Evaluation of type I fusarium head blight resistance of wheat using non-deoxynivalenol-producing fungi

A series of experiments was conducted to determine whether type I resistance (resistance to initial infection) to fusarium head blight (FHB) in wheat could be assessed using fungal species/isolates that do not produce deoxynivalenol (DON), a mycotoxin critical to the spread of Fusarium graminearum in the wheat spike. It was shown that, while the non-toxin-producing species Microdochium nivale and M. majus could infect following spray inoculation of wheat spikes, they were unable to spread within the spike following point inoculation. However, although these species might reveal type I resistance, they are not highly pathogenic towards wheat. A nivalenol (NIV)-producing isolate of F. graminearum caused high levels of disease following spray inoculation, but spread only very slowly within the spike and rarely induced bleaching above the point of inoculation. It is proposed that spray inoculation with an appropriate, aggressive, non-DON-producing FHB pathogen may be used to characterize type I resistance to complement point inoculation with a DON-producing isolate to assess type II resistance (resistance to spread within the spike).     

A comparative assessment of potential components of partial disease resistance to <Emphasis Type="Italic">Fusarium</Emphasis> head blight using a detached leaf assay of wheat,barley and oats

The relative resistance of 15 winter barley, three winter wheat and three winter oat cultivars on the UK recommended list 2003 and two spring wheat cultivars on the Irish 2003 recommended list were evaluated using Microdochium nivale in detached leaf assays to further understand components of partial disease resistance (PDR) and Fusarium head blight (FHB) resistance across cereal species. Barley cultivars showed incubation periods comparable to, and latent periods longer than the most FHB resistant Irish and UK wheat cultivars evaluated. In addition, lesions on barley differed from those on wheat as they were not visibly chlorotic when placed over a light box until sporulation occurred, in contrast to wheat cultivars where chlorosis of the infected area occurred when lesions first developed. The pattern of delayed chlorosis of the infected leaf tissue and longer latent periods indicate that resistances are expressed in barley after the incubation period is observed, and that these temporarily arrest the development of mycelium and sporulation. Incubation periods were longer for oats compared to barley or wheat cultivars. However, oat cultivars differed from both wheat and barley in that mycelial growth was observed before obvious tissue damage was detected under macroscopic examination, indicating tolerance of infection rather than inhibition of pathogen development, and morphology of sporodochia differed, appearing less well developed and being much less abundant. Longer latent periods have previously been related to greater FHB resistance in wheat. The present results suggest the longer latent periods of barley and oat cultivars, than wheat, are likely to play a role in overall FHB resistance if under the same genetic control as PDR components expressed in the head. However the limited range of incubation and latent periods observed within barley and oat cultivars evaluated was in contrast with wheat where incubation and latent periods were shorter and more variable among genotypes. The significance of the various combinations of PDR components detected in the detached leaf assay as components of FHB resistance in each crop requires further investigation, particularly with regard to the apparent tolerance of infection in oats and necrosis in barley, after the incubation period is observed, associated with retardation of mycelial growth and sporulation.     

The contribution of ground-level inoculum of Fusarium culmorum to ear blight of winter wheat

In a series of field experiments in eastern England over 5 years, severe ear blight developed only in plots of winter wheat that were inoculated by spraying with conidial suspensions of Fusarium culmorum during anthesis, and in which infection was encouraged by rainfall or mist irrigation. In the absence of artificial inoculation of the ears, F. culmorum caused less extensive ear blight, and only where soil-surface inoculum was available after its application on infested plant material (colonized oat grains) up to 3–4 weeks before anthesis; it then developed most where significant rainfall occurred close to the time of anthesis. A warm, dry period following application of inoculum to the ground in late March contributed to increased infection of grain by F. culmorum , although ear blight was not increased. Ear infection therefore depended on adequate viable inoculum on infested plant debris within the crop, and conditions tending to favour brown foot rot development as well as, subsequently, rainfall and moist conditions during anthesis. These conditions did not occur together naturally during this period. Seedling infection by F. culmorum or Microdochium nivale made no significant contribution to ear blight. Inoculation of ears at anthesis with M. nivale or a locally obtained isolate of F. langsethiae did not produce ear blight symptoms. Possibilities for minimizing the availability of inoculum of F. culmorum and the implications for various options for ear-blight control are discussed.     

