小麦镰刀菌毒素DON积累抗性研究进展

赤霉病是影响小麦生产的重要病害。小麦赤霉菌侵染寄主后,不仅影响小麦产量和品质,感病子粒中的真菌毒素（主要为脱氧雪腐镰刀菌烯醇,Deoxynivalenol,DON）还对人畜安全造成危害,培育抗病特别是抗DON积累品种是减轻赤霉病危害的有效途径。目前,在赤霉病5种抗性类型中仅抗侵染（类型Ⅰ）和抗扩展（类型Ⅱ）的研究较为深入,随着近年来对食品安全的重视,对毒素DON积累抗性类型（类型Ⅲ）的许多研究也陆续展开。本文系统地综述了抗毒素DON积累种质资源筛选、抗性遗传和抗病基因的分子标记等方面的进展。     

小麦NPR1-like基因的克隆及赤霉菌诱导下的表达分析

AtNPR1是拟南芥系统获得性抗病反应中的关键基因,对拟南芥的广谱抗性起重要调控作用。从赤霉菌诱导的小麦抗、感赤霉病近等基因系RNA差异表达谱中获得3个与AtNPR1类似的EST片段,据此检索相应序列信息并设计引物,采用RT-PCR方法从小麦中克隆得到3个cDNA全长序列,分别命名为TaNPR1、TaNPR2和TaNPR3,其开放阅读框分别编码580、607和601个氨基酸残基。序列分析表明,这3个小麦NPR1-like蛋白都含有保守的BTB/POZ、ANK和NPR1_like_C结构域及功能氨基酸,但仅TaNPR1具有2个对NPR1寡聚体形成十分必要的保守半胱氨酸残基。蛋白质聚类分析表明,TaNPR1与TaNPR2和TaNPR3的同源性均较低,其中TaNPR1与NPR1蛋白聚为一类,而TaNPR2和TaNPR3均与NPR1同源蛋白聚为一类。荧光定量PCR分析结果显示,TaNPR1、TaNPR2和TaNPR3基因都可被植物抗病相关信号分子水杨酸和茉莉酸甲酯诱导。与感病材料Apogee相比,抗病近等基因系Apogee73S2中TaNPR1和TaNPR3能够更早地响应赤霉菌的诱导并显著上调表达;而TaNPR2在感、抗材料中对赤霉菌侵染的响应都较为缓慢且变化不明显。这些结果表明,TaNPR1和TaNPR3可能在小麦对赤霉菌的防御反应中起重要作用。     

小偃麦衍生品系的赤霉病抗性评价

由镰孢属(Fusarium)真菌侵染引起的赤霉病是严重威胁小麦生产的重要病害之一,但小麦育种中可直接利用的抗源非常有限。采用单花滴注法接种赤霉菌株F0609,对来源于中间偃麦草或长穗偃麦草的119份小偃麦衍生品系进行3年6个环境的抗病鉴定,发现平均病小穗率<10%的材料有13份,抗性评价为抗病(R);平均病小穗率介于10%~25%之间的材料有61份,抗性评价为中抗(MR);其余45份材料的平均病小穗率介于25%~50%或>50%,抗性评价为中感或高感(MS和S)。在13份高抗赤霉病材料中,CH16387的抗性显著优于苏麦3号和望水白,CH16371和CH16379的抗性显著优于望水白,其余10个品系与抗病对照苏麦3号和望水白的抗性水平相当。这13份材料分别来自小麦-中间偃麦草部分双二倍体TAI8045和小麦-长穗偃麦草部分双二倍体TAP8430与普通小麦的杂交组合,TAI8045抗性显著优于对照品种望水白, TAP8430与苏麦3号和望水白的抗性相当,而杂交组合中的小麦亲本对赤霉病表现感病,推测这些材料的抗性可能来自TAI8045和TAP8430。这些抗病材料为小麦抗赤霉病育种提供了新的种质资源。     

