陕西省小麦茎基腐病病原菌鉴定及其致病力分析

为明确陕西省小麦茎基腐病病原菌的组成及其致病力,于2019年小麦灌浆期在陕西省宝鸡市、咸阳市、西安市和渭南市共63个采样点采集具有茎基腐病典型症状的病株,对其进行组织分离,结合培养性状和形态学特征,以及利用ITS和EF-1α序列分析鉴定分离菌株所属类群,并对不同病原菌进行致病力分析。结果表明：共分离到224株菌株,基于形态学特征和分子生物学鉴定结果,其中201株菌株鉴定为假禾谷镰刀菌Fusarium pseudograminearum,3株菌株鉴定为禾谷镰刀菌F. graminearum,14株菌株鉴定为三线镰刀菌F. tricinctum,6株菌株鉴定为层出镰刀菌F. proliferatum,其中假禾谷镰刀菌占总分离菌株的89.73%,是陕西省小麦茎基腐病的优势病原菌。不同种的镰刀菌对小麦植株均有一定的致病性,但假禾谷镰刀菌的致病力最强,而且分离自不同地区或者同一地区的假禾谷镰刀菌株间的致病力也存在一定分化。     

北京市及河北省小麦赤霉病菌群体遗传结构及生物学特性

本文分析了北京市与河北省小麦赤霉病菌群体遗传结构以及基础生物学特性。结果表明所有菌株均为禾谷镰刀菌(Fusarium graminearum),属于一个大的单一群体,群体内具有较高的遗传多样性。毒素化学型测定表明,北京与河北地区小麦真菌毒素污染的主要风险为DON与15ADON毒素。表型测定显示,与F.asiaticum群体相比,F.graminearum具有较高的产孢能力,而生长速率和产毒能力较低。该群体对主要杀菌剂多菌灵、戊唑醇和氰烯菌酯均无抗药性。     

河南省假禾谷镰刀菌对咯菌腈的敏感性

由假禾谷镰刀菌Fusarium pseudograminearum引起的小麦茎基腐病已成为重要的土传病害,并且影响小麦的品质和产量。为了明确中国河南省假禾谷镰刀菌对咯菌腈的敏感性,采用菌丝生长速率法测定了咯菌腈对2019年从河南省6个地市分离的105株假禾谷镰刀菌F. pseudograminearum 的敏感性,通过最小显著差异法(LSD)和SPSS聚类方法对测定结果进行了分析,并测定了假禾谷镰刀菌对多菌灵和戊唑醇的敏感性,分析了咯菌腈与这两种杀菌剂毒力的相关性。结果表明:咯菌腈对供试菌株的最低抑制浓度(MIC)为0.2400 μg/mL。敏感性频率分布图显示,EC₅₀值范围在0.0027~0.0470 μg/mL,敏感性差异达17.41倍;敏感性频率分布为连续单峰曲线,平均EC₅₀值为(0.0263 ± 0.0101) μg/mL,可作为假禾谷镰刀菌对咯菌腈的敏感性基线。方差分析结果显示,不同县市的小麦假禾谷镰刀菌对咯菌腈的敏感性差异较大,EC₅₀值变化范围为0.0150~0.0335 μg/mL,其中咯菌腈对郑州中牟的敏感性最低和最高菌株的EC₅₀值相差16.78倍。聚类分析结果显示,河南省小麦茎基腐病菌菌株对咯菌腈敏感性差异与菌株的地理来源无明显关联性。多菌灵和戊唑醇对病菌的平均EC₅₀值分别为 (0.7881 ± 0.3153) μg/mL和(0.0886 ± 0.1453) μg/mL。病菌对咯菌腈与其对多菌灵和戊唑醇的敏感性之间无明显相关性。温室防效结果显示,用咯菌腈悬浮种衣剂对小麦进行拌种处理,2020年 (咯菌腈有效成分为75.0 μg/g)对小麦茎基腐病的防治效果可达58.00%,2021年 (咯菌腈有效成分为50.0 μg/g)的防治效果可达到63.69%。本研究结果可为咯菌腈在小麦茎基腐病防治中的合理使用提供依据,为病原菌对药剂的敏感性监测提供参考。     

