Virulence and Molecular Diversity in the Kabatiella zeae Population Causing Maize Eyespot in China

Plant Disease ◽  
2020 ◽  
Vol 104 (12) ◽  
pp. 3197-3206
Author(s):  
Nan Chen ◽  
Shuqin Xiao ◽  
Jiaying Sun ◽  
Lu He ◽  
Miaomiao Liu ◽  
...  

Maize eyespot, caused by Kabatiella zeae, has become a major yield-limiting factor in maize planting areas in northeast China. Limited information is available on pathotypes, virulence, and the genetic diversity of the K. zeae population. We analyzed virulence and genetic diversity of 103 K. zeae isolates collected from six provinces in China with differential hosts and the amplified fragment length polymorphism (AFLP) technique, respectively. To evaluate the virulence, 103 isolates were inoculated on nine differential hosts (maize inbred lines)—E28, Shen137, Qi319, B73, Danhuang34, Zi330, Mo17, Huangzaosi, and CN165—and grouped into 23 pathotypes and three virulence groups according to the coded triplet nomenclature system on differential hosts. AFLP analysis resolved the set of isolates into four genetic diversity clusters (DICE similarity values of 76%). Genetic variation of K. zeae among and between pathotypes revealed that the pathogen population had a high genotypic diversity. The correlation between pathotypes, virulence, and genetic diversity grouping was low. A correlation between AFLP groups and geographic locations was detected.

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1728-1737 ◽  
Author(s):  
Dan Zhang ◽  
Fen Wang ◽  
Jiamei Zhao ◽  
Jiaying Sun ◽  
Dandan Fu ◽  
...  

Curvularia leaf spot (CuLS), caused by Curvularia lunata, is a devasting foliar disease in the maize-growing regions of China. Resistant varieties were widely planted in these regions in response to CuLS. However, over time, C. lunata has gradually adapted to the selective pressure and, in recent years, the incidence of CuLS has increased. To assess the correlation between virulence and genetic diversity, a total of 111 isolates was collected from 15 maize-growing regions located in nine provinces in China. These isolates were evaluated for virulence on maize using nine differential hosts: Shen135, CN165, Mo17, Luyuan92, 78599, Ye478, B73, E28, and Huangzaosi. To evaluate the genetic diversity, 657 polymorphic amplified fragment length polymorphism markers were generated. Results showed that the isolates could be grouped into three pathotypes according to the phenotypic expression of the differential inbred lines. Isolates were clustered into two genetic diversity groups and further divided into subgroups. However, the correlation between virulence and genetic diversity grouping was low. Also, there was a low correlation observed between pathotype and geographic distribution. The ratio of mating type I to mating type II for all isolates was close to 3:4.


2008 ◽  
Vol 133 (4) ◽  
pp. 587-592 ◽  
Author(s):  
Joseph C. Kuhl ◽  
Veronica L. DeBoer

The genus Rheum L., commonly known as rhubarb, is composed of ≈60 species, primarily distributed throughout northern and central Asia. Rhubarb species have been used for medicinal purposes for thousands of years; however, it was not until the 18th century that the culinary use of petioles was first reported. Although the origin(s) of culinary rhubarb is not clear, it is thought that they originated from hybridization of rhubarb species originally brought to Europe for medicinal purposes. Most rhubarb cultivars lack pedigree information, and the genetic relationship among cultivars is largely unknown. Amplified fragment length polymorphism (AFLP) markers were generated for fingerprint analysis of 37 cultivars and four putative Rheum species accessions. Ten EcoRI and MseI primer combinations were analyzed for a total of 1400 scored polymorphisms, with an average of 140 polymorphisms per primer combination. Results show at least two clusters of related cultivars, as well as distantly related accessions. This study provides an estimate of rhubarb cultivar genetic diversity using AFLP analysis.


2006 ◽  
Vol 1 (3) ◽  
pp. 1934578X0600100
Author(s):  
Sanjog T. Thul ◽  
Ajit K. Shasany ◽  
Mahendra P. Darokar ◽  
Suman P. S. Khanuja

Intra- and inter-specific genetic variation analysis was conducted using amplified fragment length polymorphism (AFLP) profiling in Capsicum accessions in the germplasms collected from different geographical locations in India. A total of 24 accessions were investigated belonging to six species, namely C. annuum, C. baccatum, C. chinence, C. eximium, C. frutescens and C. luteum. Average similarity within the 15 accessions of C. annuum was highest (100%) between accessions CIMAP/CA45 and CIMAP/CA49 obtained from IISR, Kerala and 43% among the species CIMAP/CC1 and CIMAP/CB2. In this analysis, accessions were clustered more pronouncedly according to their geographical locations than to their taxonomic labels. A great degree of intermixing of present day domesticated chillies is evident from the present study.


2009 ◽  
Vol 7 (03) ◽  
pp. 244-251 ◽  
Author(s):  
Didiana Gálvez-López ◽  
Sanjuana Hernández-Delgado ◽  
Maurilio González-Paz ◽  
Enrique Noe Becerra-Leor ◽  
Miguel Salvador-Figueroa ◽  
...  

