杂交后代为试验材料,采用宁夏稻瘟病菌生理小种人工接种和自然诱发相结合的方法对其进行稻瘟病抗性的大田鉴定和病圃鉴定,评价了每个材料的稻瘟病抗性;同时采用8个主效抗稻瘟病基因的功能标记对上述材料进行抗病基因的分子检测,得到了28个不同的抗稻瘟病基因型,将不同基因型的稻瘟病抗性评价进行了差异显著性分析。结果表明,同时含有Pita、Pib、Pikm、Pikh、Pi9和Pi5共6个抗病基因组成的基因型的水稻材料对稻瘟病的抗性极显著高于其他基因型的抗性。Pita基因单独与Pikm、Pikh、Pi2、Pi5基因聚合时均表现出正向聚合效应,其中Pita与Pikh基因的聚合效应最强。当Pib与Pita+Pikh聚合时,表现出负向聚合效应。这为宁夏地区通过基因聚合方法选育广谱持久抗稻瘟病水稻新品种提供了重要的参考依据。     

甜瓜抗白粉病基因SRAP分子标记筛选

以感白粉病甜瓜A120和抗白粉病甜瓜A119为亲本构建F2代分离群体,采用BSA和SRAP相结合的方法筛选与甜瓜抗白粉病基因相连锁的分子标记.结果显示,294条SRAP引物中有6条引物在抗病与感病池间表现出多态性;对8个高抗和8个高感单株进行扩增,引物me46em51和me3em6分别在高感单株中扩增出210 bp和205 bp的多态性条带,而高抗单株无此扩增带,与抗病、感病池结果一致.采用JoinMap3.0软件进行连锁分析,两标记与抗白粉病基因的连锁距离分别为18.2 cM和23.4 cM,初步推测本实验中甜瓜白粉病抗性为隐性多基因控制.     

萝卜不同抗源对黑腐病抗性的遗传分析

不同抗病基因的挖掘是作物持久抗性遗传改良的基础。本研究利用2份抗黑腐病(Xanthamonas campestris pv.campestris)萝卜(Raphanus sativus L.)材料(KB10Q-22、KB10Q-24)和1份感病材料(KB10Q-33)构建了2个F2群体,采用苗期剪叶+喷雾法接种黑腐病菌Xcc8004进行抗病性鉴定。应用P1、P2、F1、F24个世代的数量性状主基因+多基因混合遗传分析方法,研究了萝卜2个不同抗源抗黑腐病的遗传规律,结果表明2份材料的遗传规律不同。以KB10Q-22为母本的F1植株表现为抗病,其遗传模型为E_0模型,即2对加性-显性-上位性主基因+加性-显性-上位性多基因模型;而以KB10Q-24为母本的F1植株表现为感病,其遗传模型为D_0模型,即1对加性-显性主基因+加性-显性-上位性多基因模型。两群体主基因遗传率分别为87.73%和55.64%,抗性遗传以主基因为主。     

西瓜花叶病毒诱导对不同抗性美洲南瓜防卫基因表达的影响

为了明确防卫基因PAL与美洲南瓜抗西瓜花叶病毒(watermelon mosaic virus,WMV)之间的关系,通过室内接种和实时荧光定量PCR技术,测定了WMV侵染对不同抗性美洲南瓜体内防卫基因PAL表达的影响。结果表明:(1)室内测定显示,抗病品种GBRV-8发病率和病情指数(15.6%和14.2)显著低于感病品种‘光板’(91.1%和65.9)。(2)实时荧光定量PCR表明,接种WMV后不同抗感品种不同组织部位PAL基因相对表达量随着接种时间增加,整体呈现出先增加后降低的趋势,而且不同组织部位PAL基因相对表达量总体呈现出叶片较高,叶柄和茎秆次之。(3)接种后5个品种不同组织部位PAL基因相对表达量与对照相比均存在显著差异,且抗病和中抗品种不同组织部位PAL基因相对表达量显著高于感病品种,尤其抗病品种GBRV-8不同组织部位PAL基因相对表达量最高,感病品种光板最低。研究认为,防卫基因PAL表达量与美洲南瓜品种抗病毒病强弱密切相关。     

