Diversity of Epidemic Populations of Gibberella zeae from Small Quadrats in Kansas and North Dakota

ABSTRACT Gibberella zeae (anamorph Fusarium graminearum) causes Fusarium head blight (FHB) of wheat and barley and has been responsible for several billion dollars of losses in the United States since the early 1990s. We isolated G. zeae from the top, middle, and bottom positions of wheat spikes collected from 0.25-m(2) quadrats during severe FHB epidemics in a single Kansas (KS) field (1993) and in a single North Dakota (ND) field (1994). Three amplified fragment length polymorphism (AFLP) primer pairs were used to resolve 94 polymorphic loci from 253 isolates. Members of a subset of 26 isolates also were tested for vegetative compatibility groups (VCGs). Both methods indicated high levels of genotypic variability and identified the same sets of isolates as probable clones. The mean number of AFLP multilocus haplotypes per head was approximately 1.8 in each population, but this value probably underestimates the true mean due to the small number of samples taken from each head. Isolates with the same AFLP haplotype often were recovered from different positions in a single head, but only rarely were such apparently clonal isolates recovered from more than one head within a quadrat, a pattern that is consistent with a genetically diverse initial inoculum and limited secondary spread. The KS and ND samples had no common AFLP haplotypes. All G. zeae isolates had high AFLP fingerprint similarity (>70%, unweighted pair group method with arithmetic means similarity) to reference isolates of G. zeae lineage 7. The genetic identity between the KS and ND populations was >99% and the estimated effective migration rate was high (Nm approximately 70). Tests for linkage disequilibrium provide little evidence for nonrandom associations between loci. Our results suggest that these populations are parts of a single, panmictic population that experiences frequent recombination. Our results also suggest that a variety of population sampling designs may be satisfactory for assessing diversity in this fungus.     

Trichothecene genotypes of Gibberella zeae from winter wheat fields in the eastern USA

Fusarium head blight (FHB), caused principally by Gibberella zeae (Fusarium graminearum), is a devastating disease of small grains such as wheat and barley worldwide. Grain infected with G. zeae may be contaminated with trichothecene mycotoxins such as deoxynivalenol (DON) and nivalenol (NIV). Strains of G. zeae that produce DON may also produce acetylated derivatives of DON: 3‐acetyl‐DON (3‐ADON) and 15‐acetyl‐DON (15‐ADON). Gradients (clines) of 3‐ADON genotypes in Canada have raised questions about the distribution of G. zeae trichothecene genotypes in wheat fields in the eastern USA. Tri3 and Tri12 genotypes were evaluated in 998 isolates of G. zeae collected from 39 winter wheat fields in New York (NY), Pennsylvania (PA), Maryland (MD), Virginia (VA), Kentucky (KY) and North Carolina (NC). Ninety‐two percent (919/998) of the isolates were 15‐ADON, 7% (69/998) were 3‐ADON, and 1% (10/998) was NIV. A phylogenetic analysis based on portions of three genes (PHO, RED and URA) from 23 isolates revealed two species of Fusarium (F. graminearum sensu stricto and one isolate of F. cerealis (synonym F. crookwellense)). An increasing trend of 3‐ADON genotypes was observed from NC (south) to NY (north). Punctuated episodes of atmospheric transport may favour a higher frequency of 3‐ADON genotypes in the northeastern USA, near Canada, compared with the mid‐Atlantic states. Discoveries of the NIV genotype in NY and NC indicate the need for more intensive sampling in the surrounding regions.     

Genetic diversity of herbicide-resistant and -susceptible Avena fatua populations in North Dakota and Minnesota

Genetic diversity within and among 20 herbicide-resistant (HR) and 16 herbicide-susceptible (HS) Avena fatua multi-field populations was determined using 82 polymorphic loci resulting from two intersimple sequence repeat (ISSR) primers and one long-primer random amplified polymorphic DNA (LP-RAPD) primer. Collections from the Red River Valley of North Dakota and Minnesota, sampled in 1964 and 2000, represented A. fatua populations before and after intensive exposure to herbicides. A 1995 collection from south-west North Dakota represented A. fatua exposed to low herbicide selection. Despite differences in years of herbicide exposure among collections, both HR and HS populations from every collection maintained nearly similar levels of ISSR and RAPD diversity. Genetic differentiation among populations (G_ST) varied from 11% to 13% among HR populations and from 9% to 16% among HS populations, indicating that 84–91% of total variation remained within HS or within HR populations. Minimal difference in gene diversity between HR and HS is consistent with multiple origins of resistance, where HR A. fatua most likely evolved from diverse founding individuals.     