保湿时间对小麦赤霉病抗性鉴定结果的影响

为优化黄淮麦区小麦赤霉病抗性鉴定方法,于2020年在河南农业大学许昌校区试验田对4个小麦品种进行单花滴注赤霉病抗性鉴定,分析不同套袋保湿天数对病情严重度的影响,并利用与主效抗病基因Fhb1连锁的功能标记TaHRC-STS对其进行分子检测.结果显示:抗病品种'苏麦3号'宁麦9号'携带该基因,而感病品种不携带;套袋1～7...     

Biotic factors affecting the expression of partial resistance in pea to ascochyta blight in a detached stipule assay

The expression of partial resistance in pea to ascochyta blight (caused by Mycosphaerella pinodes) was studied in a detached stipule assay by quantifying two resistance components (fleck coalescence and lesion expansion) using the method of point inoculation of stipules. Factors determining optimal conditions for the observation of partial resistance are spore concentration, the age of the fungal culture prior to spore harvest and the pathogenicity of the isolate used for testing. Partial resistance was not expressed when spore concentration was high or when the selected isolate was aggressive. Furthermore, assessments of components of partial resistance were highly correlated with disease severity in a seedling test. A screening protocol was developed based on inoculations of detached stipules to study partial resistance in pea. To simplify the rating process, a more comprehensive disease rating scale which took into account fleck coalescence and lesion expansion was tested by screening a large number of genotypes.     

Visual disease and PCR assessment of stem base diseases in winter wheat

Stem base disease (eyespot, sharp eyespot and brown foot rot) was assessed visually and by the polymerase chain reaction (PCR) technique on single plants sampled at four-week intervals in two crops of winter wheat grown in the UK in 1992–3. PCR assays were conducted for Fusarium avenaceum , F. culmorum , both varieties of Microdochium nivale , both eyespot-causing species of Tapesia and Rhizoctonia cerealis . PCR diagnoses were compared with visual diagnoses at each time point. Eyespot was caused principally by T. acuformis (R-type) and developed rapidly late in the season. Visual diagnoses of eyespot were largely confirmed by PCR but T. acuformis was detected in many plants lacking eyespot symptoms. R. cerealis was detected at relatively low incidences on both sites, and sharp eyespot visual diagnoses did not correlate with the incidence of any of the pathogens assayed by PCR. Brown foot rot, caused principally by Microdochium nivale var . majus , accumulated earlier in the season than eyespot. Overall, visual diagnoses of stem base disease coincided poorly with PCR data until after growth stage (GS) 30.     

Enhanced overall resistance to Fusarium seedling blight and Fusarium head blight in transgenic wheat by co-expression of anti-fungal peptides

Introduction of alien genes into wheat has been proposed as a strategy to breed cultivars with improved resistance to Fusarium seedling blight (FSB) and Fusarium head blight (FHB). In this study, we co-transformed different anti-fungal peptides (AFPs) into an elite wheat cultivar Yangmai11. We identified the genetically stable transgenic wheat lines carrying single or multiple genes by PCR, qRT-PCR and Southern blot analyses. Transgenic wheat lines 451 and 513 expressing two AFPs displayed a consistent, significantly improved overall resistance to FSB and FHB, whereas only FHB resistance was observed from other lines. Furthermore, crude proteins extracted from the lines 451 and 513 showed a clear inhibitory activity against F. graminearum in vitro. Taken together, it was essential to properly combine and express AFPs in transgenic wheat in order to obtain an improved overall resistance to Fusarium pathogens.     

