海南普通野生稻稻瘟病抗性资源调查和鉴定

为挖掘海南普通野生稻稻瘟病抗性资源,2010年诱发鉴定了41个居群410份材料苗期叶瘟,2011年接种稻瘟病菌（YC25）鉴定了37个居群121份材料穗颈瘟,2012年调查了80个居群2461份材料田间自然状态的抗病性。结果表明：苗期叶瘟抗性鉴定有21份高抗、117份抗病。苗期抗、高抗叶瘟性的138份材料中穗颈瘟鉴定4份高抗和3份抗病,14份表现为田间自然抗病。苗期叶瘟鉴定不抗病或未作此鉴定材料中,4份表现为抗穗颈瘟和田间自然抗病。这些抗性材料来自海口、文昌、万宁、三亚、澄迈、东方等地。本研究为海南普通野生稻资源进一步研究和抗稻瘟病育种利用提供参考     

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。     

辣椒种质资源抗青枯病的鉴定与评价

采用青枯菌FJC100301菌株对田间辣椒（Capsicum annuum）抗病品种76a和感病品种TW-1分别作了不同温度、不同接种量和不同接种方法的接种试验。结果表明,辣椒青枯病抗性的室内鉴定以接种温度28℃、浸根20 min和3×10^8cfu/mL接种浓度为宜;辣椒种质田间抗青枯病接种鉴定宜选择5月上旬进行,浸根20 min,接种浓度为3×10^8cfu/mL。采用田间抗性接种鉴定的方法,用青枯菌FJC100301菌株对106份辣椒材料进行了抗性鉴定。田间接种后每隔10 d统计病情指数,划分辣椒抗青枯病鉴定分级标准,获得了高抗材料14份、抗病材料8份、中抗材料23份、中感材料23份、感病材料20份、高感材料18份;采用离体叶片接种法对田间筛选得到的高抗和高感纯度较高品种进行抗性分析,结果与田间鉴定一致。     

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。     

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。     

大豆品种对花叶病毒病株系SC3的抗性鉴定与农艺性状评价

黄淮和长江中下游地区花叶病毒主要流行株系SC3,对大豆产量有很大的影响,本研究利用室内接种鉴定的方法研究217份大豆资源对SC3的抗性,同时调查田间接种SC3后,SC3对不同抗病品种的农艺性状和品质性状的影响。为大豆抗花叶病毒病抗病品种的生产应用提供数据支持,同时为选育抗病品种提供抗性亲本。2012-2014年连续3年采用人工汁液摩擦法接种SC3,在温室鉴定217份大豆种质的病毒抗性,根据分析结果,随机选取不同抗病类型材料30份,其中抗病品种10份,中感品种10份,高感品种10份,于2013-2014年间在藁城堤上试验站进行田间接种鉴定,研究SC3对不同品种的产量相关性状和品质性状的影响。217份大豆资源SC3的鉴定结果表明:第一类抗病品种,包括免疫品种4份,占1.84%;高抗品种2份,占0.92%;中抗品种35份,占16.13%;第二类中感品种,包括中感品种92份,占42.40%;第三类高感品种,包括感病品种3份,占1.38%;高感品种81份,占37.33%。SC3对不同抗性品种的单株粒重、株高、主茎节数、蛋白和油份影响不同。第一类抗性品种的单株粒重、株高、主茎节数、蛋白和油份含量下降不显著;第二类中感品种的单株粒重、主茎节数、蛋白和油份含量下降不显著,其株高因品种差异表现出不同程度的下降;第三类高感品种的单株粒重、株高、主茎节数、蛋白和油份含量下降显著。研究表明SC3对不同抗性品种的农艺性状和品质性状的影响不同,对同种抗病类型不同品种的农艺性状和品质性状的影响也不同。SC3对抗病品种和中感品种的多数农艺性状和品质性状的影响不显著,这两类品种适合作为育种材料进行抗性育种。     

结球甘蓝根肿菌鉴定和种质抗性评价

采集湖北省长阳县火烧坪乡根肿病重发区的病土和病根,通过病原菌形态和PCR鉴定,确定是芸薹根肿菌,然后利用欧洲ECD鉴别系统确定生理小种为ECD17/31/13,此病原菌致病力极强。采用田间苗期人工接种鉴定,与田间成株期自然诱发鉴定相结合,对88份甘蓝种质进行抗性评价和筛选,结果表明:苗期获得1份高抗,7份抗病,17份耐病材料;成株期获得4份高抗,4份抗病,15份耐病材料。2个时期88份材料群体抗性鉴定级别基本一致,93.18%材料成株期病指比苗期高。CR21在2个时期均为高抗,抗性最强,表现稳定;CR55在苗期发病最严重,病指达到76.19,成株期为74.10;CR54在成株期发病最严重,病指达到81.54,苗期为75.97,2个时期发病率均达到100%。根肿病菌的鉴定和致病力的确定,及甘蓝种质抗性评价为抗病品种选育和抗病机理的研究奠定基础。     

