Fusarium ear rot(FER)is a destructive maize fungal disease worldwide.In this study,three tropical maize populations consisting of 874 inbred lines were used to perform genomewide association study(GWAS)and genomic pre...Fusarium ear rot(FER)is a destructive maize fungal disease worldwide.In this study,three tropical maize populations consisting of 874 inbred lines were used to perform genomewide association study(GWAS)and genomic prediction(GP)analyses of FER resistance.Broad phenotypic variation and high heritability for FER were observed,although it was highly influenced by large genotype-by-environment interactions.In the 874 inbred lines,GWAS with general linear model(GLM)identified 3034 single-nucleotide polymorphisms(SNPs)significantly associated with FER resistance at the P-value threshold of 1×10^(-5),the average phenotypic variation explained(PVE)by these associations was 3%with a range from 2.33%to 6.92%,and 49 of these associations had PVE values greater than 5%.The GWAS analysis with mixed linear model(MLM)identified 19 significantly associated SNPs at the P-value threshold of 1×10^(-4),the average PVE of these associations was 1.60%with a range from 1.39%to 2.04%.Within each of the three populations,the number of significantly associated SNPs identified by GLM and MLM ranged from 25 to 41,and from 5 to 22,respectively.Overlapping SNP associations across populations were rare.A few stable genomic regions conferring FER resistance were identified,which located in bins 3.04/05,7.02/04,9.00/01,9.04,9.06/07,and 10.03/04.The genomic regions in bins 9.00/01 and 9.04 are new.GP produced moderate accuracies with genome-wide markers,and relatively high accuracies with SNP associations detected from GWAS.Moderate prediction accuracies were observed when the training and validation sets were closely related.These results implied that FER resistance in maize is controlled by minor QTL with small effects,and highly influenced by the genetic background of the populations studied.Genomic selection(GS)by incorporating SNP associations detected from GWAS is a promising tool for improving FER resistance in maize.展开更多
Fusarium ear rot(FER)caused by Fusarium verticillioides is one of the most common diseases affecting maize production worldwide.FER results in severe yield losses and grain contamination with health-threatening mycoto...Fusarium ear rot(FER)caused by Fusarium verticillioides is one of the most common diseases affecting maize production worldwide.FER results in severe yield losses and grain contamination with health-threatening mycotoxins.Although most studies to date have focused on comprehensive analysis of gene regulation in maize during defense responses against F.verticillioides infection,less is known about the role of micro RNAs(mi RNAs)in this process.We used deep sequencing to compare small RNA libraries from the maize kernels of susceptible(N6)or resistant(BT-1)inbred lines from uninfected plants and upon F.verticillioides infection.We found that pathogen exposure was accompanied by dynamic alterations in expression levels of multiple mi RNAs,including new members of previously annotated mi RNA families.A combination of transcriptomic,degradomic,and bioinformatics analyses revealed that F.verticillioides-responsive mi RNAs and their potential target genes displayed opposite expression patterns in the susceptible and resistant genotypes.Functional category analysis uncovered preferential enrichment of the pathogen-responsive mi RNAs and their targets in the phenylpropanoid metabolic processes,plant–pathogen interactions,and plant phytohormone signal transduction pathways.Furthermore,transgenic maize plants overexpressing mi R408 b exhibited reduced resistance to F.verticillioides infection in a susceptible maize line.These findings provide new insights into the regulatory roles of mi RNAs in maize immunity against FER and new resources for breeding disease resistance into maize.展开更多