Towards the Development of a Novel In Vitro Strategy for Early Screening of Fusarium Ear Blight Resistance in Adult Winter Wheat Plants

A novel in vitro bioassay is described for screening Fusarium ear blight (FEB) resistance in adult winter wheat plants. Seven winter wheat cultivars were assessed for components of partial disease resistance as 28 day-old detached leaf segments in the laboratory using isolates of Microdochium nivale var. nivale and M. nivale var. majus. Results were compared with disease data obtained at anthesis using the same cultivars as whole plants and the same isolates under glasshouse conditions. Significant cultivar differences were observed using detached leaves, with cv. Avalon (a Fusarium culmorum ear susceptible cultivar) having the shortest leaf incubation period, greatest leaf lesion development and shortest leaf latent period compared to cv. Spark (a Fusarium culmorum ear resistant cultivar), which had the longest leaf incubation period, least leaf lesion development and longest leaf latent period. Using whole plants, cv. Avalon had the shortest ear incubation period and greatest ear disease severity, whilst cv. Spark had the longest incubation period and least ear disease severity. Overall, cultivars of intermediate F. culmorum ear resistance expressed intermediate responses to M. nivale isolates, using both detached leaves and whole plants. Significant correlations were found with ear disease severity and ear incubation period in whole plants and components of partial disease resistance in detached leaves, with significant correlations obtained between leaf incubation period and ear disease parameters using the M. nivale var. nivale isolate. In addition, leaf latent period and leaf lesion size showed significant correlations with whole plant reactions using M. nivale var. nivale and var. majus isolates. The in vitro screening of cultivars as detached leaves using M. nivale isolates may offer a real possibility of a rapid bioassay for the early screening of FEB resistance in wheat and other cereals.     

不同杀菌剂对小麦赤霉病和叶锈病的防治效果

为明确不同杀菌剂防治小麦赤霉病和叶锈病的效果,在大田条件下进行了不同杀菌剂对这两种病害的防治试验.对小麦赤霉病的防效结果表明:25％氰烯菌酯SC、20％叶菌唑SC、48％氰烯·戊唑醇SC和200 g/L氟唑菌酰羟胺SC的防效较好,防效为83.54％～88.92％;其次为400 g/L戊唑·咪鲜胺EW和430 g/L戊唑...     

54个小麦品种(系)抗赤霉病评价与农艺性状调查

为获得抗赤霉病且农艺性状较好的小麦种质资源, 加快小麦抗赤霉病育种进程, 采用人工接种鉴定和田间试验的方法, 于2019年-2021年, 对54个小麦品种(系)进行了赤霉病抗性鉴定与农艺性状调查。结果表明, 供试小麦品种(系)存在赤霉病抗性差异, 筛选出‘华皖麦24’‘宛1204’和‘皖垦麦1708’等9个两年表现稳定的中抗品种(系), 占总数的16.67%; 农艺性状调查结果显示, 不同小麦品种(系)的农艺性状间存在显著性差异, 抗病组品种(系)的平均变异系数小于感病组品种(系)。其中, ‘宛1204’和‘徐麦17252’中抗赤霉病, 且综合农艺性状较好, 可以作为抗赤霉病育种的抗源。     

Evaluation and characterization of resistance to fusarium head blight caused by Fusarium culmorum in UK winter wheat cultivars

