小麦赤霉病新抗源的发掘与抗性位点的检测分析

小麦赤霉病是由禾谷镰刀菌引起的世界性重要病害,发掘优异的抗性种质资源、培育抗病品种是持续防治赤霉病最经济且环境友好的措施。为发掘新的赤霉病抗源,本研究于2017—2021年在弥雾保湿大棚中,采用单花滴注法对642份小麦种质资源的赤霉病抗扩展性进行鉴定,同时利用已知抗赤霉病基因/位点Fhb1~Fhb7的分子标记对筛选出的抗性种质基因型进行分析。结果表明,不同年份间赤霉病病小穗率的相关性均达到极显著水平。筛选到3年及以上赤霉病抗性优于扬麦158的种质81份,主要来自长江中下游麦区,其中33份种质连续4年抗性优于扬麦158;筛选到3年及以上抗性与苏麦3号相当的种质9份,分别为望水白、Grandin、浩麦1号、剑子麦、魁小麦、农林26、软秆洋麦、苏麦2号和武农6号,其中剑子麦、软秆洋麦、苏麦2号和Grandin连续4年抗性与苏麦3号相当。对抗性种质携带的抗赤霉病基因/位点进行分析发现,浩麦1号、冀师7225-28、南农13Y110、石优17和武农6号不携带任何已知抗赤霉病基因/QTL,为小麦抗赤霉病研究和品种培育提供了新的种质资源和理论依据。     

小麦抗赤霉病研究现状与展望

小麦是我国最重要的口粮作物之一。在小麦生产所面临的各种病害中,赤霉病的发生具有愈来愈严重的趋势,引起小麦产业界的高度关注。近几十年来,科研人员在小麦抗赤霉病遗传育种以及防控技术领域进行了持续不懈的努力,在赤霉病病原菌致病基因、小麦赤霉病抗性基因定位、克隆及功能研究以及抗赤霉病分子育种等方面取得了重大进展。本文主要从赤霉病抗性基因资源的发掘和鉴定、不同抗源遗传基础解析、小麦赤霉病抗性基因、抗赤霉病分子标记辅助选择育种与基因聚合以及小麦抗赤霉病基因的克隆和功能研究等方面进行了综述,分析了目前小麦抗赤霉病研究中存在的问题,并提出应加强基因克隆、功能分子标记开发以及应用单体型辅助选择(HAS)和标记组辅助选择(MSAS)等小麦抗赤霉病研究的相关建议。     

抗病小麦对脱氧雪腐镰刀菌烯醇的脱毒及产物的生物活性

抗赤霉病小麦品种苏麦３号、繁９能转化镰刀菌毒素脱氧雪腐镰刀菌烯醇（ＤＯＮ）成产物Ｘ,而感病小麦品种宁麦６号、徐州２１无转化能力。产物Ｘ对小麦黄花芽鞘的伸长生长无抑制作用,而对禾谷镰刀菌分生孢子的萌发有明显抑制。说明抗性小麦品种对赤霉病菌毒素的脱毒是小麦重要的抗赤霉病机制。     

3B染色体短臂小麦赤霉病抗性主效QTL的分析

采用区间作图和复合区间作图方法对重组自交系群体宁894037／Alondram、望水白／Alondra和苏麦3号／A1ondra进行了抗赤霉病QTL分析,结果表明,用在田间和温室的赤霉病抗性鉴定资料,在3个赤霉病抗源宁894037、望水白和苏麦3号的3B染色体短臂上均检测到主效QTL的存在。宁894037主效QTL位于标记BARCl33与Xgwm493之间的5．0cM的区间内,最高可解释42．8％的赤霉病抗性;望水白的主效QTL位于标记BARCl47与Xgwm493之间11．5cM的区间内,最高可解释15．1％的赤霉病抗性;苏麦3号的主效QTL位于Xgwm533a与Xgwm493之间13．0cM的区间内,最高可解释10．6％的赤霉病抗性。与赤霉病抗性主效QTL紧密连锁的标记均为SSR标记,可直接用于分子辅助育种。     

抗病小麦对脱氧雪腐镰刀菌烯醇的脱毒及产物的生物活性

抗赤霉病小麦品种苏麦3号、繁9能转化镰刀菌毒素脱氧雪腐镰刀菌烯醇(DON)成产物X,而感病小麦品种宁麦6号、徐州21无转化能力。产物X对小麦黄化芽鞘的伸长生长无抑制作用,而对禾谷镰刀菌分生孢子的萌发有明显抑制。说明抗性小麦品种对赤霉病菌毒素的脱毒是小麦重要的抗赤霉病机制。     

