Effects of the Fhb1 gene on Fusarium head blight resistance and agronomic traits of winter wheat

The gene Fhb1 has been used in many countries to improve wheat Fusarium head blight(FHB) resistance. To make better use of this gene in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ), the most important wheat-producing region of China, it is desirable to elucidate its effects on FHB resistance and agronomic traits in different genetic backgrounds. Based on a diagnostic marker for Fhb1, six BC2 populations were developed by crossing dwarf-male-sterile(DMS)-Zhoumai 16 to three Fhb1 donors(Ningmai 9, Ningmai 13, and Jianyang 84) and backcrossing to Zhoumai 16 and Zhoumai16’s derivative cultivars(Lunxuan 136 and Lunxuan 13) using marker-assisted backcross breeding. The progenies were assessed for FHB resistance and major agronomic traits.The Fhb1 alleles were identified using the gene-specific molecular marker. The plants with the Fhb1-resistant genotype(Fhb1-R) in these populations showed significantly fewer infected spikelets than those with the Fhb1-susceptible genotype(Fhb1-S). When Lunxuan 136 was used as the recurrent parent, Fhb1-R plants showed significantly fewer infected spikelets per spike than Fhb1-R plants produced using Lunxuan 13 as the recurrent parent, indicating that the genetic backgrounds of Fhb1 influence the expression of FHB resistance. Fhb1-R plants from the DMS-Zhoumai 16/Ningmai 9//Zhoumai 16/3/Lunxuan 136 population showed the highest FHB resistance among the six populations and a significantly higher level of FHB resistance than the moderately susceptible control Huaimai 20. No significant phenotypic differences between Fhb1-R and Fhb1-S plants were observed for the eight agronomic traits investigated. These results suggest that it is feasible to improve FHB resistance of winter wheat withoutreducing yield potential by introgressing Fhb1 resistance allele into FHB-susceptible cultivars in the YHWZ.

Inhibition of the spread of endophytic Sporisorium reilianum renders maize resistance to head smut

Head smut, caused by the fungal pathogen Sporisorium reilianum, poses a grave threat to maize(Zea mays) production worldwide. Here we report cytological and molecular evidence for maize resistance to head smut. During early stages of root infection, S. reilianum mycelium was capable of penetrating the root epidermis of both resistant(Ji1037) and susceptible(HZ4) inbred lines. S. reilianum hyphae were observed in the root–stem junction at 6 days after inoculation. In an attempt to monitor hyphal spread within the maize plant,a highly specific and sensitive real-time PCR method was established to estimate the hyphal content in infected maize tissues. During the upward growth of endophytic S.reilianum, the extent of hyphal spread was markedly different between Ji1037 and HZ4. Very little or no pathogen was detected in aerial parts of Ji1037, whereas large amounts of pathogen accumulated in aboveground tissues, particularly inflorescences, of HZ4. Thus,maize resistance to S. reilianum was achieved mainly by inhibition of endophytic hyphal growth rather than by prevention of early-root penetration by the pathogen.

Response of Sorghum Accessions against Newly Documented Pathotypes 5 and 6 of Head Smut Pathogen, <i>Sporisorium reilianum</i>

This study was conducted to identify resistance sources against the newly documented pathotypes (P5 and P6) of Sporisorium reilianum, causing sorghum head smut. A subset of 67 sorghum association panel (SAP) accessions, 29 in 2017 and 38 in 2018 along with checks BTx635 (resistant) and BTx643 (susceptible) were screened in the greenhouse against P5 and P6 pathotypes in two separate experiments in both years. At 18 to 20 days after planting, accessions were inoculated by injecting the seedlings below the apical meristem with sporidial suspensions following an established inoculation procedure. Three accessions (PI656091, PI533919, and PI533821) in 2017 and 17 accessions (PI597961, PI656071, PI656048, PI576435, PI534075, PI534145, PI656057, PI576437, PI651492, PI656014, PI656025, PI655999, PI656010, PI656082, PI534123, PI533927, PI656100) in 2018 were identified as potential resistant sources to both P5 and P6 pathotypes of S. reilianum. These SAP accessions are new sources that can be further used to develop new breeding parental lines and hybrids and mapping populations for quantitative trait loci markers closely linked to head smut resistance.