Fusarium head blight (FHB) resistance of 50 cultivars from the National List of winter wheat cultivars approved for sale (or were undergoing trails for approval in 2003) in the UK was compared with 21 reference cultivars from continental Europe which had previously been characterized for resistance. Only three UK National List cultivars (Soissons, Spark and Vector) had stable resistance over trial sites that was significantly greater than that of the FHB susceptible cultivar Wizard. In addition, under moderate disease pressure, 21 of the National List cultivars had levels of the trichothecene mycotoxin deoxynivalenol (DON) above the proposed European Union limit of 1·25 ppm in grain. Surveys show that levels of FHB and DON in the UK crop are currently very low, however, should disease pressure increase for any reason, then an improvement in the overall levels of FHB resistance of UK winter wheat germplasm will be required. In order to infer the origin of resistance and to identify potentially novel resistance, allele sizes of microsatellite (simple sequence repeat, SSR) markers linked to quantitative trait loci (QTL) for FHB resistance were compared between the test cultivars and known, characterized resistance sources. The major FHB resistance QTL from the Chinese cv. Sumai-3 (3BS, 5A and 6B), the Romanian cv. Fundulea F201R (1B and 5A) and the French cv. Renan (5AL) were screened with 17 SSRs. No National List cultivar had haplotypes similar to any of these QTL. However, the highly resistant German reference cultivar Petrus had an identical haplotype to cv. Fundulea F201R on 1B indicating that this cultivar has an allelic FHB resistance QTL at that location.     

Spatial variability of fusarium head blight pathogens and associated mycotoxins in wheat crops

The spatial pattern of Fusarium‐infected kernels and their mycotoxin contamination was studied in four wheat fields in Germany using geo‐referenced sampling grids (12–15 × 20–30 m, 28–30 samples per field) at harvest. For each sample, frequency of Fusarium‐infected kernels and spectrum of species were assessed microbiologically; mycotoxin contents were determined by HPLC‐MS/MS analysis. Spatial variability of pathogens and mycotoxins was analysed using various parameters including Spatial Analysis by Distance IndicEs (sadie^® ). Microdochium majus, the most frequent head blight pathogen in 1998, was less frequent in 1999 and could not be detected in kernels from two fields in 2004. Fusarium avenaceum, F. graminearum and F. poae were the most frequent Fusarium species, with 7–8 species per field. The frequency of Fusarium‐infected kernels was 3–15% and the incidence of species showed considerable within‐field variability. Spatial patterns varied among Fusarium species as well as from field to field. Although pathogens and mycotoxin were often distributed randomly in the field, F. avenaceum, F. graminearum, F. poae, F. sporotrichioides, F. tricinctum and the mycotoxin moniliformin had an aggregated pattern in at least one field. Patterns are discussed in relation to spread of Fusarium species depending on inoculum sources, spore type, kind of dispersal, availability of susceptible host tissue and micro‐climate. Sampling of wheat fields for representative assessment of mycotoxins is complicated by random patterns of Fusarium‐infected kernels, especially where the frequency of infection is small.     

Fusarium head blight and mycotoxin contamination of wheat,a review

Summary An infection of bread wheat by fusarium head blight contaminates the crop with mycotoxins, particularly deoxynivalenol (DON) and nivalenol (NIV). The toxicity and natural occurrence of these mycotoxins in wheat are reviewed. Based on 8 years data of fusarium head blight epidemics of wheat in the Netherlands, DON contamination of the grain was estimated. Fusarium head blight ratings averaged an infection of 1.7% of all spikelets; estimates for DON contamination averaged 0.9 mg kg^–1. Taking a guideline level for DON in uncleaned bread wheat of 2 mg kg^–1, in 1979 and 1982 a wheat crop was produced with estimated DON concentrations above the limit of tolerance. Human and animal exposure to mycotoxins in the Netherlands appears to be small but chronic. The information presented in this paper illustrates the need for an annual evaluation of the crop for fusarium head blight incidence and mycotoxin content, and the necessity of fusarium head blight resistant wheat cultivars.Samenvatting Aaraantasting van tarwe doorFusarium culmorum enFusarium graminearum leidt tot vorming van mycotoxinen in het graan, waarvan deoxynivalenol (DON) en nivalenol (NIV) de belangrijkste toxinen zijn. In dit artikel wordt een overzicht gegeven van de toxicologische aspecten, en het voorkomen van deze toxinen in tarwe. Informatie over DON en NIV in tarwe in West-Europa is schaars. Gebaseerd op gegevens vanFusarium epidemieën in de jaren 1979–1986 wordt een schatting gegeven van de concentratie DON in Nederlandse tarwe. Rekening houdend met de herkomst en verwerking van tarwe, blijken zowel in dierlijk als menselijk voedsel lage concentraties DON chronisch voor te komen. Op basis van een maximaal toelaatbare dagelijkse dosis DON van 3 g kg^–1 lichaamsgewicht is de schatting van de dagelijkse opname van DON in het jaar volgend op de oogst van 1982 net op de grens. Zowel een jaarlijkse inventarisatie vanFusarium aantasting en DON besmetting van het graan, als de ontwikkeling vanFusarium-resistente rassen zijn noodzakelijk.     