黄淮麦区Fhb1基因的育种应用

小麦赤霉病是由禾谷镰孢菌引起的一种世界性重要病害,严重威胁小麦生产安全。黄淮麦区作为我国小麦主产区,赤霉病危害日趋严重,因缺乏半冬性抗源,抗赤霉病育种进展缓慢。Fhb1基因是迄今发现的效应最大、抗性最稳定,也是被广泛应用于全球小麦赤霉病抗性育种的主效基因,但Fhb1基因在黄淮麦区尚未被广泛应用。本研究以感病品种矮抗58为轮回亲本, H35为Fhb1基因供体亲本,通过有限回交和分子标记辅助选择,同时利用双单倍体育种和传统系谱选育两种方法,培育出了一批综合性状较好、具有Fhb1基因的优良新品系,其中徐麦DH9和徐麦17252经多年鉴定均达到中抗水平。在以徐麦36和徐麦2023为杂交父本的后代品系中,含Fhb1基因的家系赤霉病平均抗性明显优于感病对照。Fhb1基因的导入显著提高了赤霉病抗性,但部分家系对赤霉病仍旧表现出高感水平,说明赤霉病抗性还受到Fhb1基因以外其他遗传因素的显著影响。本研究为Fhb1基因在黄淮麦区抗赤霉病小麦育种中的应用提供了成功的经验。     

赤霉菌粗毒素对小麦幼苗MDA含量和保护酶活性的影响

为了探讨不同赤霉病抗性小麦品种对赤霉菌粗毒素胁迫的生理生化反应的差异及其与抗病性的关系,用赤霉菌粗毒素处理赤霉病抗性不同的小麦品种的幼苗,在0.5~4天内测定各品种的丙二醛（MDA）含量、超氧化物歧化酶（SOD）及过氧化物酶（POD）活性的增率。结果表明,处理后感病品种幼苗的MDA含量增率高于抗病品种和中抗品种。各品种幼苗的SOD活性先增加后下降,抗性强的品种SOD活性的增率大,活性下降慢;抗性较弱的品种SOD活性的增率小,活性下降快。各小麦品种幼苗叶片的POD活性增率在1~4天内均呈升高趋势,抗性强的品种POD活性的增率小,抗性弱的品种POD活性的增率大。对MDA含量增率、SOD及POD活性增率的第2天测定值和第2~4天测定均值作方差分析表明,三种不同抗性品种间差异显著。     

赤霉菌粗毒素胁迫对小麦幼苗生理指标的影响

为了探讨不同赤霉病抗性小麦品种对赤霉菌粗毒素胁迫的生理生化反应的差异及其与抗病性的关系,用赤霉菌粗毒素处理赤霉病抗性不同的小麦品种的幼苗,在0.5～4天内测定各品种的丙二醛(MDA)含量、超氧化物歧化酶(SOD)及过氧化物酶(POD)活性的增率。结果表明,处理后感病品种幼苗的MDA含量增率高于抗病品种和中抗品种。各品种幼苗的SOD活性先增加后下降,抗性强的品种SOD活性的增率大,活性下降慢;抗性较弱的品种SOD活性的增率小,活性下降快。各小麦品种幼苗叶片的POD活性增率在1～4天内均呈升高趋势,抗性强的品种POD活性的增率小,抗性弱的品种POD活性的增率大。对MDA含量增率、SOD及POD活性增率的第2天测定值和第2～4天测定均值作方差分析表明,三种不同抗性品种间差异显著。     

平湖剑子麦、洪湖大太宝、崇阳红麦、延岗坊主、万年2号抗赤霉病性基因分析

本试验将抗性组分分析法与单体分析法相结合,进行了小麦抗性基因染色体定位和抗性评价。结果表明,平湖剑子麦是抗性较稳定的中抗至抗病品种,其抗性基因涉及6D、7A、3B、5B和6B 等染色体。洪湖大太宝抗性基因和感病基因并存,是一个中抗偏感或中感品种。崇阳红麦属感病品种。延岗坊主的抗性基因位于染色体3A 上,感病基因位于5D 上,是一个中抗品种.万年2号麦穗前期抗病基因位于4D 和5A 上,是中抗品种。两种方法结合研究多基因控制的赤霉病抗性,能获得比较准确的结果和较多的遗传信息。     