Can effectoromics and loss-of-susceptibility be exploited for improving Fusarium head blight resistance in wheat?

Bread wheat(Triticum aestiuum L.),which provides about 20%of daily calorie intake,is the most widely cultivated crop in the world,in terms of total area devoted to its cultivation.Therefore,even small increases in wheat yield can translate into large gains.Reducing the gap between actual and potential grain yield in wheat is a crucial task to feed the increasing world population.Fusarium head blight(FHB)caused by the pathogenic fungus Fusaium graminearum and related Fusarium species is one of the most devastating wheat diseases throughout the world.This disease reduces not only the yield but also the quality by contaminating the grain with mycotoxins harmful for humans,animals and the environment.In recent years,remarkable achievements attained in omics"technologies have not only provided new insights into understanding of processes involved in pathogenesis but also helped develop effective new tools for practical plant breeding.Sequencing of the genomes of various wheat patho gens,including F.graminearum,as well as those of bread and durum wheat and their wild relatives,together with advances made in transcriptomics and bioinformatics,has allowed the identification of candidate pathogen effectors and corresponding host resistance(R)and susceptibility(S)genes.However,so far,FHB effectors and wheat susceptibility genes/factors have been poorly studied.In this paper,we first briefly highlighted recent examples of improving resistance against pathogens via new techniques in different host species.We then propose effective strategies towards developing wheat cultivars with improved resistance to FHB.We hope that the article will spur discussions and interest among researchers about novel approaches with great potential for improving wheat against FHB.

小麦新品系赤霉病抗性鉴定及基因效应分析

为创制黄淮麦区小麦新品系、提高小麦抗赤霉病育种效率,2022年在小麦扬花期利用喷洒孢子液的方法对81份抗赤霉病高代品系和4份对照品种在濉溪柳湖试验基地开展了赤霉病抗性鉴定,并利用与4个抗赤霉病主效基因Fhb1、Fhb2、Fhb4和Fhb5紧密连锁的6个标记对供试小麦材料进行了基因型检测。结果表明,供试81份材料的赤霉病抗性整体较好,平均病小穗率为27.95%,其中13份自育品系平均病小穗率低于扬麦20;携带单个或多个赤霉病抗性基因的品系共有60份,Fhb1、Fhb2、Fhb4、Fhb5检出频率分别为64.20%、12.35%、20.99%、34.57%;携带单个抗病基因Fhb1、Fhb4、Fhb5的小麦品系分别为18份、3份、2份;有45.68%品系同时携带2~3个赤霉病抗性基因。携带抗性基因的品系平均病小穗率低于不含抗性基因的品系;聚合多个抗赤霉病基因可以有效提高小麦品种的抗赤霉病水平。

Overexpression of P-glycoprotein in hepatocellular carcinoma and its clinical implication

INTRODUCTIONMost advanced hepatocellular garcinoma (HCC) isinsensitive to most anticancer drugs which might berelated to the high frequency of expression of themultidrug resistance-1(MDR1) gene and itsproduct,P-glycoprotein (p-gp).p-gp expressionmay also be concerned with tumor progression anddifferentiation.In the present study。

江苏省不同麦区小麦品种(系)对赤霉病的抗性及籽粒DON积累分析

为拓宽小麦抗赤霉病育种资源库,收集江苏省淮南和淮北麦区共69份小麦品种(系),在大田自然发病条件下调查赤霉病的发病情况,同时测定籽粒中的脱氧雪腐镰刀菌烯醇(DON)毒素;并利用抗赤霉病基因Fhb1、Fhb2和Fhb5的功能标记或连锁标记对供试小麦品种(系)进行检测。结果表明,淮北麦区小麦品种(系)的赤霉病发病程度明显高于淮南麦区品种(系);不同小麦品种(系)籽粒中DON毒素含量与病情指数、病穗率均呈极显著正相关;携带单个或多个抗性基因的小麦品种(系)的病情指数和籽粒DON含量大都有所降低,其中扬大617可能同时携带3个抗性基因(Fhb1+Fhb2+Fhb5),其病穗率、病情指数及籽粒中DON含量均较低,可作为新的赤霉病抗源加以利用。