Genetic diversity and relationships among 112 mango (Mangifera indica) plants native to 16 states of Mexico and four controls [three mango cultivars (Ataulfo, Manila and Tommy Atkins) and one accession ofMangifera odorata] were evaluated based on amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) molecular markers. Mango germplasm shows broad dispersion through Mexico and genetically similar germplasm from different agroecological regions has previously been found by our group. Both AFLP and SSR analyses indicated high genetic similarity among mango populations that were clustered in two major groups: mangos from Gulf of Mexico coastline and mangos from Pacific Ocean coastline and locations far away from the sea. The highest genetic diversity was found within plants from each state, and significant genetic differentiation (FST = 0.1921, AFLPs and 0.1911, SSRs) was also observed among mango populations based on geographical origin and genetic status (cultivars versus landraces). Heterozygosity values ranged from low (0.38) to moderate (0.68), and no heterozygote deficits were found. The highest genetic variability was found in mango populations from Tabasco, Michoacán and Oaxaca. Data suggested that mangoes are subjected to natural or induced pollination, so segregation as well as genetic recombination plays major roles on genetic diversification of Mexican mangos. AFLP analysis was more robust than SSR for determining the genetic relationships among mango landraces from Mexico.


2008 ◽  
Vol 7 (02) ◽  
pp. 122-126 ◽  
Author(s):  
Rouxlene Coetzee ◽  
Liezel Herselman ◽  
Maryke T. Labuschagne

Nineteen kenaf genotypes from Cuba, Taiwan, the USA, El Salvador, Guatemala, Russia, Spain and Indonesia, and three wild types collected in South Africa were analysed for genetic diversity using AFLP analysis. All could be uniquely distinguished from one another, but only a low level of genetic diversity was present. The most distinct accession, Guatemala 4, was 85% similar to all other accessions. The accessions clustered more or less according to known pedigree and/or origin. Two of the three wild types (Hibiscus cannabinusc andH. cannabinusa) clustered separately from the commercial and Russian accessions. One of the wild types,H. cannabinusb clustered with some of the commercial accessions. Commercial accessions in the first subgroup all originated from central and North America, and surrounding islands (Cuba and El Salvador). The Russian accessions are all grouped together. The second subgroup was the only group that contained accessions from different geographical origins.


2000 ◽  
Vol 90 (10) ◽  
pp. 1126-1130 ◽  
Author(s):  
Paul W. Tooley ◽  
Nichole R. O'Neill ◽  
Erin D. Goley ◽  
Marie M. Carras

Genetic diversity among isolates of Claviceps africana, the sorghum ergot pathogen, and isolates of other Claviceps spp. causing ergot on sorghum or other hosts, was analyzed by random amplified microsatellite (RAM) and amplified fragment length polymorphism (AFLP) analyses. Of the RAM primer sets tested, one revealed polymorphism in C. africana isolates, with Australian and Indian isolates possessing a unique fragment. AFLP analysis, in addition to clearly distinguishing Claviceps spp., revealed polymorphisms in C. africana. A group of isolates from the United States, Puerto Rico, and South Africa exhibited 95 to 100% similarity with one another. Several isolates from Isabela, Puerto Rico were 100% similar to an isolate from Texas, and another isolate from Puerto Rico was identical with one from Nebraska. Australian and Indian isolates showed greater than 90% similarity with isolates from the United States., Puerto Rico, and South Africa. A number of polymorphisms existed in the United States group, indicating that the recently introduced population contains multiple genotypes. Isolates of C. sorghicola, a newly described sorghum pathogen from Japan, were very distinct from other species via RAM and AFLP analyses, as were isolates from outgroups C. purpurea and C. fusiformis. Both RAM and AFLP analysis will be useful in determining future patterns of intercontinental migration of the sorghum ergot pathogen, with the AFLP method showing greater ability to characterize levels of intraspecific variation.


2006 ◽  
Vol 189 (3) ◽  
pp. 818-832 ◽  
Author(s):  
K. K. Hill ◽  
T. J. Smith ◽  
C. H. Helma ◽  
L. O. Ticknor ◽  
B. T. Foley ◽  
...  

ABSTRACT Clostridium botulinum is a taxonomic designation for many diverse anaerobic spore-forming rod-shaped bacteria that have the common property of producing botulinum neurotoxins (BoNTs). The BoNTs are exoneurotoxins that can cause severe paralysis and death in humans and other animal species. A collection of 174 C. botulinum strains was examined by amplified fragment length polymorphism (AFLP) analysis and by sequencing of the 16S rRNA gene and BoNT genes to examine the genetic diversity within this species. This collection contained representatives of each of the seven different serotypes of botulinum neurotoxins (BoNT/A to BoNT/G). Analysis of the16S rRNA gene sequences confirmed previous identifications of at least four distinct genomic backgrounds (groups I to IV), each of which has independently acquired one or more BoNT genes through horizontal gene transfer. AFLP analysis provided higher resolution and could be used to further subdivide the four groups into subgroups. Sequencing of the BoNT genes from multiple strains of serotypes A, B, and E confirmed significant sequence variation within each serotype. Four distinct lineages within each of the BoNT A and B serotypes and five distinct lineages of serotype E strains were identified. The nucleotide sequences of the seven toxin genes of the serotypes were compared and showed various degrees of interrelatedness and recombination, as was previously noted for the nontoxic nonhemagglutinin gene, which is linked to the BoNT gene. These analyses contribute to the understanding of the evolution and phylogeny within this species and assist in the development of improved diagnostics and therapeutics for the treatment of botulism.