Gibberella ear rot(GER)caused by Fusarium graminearum(teleomorph Gibberella zeae)is a common maize disease that not only severely reduces grain yield but also contaminates maize grain with mycotoxins.We investigated t...Gibberella ear rot(GER)caused by Fusarium graminearum(teleomorph Gibberella zeae)is a common maize disease that not only severely reduces grain yield but also contaminates maize grain with mycotoxins.We investigated the molecular mechanism underlying the host defense responses against pathogen infection using comparative transcriptomic analysis.We injected F.graminearum spore suspensions into plants of resistant(IBM-81)and a susceptible(IBM-85)maize inbred line after pollination and performed RNA-seq 48,72,and 96 h after inoculation.Respectively 487 and 410 differentially expressed genes(DEGs)were induced in the resistant and susceptible lines across three time points,indicating that a stronger defense response was activated in the resistant than in the susceptible line.Among them,198 genes commonly induced in the two lines were subjected to pathway analysis,revealing that most of the DEGs were closely associated with defense and a wide range of metabolic activities.DEGs associated with pathogenesis-related protein 1(PR1)and regulation of salicylic acid were significantly enriched during F.graminearum infection,suggesting that these DEGs play dominant roles in maize resistance to GER.Our results provide a resource for future gene discovery and facilitate elucidation of the complex defense mechanisms involved in resistance to GER.展开更多
Widespread corn ear mold development in North Dakota and in other states was associated with cool, wet weather after physiological maturity in 2009. In response to concerns about possible grain mold and mycotoxin cont...Widespread corn ear mold development in North Dakota and in other states was associated with cool, wet weather after physiological maturity in 2009. In response to concerns about possible grain mold and mycotoxin contamination in North Dakota, a survey of corn ear diseases was conducted in 2009 prior to harvest. Corn ears were collected from 94 field locations from 24 counties and were examined macroscopically and microscopically for mold identification. Mycotoxin testing was done with a screen for 17 tricothecenes using gas chromatography/mass spectrometry techniques. Cladosporium was the most commonly identified fungus with some Fusarium contaminated samples being observed. Other fungi identified include Alternaria, Penicillium, Aureobsidium, Rhizopus, Stemphylium and an unidentified non-pigmented fungus. Five mycotoxins were identified in 25 out of the 94 samples;deoxynivalenol, T-2, HT-2, zearalenone and nivalenol. Of the mycotoxin-positive samples, 88% had less than 2 ppm of any mycotoxin. Despite the growing season’s weather being favorable for corn ear mold development late in the season, observed mycotoxin levels were surprisingly low and most grain was deemed safe for use in food and feed channels. Surveys were planned in subsequent years, but late season molds did not develop in the 2010-2015 growing seasons.展开更多