黄淮冬麦区小麦主栽品种赤霉病综合抗性鉴定及其FHB1抗性基因检测

本研究明确了黄淮冬麦区主栽小麦品种对赤霉病的抗侵染、抗扩展、抗毒素积累和抗籽粒侵染能力以及几种抗性之间的相互关系,并检测了各品种是否带有FHB1抗性基因,旨在为该区小麦赤霉病抗性鉴定评价、抗性品种培育和利用提供科学依据。小麦赤霉病综合抗性鉴定结果表明:22个黄淮冬麦区主栽品种中,有20个为感病品种,只有‘郑麦9023’和‘西农979’为中感品种,所有品种均不含FHB1基因;长江中下游麦区的9个品种中,‘扬麦17’和‘宁麦9号’等6个品种表现中抗,‘扬麦23’表现中感,‘苏麦3号’和‘扬麦21’表现抗,‘扬麦14’‘扬麦17’和‘扬麦23’不含有FHB1基因,其他品种均含FHB1基因。小麦品种的抗扩展能力与抗侵染能力无显著相关性(r=0.27,P0.05);两种接种条件下小麦品种的病粒率与抗脱氧雪腐镰刀菌烯醇(DON)毒素积累能力呈极显著正相关(r=0.86,P0.01;r=0.88,P0.01);单小花滴注法接种条件下,小麦品种的平均病级与病粒率和籽粒中DON含量都呈极显著正相关(r=0.71,P0.01;r=0.81,P0.01);喷雾接种条件下,小麦品种的病小穗率与平均病级、病粒率、籽粒中DON含量和ZEN含量都呈极显著正相关(r=0.78,P0.01;r=0.73,P0.01;r=0.78,P0.01;r=0.63,P0.01)。在毒素积累抗性上,DON含量和ZEN含量呈极显著正相关(r=0.70,P0.01)。在目前黄淮冬麦区没有中抗品种的情况下,可以增加育种和鉴定目标为抗籽粒侵染和抗毒素积累的品种,在小麦品种推广过程中加以运用,可以达到较好的效果。     

江苏小麦赤霉病综合防控关键技术研究

近年来气候变暖、秸秆还田和赤霉病菌对多菌灵的抗性上升使江苏省小麦赤霉病流行频率提高。本研究通过田间小区试验,对小麦赤霉病的综合防控关键技术进行了比较。试验结果表明,目前赤霉病菌对多菌灵抗药性频率已达60%以上,多菌灵的防效明显下降,低于60%。研究明确了赤霉病的防控适期和防治次数,对淮南、淮北主要小麦品种进行赤霉病自然发病鉴定,并阐述了品种抗性和药剂防治间的互作效应。研究结果揭示,选育推广对小麦赤霉病具有抗性的品种是小麦赤霉病防控的基础,把握适期于小麦扬花期施用非多菌灵类的戊唑醇、氰烯菌酯、丙硫菌唑等其他杀菌剂可有效控制病害的发生。     

麦类赤霉病研究进展

由镰刀菌引起的麦类赤霉病是大麦和小麦最重要的病害之一。本文综述了近年来在麦类赤霉病致病病原菌种及分子鉴定、病原菌产毒及毒素化学型分子检测、大、小麦赤霉病病原菌种群结构、病原菌抗药性及新药剂研发、病害流行预测和品种抗病性研究等方面的进展。     