2002 ◽  
Vol 37 (8) ◽  
pp. 1105-1114 ◽  
Author(s):  
Edson Barcelos ◽  
Philippe Amblard ◽  
Julien Berthaud ◽  
Marc Seguin

The objective of this work was to evaluate the genetic diversity, its organization and the genetic relationships within oil palm (Elaeis oleifera (Kunth) Cortés, from America, and E. guineensis (Jacq.), from Africa) germplasm using Restriction Fragment Length Polymorphism (RFLP) and Amplified Fragment Length Polymorphism (AFLP). In complement to a previous RFLP study on 241 E. oleifera accessions, 38 E. guineensis accessions were analyzed using the same 37 cDNA probes. These accessions covered a large part of the geographical distribution areas of these species in America and Africa. In addition, AFLP analysis was performed on a sub-set of 40 accessions of E. oleifera and 22 of E. guineensis using three pairs of enzyme/primer combinations. Data were subjected to Factorial Analysis of Correspondence (FAC) and cluster analysis, with parameters of genetic diversity being also studied. Results appeared congruent between RFLP and AFLP. In the E. oleifera, AFLP confirmed the strong structure of genetic diversity revealed by RFLP, according to geographical origin of the studied material, with the identification of the same four distinct genetic groups: Brazil, French Guyana/Surinam, Peru, north of Colombia/Central America. Both markers revealed that genetic divergence between the two species is of the same magnitude as that among provenances of E. oleifera. This finding is in discrepancy with the supposed early tertiary separation of the two species.


2004 ◽  
Vol 70 (5) ◽  
pp. 2786-2790 ◽  
Author(s):  
S. A. Burke ◽  
J. D. Wright ◽  
M. K. Robinson ◽  
B. V. Bronk ◽  
R. L. Warren

ABSTRACT Phenotypically, Bacillus atrophaeus is indistinguishable from the type strain of Bacillus subtilis except by virtue of pigment production on certain media. Several pigmented variants of B. subtilis have been reclassified as B. atrophaeus, but several remain ambiguous in regard to their taxonomic placement. In this study, we examined strains within the American Type Culture Collection originally deposited as Bacillus globigii, B. subtilis var. niger, or Bacillus niger using 16S rRNA gene sequencing and amplified fragment length polymorphism (AFLP) analysis to determine the level of molecular diversity among these strains and their relationship with closely related taxa. The 16S rRNA gene sequences revealed little variation with one base substitution between the B. atrophaeus type strain ATCC 49337 and the other pigmented bacilli. AFLP analysis produced high-quality DNA fingerprints with sufficient polymorphism to reveal strain-level variation. Cluster analysis of Dice similarity coefficients revealed that three strains, ATCC 31028, ATCC 49760, and ATCC 49822, are much more closely related to B. atrophaeus than to B. subtilis and should be reclassified as B. atrophaeus. A very closely related cluster of B. atrophaeus strains was also observed; this cluster was genetically distinct from the type strain. The level of variation between the two groups was approximately the same as the level of variation observed between members of the two B. subtilis subspecies, subtilis and spizizenii. It is proposed that the cluster of strains typified by ATCC 9372 be designated a new subspecies, B. atrophaeus subsp. globigii.


2017 ◽  
Vol 107 (6) ◽  
pp. 769-776 ◽  
Author(s):  
Justine Beaulieu ◽  
Blaine Ford ◽  
Yilmaz Balci

Genetic diversity of two Phytophthora spp.—P. cinnamomi (102 isolates), commonly encountered in Maryland nurseries and forests in the Mid-Atlantic United States, and P. plurivora (186 isolates), a species common in nurseries—was characterized using amplified fragment length polymorphism. Expected heterozygosity and other indices suggested a lower level of diversity among P. cinnamomi than P. plurivora isolates. Hierarchical clustering showed P. cinnamomi isolates separated into four clusters, and two of the largest clusters were closely related, containing 80% of the isolates. In contrast, P. plurivora isolates separated into six clusters, one of which included approximately 40% of the isolates. P. plurivora isolates recovered from the environment (e.g., soil and water) were genotypically more diverse than those found causing lesions. For both species, isolate origin (forest versus nursery or among nurseries) was a significant factor of heterozygosity. Clonal groups existed within P. cinnamomi and P. plurivora and included isolates from both forest and nurseries, suggesting that a pathway from nurseries to forests or vice versa exists.


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