Maize is the main crop for Mexicans;however, it is affected by species of fungi causing ear rot. This research aimed to evaluate the effect of T. asperellum T11, T. harzianum T1 4 y T. longibrachiatum T1 40 on some ag...Maize is the main crop for Mexicans;however, it is affected by species of fungi causing ear rot. This research aimed to evaluate the effect of T. asperellum T11, T. harzianum T1 4 y T. longibrachiatum T1 40 on some agronomic variables of four maize genotypes. The seeds of the genotypes H-515, Zapata 7, and H-507 were treated with a suspension of Trichoderma spp. to 1 × 10<sup>8</sup> spores mL<sup>-1</sup>, using a control (untreated seed), and Benomyl as chemical control. The planting was in Morelos, in a completely random block design with a factorial arrangement. The ear rot was natural. Data were obtained at the end of the crop cycle and processed in SAS 9.4<sup><sup>®</sup></sup>. H-515 genotype had the greatest effect on the treatment of maize seeds with Trichoderma spp. (5.562 kg);T. asperellum T11 was the strain that stood out with a mean yield of 50 ears in an area of 16 m<sup>2</sup> of 4.904 kg, and control of 4.448 kg. Our results are an economic option for farmers to contemplate the use of Trichoderma and obtain its benefits.展开更多
【目的】明确吉林省玉米穗腐病主要致病镰孢种群分布及杀菌剂对镰孢菌菌丝生长的抑制效果,为针对性地开展玉米镰孢穗腐病的防治提供依据。【方法】通过组织分离法和分子生物学方法对2020年采自吉林省36个市(县)的149份玉米穗腐病样品进...【目的】明确吉林省玉米穗腐病主要致病镰孢种群分布及杀菌剂对镰孢菌菌丝生长的抑制效果,为针对性地开展玉米镰孢穗腐病的防治提供依据。【方法】通过组织分离法和分子生物学方法对2020年采自吉林省36个市(县)的149份玉米穗腐病样品进行病原菌分离鉴定,利用禾谷镰孢复合种(Fusarium graminearum species complex,FGSC)毒素合成相关基因特异性引物检测其产生毒素的化学型,对部分禾谷镰孢复合种进行致病力测定;采用菌丝生长速率法测定7种杀菌剂对禾谷镰孢复合种的抑制效果。【结果】分离获得233株镰孢菌,隶属4个镰孢复合种,含9种镰孢菌,包括拟轮枝镰孢(F.verticillioides)、布氏镰孢(F.boothii)、禾谷镰孢(F.graminearum)、层出镰孢(F.proliferatum)、亚洲镰孢(F.asiaticum)、厚垣镰孢(F.chlamydosporum)、藤仓镰孢(F.fujikuroi)、木贼镰孢(F.equiseti)和亚黏团镰孢(F.subglutinans),分离频率依次为33.05%、26.18%、25.32%、12.45%、0.86%、0.86%、0.43%、0.43%和0.43%,其中禾谷镰孢复合种分离频率最高,为52.36%,是吉林省玉米穗腐病的优势致病镰孢菌。布氏镰孢、禾谷镰孢和亚洲镰孢在禾谷镰孢复合种中的占比分别为50.00%、48.36%和1.46%。系统发育树结果表明禾谷镰孢复合种种间、种内遗传多样性均较为丰富。致病力测定结果表明52.73%的禾谷镰孢复合种为中致病型菌株,东部玉米主产区分离的禾谷镰孢致病力最强。毒素化学型检测表明,亚洲镰孢为雪腐镰刀烯醇(NIV)化学型,禾谷镰孢与布氏镰孢为15-乙酰基-脱氧雪腐镰刀烯醇(15-AcDON)化学型。7种杀菌剂抑制禾谷镰孢复合种菌丝生长的EC50介于0.02-19.45μg·mL^(-1),其中咯菌腈(FS)、抑霉唑(FS)、氟硅唑(EC)、戊唑醇(TC)和腈菌唑(EW)对禾谷镰孢复合种抑制效果较好且差异不大,EC50小于1.20μg·mL^(-1),EC90小于100μg·mL^(-1);30%吡唑醚菌酯抑制禾谷镰孢和布氏镰孢生长的EC50差异明显,抑制禾谷镰孢的EC50是布氏镰孢的10.24倍。【结论】吉林省不同玉米产区的玉米穗腐病的优势致病镰孢不同,东部和西部为禾谷镰孢和布氏镰孢,中部为拟轮枝镰孢。禾谷镰孢复合种种间、种内遗传多样性均较丰富。咯菌腈、抑霉唑、氟硅唑、戊唑醇和腈菌唑对禾谷镰孢复合种的抑菌效果较好且在禾谷镰孢复合种间的药剂敏感性差别不明显。展开更多
基金The authors gratefully acknowledge the financial support from the MasAgro project funded by Mexico’s Secretary of Agriculture and Rural Development(SADER),the Genomic Open-source Breeding Informatics Initiative(GOBII)(grant number OPP1093167)supported by the Bill&Melinda Gates Foundation,and the CGIAR Research Program(CRP)on maize(MAIZE)MAIZE receives W1&W2 support from the Governments of Australia,Belgium,Canada,China,France,India,Japan,the Republic of Korea,Mexico,Netherlands,New Zealand,Norway,Sweden,Switzerland,the United Kingdom,USA,and the World Bank+2 种基金The authors also thank the National Natural Science Foundation of China(grant number 31801442)the CIMMYT–China Specialty Maize Research Center Project funded by the Shanghai Municipal Finance Bureauthe China Scholarship Council.
