黑龙江省近年审定水稻品种基于SSR标记的遗传多样性分析

为评估黑龙江省水稻品种的遗传基础,利用24个用于水稻DNA指纹图谱构建的SSR标记以及其他均匀分布于水稻12条染色体的38个SSR标记,对黑龙江省近年审定的73个水稻常规稻品种进行遗传多样性分析。结果表明,在62个SSR标记位点中,共检测到142个等位基因,平均每个标记2.3个,多态性比率平均为71.0%,多态性频率变幅为0~0.775,平均值为0.246。供试品种间两两遗传相似系数的平均值为0.759,变幅为0.622~0.966,且96.4%的品种间遗传相似系数在0.66~0.86之间,表明供试的73个品种亲缘关系较近。通过SSR标记基因型聚类分析将这些品种划分为6个类群,与系谱分析趋势一致,类群间的差异主要表现在生育期和米质方面。综上所述,黑龙江省近年审定的水稻品种遗传基础狭窄,在育种中需要导入新的种质资源,加强种质资源创新,以期丰富水稻品种的遗传多样性,进一步提高水稻产量和抗性。     

糯玉米种质品质性状鉴定和SSR标记遗传多样性分析

对165份来源不同的糯玉米农家种和自交系的穗粒性状和淀粉品质性状进行了鉴定,并利用60对SSR标记进行了遗传多样性分析。结果表明,165份糯玉米种质穗长、秃顶长、行数、行粒数和穗粗变异较大,粗淀粉含量、支链淀粉含量和淀粉糊化特性RVA特征谱带值各指标变异丰富。60 对SSR引物在165份材料间共检测到281个等位基因变异,PCR扩增片段大小介于90～690bp,每对引物检测到2～9个等位基因,平均为4.68个;每对SSR 引物的多态信息量( PIC) 在0.332～0. 860之间,平均为0. 690。利用UPGMA 聚类分析方法将供试种质自交系分为3类,划分结果基本符合品系的来源情况,生产应用的多数糯玉米自交系材料与我国西南地区糯玉米地方品种材料具有较远的亲缘关系。显示出165份糯玉米种质具有丰富的遗传多样性,可为糯玉米杂优利用和遗传改良提供遗传基础。     

应用SSR标记分析中国糯大麦种质的遗传多样性

利用SSR标记对来自中国不同省市的76份糯大麦种质的遗传多样性进行分析,并以遗传相似系数为基础进行聚类分析。SSR标记分析表明,50对大麦SSR引物在76份糯大麦中共扩增出203个等位基因,属于高度多态性位点范畴。当遗传相似系数为0.70时可将76个糯大麦品种划分为5个类群,在一定程度上反映了与材料的地理来源和皮裸性。糯大麦资源平均Shan-non多样性指数显示,来自云南和西藏的糯大麦品种遗传多样性略高。SSR标记分析表明,中国糯大麦具有丰富的遗传多样性,对揭示糯大麦的起源与传播以及对资源的有效利用具有现实意义。     

甘蔗属不同种及优良甘蔗栽培品种的SSR标记遗传多样性分析

应用21对SSR引物与毛细管电泳技术,分析了52个甘蔗属品种的遗传多样性。共检测出327个SSR标记,平均每对引物检测15.6个。选择141个共显性标记构建SSR标记指纹图谱数据库,利用DNAMAN软件与UPGMA统计方法分析参试材料遗传多样性。DNAMAN软件同源分析显示,新台糖16号与台优1号之间的同源性最高(87%),品种之间最小的同源性为55%;利用UPGMA统计方法可把参试材料分成4个遗传相似性较高的类群。结果表明,SSR标记与毛细管技术的结合,可构建甘蔗种质资源SSR标记指纹图谱、分析甘蔗种质资源遗传多样性。聚类分析显示参试甘蔗材料的遗传基础相近,为了提高甘蔗选育种效率,应拓宽甘蔗选育种亲本的遗传基础,提高杂交栽培品种的抗虫、抗病等特性。     

宁夏水稻选育品种遗传多样性和亲缘关系分析

选择31份宁夏近年来育成或审定的水稻品种(系),利用分布于12条染色体的36对SSR引物进行遗传多样性和遗传距离分析.共检测到159个等位基因,品种间不同位点等位基因数目不等,平均4.4个.Nei基因多样性指数变幅为0.031 7～0.844 4,平均为0.508 8.按育成或审定年份,把31份水稻分为3组,SSR分析...     