江苏省水稻赤霉病病原菌分离鉴定与致病力分析

为明确江苏省水稻赤霉病的病原菌组成及致病特征,于2018—2019年从江苏省13个市41个县区采集341份水稻样品,采用组织分离法对病原菌进行分离纯化,基于翻译延伸因子（translationelongation factor-1α,TEF-1α）序列分析对分离菌株进行鉴定,通过TRI11基因序列鉴定及产毒力测定对其产毒化学型进行分析,并按照柯赫氏法则对其致病力进行验证。结果显示,从水稻样品中共分离获得病原菌392株,其中亚洲镰刀菌Fusarium asiaticum为385株,禾谷镰刀菌F. graminearum为7株。亚洲镰刀菌分为3-乙酰化脱氧雪腐镰刀菌烯醇（3-acetyldeoxynivalenol,3ADON）化学型和雪腐镰刀菌烯醇（nivalenol,NIV）化学型菌株,分别占亚洲镰刀菌总菌株数的 66.8% 和 33.2%;禾谷镰刀菌均为（15-acetyldeoxynivalenol,15ADON）化学型。产3ADON的亚洲镰刀菌在全省范围内为优势群体,而产15ADON的禾谷镰刀菌仅在淮北地区被发现;产NIV的亚洲镰刀菌对水稻的致病性要显著高于产3ADON的亚洲镰刀菌。不同产毒化学型亚洲镰刀菌对水稻均有一定致病性,但NIV化学型亚洲镰刀菌对水稻的致病力最强。     

福建小麦赤霉病的致病菌种及致病型的研究

 1978~1981年采集54个县市小麦病穗标样,单孢分离获1081菌株。经室内外综合鉴定明确本省引起小麦赤霉病的致病病原有禾谷镰刀菌(Fusarium gra-minearum Schwabe),雪腐镰刀菌[F.nival (Fr.) Ces.],本色镰刀菌(F.concolor Rg.),弯角镰刀菌(F.camptoceras Wr.&Rg.),串珠镰刀菌(F.moniliforme Sheld),硫色镰刀菌(F.sulphureum schecht Sacc.)和燕麦镰刀菌草类变种(F.avenaceum var.herberum)。其中禾谷镰刀菌分离频率最高,占绝对优势,分布遍及全省。7个种致病力测定,F=10.48,F> 0.01,不同种致病力差异极显著;禾谷镰刀菌、弯角镰刀菌和硫色镰刀菌致病力最强。     

2019—2020年河南省小麦茎基腐病病原菌鉴定及致病力测定

为监测小麦茎基腐病病原菌的变化,2019—2020年自河南省安阳、濮阳和鹤壁等17个市129个采样点采集小麦茎基腐病病株样品并分离病原菌,对所有分离物进行形态学鉴定,利用特异性引物、ITS和EF-1α基因序列进行分子生物学鉴定,并于室内对优势病原菌菌株进行致病力测定。结果表明,共分离得到892株镰孢菌Fusarium分离物,所得分离物中假禾谷镰孢F. pseudograminearum共851株,所占比例为95.41%,为优势种;禾谷镰孢F. graminearum共16株,所占比例为1.79%。除信阳市外,其他16个市优势病原菌均为假禾谷镰孢。不同假禾谷镰孢菌株存在明显的致病力分化,但多数为强致病力菌株。     

温度对假禾谷镰刀菌生长、侵染及茎基腐病发生的影响

 研究温度对小麦茎基腐病发生的影响,可为病害的发生规律和生态防控措施的研究提供依据。本研究测定了温度对假禾谷镰刀菌菌丝生长、孢子萌发、对寄主小麦侵染以及在植株体内扩展的影响,结果表明,假禾谷镰刀菌菌丝生长的温度范围为4℃~30℃,其中28℃最适于菌丝的生长,孢子萌发的温度范围为4℃~35℃,其中12℃~30℃较适宜分生孢子萌发,17℃~28℃为假禾谷镰刀菌侵染小麦的适宜温度范围,假禾谷镰刀菌在小麦植株体内扩展的适宜温度范围在22℃~30℃;通过不同温度培养试验以及田间小麦不同生育期接种试验测定温度对小麦茎基腐病发生的影响,结果表明,播种期、起身期接种的小麦茎基腐病发生高于越冬苗期接种处理,而此期的温度较越冬苗期利于假禾谷镰刀菌的侵染和小麦茎基腐病的发生。     