玉蜀黍赤霉有性重组体的诱导及其生物学特性

 本研究以硝酸盐营养缺陷型突变体(nit)和多菌灵抗性为遗传标记,在5个所选菌株中设计了3个玉蜀黍赤霉病菌Gibberella zeae的杂交组合,使各菌株之间进行杂交,从而诱导有性重组体。从各杂交组合的后代中任意挑选出3个有性重组体,比较了这些有性重组体与其亲本在无性和有性阶段的主要生物学性状。结果表明,玉蜀黍赤霉中的nit基因及对杀菌剂多菌灵的抗药性基因可以通过有性杂交的方式重组,即发生了有性重组。有性重组体与其亲本在菌落生长、培养性状和致病性方面没有显著差异;但某些有性重组体中,产孢量和产子囊壳能力方面存在一定差异。总体看来,有性重组体仍然保持了较高的适合度。因此,可以认为有性重组在玉蜀黍赤霉群体对多菌灵抗药性发生发展以及群体遗传进化中可能起着重要的作用。     

Virulence profile and genetic structure of a North Dakota population of Pyrenophora teres f. teres, the causal agent of net form net blotch of barley

A Pyrenophora teres f. teres population in North Dakota was analyzed for virulence variation and genetic diversity using 75 monospore isolates that were collected across a 4-year period (2004 to 2007) from two North Dakota State University agricultural experiment stations at Fargo and Langdon. Pathogenicity tests by inoculation onto 22 barley differential lines at seedling stage revealed 49 pathotypes, indicating a wide range of pathogenic diversity. Two-way analysis of variance of disease ratings revealed a significant difference in the virulence among isolates and in the resistance among barley lines, as well as in the interactions between the two. 'CI5791', 'Algerian', and 'Heartland' were three barley lines showing a high level of seedling resistance to all North Dakota isolates tested; however, many previously reported resistance genes have been overcome. Forty multilocus genotypes were identified from this set of isolates by genotyping at 13 simple-sequence repeat loci. High percentages of clonal cultures were detected in the samplings from 2005 and 2007 in Fargo and 2005 in Langdon. Using a clone-corrected sample set, the mean gene diversity (h) was estimated to be 0.58, approximately the same for both locations. The calculated Wright's F(ST) value is small (0.11) but was significantly >0, indicating a significant differentiation between the Fargo and Langdon populations. In the gametic disequilibrium test, only 3 of 78 possible pairwise comparisons over all isolates showed significant (P < 0.05) nonrandom association, suggesting a random mating mode. Our results suggest that the populations from the two locations are derived from a common source and undergo frequent recombination. This research provides important information for barley breeders regarding development and deployment of cultivars with resistance to net form net blotch in this region.     

Genetic relationships among populations of Gibberella zeae from barley, wheat, potato, and sugar beet in the upper Midwest of the United States

Gibberella zeae, a causal agent of Fusarium head blight (FHB) in wheat and barley, is one of the most economically harmful pathogens of cereals in the United States. In recent years, the known host range of G. zeae has also expanded to noncereal crops. However, there is a lack of information on the population genetic structure of G. zeae associated with noncereal crops and across wheat cultivars. To test the hypothesis that G. zeae populations sampled from barley, wheat, potato, and sugar beet in the Upper Midwest of the United States are not mixtures of species or G. zeae clades, we analyzed sequence data of G. zeae, and confirmed that all populations studied were present in the same clade of G. zeae. Ten variable number tandem repeat (VNTR) markers were used to determine the genetic structure of G. zeae from the four crop populations. To examine the effect of wheat cultivars on the pathogen populations, 227 strains were sampled from 10 subpopulations according to wheat cultivar types. The VNTR markers also were used to analyze the genetic structure of these subpopulations. In all populations, gene (H = 0.453 to 0.612) and genotype diversity (GD = or >0.984) were high. There was little or no indication of linkage disequilibrium (LD) in all G. zeae populations and subpopulations. In addition, high gene flow (Nm) values were observed between cereal and noncereal populations (Nm = 10.69) and between FHB resistant and susceptible wheat cultivar subpopulations (Nm = 16.072), suggesting low population differentiation of G. zeae in this region. Analysis of molecular variance also revealed high genetic variation (>80%) among individuals within populations and subpopulations. However, low genetic variation (<5%) was observed between cereal and noncereal populations and between resistant and susceptible wheat subpopulations. Overall, these results suggest that the populations or subpopulations are likely a single large population of G. zeae affecting crops in the upper Midwest of the United States.     