Fhb1基因改良‘周麦’品种赤霉病抗性研究

为加快‘周麦’品种赤霉病抗性改良,利用当地主栽‘周麦’品种（系）‘周麦22号’、‘周麦32号’、‘周11550’为母本,‘宁麦9号’、‘生选6号’、‘扬麦21号’等长江中下游地区抗赤霉病材料为父本配制一系列杂交组合,经过选择获得621份F₃~F₆后代材料。在田间选用来源于江苏和河南两地不同的赤霉病菌株,通过单花滴注法接种小穗进行赤霉病抗性鉴定,同时利用抗赤霉病主效基因Fhb1紧密连锁的诊断性标记His-InDel对后代材料进行分子检测。结果表明,江苏的赤霉病菌株接种后代材料田间鉴定为高抗和中抗的占总数的23.9%,而河南的赤霉病菌株感染后代材料田间鉴定为高抗和中抗占比为35.1%,说明后代材料的赤霉病抗性比感病亲本有明显的改良,而且材料对江苏的赤霉菌菌株的抗性比河南的赤霉菌菌株的抗性低。分子检测结果显示,携带Fhb1和不携带Fhb1的材料之间赤霉病抗性差异极显著。这表明利用Fhb1基因分子标记辅助选择技术可用于改良‘周麦’品种的赤霉病抗性。     

小麦TaLTP5参与小麦与条锈菌的非亲和互作反应

为明确非特异性脂质转移蛋白基因Ta LTP5在小麦抗条锈性产生过程中的作用,本研究对该基因进行了染色体定位分析,并利用实时荧光定量PCR(q RT-PCR)技术分析了其转录表达特征。研究结果显示,小麦Ta LTP5基因定位在小麦3B染色体的短臂上,位于3BS8-0.78-1.00染色体区段;Ta LTP5在小麦与条锈菌的非亲和过程前期表达量显著升高,而在亲和过程中没有明显变化;Ta LTP5的表达受到外源水杨酸(SA)、聚乙二醇(PEG)模拟的干旱和外源脱落酸(ABA)的胁迫强烈诱导,而外源茉莉酸甲酯(Me JA)、乙烯(ET)和低温在一定程度上抑制基因的表达。研究结果表明,在小麦-条锈菌非亲和互作中,Ta LTP5可能是小麦对条锈菌的抗性产生信号转导途径的正调控因子,而且参与了小麦的非生物胁迫应答过程。本研究结果对于调控植物抗性和培育抗病品种均有重要意义。     

拟南芥NSP家族基因序列分析及响应干旱胁迫表达分析

芥子油苷是十字花科植物中的一种重要的次生代谢产物,它被酶水解的降解过程与植物响应逆境胁迫有关。NSP蛋白是一类能与黑芥子酶结合从而改变芥子油苷降解途径最终生成腈类物质的特异蛋白,其与ESP家族蛋白在功能上存在冗余。本研究以拟南芥NSP家族基因为对象,对家族成员基因序列、蛋白质序列、启动子序列进行生物信息学分析,并使用实时荧光定量PCR技术检测了该家族基因在干旱胁迫下的表达量。结果表明:该家族成员基因分布于3条染色体上,外显子数目2～4个;AtNSP5蛋白亚细胞定位于细胞核,其他成员定位于细胞质;结构域预测显示,该家族蛋白均含有4个Kelch结构域,除AtNSP5外,其他四个成员还含有1～2个Jacalin结构域;启动子序列中均含有CAAT-box、TATA-box核心元件及数量不一的逆境响应元件;干旱胁迫表达量分析显示,该家族中AtNSP5基因受干旱胁迫诱导表达,其他成员响应干旱胁迫不显著。本研究为进一步研究NSP蛋白在植物响应干旱胁迫中的分子机制提供依据,并为植物抗旱基因工程提供潜在候选基因。     

过表达TaJRL53基因提高了小麦赤霉病抗性

小麦——偃麦草杂种夭亡与不孕现象是多式多样的,表现在各个发育时期,概括可分为九种。其产生原因比较复杂,它受亲本遗传特性的制约,又受外界环境条件的影响,也因个体发育的年龄等而有变化。作者认为,采用以下四种方法配合使用,是克服小麦——偃麦草杂种夭亡与不孕的有效方法：1、在选择适合性强的杂交亲本的基础上,     