湖北夏大豆种质 SSR 标记的遗传多样性研究

利用SSR标记和系统聚类分析,对92个湖北夏大豆种质进行遗传多样性分析。结果表明,28个SSR位点检测到134个等位变异,每个SSR位点的等位变异范围为2~9个,平均4.78个。鄂西南山区的遗传多样性指数和等位变异数最高,其次为江汉平原区。83.6%以上的遗传差异是由于地区差异引起,表现较高程度的地理分化。系统聚类将92个大豆品种分为3个类群,Ⅰ类和Ⅲ类分别以鄂西南山区品种和江汉平原区品种为主。鄂西南山区和江汉平原区的大豆地方品种表现遗传多样性水平较高。     

番茄栽培品种SSR标记和形态标记的遗传多样性分析

比较了SSR标记和形态标记在研究番茄栽培品种遗传多样性上的应用。用7对SSR引物检测了11个番茄栽培品种的遗传多样性,共得到53条带,每一个位点上扩增出2-9条带,平均为6条;品种间遗传相似系数在0.39-0.84之间,平均遗传相似系数为0.60。根据11个形态学性状表型值计算的遗传相似系数在0.27-0.72之间,平均遗传相似系数0.58。用UPGMA进行聚类分析,SSR标记和形态标记都可依果肉颜色和果实大小将供试材料分组,即黄色和红色果肉,樱桃小番茄和大、中果形的混合型;两种方法对番茄栽培品种遗传多样性的评价相近。     

SSR标记揭示的云南地方稻品种遗传多样性及其保育意义

为了探索水稻(Oryza sativa L.)地方品种的遗传多样性及其有效保育方法,对采自云南省17个村寨的82个水稻地方品种和3个国际常用的典型籼稻和粳稻品种进行了微卫星(SSR)分子标记的分析.利用19对SSR引物在85个水稻品种中共扩增出了83个基因型,其分子量变异在100～500 bp之间.基于各品种SSR基因型遗传相似系数聚类分析而获得的UPGMA树状图表明各水稻品种之间存在较大的遗传多样性,其相似系数变异在0.15～0.90之间.但这些地方品种的遗传多样性并非呈均等的地理分布.这85个水稻品种在相似系数为0.52之处分为二组,其中一组包括几乎所有的籼稻品种,而另一组包括全部的粳稻品种,表明SSR标记能很好揭示水稻籼-粳分化.同时,有些来自不同采集地的同名品种表现出一定的遗传差异,说明同名异物的现象存在.云南水稻地方品种具有丰富的遗传多样性,对其有效保育十分重要和迫切,但只有根据遗传多样性的水平和分布特点,采用正确的保育对策和取样方法才能确保对云南水稻地方品种的有效保育.结果进一步表明,选用适当的微卫星引物,可以为准确鉴定籼稻和粳稻品种及研究其进化规律提供有效的分子标记方法,并有利于有目标的水稻遗传资源保育和育种创新.     

SSR标记揭示的云南地方稻品种遗传多样性及其保育意义

为了探索水稻(Oryza　sativa　L.)地方品种的遗传多样性及其有效保育方法,对采自云南省17个村寨的82个水稻地方品种和3个国际常用的典型籼稻和粳稻品种进行了微卫星(SSR)分子标记的分析。利用19对SSR引物在85个水稻品种中共扩增出了83个基因型,其分子量变异在100～500　bp之间。基于各品种SSR基因型遗传相似系数聚类分析而获得的UPGMA树状图表明各水稻品种之间存在较大的遗传多样性,其相似系数变异在0.15～0.90之间。但这些地方品种的遗传多样性并非呈均等的地理分布。这85个水稻品种在相似系数为0.52之处分为二组,其中一组包括几乎所有的籼稻品种,而另一组包括全部的粳稻品种,表明SSR标记能很好揭示水稻籼-粳分化。同时,有些来自不同采集地的同名品种表现出一定的遗传差异,说明同名异物的现象存在。云南水稻地方品种具有丰富的遗传多样性,对其有效保育十分重要和迫切,　但只有根据遗传多样性的水平和分布特点,采用正确的保育对策和取样方法才能确保对云南水稻地方品种的有效保育。结果进一步表明,选用适当的微卫星引物,可以为准确鉴定籼稻和粳稻品种及研究其进化规律提供有效的分子标记方法,并有利于有目标的水稻遗传资源保育和育种创新。     

基于表型性状和SSR分子标记的云南省水稻主要育成品种(系)的遗传相似性分析

利用株高等17个表型性状和48个SSR标记,对云南省18个育种部门(或课题组)自20世纪60年代以来选育的40个品种(系)进行遗传相似性分析.结果显示,基于17个表型性状,40个品种(系)间的遗传相似性系数值平均为0.244,籼型品种间为0.289,粳型为0.309,籼粳亚种间为0.162;基于48个SSR分子标记,40个品种(系)间的遗传相似性系数值平均为0.383,籼型为0.318,粳型为0.478,籼粳亚种间为0.267;表明表型遗传相似性低于DNA水平.48个SSR分子标记共检测到214个等位基因(Na),每个标记平均为4.458个,变幅为2～8个;有效等位基因数(Ne)平均值为2.8336,变幅为1.1515～5.2981;多态性信息含量(PIC)平均值为0.6058,变幅为0.2118～0.8816;基因型多样性指数(H’)平均值为1.1328,变幅为0.3768～1.8087;其中RM84、RM249、RM152、RM222和RM528是评价云南省水稻选育品种(系)遗传相似性比较理想的SSR标记.聚类分析显示,云南省水稻主要选育品种(系)表现为亚种间遗传差异明显,亚种内遗传差异较小,粳型品种间遗传相似性高于籼型,表明云南省选育的粳型品种(系)遗传多样性低,尤其是同一育种部门(或课题组)选育的品种间遗传相似度较高.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.