河南省首次发现梨孢镰刀菌引起的小麦赤霉病

2015年从河南省田间小麦赤霉病病穗上分离得到一种生长速度较慢的镰刀菌, 通过形态学和分子鉴定明确其分类地位, 通过田间单小花滴注法和喷雾法接种测定其致病力, 并通过高效液相色谱串联质谱分析对麦穗中的毒素种类进行测定, 明确其产毒特征?结果表明:分离得到的8个菌株均为梨孢镰刀菌, 在马铃薯葡萄糖琼脂(PDA)培养基上为白色菌落, 菌落底部产生少量红色色素, 平均生长速度为13.3 mm/d; 小型分生孢子为椭球形葡萄状, 平均大小为7.1 μm×5.8 μm, 未见大型分生孢子和厚垣孢子; 致病力弱, 且不侵染穗轴, 单小花滴注法接种条件下平均病级为0.1, 喷雾法接种条件下平均病小穗率为6.5%; 供试的8个镰刀菌菌株均不产生T-2和HT-2毒素, 均产生雪腐镰刀菌烯醇(NIV)毒素, NIV毒素含量水平为371.74~5 282.80 μg/kg, 其中3个菌株产生少量脱氧雪腐镰刀菌烯醇(DON)毒素(86.13~227.22 μg/kg)?     

A novel QTL on chromosome 5AL of Yangmai 158 increases resistance to Fusarium head blight in wheat

Fusarium head blight (FHB) of wheat is a destructive fungal disease worldwide and has become more severe over the last two decades. Development of FHB resistant wheat varieties is the most effective way to manage FHB. The middle and lower reaches of the Yangtze River are the traditional FHB epidemic areas in China. The landraces and germplasms with resistance to FHB originating from this region were used to identity FHB resistance quantitative trait loci (QTLs). Yangmai 158 and Ningmai 9 are the most popular varieties for commercial wheat production in this region and both have moderate FHB resistance. A high-density genetic map was constructed using 282 recombinant inbred lines (RILs) from a cross between Ningmai 9 and Yangmai 158. Ten QTLs related to Type II FHB resistance were identified, and QFhb-3B.1 and QFhb-5A were stably detected across all environments. Based on position alignment, QFhb-3B.1 from Ningmai 9 is likely to be Fhb1 and QFhb-5A from Yangmai 158 is a novel QTL not previously described. A competitive allele-specific PCR (KASP) marker closely linked to QFhb-5A was developed and could be used for marker-assisted selection. Distribution of QFhb-5A was tested with numerous accessions from a widespread core collection. The results suggest that QFhb-5A has undergone both natural and artificial selection. Some RILs with both Fhb1 and QFhb-5A presented better FHB resistance than the parents and could be used in FHB resistance breeding.     

湖北省小麦品种(系)对赤霉病、条锈病、白粉病和纹枯病的抗性评价

为了解湖北省小麦品种(系)的抗病性水平,对2001年以来湖北省审定的46个小麦品种和在湖北省进行区域试验的447份小麦品系进行赤霉病、条锈病、白粉病和纹枯病等4种主要病害的抗病性评价。结果表明:1)参试品系中有1份材料对赤霉病表现高抗,未发现对纹枯病表现高抗或免疫的材料;对赤霉病和纹枯病的平均抗性评价分值分别为14.30和3.49,介于中感和高感之间;对条锈病和白粉病的平均抗性评价分值分别为13.43和8.34,介于中抗和中感之间。2)审定品种的综合抗性水平不高,对条锈病的抗性评价分值为12.47,介于中抗和中感之间,对其他3种病害的抗性介于中感和高感之间;审定品种的单产呈增加趋势,株高在不断降低,生育期相应延长,综合抗病性也在增强。3)审定品种的综合抗病性与对条锈病抗性的相关系数最高,为0.738;对纹枯病的抗性与株高呈显著正相关,与单产呈显著负相关;对赤霉病的抗性与株高无显著相关。鉴于此,湖北省需加强抗病育种力度,同时应充分做好小麦病害的防控。