长江中下游地区亚洲镰刀菌NX-2毒素群体的检测

由禾谷镰刀菌复合种(Fusarium graminearum species complex,FGSC)引起的麦类赤霉病,是农业生产上的重要病害。为明确中国长江中下游冬小麦主产区小麦赤霉病菌种的构成及其地理分布,对2008年从江苏、浙江和湖北3省采集的656株小麦赤霉病菌株进行了分类鉴定。结果显示,其中558个菌株为亚洲镰刀菌(Fusarium asiaticum),98个菌株为禾谷镰刀菌(Fusarium graminearum sensu stricto),表明中国长江中下游冬小麦主产区小麦赤霉病的主要致病菌是亚洲镰刀菌。选择亚洲镰刀菌(F.asiaticum)为研究对象,通过PCR-RFLP的方法对其进行产NX-2毒素菌株的检测。结果没有检测到产NX-2毒素菌株,表明中国长江中下游冬小麦主产区并未出现NX-2毒素群体。本研究旨在了解NX-2毒素群体在中国长江中下游地区的地理分布,为进一步研究麦类赤霉病菌群体遗传多样性和演化趋势奠定基础,为麦类赤霉病的防治和毒素污染的控制提供理论依据。     

玉米茎腐病菌毒素致病力初报

通过提取玉米茎腐病菌毒素粗提液,证实玉米茎腐病原菌(镰刀菌和腐霉菌为主)在镰刀菌毒素培养液、查氏培养液和普通培养液中,能产生和玉米小斑病菌毒素(简称HM毒素,下同)类似的致病毒素。该物质能抑制种子根的生长。接种在玉米叶片上能产生典型的萎蔫枯死斑;用上述3种培养液培养病原菌,产生的毒素致病力差异不显著;不同类型病原菌产生的毒素致病力和同一类型病原菌不同菌株产生的毒素致病力差异都极显著。玉米品系对茎腐病原菌产生的毒素抗病性差异也极显著。     

山东玉米茎基腐病病原菌的初步研究

 1979~1983年,从山东省主要病区采集的玉米茎基腐病病株分离得到的菌种有腐霉菌、禾谷镰刀菌、串珠镰刀菌、尖孢镰刀菌以及其它真菌。这些菌种经室内、外多次土壤接种试验表明,只有瓜果腐霉菌Pythium aphanidermatum(Edson) Fitzpatrick和禾谷镰刀菌Fusarium graminearum Schw.两种,对玉米苗期和成株期具有较高的致病力。如两种菌混合接种,则有加重发病的趋势。因此,可以初步认为玉米茎基腐病是以瓜果腐霉菌为主,与禾谷镰刀菌复合侵染而引起的玉米病害。     

Comparison of genetic diversity and pathogenicity of fusarium head blight pathogens from China and Europe by SSCP and seedling assays on wheat

The genetic diversity and pathogenicity of isolates of Fusarium graminearum and F. asiaticum isolated from wheat heads in China were examined and compared with those of isolates of F. graminearum , F. asiaticum and F. meridionale from Europe, USA and Nepal. Genetic diversity was assessed by SSCP (single strand conformation polymorphism) and AFLP (amplified fragment length polymorphism) analysis and by molecular chemotyping. SSCP analysis of the Fg16F/Fg16R PCR amplicon differentiated F. graminearum , F. asiaticum and F. meridionale and revealed three haplotypes among sequence-characterized amplified region (SCAR) type 1 F. graminearum isolates. AFLP analysis showed a high level of genetic diversity and clustered the majority of Chinese isolates in one group along with other isolates of Asian origin. The second cluster contained F. graminearum isolates from China, Europe and the USA. Of the Chinese isolates, 79% were F. asiaticum and 81% of these were of the 3-AcDON chemotype, with only 9·5% of either chemotype 15-AcDON or NIV. All the Chinese and USA isolates of F. graminearum were 15-AcDON, whereas among the isolates from Europe, 21% were NIV and 8% were 3-AcDON chemotype. No evidence was found for possible differences in aggressiveness between F. graminearum and F. asiaticum . Highly aggressive isolates were present in each region and no evidence was found for any association between aggressiveness and geographical origin or chemotype among the isolates examined. No difference was observed in pathogenicity towards wheat seedlings between Chinese isolates and those from Europe, the USA or Nepal.     