绿豆种质资源枯萎病抗性鉴定及抗性资源筛选北大核心CSCD

绿豆枯萎病是影响绿豆产量最严重的病害之一。筛选苗期抗性资源,培育抗病品种对枯萎病防治具有重要意义。本研究采用剪根浸根接种法,对来自全国18个省市及国外的215份绿豆核心种质资源和85份绿豆新品系进行了苗期枯萎病抗性鉴定。结果显示,不同地区种质间的枯萎病抗性水平存在差异。国内产区中,东北、华东、华中地区约50%的种质具有枯萎病抗性;华北地区抗枯萎病种质占比40.4%;西北、西南和华南地区种质抗病水平较高;国外材料抗病种质占比40.0%。本研究共筛选出17份高抗(HR)枯萎病种质资源,并利用部分材料建立了枯萎病抗性研究RIL群体;6份高抗高代品系材料,在田间全生育期表现高抗且农艺性状优异。本研究期望为今后抗枯萎病绿豆新品种选育及抗性遗传相关研究提供优异资源和理论依据。     

甘蔗优良品种材料抗高粱花叶病毒鉴定与评价

采用生长期人工切茎接种和RT-PCR检测相结合方法,于2011—2012年2次对国家甘蔗体系近年选育的49份优良新品种(系)和19份云蔗系列优良中间材料进行由高粱花叶病毒(SrMV-HH,GenBank登录号DQ530434)引起的甘蔗花叶病的抗性鉴定与评价。结果表明,49份优良新品种(系)中,1级高抗到3级中抗的有29份,占59.18%。其中粤甘40号、粤甘42号、粤糖55号、云蔗03-194、云蔗99-596、云瑞06-189、桂糖30号、德蔗03-83、闽糖01-77等9份材料表现1级高抗,占18.37%;福农0335、柳城05-129、粤糖96-86、云蔗01-1413、云蔗03-258、云蔗06-80、桂糖02-351等7份材料表现2级抗病,占14.29%。19份云蔗系列优良中间材料中,1级高抗到3级中抗的有13份,占68.42%。其中云蔗04-622、云蔗05-197、云蔗06-267、云蔗05-194、云蔗06-160、云蔗07-2384、云瑞05-704等7份材料表现1级高抗,占36.84%;云蔗06-362表现2级抗病,占5.26%。研究结果为深入开展甘蔗抗花叶病育种,选育和推广优良抗病品种,有效防控甘蔗花叶病提供了科学依据和优良抗源材料。     

菊属与蒿属植物苗期抗蚜虫性鉴定

为发掘对蚜虫有抗性的菊花近缘种属植物,对11份菊属及蒿属植物苗期进行了田间和室内抗蚜虫性鉴定。结果发现:在田间鉴定条件下,随着平均蚜害指数(I*)值的升高,蚜虫抗性等级逐渐降低,其中:黄金艾蒿、黄蒿、香蒿的I*值为0.00,属于免疫性;牡蒿的I*值为0.13,属于高抗性;大岛野路菊的I*值为0.25,属于抗性;异色菊的I*值为0.37,属于中抗性;那贺川野菊、龙脑菊的I*值为0.51—0.75,属于感性;泡黄金菊、紫花野菊、菊花脑的I*值>0.75,属于高感性;在室内鉴定条件下,不同材料对蚜虫的抗性表现出很大差异,根据繁殖倍率的不同,11份材料分为5个抗性等级,其中黄金艾蒿、牡蒿、黄蒿、香蒿繁殖倍率为0.00,属于极高抗性;大岛野路菊繁殖倍率为5.86,属于中抗性;异色菊、那贺川野菊、龙脑菊繁殖倍率为7—10,属于低抗性;泡黄金菊、紫花野菊、菊花脑繁殖倍率>10,属于无抗性。综合分析表明:田间鉴定与室内鉴定结果基本一致,其中黄金艾蒿、黄蒿等8份材料田间和室内鉴定结果无差别;牡蒿田间鉴定表现为高抗性,而室内鉴定表现为极高抗性;大岛野路菊田间鉴定表现为抗性,而室内鉴定表现为中抗性;异色菊田间鉴定表现为中抗性,而室内鉴定表现为低抗性。黄金艾蒿、黄蒿、牡蒿、香蒿、大岛野路菊对蚜虫表现良好抗性,可用于栽培菊花抗蚜性遗传改良。     

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.