小麦新品系的赤霉病抗性及分子标记分析

为有效降低赤霉病对我国黄淮麦区小麦生产的影响,培育抗赤霉病小麦新品种,以自主创制的13个抗赤霉病稳定的小麦新品系为材料,利用赤霉病菌地表接种和单花滴注法接种鉴定、分子标记检测等技术,鉴定其抗病性、主要农艺性状及赤霉病抗性相关的遗传基础。结果表明:(1)品系Xn12-2和Xn13-2对赤霉病表现为抗,平均病小穗率为11.5%和13.4%,严重度为1.9;其余11个品系表现中抗,平均病小穗率均小于30%,严重度均小于3.0,其中4个品系(Xn12-2、Xn10-2、Xn12-3和Xn12-7)兼抗条锈病;(2)参试新品系的越冬抗寒性较好,株高较矮(67~82 cm),穗较长(9.6~11.3 cm),千粒重高(39.2~50.2 g);(3)11个品系携带有苏麦3号的Fhb1基因,部分品系兼具苏麦3号的Fhb2、Fhb5或QFhs.crc-2DL位点的优异等位变异。综上所述,参试部分品系不仅具有良好的赤霉病和条锈病抗性,其主要农艺性状基本满足黄淮南部麦区的主要育种目标要求,可作为小麦抗赤霉病改良的材料。

Enhancing disease resistances of Super Hybrid Rice with four antifungal genes

A plant expression vector harboring four antifungal genes was delivered into the embryogenic calli of ‘9311’, an indica restorer line of Super Hybrid Rice, via modified biolistic particle bombardment. Southern blot analysis indicated that in the regenerated hygromycin-resistant plants, all the four anti-fungal genes, including RCH10, RAC22, β-Glu and B-RIP, were integrated into the genome of ‘9311’, co-transmitted altogether with the marker gene hpt in a Mendelian pattern. Some transgenic R1 and R2 progenies, with all transgenes displaying a normal expression level in the Northern blot analysis, showed high resistance to Magnaporthe grisea when tested in the typical blast nurseries located in Yanxi and Sanya respectively. Furthermore, transgenic F1 plants, resulting from a cross of R2 homo-zygous lines with high resistance to rice blast with the non-transgenic male sterile line Peiai 64S, showed not only high resistance to M. grisea but also enhanced resistance to rice false smut (a disease caused by Ustilaginoidea virens) and rice kernel smut (another disease caused by Tilletia barclayana).

玉米抗丝黑穗病种质鉴定及遗传研究

丝黑穗病是我国玉米生产的重要病害之一。试验采用人工接种鉴定法研究黑龙江省常用玉米自交系和部分国内骨干系对丝黑穗病的抗性。在54份自交系中,鉴定出4份高抗系和8份抗病系,感病和高感系占64.9%。PB血缘材料中既有高抗材料,也有感或高感材料;含Mo17和自330血缘的材料多数抗或高抗玉米丝黑穗病,尤其是含Mo17血缘材料抗性更强;而含黄早四血缘的材料多高感玉米丝黑穗病;Ried血缘材料多属于中抗或感病类型。玉米对丝黑穗病的抗性遗传属核遗传,F1的发病率介于抗、感亲本之间,接近于双亲的平均值,不存在正反交差异。欲培育中抗以上类型杂交种,其双亲发病率应较低,杂交方式应为高抗×高抗;高抗×抗病;高抗×中抗;高抗×感病;抗病×抗病;抗病×中抗。

玉米丝黑穗病的研究进展

玉米丝黑穗病是玉米生产的重要病害。本文首次系统地综述了丝黑穗病的危害、病原、防治措施、抗源鉴定和抗性遗传研究进展 ,探讨了该领域存在的主要问题。我国应加强对玉米丝黑穗病的抗源鉴定与抗性遗传研究 。