萝卜种质资源对黑腐病的抗性鉴定与筛选

对40份初选萝卜种质分别接种Xcc8004和XccBJ两个菌株,进行黑腐病苗期抗性鉴定,对其中8份代表性萝卜种质肉质根切片接种Xcc8004进行抗性鉴定和27份萝卜种质幼苗接种8个效应物基因进行过敏反应鉴定。结果表明:不同萝卜种质苗期对黑腐病的抗性存在显著差异,筛选出高抗Xcc8004的材料3份、抗病1份、中抗4份,高抗XccBJ的材料1份、抗病2份、中抗5份。萝卜苗期对Xcc8004和XccBJ的抗病性极显著相关,幼苗和肉质根对Xcc8004的抗病性极显著相关。筛选出17份对不同效应物表现过敏反应的萝卜种质。对效应物XC₀241表现过敏反应的种质数最多,对XC₀542和XC₀541表现过敏反应的种质数次之。不同抗源对不同效应物的过敏反应程度有所不同。稳定可靠抗病资源的获得为萝卜抗病育种和抗病机理的深入研究提供了基础材料。     

药用野生稻对褐飞虱抗性基因的遗传分析及利用研究

从198份广西药用野生稻中筛选出3份对褐飞虱高抗（0级）的材料,用高抗材料与感虫材料杂交,结果表明其抗性是受一对显性基因控制;与14个已知抗褐飞虱基因品种杂交、回交和自交,对BC2F2后代材料进行了抗性遗传分析,等位性测定结果表明,抗源材料与已知的14个抗性基因不等位,结果发现广西药用野生稻与国外药用野生稻的抗性基因（隐性基因）不同。初步认为它是一个新的抗性基因。在利用方面,通过幼胚离体培养获得绿苗,经多代回交和自交,成功地将CC染色体组中的抗性基因转育到栽培稻中,获得了BC4F5高世代、异源附加系。     

抗稻瘟病水稻资源抗性基因Pita、Pib、Pi9以及Pikm的分布研究

利用抗稻瘟病水稻资源品种杂交,聚合多个抗性基因是培育持久抗稻瘟病水稻新品种的主要育种途径.利用分子标记技术对水稻抗性资源进行基因型鉴定是分子辅助聚合育种的基础.通过以亚华种业科学院稻瘟病病圃抗病水稻资源为材料,利用特异性分子标记对Pi9、Pita、Pib以及Pikm基因在水稻抗稻瘟病资源的分布进行了鉴定,初步建立了抗性基因数据库.同时对抗性基因及与抗性反应的相关性进行了探讨,结果表明以Pi9为主效基因,同时聚合Pita和Pib抗性基因能提高持久抗稻瘟病能力.     

抗青枯病烟草种质资源在云南省的评价

筛选出抗性稳定的种质资源是选育抗病品种的重要基础。本文采用人工接种和病田自然发病方法鉴定了48份烟草种质的青枯病抗性表现。土壤盆栽接种鉴定表现为高抗的材料有CF207、岩烟97、TI448A、DB101、G80、RG17、GTH-1等7份材料,表现抗病的有MSK149、Oxford 2028、NC95、YN108、K346、K358、Enshu FC、Oxford 207、RG11等9份材料。苗期恒温水培接种鉴定结果表明,Oxford 207和岩烟97表现为高抗,Enshu FC表现抗病,抗病材料与云烟85和K326杂交F1的抗性表现为中感至抗病。田间自然发病鉴定结果表明,我国审定的中抗青枯病的品种RG17、RG11、K358和K346,在云南省田间抗性表现为中抗,产值较高。TI448A田间表现为抗青枯病,但易感黑胫病和空茎病。Oxford 2028和Oxford 207田间表现为抗病至高抗,产值较高。G3和岩烟97田间分别表现为高抗和抗病,产值较低。根据接种鉴定和田间病圃2年抗性鉴定,筛选出育种潜力较大的青枯病抗源Oxford 207、Enshu FC,岩烟97和TI448A。     

巴西橡胶树HbWRKY1基因的克隆及转化烟草的初步研究

利用RACE结合RT-PCR技术,从巴西橡胶树(Hevea brasiliensis)总RNA中扩增得到长度为1234 bp的WRKY基因cDNA全长编码序列。通过氨基酸同源性比对,该序列推导的氨基酸序列与蓖麻、白杨的WRKY同源性分别为79%和73%,表明分离的cDNA序列为橡胶树WRKY基因,命名为HbWRKY1。通过构建pCAMBIA1304-HbWRKY1植物表达载体,经农杆菌GV3101介导,将HbWRKY1基因导入烟草(Nicotiana tabacum)中,对所获得的潮霉素抗性烟草株系进行PCR鉴定。结果表明,HbWRKY1基因已整合到65株转基因植株中。干旱胁迫试验表明,HbWRKY1的过量表达可以明显提高转基因烟草对干旱胁迫的耐受能力。这说明WRKY基因与橡胶树抗旱能力之间存在一定的关系。     