文摘Fusarium ear rot(FER)is a destructive maize fungal disease worldwide.In this study,three tropical maize populations consisting of 874 inbred lines were used to perform genomewide association study(GWAS)and genomic prediction(GP)analyses of FER resistance.Broad phenotypic variation and high heritability for FER were observed,although it was highly influenced by large genotype-by-environment interactions.In the 874 inbred lines,GWAS with general linear model(GLM)identified 3034 single-nucleotide polymorphisms(SNPs)significantly associated with FER resistance at the P-value threshold of 1×10^(-5),the average phenotypic variation explained(PVE)by these associations was 3%with a range from 2.33%to 6.92%,and 49 of these associations had PVE values greater than 5%.The GWAS analysis with mixed linear model(MLM)identified 19 significantly associated SNPs at the P-value threshold of 1×10^(-4),the average PVE of these associations was 1.60%with a range from 1.39%to 2.04%.Within each of the three populations,the number of significantly associated SNPs identified by GLM and MLM ranged from 25 to 41,and from 5 to 22,respectively.Overlapping SNP associations across populations were rare.A few stable genomic regions conferring FER resistance were identified,which located in bins 3.04/05,7.02/04,9.00/01,9.04,9.06/07,and 10.03/04.The genomic regions in bins 9.00/01 and 9.04 are new.GP produced moderate accuracies with genome-wide markers,and relatively high accuracies with SNP associations detected from GWAS.Moderate prediction accuracies were observed when the training and validation sets were closely related.These results implied that FER resistance in maize is controlled by minor QTL with small effects,and highly influenced by the genetic background of the populations studied.Genomic selection(GS)by incorporating SNP associations detected from GWAS is a promising tool for improving FER resistance in maize.
基金Acknowledgments This research was supported by the Natural National Science Foundation of China （No. 30571173, No. 31201274）, National High Technology Research and Development Program of China （863 Program） （No. 2012AA10A307）.
基金the Projects of International Cooperation and Exchanges of the National Natural Science Foundation of China(Grant No.3171101241)the Natural Science Foundation of Henan Province,China(Grant No.182300410073)the Foundation of He’nan Educational Committee,China(Grant No.19HASTIT016)。
文摘Fusarium ear rot(FER)caused by Fusarium verticillioides is one of the most common diseases affecting maize production worldwide.FER results in severe yield losses and grain contamination with health-threatening mycotoxins.Although most studies to date have focused on comprehensive analysis of gene regulation in maize during defense responses against F.verticillioides infection,less is known about the role of micro RNAs(mi RNAs)in this process.We used deep sequencing to compare small RNA libraries from the maize kernels of susceptible(N6)or resistant(BT-1)inbred lines from uninfected plants and upon F.verticillioides infection.We found that pathogen exposure was accompanied by dynamic alterations in expression levels of multiple mi RNAs,including new members of previously annotated mi RNA families.A combination of transcriptomic,degradomic,and bioinformatics analyses revealed that F.verticillioides-responsive mi RNAs and their potential target genes displayed opposite expression patterns in the susceptible and resistant genotypes.Functional category analysis uncovered preferential enrichment of the pathogen-responsive mi RNAs and their targets in the phenylpropanoid metabolic processes,plant–pathogen interactions,and plant phytohormone signal transduction pathways.Furthermore,transgenic maize plants overexpressing mi R408 b exhibited reduced resistance to F.verticillioides infection in a susceptible maize line.These findings provide new insights into the regulatory roles of mi RNAs in maize immunity against FER and new resources for breeding disease resistance into maize.
基金supported by the National Natural Science Foundation of China(31471513,31601316)Innovation Training Program of Sichuan Agricultural University(201710626050)
文摘Gibberella ear rot(GER)caused by Fusarium graminearum(teleomorph Gibberella zeae)is a common maize disease that not only severely reduces grain yield but also contaminates maize grain with mycotoxins.We investigated the molecular mechanism underlying the host defense responses against pathogen infection using comparative transcriptomic analysis.We injected F.graminearum spore suspensions into plants of resistant(IBM-81)and a susceptible(IBM-85)maize inbred line after pollination and performed RNA-seq 48,72,and 96 h after inoculation.Respectively 487 and 410 differentially expressed genes(DEGs)were induced in the resistant and susceptible lines across three time points,indicating that a stronger defense response was activated in the resistant than in the susceptible line.Among them,198 genes commonly induced in the two lines were subjected to pathway analysis,revealing that most of the DEGs were closely associated with defense and a wide range of metabolic activities.DEGs associated with pathogenesis-related protein 1(PR1)and regulation of salicylic acid were significantly enriched during F.graminearum infection,suggesting that these DEGs play dominant roles in maize resistance to GER.Our results provide a resource for future gene discovery and facilitate elucidation of the complex defense mechanisms involved in resistance to GER.