玉米种质对丝黑穗病的抗性分析及发病条件研究

为明确不同玉米种质资源对丝黑穗病的抗性差异,本研究于2012—2015年间采用人工接种法对1 164份玉米种质进行了田间抗性鉴定,结果表明,38份材料03GEM00041、07GEM02289、07GEM02902等表现高抗,占比3.26%;61份材料W6、478、4619、A580等表现抗病,占鉴定种质的5.24%;W22、W216、W286等140份表现中抗,占比12.03%;其余566份和359份分别表现感病和高感,分别占总鉴定材料的48.63%和30.84%。经过对比发现,不同地区玉米种质抗性强弱以及抗性多样性存在较大的差异,来自云南和广东的种质其抗性水平明显低于内蒙古和黑龙江。通过聚类分析发现,41份材料可划分为5类。在系谱图上,抗病性相同的品种大致划分在同一个类中,但也存在一定的偏差。研究结果同时表明0～10cm的土壤温度在15.8～17.9℃,病株率在85%以上,为适宜发病温度,其中15.8℃为最佳发病温度;接菌量为0.3%时的病株率明显高于接菌量为0.1%和0.2%的病株率。

高粱丝黑穗病菌4号生理小种抗性基因的定位

【目的】对高粱的丝黑穗病菌4号生理小种抗性基因进行定位分析,筛选与抗病基因连锁的分子标记,为抗丝黑穗病育种奠定基础。【方法】以对高粱丝黑穗病菌1、2、3、4号生理小种均表现免疫的材料961541为母本,以对1、2、3号生理小种免疫、对4号生理小种感病的材料V4B及高感材料PI550607为父本,进行杂交,构建F2群体。采用菌土法在播种时进行田间接种,抽穗后对抗/感亲本、F1及F2群体材料进行发病率调查。利用微卫星分子标记技术(SSR)和分离群体分组分析法(BSA)对961541/V4B的F2群体进行抗病基因的定位分析。【结果】961541/V4B组合中,抗病亲本961541发病率为0,感病亲本V4B发病率为21.5%,F1发病率为0,F2群体发病率为7.25%;961541/PI550607组合中,高感亲本PI550607的发病率为64.81%,F1及F2群体发病率分别为0和5%。适合性检验表明,2个组合的F2群体的抗、感病株比率均符合15﹕1(χ2=0.201、0.322,P>0.05),4号生理小种的抗病性受2对非等位基因控制。所试274对SSR引物中共有53对引物在抗、感亲本间存在差异。利用筛选出的53对引物进一步对抗、感池进行特异引物筛选,仅位于高粱第1染色体上的SSR引物Xtxp325在抗、感池间表现差异。其中,抗池与免疫材料961541的带型一致,感池与鉴别寄主V4B的带型一致;选取5对引物(Xtxp325、Xtxp302、Xtxp32、Xtxp340和Xtxp248)进行连锁图谱构建,构建的连锁图谱全长355.3 c M,4号生理小种抗性基因Shs1与Xtxp325之间的遗传距离为27.7 c M。【结论】高粱丝黑穗病菌4号生理小种的抗病性受2对非等位基因控制。构建的连锁图谱全长355.3 c M,与发表的连锁图谱有较好的对应关系,高粱丝黑穗病菌4号生理小种抗病基因位于第1染色体上,Shs1与Xtxp325的遗传距离为27.7 c M。

水稻稻曲病抗性的主基因+多基因混合遗传模型分析

稻曲病是由稻曲病菌引起的水稻真菌病害,目前已上升为我国水稻主要病害之一,探明水稻稻曲病的抗性遗传机制对制定抗病育种策略具有现实指导意义。本研究以病情指数为指标,利用高效引发稻曲病人工接种方法对来自抗病亲本IR28(籼稻)与感病亲本大关稻(粳稻)组合的亲本及其衍生的F10代重组自交系群体(RIL)进行抗病性评价,采用数量性状的主基因+多基因混合遗传模型对抗性的遗传模型进行判别与遗传参数的估计。结果表明,水稻稻曲病抗性的遗传除受主基因控制外还受多基因的影响,符合E-1-3遗传模型,即2对主基因+多基因混合遗传模型,2对主基因间表现为等加性作用,加性效应为11.41;主基因遗传率为76.67%,多基因遗传率为22.86%,抗性遗传存在明显的主基因效应。提示抗稻曲病育种时不仅要考虑主基因对抗病性的作用,也不能忽视基因对抗性的影响。

玉米种质资源对丝黑穗病的抗性鉴定

采用新的抗性评价标准,对162份普通玉米自交系、22份爆裂玉米自交系、59份甜玉米自交系及122份糯玉米自交系人工接种丝黑穗病菌并进行抗性鉴定,筛选出US3195等127份抗病系,占鉴定总数的34.80%,多数材料尤其是特用玉米材料感或高感丝黑穗病,无免疫及高抗材料。