转MhGlu基因烟草灰霉病抗性及光合特性研究

以湖北海棠盆栽及组培苗叶片为材料,经NaCl、PEG-6000及4℃下ABA处理后,通过RT-PCR技术克隆了湖北海棠β-1,3-葡聚糖酶基因MhGlu;构建MhGlu基因的植物表达载体,通过农杆菌介导法将MhGlu基因转入烟草中,并通过PCR和RT-PCR检测,成功获得了4个转基因株系T6、T8、T11和T18;以转基因烟草株系T6及T8和非转基因对照植株为材料,对MhGlu基因的功能进行了进一步分析。结果显示:(1)半定量qRT-PCR显示,NaCl、PEG-6000及4℃下ABA处理均可以诱导湖北海棠盆栽及组培苗叶片MhGlu基因的表达;NaCl和PEG-6000处理48h内MhGlu基因的表达随处理时间延长逐渐增强,4℃下ABA处理的MhGlu基因表达量在4h时开始上调,12h时略降低,48h时又达到最大。(2)半定量RT-PCR检测转基因烟草植株几个病程相关基因PRs的表达量,表明过表达的MhGlu基因诱导并增强了烟草病程相关基因NtPR1、NtPR3和NtPR5的表达。(3)用灰霉病侵染烟草叶片,转基因烟草株系T6、T8均表现出较强的抗灰霉病特性。(4)测定烟草植株光合特性参数,转MhGlu基因烟草株系的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)较对照组均显著提高,且T8的净光合速率和蒸腾速率均显著高于T6,而T8与T6的气孔导度差异不显著。MhGlu基因在烟草中的过量表达能诱导病程相关基因PRs的表达,激活了烟草的光合特性保护机制,提高了转MhGlu基因烟草植株的灰霉病抗性。     

Effects of MULTIFOLIATE-PINNA, AFILA, TENDRIL-LESS and UNIFOLIATA genes on leafblade architecture in Pisum sativum

In order to dissect the genetic regulation of leafblade morphogenesis, 16 genotypes of pea, constructed by combining the wild-type and mutant alleles of MFP, AF, TL and UNI genes, were quantitatively phenotyped. The morphological features of the three domains of leafblades of four genotypes, unknown earlier, were described. All the genotypes were found to differ in leafblade morphology. It was evident that MFP and TL functions acted as repressor of pinna ramification, in the distal domain. These functions, with and without interaction with UNI, also repressed the ramification of proximal pinnae in the absence of AF function. The expression of MFP and TL required UNI function. AF function was found to control leafblade architecture multifariously. The earlier identified role of AF as a repressor of UNI in the proximal domain was confirmed. Negative control of AF on the UNI-dependent pinna ramification in the distal domain was revealed. It was found that AF establishes a boundary between proximal and distal domains and activates formation of leaflet pinnae in the proximal domain.     

Presence of Rhizobium Etli bv . Phaseoli and Rhizobium Gallicum bv . Gallicum in Egyptian Soils

Seven bean rhizobial strains EBRI 2, 3, 21, 24, 26, 27 and 29 identified as Rhizobium etli, and EBRI 32 identified as Rhizobium gallicum, isolated from Egyptian soils and which nodulated Phaseolus vulgaris efficiently, were subjected to hybridization with a nifH probe in order to estimate the copy number of this gene. Seven strains (EBRI 2, 3, 21, 24, 26, 27 and 29) which were only able to nodulate Phaseolus vulgaris, contained three copies of the nifH gene, consistent with their identification as Rhizobium etli bv. phaseoli. Only one strain (EBRI 32) which nodulated both Phaseolus vulgaris and Leucaena leucocephala, had one copy of nifH gene. This confirmed the classification of this strain as Rhizobium gallicum bv. gallicum.     

Characterisation of cell wall polysaccharides, arabinogalactans-proteins (AGPs) and phenolics of Cola nitida, Cola acuminata and Garcinia kola seeds