Rain Splash Dispersal of Gibberella zeae Within Wheat Canopies in Ohio

ABSTRACT Rain splash dispersal of Gibberella zeae, causal agent of Fusarium head blight of wheat, was investigated in field studies in Ohio between 2001 and 2003. Samplers placed at 0, 30, and 100 cm above the soil surface were used to collect rain splash in wheat fields with maize residue on the surface and fields with G. zeae-infested maize kernels. Rain splash was collected during separate rain episodes throughout the wheat-growing seasons. Aliquots of splashed rain were transferred to petri dishes containing Komada's selective medium, and G. zeae was identified based on colony and spore morphology. Dispersed spores were measured in CFU/ml. Intensity of splashed rain was highest at 100 cm and ranged from 0.2 to 10.2 mm h(-1), depending on incident rain intensity and sampler height. Spores were recovered from splash samples at all heights in both locations for all sampled rain events. Both macroconidia and ascospores were found based on microscopic examination of random samples of splashed rain. Spore density and spore flux density per rain episode ranged from 0.4 to 40.9 CFU cm(-2) and 0.4 to 84.8 CFU cm(-2) h(-1), respectively. Spore flux density was higher in fields with G. zeae-infested maize kernels than in fields with maize debris, and generally was higher at 0 and 30 cm than at 100 cm at both locations. However, on average, spore flux density was only 30% lower at 100 cm (height of wheat spikes) than at the other heights. The log of spore flux density was linearly related to the log of splashed rain intensity and the log of incident rain intensity. The regression slopes were not significantly affected by year, location, height, and their interactions, but the intercepts were significantly affected by both sampler height and location. Thus, our results show that spores of G. zeae were consistently splash dispersed to spike heights within wheat canopies, and splashed rain intensity and spore flux density could be predicted based on incident rain intensity in order to estimate inoculum dispersal within the wheat canopy.     

Pathogenic and genetic diversity of Xanthomonas translucens pv. undulosa in North Dakota

Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa, has become more prevalent recently in North Dakota and neighboring states. From five locations in North Dakota, 226 strains of X. translucens pv. undulosa were collected and evaluated for pathogenicity and then selected strains were inoculated on a set of 12 wheat cultivars and other cereal hosts. The genetic diversity of all strains was determined using repetitive sequence-based polymerase chain reaction (rep-PCR) and insertion sequence-based (IS)-PCR. Bacterial strains were pathogenic on wheat and barley but symptom severity was greatest on wheat. Strains varied greatly in aggressiveness, and wheat cultivars also showed differential responses to several strains. The 16S ribosomal DNA sequences of the strains were identical, and distinct from those of the other Xanthomonas pathovars. Combined rep-PCR and IS-PCR data produced 213 haplotypes. Similar haplotypes were detected in more than one location. Although diversity was greatest (≈92%) among individuals within a location, statistically significant (P ≤ 0.001 or 0.05) genetic differentiation among locations was estimated, indicating geographic differentiation between pathogen populations. The results of this study provide information on the pathogen diversity in North Dakota, which will be useful to better identify and characterize resistant germplasm.     

Spatial Patterns of Viable Spore Deposition of Gibberella zeae in Wheat Fields

ABSTRACT An increased understanding of the epidemiology of Gibberella zeae will contribute to a rational and informed approach to the management of Fusarium head blight (FHB). An integral phase of the FHB cycle is the deposition of airborne spores, yet there is no information available on the spatial pattern of spore deposition of G. zeae above wheat canopies. We examined spatial patterns of viable spore deposition of G. zeae over rotational (lacking cereal debris) wheat fields in New York in 2002 and 2004. Viable, airborne spores (ascospores and macroconidia) of G. zeae were collected above wheat spikes on petri plates containing a selective medium and the resulting colonies were counted. Spores of G. zeae were collected over a total of 68 field environments (three wheat fields during 54 day and night sample periods over 2 years) from spike emergence to kernel milk stages of local wheat. Spatial patterns of spore deposition were visualized by contour plots of spore counts over entire fields. The spatial pattern of spore deposition was unique for each field environment during each day and night sample period. Spore deposition patterns during individual sample periods were classified by spatial analysis by distance indices (SADIE) statistics and Mantel tests. Both analyses indicated that the majority (93%) of the spore deposition events were random, with the remainder being aggregated. All of the aggregated patterns were observed during the night. Observed patterns of spore deposition were independent of the mean number of viable spores deposited during individual sample periods. The spatial pattern for cumulative spore deposition during anthesis in both years became aggregated over time. Contour maps of daily and cumulative spore deposition could be compared with contour maps of FHB incidence to gain insights into inoculum thresholds and the timing of effective inoculum for infection.     

