Genetic diversity of poplar leaf rust populations in the north-central United States

2006 ◽  
Vol 36 (8) ◽  
pp. 2047-2057 ◽  
Author(s):  
W Chen ◽  
T C Harrington
Keyword(s):  
Leaf Rust ◽  
Populus Deltoides ◽  
Gene Diversity ◽  
Early Stage ◽  
Alternate Host ◽  
Weinberg Equilibrium ◽  
The North ◽  
Hardy Weinberg Equilibrium ◽  
Poplar Leaf ◽  
Poplar Leaf Rust

Uredinia of poplar leaf rust, Melampsora medusae Thüm f.sp. deltoides, appeared in late July 1998, June 1999, and August 2000 in a cottonwood (Populus deltoides Bartr.) stand in Ames, Iowa. Seedlings of the alternate host (eastern larch, Larix laricina (Du Roi) K. Koch) set out at the site in spring 2000 formed aecia 3 months before uredinia appeared. Using three PCR-based microsatellite markers, the aecial population was genetically diverse and in Hardy–Weinberg equilibrium, typical of a population that had gone through sexual reproduction. Uredinia populations in 1998–2000 had lower levels of gene diversities (from 0.58 to 0.71) and were not in Hardy–Weinberg equilibrium. Of nine populations in Minnesota, Iowa, and Missouri during the early stage of the 1999 epidemic, the two populations with the highest gene diversity, the highest level of heterozygosity, and the greatest number of unique genotypes were within the natural geographic range of larch. However, the southernmost population in Missouri was also in Hardy–Weinberg equilibrium. Epidemics started sooner in Iowa than in Minnesota, which contradicts the hypothesis that epidemics begin in northern regions where the alternate hosts naturally overlap. Epidemics appeared to commence independently in the various locations, perhaps focused around areas where ornamental larch is in proximity to P. deltoides.

scholarly journals Specificity of SSR loci for Melampsora species on poplars

Genetika ◽  
2010 ◽  
Vol 42 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Vladislava Galovic ◽  
Sasa Orlovic ◽  
Predrag Pap ◽  
Branislav Kovacevic ◽  
Miroslav Markovic
Keyword(s):  
Leaf Rust ◽  
Ssr Markers ◽  
Populus Deltoides ◽  
Rust Fungi ◽  
Population Composition ◽  
Melampsora Medusae ◽  
Ssr Loci ◽  
Poplar Leaf ◽  
Growing Region ◽  
Poplar Leaf Rust

Two rust fungi, Melampsora larici populina and Melampsora medusae are common in all poplar growing regions worlwide. M. larici populina is native to Eurasia, while M. medusae is endemic to eastern Unated States on Populus deltoides. Poplar leaf rust (Melampsora sp.) is widely spread disease in our country, and can cause significant growing problems. Race that prevails in our growing region is M. Larici populina. This work initiated the research of population composition, i.e. qualitative participation of Melampsora races in popoluation of black poplars hybrid progenies using molecular methods. When five SSR markers were used the results showed that M. larici populina was found in three tested clones, while only M. medusae was determined in clone I-214.

scholarly journals The First Record of a North American Poplar Leaf Rust Fungus, Melampsora medusae, in China

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 182 ◽  
Author(s):  
Wei Zheng ◽  
George Newcombe ◽  
Die Hu ◽  
Zhimin Cao ◽  
Zhongdong Yu ◽  
...  
Keyword(s):  
Leaf Rust ◽  
North American ◽  
Populus Deltoides ◽  
Large Subunit ◽  
Morphological Characteristics ◽  
Rrna Gene ◽  
Melampsora Medusae ◽  
Wide Range ◽  
Poplar Leaf ◽  
Poplar Leaf Rust