文摘Widespread corn ear mold development in North Dakota and in other states was associated with cool, wet weather after physiological maturity in 2009. In response to concerns about possible grain mold and mycotoxin contamination in North Dakota, a survey of corn ear diseases was conducted in 2009 prior to harvest. Corn ears were collected from 94 field locations from 24 counties and were examined macroscopically and microscopically for mold identification. Mycotoxin testing was done with a screen for 17 tricothecenes using gas chromatography/mass spectrometry techniques. Cladosporium was the most commonly identified fungus with some Fusarium contaminated samples being observed. Other fungi identified include Alternaria, Penicillium, Aureobsidium, Rhizopus, Stemphylium and an unidentified non-pigmented fungus. Five mycotoxins were identified in 25 out of the 94 samples;deoxynivalenol, T-2, HT-2, zearalenone and nivalenol. Of the mycotoxin-positive samples, 88% had less than 2 ppm of any mycotoxin. Despite the growing season’s weather being favorable for corn ear mold development late in the season, observed mycotoxin levels were surprisingly low and most grain was deemed safe for use in food and feed channels. Surveys were planned in subsequent years, but late season molds did not develop in the 2010-2015 growing seasons.
文摘Maize is the main crop for Mexicans;however, it is affected by species of fungi causing ear rot. This research aimed to evaluate the effect of T. asperellum T11, T. harzianum T1 4 y T. longibrachiatum T1 40 on some agronomic variables of four maize genotypes. The seeds of the genotypes H-515, Zapata 7, and H-507 were treated with a suspension of Trichoderma spp. to 1 × 10<sup>8</sup> spores mL<sup>-1</sup>, using a control (untreated seed), and Benomyl as chemical control. The planting was in Morelos, in a completely random block design with a factorial arrangement. The ear rot was natural. Data were obtained at the end of the crop cycle and processed in SAS 9.4<sup><sup>®</sup></sup>. H-515 genotype had the greatest effect on the treatment of maize seeds with Trichoderma spp. (5.562 kg);T. asperellum T11 was the strain that stood out with a mean yield of 50 ears in an area of 16 m<sup>2</sup> of 4.904 kg, and control of 4.448 kg. Our results are an economic option for farmers to contemplate the use of Trichoderma and obtain its benefits.