Vegetative Compatibility and Mycotoxin Chemotypes among Fusarium graminearum (Gibberella zeae) Isolates from Wheat in Argentina

Gibberella zeae (anamorph Fusarium graminearum) is the main pathogen causing Fusarium head blight of wheat in Argentina. The objective of this study was to determine the vegetative compatibility groups (VCGs) and mycotoxin production (deoxynivalenol, nivalenol and 3-acetyl deoxynivalenol) by F. graminearum populations isolated from wheat in Argentina. VCGs were determined among 70 strains of F. graminearum isolated from three localities in Argentina, using nitrate non-utilizing (nit) mutants. Out of 367 nit mutants generated, 41% utilized both nitrite and hypoxanthine (nit1), 45% utilized hypoxanthine but not nitrite (nit3), 9% utilized nitrite but not hypoxanthine (NitM) and 5% utilized all the nitrogen sources (crn). The complementations were done by pairing the mutants on nitrate medium. Fifty-five different VCGs were identified and the overall VCG diversity (number of VCGs/number of isolates) averaged over the three locations was 0.78. Forty-eight strains were incompatible with all others, thus each of these strains constituted a unique VCG. Twenty-two strains were compatible with other isolates and were grouped in seven multimembers VCGs. Considering each population separately, the VCG diversity was 0.84, 0.81 and 1.0 for San Antonio de Areco, Alberti and Marcos Juarez, respectively. Toxin analysis revealed that of the 70 strains of F. graminearum tested, only 90% produced deoxynivalenol, 10% were able to produce deoxynivalenol and very low amounts of 3-acetyldeoxynivalenol. No isolate produced nivalenol. The results indicate a high degree of VCG diversity in the F. graminearum populations from wheat in Argentina. This diversity should be considered when screening wheat germplasm for Fusarium head blight resistance.     

2003年江苏省小麦赤霉病致灾原因分析

小麦赤霉病犤Gibberellazeae(Schw.)犦是困扰我国长江中、下游地区小麦生产持续发展的重要因素之一。江苏河网交错,春雨较多,赤霉病流行频率高。2003年赤霉病见病时间早、发生范围广、自然为害重,是江苏历史上的第九个大流行年。12003年小麦赤霉病流行概况江苏淮南往年是小麦赤霉病的主要流行区域;淮北属于偶发区,基本上不作为主要防治对象。2003年全省以沿江、苏南局部及丘陵地区发病最重,自然发病病穗率高达60%～80%;其次是沿淮及江淮地区,自然发病病穗率40%～60%;再次是徐州、宿迁、连云港3市,自然发病病穗率在10%以下。据各地调查,赤霉…     

Head Blight Gradients Caused by Gibberella zeae from Area Sources of Inoculum in Wheat Field Plots

ABSTRACT The spread of Fusarium head blight of wheat from a small area inoculum source was examined in wheat plots (100, 625, or 2,500 m(2)) inoculated in the center with Gibberella zeae-colonized corn kernels or macro-conidia sprayed on heads at anthesis. With the first inoculation method, disease foci were produced from ascospores released from perithecia formed on inoculated kernels. With the second inoculation method, disease foci were produced by macroconidia directly applied to the heads. Some plots were misted during anthesis. Plots were divided into grids, and disease incidence on spikelets and seeds was assessed at the grid intersections. Isopath contour maps were constructed using an interpolation procedure based on a weighted least squares method. Disease gradients were constructed from the isopath contours in the direction parallel to average nightly wind vectors using an exponential model. This study was conducted over a 3-year period at two sites: one in Quebec and one in Ontario. Both inoculation methods resulted in a discrete, primary focus of head blight in each plot, with one or two smaller secondary foci in some plots. The highest incidence of disease on spikelets or seed was commonly displaced somewhat from the inoculum source, usually downwind. The gradient slopes of seed and spikelet infection ranged from -0.10 to -0.43 m(1) in plots with ascospore inoculum and from -0.48 to -0.79 m(1) in plots inoculated with macroconidia. Seed infection declined to 10% of the maximum within 5 to 22 m from the focal center in asco-spore-inoculated plots, and within 5 m in a macroconidia-inoculated plot. Gradients were usually steeper upwind compared with downwind of the inoculum source. In misted plots, incidence of disease was higher and more diffuse than in nonirrigated plots. Based on gradients and dispersal patterns, disease foci in plots inoculated with G. zeae-colonized corn kernels probably arose from airborne ascospores rather than from splash-borne macroconidia and were the result of infection events that occurred over a short period of time. Comparison of conidial- and ascospore-derived disease gradients indicated a lack of secondary infection, confirming that Fusarium head blight is primarily a monocyclic disease.     