小麦近缘野生植物的赤霉病抗源筛选及其利用

赤霉病是禾谷镰刀菌等真菌侵染所造成的生育后期的气候型病害。世界各产麦区均有此病害发生,在气候潮湿、温暖多雨的地区尤为严重。培育抗病品种是解决赤霉病危害的根本途径。在披碱草、偃麦草、山羊草和鹅冠草等小麦近缘种属植物中已经鉴定出赤霉病抗性基因。携带赤霉病抗性基因的外源染色体可以通过附加、代换和易位导入小麦。本文综述了小麦近缘野生植物的赤霉病抗源,以及利用这些抗源进行小麦赤霉病抗性育种的研究进展。     

Common resistance of wheat to members of the Fusarium graminearum species complex and F. culmorum

Fusarium head blight (FHB) is the most important disease of wheat in Central Europe. Although common resistance of wheat against several Fusarium species has been proposed recently, no data were available for the recently described species/lineages of F. graminearum and F. culmorum . In this study, twenty wheat genotypes were tested under field conditions by spraying inocula of isolates of eight species of the F. graminearum species complex, and three lineages of F. culmorum in 2003–2004. The severity of FHB, Fusarium damaged kernels, yield reduction and deoxynivalenol/nivalenol contamination were measured. F. culmorum isolates were in general more aggressive to wheat than those belonging to the F. graminearum species complex. The various wheat genotypes exhibited similar reactions against the different Fusarium isolates, indicating that resistance to F. graminearum sensu stricto was similar to that for the other species of the F. graminearum species complex examined. This is an important message to breeders as the resistance relates not only to any particular isolate of F. graminearum , but similarly to isolates of other Fusarium species.     

Utilization of alien genes to enhance Fusarium head blight resistance in wheat – A review

Fusarium head blight (FHB) is a destructive disease of wheat worldwide. Sources of resistance to FHB are limited in wheat. Search for novel sources of effective resistance to this disease has been an urgent need in wheat breeding. Fusarium head blight resistance has been identified in relatives of wheat. Alien chromatin carrying FHB resistance genes has been incorporated into wheat through chromosome addition, substitution, and translocation. Relatives of wheat demonstrate a great potential to enhance resistance of wheat to FHB.     

小麦品种赤霉病抗性的遗传研究

利用8个不同抗性小麦品种双列杂交的F1及其亲本,以赤霉病病粒率为抗性指标,研究了小麦赤霉病抗性的遗传。结果表明,参试品种间存在3～4对赤霉病抗性基因的差异,苏麦3号、宁麦9号和扬麦158具有较多控制赤霉病抗性遗传的显性基因,对于减少它们杂交后代的病粒率有较高的一般配合力。小麦赤霉病抗性符合加性-显性模型。赤霉     

利用小麦单染色体代换系研究赤霉病抗性和抑制毒素产生的基因

由赤霉菌引起的小麦赤霉病是小麦生产的主要病害之一,小麦赤霉病抗源十分贫乏,而且多数表现为多基因遗传,在小麦育种中较难应用。从小麦近缘属种中寻求赤霉病抗性基因并把它引入栽培品种中,有重要的学术意义和经济价值。本研究以来自抗病小麦材料PI481521和栽培小麦Langdon杂交得到的14个4倍体小麦单条染色体代换系为试验材料,进行室内赤霉病的抗性鉴定,同时用脱氧雪腐镰刀菌烯醇(DON)试剂盒来测定接种后籽粒中的毒素含量。表型鉴定结果表明,14个代换系的抗病性存在较大的差异,其中代换系LDN(PI481521-3A)和LDN(PI481521-7B)分别在感染小穗数和小穗感染百分率上与抗性亲本无显著性差异,不存在抗病性高于抗性亲本的类型;毒素含量分析表明,2个亲本的毒素含量没有显著差异,各代换系的毒素含量均高于抗性亲本PI481521、LDN(PI481521-1A)、LDN(PI481521-2A)及LDN(PI481521-6A)的毒素含量较高,与2个亲本存在显著差异。这一鉴定结果为下一步抗性基因和毒素基因的定位研究提供了基础材料,对赤霉病抗性指标进行相关性分析,发现小穗感染百分率与麦粒毒素含量呈显著正相关。因此,在田间进行抗赤霉病种质筛选及抗病育种后代选择时,可以小穗感染百分率作为衡量指标以简化操作程序。     