Many Cola plant species are endemic to West and Central Africa. Cola acuminata and Cola nitida are used as masticatory when fresh, while the dried nuts are used for beverages and pharmaceutical purposes in Europe and North America. Garcinia kola seeds, that serve as a substitute for the true kola nuts, are used in African traditional medicine for the treatment of various diseases, including colic, headache and liver cirrhosis. Seeds extracts of G. kola are also known for their anti-inflammatory, antimicrobial and antiviral properties. To gain information on the chemical properties of the kolas, we have isolated and analyzed cell wall polysaccharides, arabinogalactan-proteins and phenolic substances from the seeds of the three kola species. The sugar composition of cell wall material of C. acuminata, C. nitida and G. kola revealed that Gal (up to 30%), Ara, GalA and Glc as the predominant monosaccharides, representing approximately 90% by mol of the total hydrolysable sugar present in this material. In Ammonium oxalate cell wall fraction, GalA was found to be the major sugar present in all kola species. In the alkali-soluble fraction, there were significant differences in the level of Glc and Gal. The level of Glc was high in C. acuminata and C. nitida while the level of Gal and Xyl were high in C. nitida and G. cola. Isolation and quantification of arabinogalactan-proteins demonstrate that G. kola seeds contained four to eight times more of these proteoglycans than the seeds of the other two species. Finally, analysis of soluble phenolic substances shows that caffeine and catechin were largely represented in C. acumina and C. nitida seeds, with caffeine accounting for 50% of all soluble phenolics. These findings indicate that the three Kola seeds are highly enriched in pectins and proteoglycans and that C. acuminata and C. nitida can be used as a possible source of caffeine and catechin.     

致病性葡萄球菌cfr基因介导的多重耐药机制研究进展

葡萄球菌是临床常见致病菌及食源性致病菌,可在食品原料加工、包装及运输过程中污染食品,引起人体多种严重感染,其耐药性的不断增强对公共卫生安全产生了重大的威胁。葡萄球菌中cfr (chloramphenicol-florfenicol resistance)基因编码的甲基转移酶,可引起细菌核糖体RNA的甲基化,从而阻碍或减弱多种化学结构不同的抗生素与肽基转移酶活性中心(peptidyl transferase center,PTC)的结合,导致葡萄球菌多重耐药表型的出现。噁唑烷酮类药物−利奈唑胺是继万古霉素后治疗耐药革兰氏阳性菌所致感染的最后一道防线,cfr基因的出现大大加速了利奈唑胺耐药性的传播。cfr基因广泛分布于多种致病性葡萄球菌中,cfr基因与各类型可转移元件(质粒、转座子和整合相关元件等)密切关联的遗传环境是其广泛传播的结构基础。在cfr基因水平传播的过程中,食源性致病葡萄球菌作为中间者扮演着重要的角色。本文就近年来国内外对致病性葡萄球菌中cfr基因的分布状况、耐药机制、遗传环境、传播机制等进行综述,以期为防控致病性葡萄球菌的传播提供参考,以遏制多重耐药菌的进一步传播。     

鸭疫里默氏杆菌流行菌株的分离鉴定及生物学特性

【背景】鸭疫里默氏杆菌(Riemerella anatipestifer,RA)是引起雏鸭、鹅、火鸡等多种家禽、野禽发生传染性浆膜炎的病原,在全世界范围内广泛存在,危害养禽业发展,造成严重的经济损失。【目的】了解国内RA的流行现状,探究该菌的生物学特性,更好地指导防控鸭疫里默氏杆菌病。【方法】对2020-2021年从山东省、河北省、广东省、山西省等地分离的RA疑似菌株进行PCR、生化和血清型鉴定,并根据药物敏感性结果分析耐药现象,根据半数致死量(median lethal dose,LD₅₀)测定结果分析致病力差异。【结果】共鉴定78株RA分离株,其中,血清1型4株、2型21株、10型11株、6型3株、7型17株,1株有交叉凝集现象,21株血清型未定型;药敏结果显示78株分离株对多粘菌素B、磷霉素、克林霉素等的耐药性最强,对头孢拉定、多西环素、呋喃唑酮、氟苯尼考等抗生素最为敏感,并且78株分离株均存在多重耐药性,其中77株耐药5重及以上;动物试验结果显示,RA的分离株致病力普遍较强,而且不同地区分离株、同地区不同分离株之间均存在差异,数株RA分离株的LD₅₀在10⁴-10⁷ CFU不等。【结论】RA在国内流行表现了强致病力及严重耐药情况,本研究结果为更好地预防控制、临床用药及后续致病机制研究提供了参考依据。     

Genome Analysis inNeurospora crassa;Cloning of Four Lociarginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) and Associated Chromosome Walking

We have cloned fourNeurospora crassagenes by complementation analysis. Cloned genes include thearginine-1(arg-1),methionine-6(met-6),unknown-7(un-7), andribosome production-1(rip-1) loci. Chromosome walks were initiated in ordered cosmid libraries from the cloned loci. A total of about 700 kb of theNeurosporagenome is covered in these walks.     

Nomenclatural changes resulting from the transfer of tropical African Sarcostemma to Cynanchum ( Apocynaceae : Asclepiadoideae )

Summary  Four species of tropical African Sarcostemma are transferred to Cynanchum together with two subspecies of S. viminale. In addition, Sarcostemma mulanjense is reduced to subspecific rank under C. viminale.