小麦赤霉病特大流行年不同品种(品系)间抗性试验分析

田间对比试验结果表明,赤霉病特大流行年不同小麦品种对赤霉病的抗性存在极显著差异,可分为高感、中感和中抗3个类型。因此,生产上应以中抗品种扬麦158作为当家品种,适当示范种植扬麦11、扬麦13等抗病、耐病性较强、产量较高的品种,并加强测报,适时开展药剂防治,综合控制病害的流行为害。     

Genetic Mapping of Pathogenicity and Aggressiveness of Gibberella zeae (Fusarium graminearum) Toward Wheat

ABSTRACT Gibberella zeae is the major fungal pathogen of Fusarium head blight of wheat and produces several mycotoxins that are harmful to humans and domesticated animals. We identified loci associated with pathogenicity and aggressiveness on an amplified fragment length polymorphism based genetic map of G. zeae in a cross between a lineage 6 nivalenol producer from Japan and a lineage 7 deoxynivalenol producer from Kansas. Ninety-nine progeny and the parents were tested in the greenhouse for 2 years. Progeny segregated qualitatively (61:38) for pathogenicity:nonpathogenicity, respectively. The trait maps to linkage group IV, which is adjacent to loci that affect colony pigmentation, perithecium production, and trichothecene toxin amount. Among the 61 pathogenic progeny, the amount of disease induced (aggressiveness) varied quantitatively. Two reproducible quantitative trait loci (QTL) for aggressiveness were detected on linkage group I using simple interval analysis. A QTL linked to the TRI5 locus (trichodiene synthase in the trichothecene pathway gene cluster) explained 51% of the variation observed, and a second QTL that was 50 centimorgans away explained 29% of the phenotypic variation. TRI5 is tightly linked to the locus controlling trichothecene toxin type. The two QTLs, however, were likely part of the same QTL using composite interval analysis. Progeny that produced deoxynivalenol were, on average, approximately twice as aggressive as those that produced nivalenol. No transgressive segregation for aggressiveness was detected. The rather simple inheritance of both traits in this interlineage cross suggests that relatively few loci for pathogenicity or aggressiveness differ between lineage 6 and 7.     

Mitochondrial DNA Diversity and Lineage Determination of European Isolates of Fusarium graminearum (Gibberella zeae)

Restriction fragment length polymorphisms (RFLPs) were used to assess genetic diversity of mitochondrial DNA (mtDNA) among standard isolates of seven lineages of Fusarium graminearum. The mtDNA patterns within each lineage were very similar (>89%), whereas significant differences were observed between the isolates belonging to different lineages, with the exception of lineages 1 and 4 where strong similarity was found between the RFLPs. Analysis of different band patterns resulted in characteristic HhaI and HaeIII bands that were suitable for identification of members of lineages 7, 6, 5, 3 and 2. Investigation of lineage distribution of 144 European isolates revealed that 142 belong to lineage 7. These data, therefore, confirmed the hypothesis that members of lineage 7 are predominant in Europe. Further analysis of isolates belonging to lineage 7 resulted in five haplotypes. These haplotypes have arisen as different combinations of three RFLP patterns for both HaeIII and HhaI restriction enzymes. Two isolates from Hungary, however, shared the same mtDNA RFLP profiles with a standard isolate of lineage 3, indicating that members of lineage 3, at a lower frequency, may also occur in Europe.     

Germination of Ascospores of Gibberella zeae after exposure to various levels of relative humidity and temperature

Fusarium head blight (FHB) is one of the most important cereal diseases in the world and has caused major losses to the grain industry. The principal pathogen causing FHB in North America is Gibberella zeae (anamorph Fusarium graminearum). Information on survival and the conditions under which ascospores remain viable once released from perithecia may assist in refining disease forecasting models. This study measured germination of ascospores after exposure to different temperatures, 15, 20, and 30 degrees C, and levels of relative humidity (RH), 30, 60, and 90% for 4, 24, or 48 h periods. Viability was tested by germination on water agar. Germination rates fell with increasing temperatures at all observation times and at all humidity levels. At 15 and 20 degrees C after 48 h, germination ranged from 74 to 85%, and 52 to 72%, respectively. At 30 degrees C, germination ranged from 36 to 59% after 24 h and from 13 to 47% after 48 h. Germination was highest at 90% RH, except at 30 degrees C after 48 h, and lowest at 60% RH. Successful germination, even under extreme conditions, suggests that ascospores are sufficiently robust to constitute a source of inoculum under most environmental conditions encountered during the growing season.     