小麦赤霉病流行区镰刀菌致病种及毒素化学型分析

 为从分子水平上明确小麦赤霉病流行区镰刀菌致病种及其B 型毒素化学型的分布特点,本研究对2008 年度采自四川、重庆、湖北、安徽、江苏、河南6 省33 县市的赤霉病穗上分离获得的433 个镰刀菌单孢菌株,用鉴定种和鉴定B 型毒素化学型的特异性引物进行了鉴定分析。致病种检测结果表明,四川病穗检测到Fusarium asiaticum、F. graminearum、F.avenaceum 和F. meridionale 4 个镰刀菌种,重庆、湖北、安徽和江苏病穗检测到F. asiaticum 和F. graminearum 2 个种,河南病穗仅检测到F. graminearum 1 个种。毒素化学型检测结果表明,Nivalenol(NIV)是四川和重庆镰刀菌主要毒素化学型,Deoxynivalenol(DON)是湖北、河南、安徽和江苏镰刀菌主要毒素化学型;将DON 化学型进一步划分为3-AcDON 和15-AcDON 显示,四川、湖北、江苏镰刀菌毒素以3-AcDON 为主,安徽镰刀菌毒素为3-AcDON 和15-AcDON 两者参半,河南镰刀菌全部产生15-AcDON。结果揭示,F. asiaticum 是四川、重庆、湖北和江苏等赤霉病流行麦区的优势致病种;镰刀菌产生的DON 和NIV 毒素化学型存在明显的地域分布,长江上游的麦区以NIV 为优势化学型,长江中下游麦区以DON 为优势化学型;镰刀菌致病种与DON 毒素的化学型间存在一定关系。     

Mycelial compatibility reactions of Australian Fusarium graminearum and F. pseudograminearum isolates compared with AFLP groupings

Using the mycelial reactions of 435 combinations of 14 Fusarium pseudograminearum and 15 F. graminearum isolates, it was demonstrated for the first time that mycelial reactions/barrage formation cannot be clearly used to distinguish F. graminearum and F. pseudograminearum. Mutually compatible isolates produced very different patterns of compatibility with other isolates. However, about 60% of pairings between F. graminearum and F. pseudograminearum isolates were compatible, indicating common ancestry. The Mantel tests used to determine any possible associations between mycelial compatibility reactions and AFLP genotypic diversity data revealed no association between the two systems in either species. In addition, no association was found between mycelial compatibility reactions and sexual reproduction in the two species. Implications of the higher frequency of mycelial compatibility reactions observed in F. pseudograminearum than in F. graminearum are discussed.     

大豆根腐病原镰孢菌种群多样性DGGE分析及其致病性研究

 应用变性梯度凝胶电泳(DGGE)技术以及主成分分析方法,结合植物病原菌传统分离、鉴定及致病力测定,检测位于黑龙江省海伦市大豆连作定位试验区根腐病原镰孢菌的种群构成及其致病力。采用真菌传统分离和鉴定方法共确定镰孢菌6个种,包括燕麦镰孢Fusarium avenaceum、木贼镰孢F. equiseti、禾谷镰孢F. graminearum、腐皮镰孢F. solani、尖镰孢F. oxysporum和拟轮枝镰孢F. verticillioides。其中,尖镰孢菌的分离频率最高,为56.7%。结合DGGE条带克隆测序及系统发育分析鉴定出8种镰孢菌,较传统方法增加了黄色镰孢F. culmorum和一个尖镰孢近似种。同时,DGGE图谱中尖镰孢所占百分比下降为37.4%。采用主成分分析方法将大豆生育指标相关的多种变量进行降维分析,得到第一主成分贡献值为91.2%。按照贡献值的正负结果,将30株镰孢菌分为致病和非致病类群。第二主成分贡献值为5.8%,根据其正负值可以矫正被错误估计的致病能力。综合所有研究结果,该定位试验区大豆根腐病主要病原镰孢菌为尖镰孢、禾谷镰孢和燕麦镰孢,且以尖镰孢菌为优势病原菌。     

Genetic diversity of Australian Fusarium graminearum and F. pseudograminearum

Genotypic diversity in Fusarium pseudograminearum and F. graminearum from Australia and the relationship between diversity and pathogen aggressiveness for head blight and/or crown rot of wheat were examined. Amplified fragment length polymorphism (AFLP) analysis revealed a high level of genotypic diversity within each species. Sixty-three of the 149 AFLP loci were significantly different between the two species and 70 of 72 F. pseudograminearum and 56 of 59 F. graminearum isolates had distinct haplotypes. When head blight and crown rot severity data from a recently published work on isolates representing the entire range of aggressiveness were used, only the genotypic diversity of F. pseudograminearum was significantly associated with its aggressiveness for the two diseases. Cluster analyses clearly demonstrated the polyphyletic structures that exist in both pathogen populations. The spatial diversity within F. graminearum was high within a single field, while frequent gene flow ( N _m ∼ 14) and a low fixation index ( G _st = 0·03) were recorded among F. pseudograminearum isolates from the adjacent states of New South Wales and Queensland. The differences in population structure between the heterothallic F. pseudograminearum (teleomorph G. coronicola ) and the homothallic F. graminearum (teleomorph G. zeae ) were not as pronounced as expected given their contrasting mating systems. Neither species was panmictic or strictly clonal. This points to sexual recombination in F. pseudograminearum , suggesting that ascospores of G. coronicola may also play a role in its biology and epidemiology.     