A wide range of species and hybrids of black and balsam poplars or cottonwoods (Populus L., sections Aigeiros and Tacamahaca) grow naturally, or have been introduced to grow in plantations in China. Many species of Melampsora can cause poplar leaf rust in China, and their distributions and host specificities are not entirely known. This study was prompted by the new susceptibility of a previously resistant cultivar, cv. ‘Zhonghua hongye’ of Populus deltoides (section Aigeiros), as well as by the need to know more about the broader context of poplar leaf rust in China. Rust surveys from 2015 through 2018 in Shaanxi, Sichuan, Gansu, Henan, Shanxi, Qinghai, Beijing, and Inner Mongolia revealed some samples with urediniospores with the echinulation pattern of M. medusae. The morphological characteristics of urediniospores and teliospores from poplar species of the region were further examined with light and scanning electron microscopy. Phylogenetic analysis based on sequences of the rDNA ITS region (ITS1, 5.8S rRNA gene, and ITS2) and the nuclear large subunit rDNA (D1/D2) was used to further confirm morphology-based identification. Based on combined analyses, five of the fifteen fully characterized samples were identified as Melampsora medusae: one from Shaanxi and four from Sichuan. Two of the five were from Populus deltoides cv. ‘Zhonghua hongye’. Three others were identified on Populus szechuanica, P. simonii, and P. yunnanensis. Additional samples of M. medusae were collected in Shaanxi in 2017 and 2018, and from Henan in 2015 through 2018. Altogether these findings show that this introduced pathogen is widespread and persistent from year to year in China. This is the first report of this North American poplar leaf rust species, Melampsora medusae, in China. It has previously been reported outside North America in Argentina, Europe, Australia, New Zealand, Japan, and Russia.

scholarly journals Bulked Segregant Analysis Identifies Molecular Markers Linked to Melampsora medusae Resistance in Populus deltoides

2000 ◽  
Vol 90 (9) ◽  
pp. 1039-1042 ◽  
Author(s):  
G. M. Tabor ◽  
T. L. Kubisiak ◽  
N. B. Klopfenstein ◽  
R. B. Hall ◽  
H. S. McNabb McNabb
Keyword(s):  
Molecular Markers ◽  
Leaf Rust ◽  
Populus Deltoides ◽  
Bulked Segregant Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Genetic Distances ◽  
Resistance Locus ◽  
The North ◽  
Melampsora Medusae ◽  
Central United States

In the north central United States, leaf rust caused by Melampsora medusae is a major disease problem on Populus deltoides. In this study we identified molecular markers linked to a M. medusae resistance locus (Lrd1) that was segregating 1:1 within an intraspecific P. deltoides family (C9425DD). Previous field results were confirmed in the controlled environment of a growth chamber through an excised whole-leaf inoculation method. Using bulked segregant analysis we identified two random amplified polymorphic DNA (RAPD) markers (OPG10340 and OPZ191800) that are linked to Lrd1. Based on segregation in a total of 116 progeny, the genetic distances between OPG10340 and OPZ191800 and the resistance locus were estimated as 2.6 and 7.4 Haldane centimorgans (cM), respectively. Multipoint linkage analyses strongly suggest the most likely order for these loci is Lrd1, OPG10340, and OPZ191800. These markers may prove to be instrumental in the eventual cloning of Lrd1, as well as for marker-assisted selection of leaf-rust resistant genotypes.

scholarly journals Genetic Diversity in Poplar Leaf Rust (Melampsora medusae f. sp. deltoidae) in the Zones of Host Sympatry and Allopatry

2007 ◽  
Vol 97 (5) ◽  
pp. 603-610 ◽  
Author(s):  
M. Bourassa ◽  
L. Bernier ◽  
R. C. Hamelin
Keyword(s):  
Leaf Rust ◽  
Geographic Origin ◽  
Allelic Diversity ◽  
Genotypic Frequency ◽  
Single Strand Conformational Polymorphism ◽  
Melampsora Medusae ◽  
Natural Stands ◽  
Almost All ◽  
Poplar Leaf ◽  
Poplar Leaf Rust