小麦赤霉病田间病情与病粒率关系探讨

采用病情普查、不同严重度病穗病粒率测定、田间病粒率调查测算及多元回归分析等方法,研究了小麦赤霉病田间病情与病粒率的关系,并建立了由田间病情直接换算病粒率的数学模型,经拟合检验平均误差为0.09个百分点。     

2003年楚州区小麦赤霉病大流行原因分析与防治建议

2003年淮安市楚州区种植小麦66万亩(其中温麦6号约25万亩,温麦8号、淮麦18、淮麦20、豫麦34各约10万亩,其他品种为扬麦、3039等)。据本区植保站调查,虽然2003年防治面积和防治力度都远远超过历史,但小麦赤霉病在本区仍然达到大流行程度。现对其流行概况和原因简要总结分析如下。12003年小麦赤霉病流行及防治概况据调查,全区平均病穗率54.5%(1.8%～100%),平均病指43.1(0.3～96.7),平均产量损失37.1%,其中主要以温麦品种发病最为严重,全区近6万亩绝收。而造成小麦品质下降,商品性降低的间接损失更难以估量,为本区植保站自1963年有记载以来病害…     

Genetic variation and covariation for aggressiveness, deoxynivalenol production and fungal colonization among progeny of Gibberella zeae in wheat

Gibberella zeae (anamorph Fusarium graminearum ) causes head blight of cereals and contaminates grains with mycotoxins such as deoxynivalenol (DON). To determine the correlations among aggressiveness traits, fungal colonization and DON production, 50 progeny from a segregating population of G. zeae were inoculated onto a susceptible winter wheat cultivar in three field environments (year–location combinations). Aggressiveness traits were measured as head-blight rating and plot yield relative to noninoculated plots. Fungal colonization, measured as Fusarium exoantigen (ExAg) content, and DON production were analysed with two ELISA formats. Disease severity was moderate to high based on head-blight rating and relative plot yield. Fusarium ExAg content and DON production ranged from 0·26–1·41 units and from 4·18–43·70 mg kg⁻¹, respectively. Significant ( P  = 0·01) genotypic variation was found for all traits. Heritability for Fusarium ExAg content was rather low because of high progeny–environment interaction and error. DON/ Fusarium ExAg ratio did not vary significantly ( P  > 0·1) among progeny. Correlation between DON production and Fusarium ExAg content across environments was high ( r  = 0·8, P  = 0·01), but no covariation existed between aggressiveness traits and DON/ Fusarium ExAg content ratio.     

吉林和黑龙江两省玉米北方炭疽病菌群体生物学特性分析

由玉蜀黍球梗孢Kabatiella zeae引起的玉米北方炭疽病在我国东北地区普遍发生,在一些地区已成为玉米生产上的主要病害,严重影响玉米高产稳产,威胁我国粮食安全。为明确玉米北方炭疽病菌群体生物学特性,本研究于2020年7月-10月在吉林和黑龙江两省共17个地点采集了玉米北方炭疽病样品180份,并分离纯化到624个玉米北方炭疽病菌单孢菌株,通过形态学观测,科赫氏法则验证及分子生物学鉴定,确定所分离的病原菌均为Kabatiella zeae。依据菌落产黑色素能力与菌落生长情况将病原菌划分为4种不同菌落形态类型。本研究选择4株代表性菌株SH10-1(类型Ⅰ)、HB10-1(类型Ⅱ)、HN10-1(类型Ⅲ)和NA10-1(类型Ⅳ),对病原菌在两省分布比例、产孢能力、菌落生长速率,产孢方式和致病性等的比较结果显示,类型Ⅰ、类型Ⅱ和类型Ⅲ在两省份病原菌群体总数中占98.8%;类型Ⅳ在两省份中只分离到7株,其生长速率较快。对类型Ⅰ、类型Ⅱ和类型Ⅲ病原菌分析得出结论：产黑色素能力强的病原菌致病性较强且产孢能力较弱。研究结果可为玉米北方炭疽病的防治提供一定参考。