文摘【目的】明确吉林省玉米穗腐病主要致病镰孢种群分布及杀菌剂对镰孢菌菌丝生长的抑制效果,为针对性地开展玉米镰孢穗腐病的防治提供依据。【方法】通过组织分离法和分子生物学方法对2020年采自吉林省36个市(县)的149份玉米穗腐病样品进行病原菌分离鉴定,利用禾谷镰孢复合种(Fusarium graminearum species complex,FGSC)毒素合成相关基因特异性引物检测其产生毒素的化学型,对部分禾谷镰孢复合种进行致病力测定;采用菌丝生长速率法测定7种杀菌剂对禾谷镰孢复合种的抑制效果。【结果】分离获得233株镰孢菌,隶属4个镰孢复合种,含9种镰孢菌,包括拟轮枝镰孢(F.verticillioides)、布氏镰孢(F.boothii)、禾谷镰孢(F.graminearum)、层出镰孢(F.proliferatum)、亚洲镰孢(F.asiaticum)、厚垣镰孢(F.chlamydosporum)、藤仓镰孢(F.fujikuroi)、木贼镰孢(F.equiseti)和亚黏团镰孢(F.subglutinans),分离频率依次为33.05%、26.18%、25.32%、12.45%、0.86%、0.86%、0.43%、0.43%和0.43%,其中禾谷镰孢复合种分离频率最高,为52.36%,是吉林省玉米穗腐病的优势致病镰孢菌。布氏镰孢、禾谷镰孢和亚洲镰孢在禾谷镰孢复合种中的占比分别为50.00%、48.36%和1.46%。系统发育树结果表明禾谷镰孢复合种种间、种内遗传多样性均较为丰富。致病力测定结果表明52.73%的禾谷镰孢复合种为中致病型菌株,东部玉米主产区分离的禾谷镰孢致病力最强。毒素化学型检测表明,亚洲镰孢为雪腐镰刀烯醇(NIV)化学型,禾谷镰孢与布氏镰孢为15-乙酰基-脱氧雪腐镰刀烯醇(15-AcDON)化学型。7种杀菌剂抑制禾谷镰孢复合种菌丝生长的EC50介于0.02-19.45μg·mL^(-1),其中咯菌腈(FS)、抑霉唑(FS)、氟硅唑(EC)、戊唑醇(TC)和腈菌唑(EW)对禾谷镰孢复合种抑制效果较好且差异不大,EC50小于1.20μg·mL^(-1),EC90小于100μg·mL^(-1);30%吡唑醚菌酯抑制禾谷镰孢和布氏镰孢生长的EC50差异明显,抑制禾谷镰孢的EC50是布氏镰孢的10.24倍。【结论】吉林省不同玉米产区的玉米穗腐病的优势致病镰孢不同,东部和西部为禾谷镰孢和布氏镰孢,中部为拟轮枝镰孢。禾谷镰孢复合种种间、种内遗传多样性均较丰富。咯菌腈、抑霉唑、氟硅唑、戊唑醇和腈菌唑对禾谷镰孢复合种的抑菌效果较好且在禾谷镰孢复合种间的药剂敏感性差别不明显。
文摘玉米穗腐病是严重的世界性真菌病害,而轮枝镰刀菌Fusarium verticillioide是我国玉米穗腐病的主要致病菌。为明确叶菌唑在我国玉米穗腐病防治中的应用潜力,采用菌丝生长速率法和孢子萌发法,分别测定了叶菌唑对2019至2021年采自我国山东、河南和江苏3个省份的35株轮枝镰刀菌菌丝生长以及分生孢子形成、萌发和芽管伸长的影响,并测定了该药剂对轮枝镰刀菌产毒(B族伏马毒素,type B fumonisins,FBs)能力及产毒基因表达的影响;通过测定叶菌唑处理后轮枝镰刀菌菌丝麦角甾醇、胞内甘油和丙二醛(MDA)含量以及电导率的变化,探究了其作用机制;同时评价了叶菌唑对田间玉米穗腐病的防治效果。结果显示:叶菌唑对35株轮枝镰刀菌均表现出较强的抑制活性,其对轮枝镰刀菌的菌丝生长以及分生孢子形成、萌发及芽管伸长具有显著的剂量依赖性抑制作用。其中:叶菌唑抑制菌丝生长的EC_(50)值在0.005~0.029μg/mL之间,平均EC_(50)值为(0.012±0.006)μg/mL;EC_(50)浓度的叶菌唑对轮枝镰刀菌分生孢子形成、萌发及芽管伸长的平均抑制率分别为(20.59±5.75)%、(24.88±5.15)%和(59.98±9.11)%;叶菌唑能显著降低轮枝镰刀菌FBs毒素的产生量和与毒素生物合成相关基因的表达水平,其对FBs毒素合成的抑制率为29.04%;显著降低了轮枝镰刀菌菌丝麦角甾醇的合成量,抑制率为39.10%,同时提高了其胞内甘油、丙二醛含量以及相对电导率,对甘油和丙二醛的诱导率分别为66.39%和33.74%。田间试验表明,有效成分90、135和180 g/hm2剂量的叶菌唑对玉米穗腐病的防效分别为(20.93±4.65)%、(27.75±5.71)%和(46.05±9.90)%,增产率分别为(8.86±8.84)%、(17.28±11.91)%和(33.20±12.07)%,均优于对照药剂丙硫菌唑•戊唑醇。本研究评估了叶菌唑防治玉米穗腐病的潜力,并可为了解其对轮枝镰刀菌的活性和作用机制提供理论依据。