Effect of temperature on head blight of wheat caused by Fusarium culmorum and F. graminearum

The effect of small temperature differentials (16 vs. 20°C) on the pathogenicity of deoxynivalenol producing single isolates of Fusarium culmorum and F. graminearum and on the fusarium head blight (FHB) response of eight wheat cultivars was examined. Fusarium culmorum inoculation caused greater visual disease symptoms at 20°C than at 16°C, both overall and on an individual cultivar basis (overall AUDPC = 13·5 and 9·6, respectively) ( P  < 0·05). In contrast, F. graminearum inoculation caused greater overall visual disease symptoms at 16°C than at 20°C, both overall and at the individual cultivar level (overall AUDPC = 12·8 and 10·9, respectively) ( P  < 0·05). Results showed both F. culmorum and F. graminearum inoculations caused a greater loss in yield at 20°C (54·3 and 46·9% relative 1000-grain weight, respectively) compared with 16°C (73·3 and 66·9% relative 1000-grain weight, respectively) ( P  < 0·05). Fusarium culmorum -inoculated heads contained similar amounts of fungal DNA at both 16 and 20°C (1·9 and 1·7 ng mg⁻¹ of plant material, respectively) (not significant), while for F. graminearum inoculation, plants contained higher amounts of fungal DNA at 20°C (2·0 and 1·0 ng mg⁻¹ of plant material, respectively) ( P  < 0·05). Overall, there was a significant negative correlation between AUDPC and percentage relative 1000-grain weight at both 16 and 20°C ( r  =−0·693 and −0·794, respectively, P  < 0·01).     

Molecular characterization of the Fusarium graminearum species complex in Eastern China

Members of the Fusarium graminearum species complex (FGSC) cause Fusarium head blight in small cereal grains all over the world. To determine the species and trichothecene chemotype composition and population structure of FGSC in Jiangsu and Anhui provinces, an area where epidemics occur regularly, 891 isolates were collected in two consecutive years (2011 and 2012) and characterized with species- and chemotype-specific polymerase chain reaction. Of the 891 isolates typed, 83 were F. graminearum sensu stricto (s. str.) and 808 were F. asiaticum. All 83 F. graminearum s. str. isolates were of a 3ADON (26.51 %) or 15ADON (73.49 %) type, while F. asiaticum isolates included 696 3ADON producers, 46 15ADON producers, and 66 NIV producers. Eight variable number tandem repeat (VNTR) markers were tested on a representative 384 F. asiaticum isolates from 55 sampling sites. VNTR analysis showed high gene diversity and genotypic diversity but low linkage disequilibrium in both populations Fg2011 and Fg2012 grouped based on the year of collection. Low genetic differentiation (F _ST ? =?0.026) and high gene flow (N _m ?=?15.13) was observed between the two populations and among subpopulations within the same population (N _m ?=?3.53 to 48.37), indicating that few influence of temporal and spatial variations on population differentiation in this area. Similar result was obtained from 3ADON, 15ADON and NIV populations or carbendazim resistant and sensitive populations, indicating that chemotype of Fusarium isolates and carbendazim application had minor influence on population subdivision.     

Molecular characterization of the Fusarium graminearum species complex in Japan

Members of the Fusarium graminearum species complex are important cereal pathogens worldwide and belong to one of at least nine phylogenetically distinct species. We examined 298 strains of the F. graminearum species complex collected from wheat or barley in Japan to determine the species and trichothecene chemotype. Phylogenetic analyses and species-diagnostic polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLPs) revealed the presence and differential distribution of F. graminearum sensu stricto (s. str.) and F. asiaticum in Japan. F. graminearum s. str. is predominant in the north, especially in the Hokkaido area, while F. asiaticum is predominant in southern regions. In the Tohoku area, these species co-occurred. Trichothecene chemotyping of all strains by multiplex PCR revealed significantly different chemotype compositions of these species. All 50 strains of F. graminearum s. str. were of a 15- or 3-acetyl deoxynivalenol type, while 173 (70%) out of 246 strains of F. asiaticum were of a nivalenol type. The possibility of gene flow between the two species was investigated by use of 15 PCR-RFLP markers developed in this study. However, no obvious hybrids were detected from 98 strains examined, including strains collected from regions where both species co-occur.