Characterization of Chinese wheat germplasm for resistance to Fusarium head blight at CIMMYT, Mexico

Fusarium head blight (FHB) poses a challenge for wheat breeders worldwide; there are limited sources of resistance and the genetic basis for resistance is not well understood. In the mid-1980s, a shuttle breeding and germplasm exchange program launched between CIMMYT-Mexico and China, enabled the incorporation of FHB resistance from Chinese bread wheat germplasm into CIMMYT wheat. Most of the Chinese wheat materials conserved in the CIMMYT germplasm bank had not been fully characterized for FHB reaction under Mexican environments, until 2009, when 491 Chinese bread wheat lines were evaluated in a FHB screening nursery in Mexico, and 304 (61.9 %) showed FHB indices below 10 %. Subsequent testing occurred in 2010 for plant height (PH), days to heading (DH), and leaf rust response. In 2012, 140 elite lines with good agronomic types were further evaluated for field FHB reaction and deoxynivalenol (DON) accumulation. Most of the tested lines showed good resistance: 116 (82.9 %) entries displayed FHB indices lower than 10 %, while 89 (63.6 %) had DON contents lower than 1.0 ppm. Significant negative correlations were observed between FHB traits (FHB index, DON content, and Fusarium damaged kernels) and PH, DH, and anther extrusion. A subset of 102 elite entries was selected for haplotyping using markers linked to 10 well known FHB quantitative trait loci (QTL). 57 % of the lines possessed the same 2DL QTL marker alleles as Wuhan 1 or CJ 9306, and 26.5 % had the same 3BS QTL allele as Sumai 3. The remaining known QTL were of low frequency. These materials, especially those with none of the above tested resistance QTL (26.5 %), could be used in breeding programs as new resistance sources possessing novel genes for FHB resistance and DON tolerance.     

Fusarium head blight-resistant wheat line 'Bizel' does not contain rye chromatin

Fusarium head blight (FHB), primarily caused by Fusarium graminearum in North America can result in significant losses in the yield and quality of wheat (Triticum aestivum L). Resistance sources have been largely limited to Chinese germplasm and, in particular, Sumai 3 or its derivatives. In recent years, resistance has been identified in Europe. Previous studies using the wheat line ‘Bizel’, developed in France, have shown that it has resistance to Fusarium head blight. Pedigree information shows that one of its progenitors is rye. This experiment was conducted to determine if ‘Bizel’ has rye chromatin, with the goal of developing a strategy for mapping FHB resistance genes. Two methods based on repetitive DNA sequences specific to rye were implemented. With both approaches, it was demonstrated that ‘Bizel’ does not contain rye chromatin. Consequently, wheat SSRs can be used to map ‘Bizel’ resistance genes for FHB.     

The potential of genomic‐assisted breeding to improve Fusarium head blight resistance in winter durum wheat

Durum wheat is the most important tetraploid wheat mainly used for semolina and pasta production, but is notorious for its high susceptibility to Fusarium head blight (FHB). Our objectives were to identify and characterize quantitative trait loci (QTL) in winter durum and to evaluate the potential of genomic approaches for the improvement of FHB resistance. Here, we employed an international panel of 170 winter and 14 spring durum lines, phenotyped for Fusarium culmorum resistance at five environments. Heading date, plant height and mean FHB severity showed significant genotypic variation with high heritabilities and FHB resistance was negatively correlated with both heading date and plant height. The dwarfing gene Rht‐B1 significantly affected FHB resistance and the genome‐wide association scan identified eight additional QTL affecting FHB resistance, explaining between 1% and 14% of the genotypic variation. A genome‐wide prediction approach yielded only a slightly improved predictive ability compared to marker‐assisted selection based on the four strongest QTL. In conclusion, FHB resistance in durum wheat is a highly quantitative trait and in breeding programmes may best be tackled by classical high‐throughput recurrent phenotypic selection that can be assisted by genomic prediction if marker profiles are available.