629份国内外玉米种质及杂交种对丝黑穗病的抗性评价

为明确629份国内外玉米(Zea mays)种质及杂交种抗丝黑穗病差异,本研究于2016-2018年间采用人工接种法对其进行了田间抗性鉴定,研究结果表明:L311,18236(2),黄糯包谷(221103)等共25份材料表现高抗,占总鉴定材料的3.97%;HVN-1,B07060-1,YJ001496等34份抗病材料表现抗,占总鉴定材料的5.41%;C7172,zce-4,CI103等55份材料表现中抗,分别占总鉴定材料的8.74%;其余322份和193份表现感和高感,分别占总鉴定材料的51.20%和30.68%。分析发现,在266份自交系中,表现中抗及以上自交系共32份,占供试自交系的12.03%;在142份杂交种中,表现中抗及以上杂交种有23份,占供试杂交种的16.20%;在216份农家种中,表现中抗及以上农家种有59份,占供试农家种的27.31%。进一步分析发现,来自于中国贵州的种质,其整体抗丝黑穗病的水平明显高于中国云南、内蒙古和四川,也高于俄罗斯和墨西哥种质。同时比较142份国外杂交种的抗性情况,发现来自乌拉圭的杂交种抗丝黑穗病的比例高于巴西。

高粱三系抗丝黑穗病鉴定与评价

采用土壤接种技术,对目前我国高粱育种上广泛应用的150份高粱种质资源(包括高粱不育系、保持系和恢复系)进行抗高粱丝黑穗病鉴定评价。经两年重复鉴定,在150份高粱种质中,筛选出对高粱丝黑穗病菌优势小种表现免疫(IM)的47份,占总数的31.3%;高抗(HR)和中抗(MR)的各6份,分别占鉴定材料总数4.0%;抗病(R)的4份,占2.7%;感病(S)的13份,占8.7%;高感(HS)的74份,占49.3%。上述结果表明,目前高粱育种中广泛应用的育种种质中抗丝黑穗病材料较为丰富。

抗玉米丝黑穗病品种鉴定及抗性机制初探

本文采用人工接种方式鉴定了西南地区常用90个玉米品种对玉米丝黑穗病的抗性水平,并通过测定3个不同抗性等级的6个玉米品种在接菌环境和正常环境下的可溶性总糖和可溶性蛋白含量及SOD和POD活性变化情况,对其抗性机制进行了初步研究。结果表明,80%以上的玉米品种对丝黑穗病有较好的抗性,且不同抗性水平的玉米品种与其相关生理指标变化程度密切相关,表现为可溶性总糖、可溶性蛋白含量、SOD活性升高程度越高及POD活性下降程度越大,玉米品种抗性水平越低。

玉米自交系抗丝黑穗病鉴定与评价

玉米丝黑穗病是由丝轴黑粉菌(Sporisorium reiliana)属病原真菌侵染引起的世界性土传病害。选育和种植抗病品种是防治玉米丝黑穗病最经济、有效的措施。研究采用人工接种鉴定方法,评价了96份玉米自交系对丝黑穗病的抗病性。结果表明,高抗型占13.5%;抗病型占13.5%;中抗型占21.9%;感病型占27.1%;高感型占24.0%。在不同种质类群自交系中,Mo17类群的全部抗病,自330类群、旅大红骨类群和PB类群抗病的较多,Ried类群和其他类群抗病的次之,PA类群和唐四平头类群中抗病材料缺少。

玉米丝黑穗病的发生与防治及对抗病育种的一些探讨

研究结果表明 :①选育和推广抗丝黑穗病玉米杂交种是当前抗御晋东南地区玉米丝黑穗病既经济又有效的重要措施。在杂交选育中 ,应尽可能用优质高抗自交系作亲本 ,决不能用高感材料。②带菌土壤是玉米丝黑穗病的主要侵染源 ,药剂拌种可有效地防治玉米丝黑穗病的发生。③玉米丝黑穗病是土壤、粪肥传病 ,土壤中病菌厚垣孢子越多 ,发病越重 ,因此因地制宜采取栽培措施 ,促进幼苗健壮生长 ,并有效地减少侵染来源 ,可减轻发病。