家蚕抗核型多角体病分子标记筛选

对家蚕抗核型多角病毒病以不同的杂交方式,构建3种近等基因系,用RAPD技术筛选出抗病主基因连锁分子标记OPA-18700和感病连锁分子标记OPY-11400。同时在F2群体中验证了抗性分子标记的有效性。     

小麦抗条锈病基因YrCN19的诊断检测和遗传分析

用小麦条锈病抗性基因YrCN19的诊断标记Xgwm410对19个小麦品种或品系进行PCR筛选,其中川农19、新抗5号、爱民5号和爱民6号扩增出与条锈病抗性基因YrCN19共分离的特征片断,其大小为391个碱基,而在其他的小麦品种或品系中未能检测到该片断。系谱分析和抗性鉴定结果表明川农19、新抗5号、爱民5号和爱民6号含有小麦条锈病基因YrCN19。抗性遗传分析发现小麦条锈病抗性在川农19,新抗5号和爱民5号中的遗传符合单个显性基因的遗传规律(3抗:1感);杂交组合烟辐188/爱民6号的抗性遗传也符合单个显性基因的遗传规律,而另外一些杂交组合(如R25/爱民6号,鲁955159/爱民6号和苏3110/爱民6号)中的抗性分离则符合两对基因互补的遗传规律(9抗:7感)。本研究揭示了小麦条锈病抗性基因YrCN19在不同遗传背景和杂交组合的抗性表达和分离有差异,从而加速YrCN19在小麦抗条锈育种中的开发与利用。     

小麦抗条锈病近等基因系感染条锈病后丁布含量变化

选用2套遗传背景不同的抗条锈病近等基因系作为供试寄主材料,研究了不同抗条锈病近等基因系丁布的含量及其在感病过程中丁布含量的动态变化.结果表明,在未受病菌侵染情况下,2套分别含有Yr2、Yr9和YrSpP基因的近等基因系（抗病系）与其轮回亲本Taichung 29、铭贤169(感病系)间丁布含量没有显著差异（P＞0.05）.接种条锈病菌后,感病系在病菌侵染初期丁布含量下降,而抗病系在病菌侵染初期丁布含量迅速大幅度上升.感染条锈病最终导致感病植株丁布含量比未接种的植株明显减少, 感病系的减少幅度明显高于抗病系.在整个病程中,抗病系丁布的含量始终高于感病系,表明接种条件下小麦植株体内丁布含量变化与小麦抗条锈近等基因系的抗性有关.     

普通小麦-大赖草易位系NAU601和NAU618的选育及双端二体测交分析

利用根尖体细胞有丝分裂中期染色体Giemsa C-分带和荧光原位杂交从普通小麦-大赖草Lr.2、Ir.7异附加系辐射后代中选育出2个纯合易位系：（1）易位系NAU618(MS142-3),2n=44,易位染色体由大赖草Lr.7染色体的大部分（约5/6,包括着丝粒）及小麦染色体1A短臂的一部分（近端1/3）组成,外源染色体片段的长度约占易位染色体总长度的4/5;（2）易位系MAU601（MS101-4）,2n=42,易位染色体由小麦染色体4B的整个短臂和4B长臂近着丝粒部分（1/3）及大赖草Lr.2短臂的绝大部分组成,外源染色体片段占易位染色体长臂的1/2。对易位系进行的双端二体侧交分析证交易位所涉及的小麦染色体分别为1A和4B。连续3年单花滴注法进行的田间赤霉病抗性接种鉴定结果表明,普通小麦-大赖草异源异位系MAU618(MS142-3)对赤霉病的抗性与抗病对照品种苏麦3号相仿,易位系MAU601（MS101-4）对赤霉病抗性低于苏麦3号,但明显高于感病亲本中国春。     

抑制差减杂交分离赤霉病菌诱导的小麦特异表达基因

为了全面探索小麦赤霉病抗性机理,以抗赤霉病小麦品种‘苏麦3号’及其感病的近等基因系(Hwo4)为实验材料,构建了一个‘苏麦3号’受赤霉病菌诱导表达的正向差减杂交文库。随机选取了141个阳性克隆测序,共获得133条通读EST。将获得的EST去除载体及接头序列后,利用CAP3软件进行聚类分析,133条EST被聚成90个序列重叠群(contigs),片段大小介于106~643 bp间,平均长度为274 bp。利用NCBI的Blastx软件对序列进行蛋白序列同源性比对,结果显示76条序列在蛋白数据库中可以找到同源序列,功能涉及能量代谢、物质代谢、疾病/防御、转录及细胞结构等。其中以能量及物质代谢相关的基因数量最多,分别占总EST的21.1%及17.1%;其次是与抗病及防御反应有关的EST,数量占总EST的15.8%。进一步的分析表明与抗病及防御相关的EST功能主要涉及抗氧化、细胞解毒及相关物质的代谢。     

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.     

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     

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.     

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