Poplar leaf rust caused by Melampsora medusae f. sp. deltoidae is a widespread disease in North America, where epidemics occur within zones of sympatry and allopatry of telial hosts (Populus spp.) and aecial hosts (Larix spp.). To test the hypothesis that epidemics originate in the zone of sympatry where the rust can complete its life cycle, populations in sympatry and allopatry were analyzed with single-strand conformational polymorphism for codominant detection of alleles directly from uredinia. More alleles were detected in rust populations in the zone of host sympatry than in allopatry. Almost all alleles found in the zone of allopatry were a subset of the allelic diversity present in the zone of host sympatry. Distance analyses clustered populations according to geographic origin, but not sampling year or type of stand (plantation or natural stands). Large differences in allelic and genotypic frequency were observed between years in allopatry but not in sympatry, suggesting new colonizations in allopatric populations. Our results point to a dynamic and complex pattern of inoculum dissemination in polar leaf rust. The hypothesis most consistent with our results is that populations in sympatry represent a source of inoculum for epidemics, with some annual recolonization in allopatry, possibly via intermediate population jumps.

scholarly journals Association Analysis Identifies Melampsora ×columbiana Poplar Leaf Rust Resistance SNPs

PLoS ONE ◽  
2013 ◽  
Vol 8 (11) ◽  
pp. e78423 ◽  
Author(s):  
Jonathan La Mantia ◽  
Jaroslav Klápště ◽  
Yousry A. El-Kassaby ◽  
Shofiul Azam ◽  
Robert D. Guy ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Association Analysis ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Poplar Leaf ◽  
Poplar Leaf Rust

Influence of leaf wetness, temperature, and rain on poplar leaf rust epidemics

1992 ◽  
Vol 22 (9) ◽  
pp. 1249-1254 ◽  
Author(s):  
Richard C. Hamelin ◽  
Louis Shain ◽  
Bart A. Thielges
Keyword(s):  
Leaf Rust ◽  
Limiting Factors ◽  
Leaf Wetness ◽  
Natural Stand ◽  
Eastern Cottonwood ◽  
High Maximum ◽  
Detached Leaves ◽  
Maximum Temperatures ◽  
Poplar Leaf ◽  
Poplar Leaf Rust

Severe epidemics of poplar leaf rust, caused by Melampsoramedusae Thüm. f.sp. deltoidae, developed on eastern cottonwood, Populusdeltoides Bartr., in 1988 and 1989 in a mixed clonal plantation and in a natural stand in western Kentucky despite precipitation deficits and high maximum temperatures during the exponential phase of the epidemic. Minimum temperatures during that period, however, were within the range reported to be optimal for uredospore germination (15–21 °C). Average duration of leaf wetness for the entire epidemic was 10.6 h in 1988, and 11.2 and 11.7 h in 1989 in the natural stand and the plantation, respectively. Maximum infection of artificially inoculated detached leaves of eastern cottonwood occurred after 8 h of continuous leaf wetness. These results suggest that rain deficit and high maximum temperatures are not limiting factors for poplar leaf rust epidemics when night conditions frequently offer optimal temperature and leaf wetness for infection.

Prediction of poplar leaf rust epidemics from a leaf-disk assay

1994 ◽  
Vol 24 (10) ◽  
pp. 2085-2088 ◽  
Author(s):  
Richard C. Hamelin ◽  
Richard S. Ferriss ◽  
Louis Shain ◽  
Bart A. Thielges
Keyword(s):  
Leaf Rust ◽  
Field Tests ◽  
Leaf Disk ◽  
Relative Area ◽  
Progress Curve ◽  
Intermediate Resistance ◽  
Poplar Leaf ◽  
Parent Ratio ◽  
Poplar Leaf Rust ◽  
Leaf Disks

The reliability of a leaf-disk assay to assess resistance of Populusdeltoides Bartr. to Melampsoramedusae Thuëm. f.sp. deltoidae, the causal agent of poplar leaf rust, was evaluated. Leaf disks of eight host genotypes were inoculated in a spore settling tower with 11 isolates of the pathogen in all possible combinations, and the latent period, infection probability, sporulation, and progeny/parent ratio were recorded. Correlations were established between these measures and measures derived from field epidemics, namely the relative area under the disease progress curve, the apparent rate of infection, the final disease severity, and the number of days before defoliation. Four genotypes were highly resistant to all 11 isolates tested with the leaf-disk assay and to the local inoculum in field tests. Three genotypes were highly susceptible in inoculation assays and were also susceptible in the field. One genotype was highly resistant in inoculation assays but had intermediate resistance in the field. Significant correlations (p < 0.05) were found between all leaf-disk and all field parameters.

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