Clone by isolate interaction in the hybrid poplar – Septoria musiva pathosystem

2008 ◽  
Vol 38 (7) ◽  
pp. 1888-1896 ◽  
Author(s):  
Jared M. LeBoldus ◽  
Peter V. Blenis ◽  
Barb R. Thomas
Keyword(s):  
Native Species ◽  
Populus Deltoides ◽  
Hybrid Poplar ◽  
Interaction Effects ◽  
Resistance Screening ◽  
Preliminary Screening ◽  
Screening Programs ◽  
Hybrid Poplars ◽  
Septoria Musiva ◽  
Explained Variation

Fourteen clones of hybrid poplar were inoculated with 19 isolates of Septoria musiva Peck under greenhouse conditions to determine the magnitude of the clone, isolate, and clone × isolate interaction effects. Septoria musiva isolates were collected from five geographic areas, two symptoms (canker and leaf spot), and two host types (native species and hybrid poplar). The hybrid poplar clones were classified by parent type ( Populus deltoides Bartr. ex Marsh., Populus laurifolia Lebed. × Populus nigra L., and P. deltoides × (P. laurifolia × P. nigra)). There were no significant differences among geographic areas (p = 0.443), symptoms (p = 0.842), or hosts (p = 0.304) of origin for the 19 isolates nor significant differences among the three parent types (p = 0.089). Clone, isolate, and clone × isolate interaction effects were all significant, accounting for 65%, 15%, and 18%, respectively, of the explained variation. These results indicate that clones rather than parent types should be the focus of resistance screening programs and that the pathosystem should be stable given the relatively small clone × isolate interaction. These results also indicate that a single isolate should be sufficient for preliminary screening of disease resistance in hybrid poplars.

scholarly journals Biological Control of Septoria Leaf Spot Disease of Hybrid Poplar in the Field

Plant Disease ◽  
2003 ◽  
Vol 87 (7) ◽  
pp. 809-813 ◽  
Author(s):  
Laszlo Gyenis ◽  
Neil A. Anderson ◽  
Michael E. Ostry
Keyword(s):  
Biological Control ◽  
Leaf Spot ◽  
Field Experiments ◽  
Hybrid Poplar ◽  
Leaf Spot Disease ◽  
Leaf Disease ◽  
Hybrid Poplars ◽  
Septoria Musiva ◽  
Triton X ◽  
Septoria Leaf Spot

Biological control of Septoria leaf spot of hybrid poplars was investigated using disease-suppressive Streptomyces strains. Field experiments were conducted in 1998 and 1999 on potted trees placed in a hybrid poplar plantation near Rosemount, MN, and on field-planted trees in 1998 at St. Paul. At both locations, one resistant and three susceptible hybrid poplar clones were sprayed with Streptomyces spore suspensions and exposed to natural field inoculum of Septoria musiva. In the 1998 potted-tree experiment, strains GS-93-3, 93, and Mycostop in Tergitol or Triton X-100 solutions applied every 7 days significantly reduced leaf disease by 29 to 83% compared with the controls. In the 1999 potted-tree experiment, Streptomyces strain mixtures in Tergitol solution applied every 5 days significantly reduced leaf disease by 50 to 87% compared with the controls. In the 1998 plantation experiment, strains GS-93-3, 93, or Mycostop in Tergitol solution applied weekly, bi-monthly, or monthly significantly reduced leaf disease in all treatments by 64 to 78% compared with the controls.

scholarly journals Variation in Septoria musiva and Implications for Disease Resistance Screening of Poplars

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1077-1082 ◽  
Author(s):  
K. T. Ward ◽  
M. E. Ostry
Keyword(s):  
Disease Resistance ◽  
Random Amplified Polymorphic Dna ◽  
Molecular Genetic ◽  
Hybrid Poplar ◽  
Field Resistance ◽  
Leaf Disk ◽  
Resistance Screening ◽  
Septoria Musiva ◽  
Disease Resistance Screening

A set of isolates of Septoria musiva differed in aggressiveness in hybrid poplar leaf disk and stem assays and culture growth in vitro. Clone × isolate interactions were observed in one of the stem assay experiments, but not in the leaf disk assay experiments. Random amplified polymorphic DNA (RAPD) analyses were performed using 52 isolates of S. musiva collected from hybrid poplars and a native poplar species in Minnesota, Wisconsin, Iowa, South Dakota, and North Dakota. There was a large degree of genetic similarity, although each isolate had a unique RAPD pattern. No relationships among isolates were found for molecular genetic distance and host clone, parentage, or taxonomic classification section; location or date of collection; or the previously determined level of field resistance of the host clones to Septoria canker. Results of the stem and leaf disk assays indicate that it may not be necessary to choose the most aggressive isolate for disease resistance screening. It may be more useful to select isolates that will discriminate the greatest variation in levels of disease resistance among the clones that are being screened.

Test précoce pour l'évaluation de la sensibilité de peupliers hybrides au chancre septorien

1991 ◽  
Vol 67 (4) ◽  
pp. 411-416 ◽  
Author(s):  
Marie-Josée Mottet ◽  
Gilles Vallée ◽  
Guy Bussières
Keyword(s):  
Fungal Pathogen ◽  
Hybrid Poplar ◽  
Hybrid Poplars ◽  
Leaf Spots ◽  
Low Degree ◽  
Septoria Musiva ◽  
High Incidence ◽  
Screening For Resistance ◽  
Poplar Plantations ◽  
Populus Spp

Septoria musiva, a fungal pathogen that causes cankers and leaf spots, is found in hybrid poplar plantations (Populus spp.) in southern Québec. A high incidence of severe cankers is observed on susceptible poplars. To accelerate the evaluation for resistance to Septoria canker, sprouts were inoculated with S. musiva twice in the nursery. From the 725 clones tested, 100 showed a low degree of susceptibility. Among these, 45 belong to the Ageiros section, 13 to the Tacamahaca section and 42 are hybrids between the two sections. The four isolates used in this test demonstrate variations in aggressiveness. Key words: Septoria musiva, Septoria canker, screening for resistance, hybrid poplars.

Species-specific single nucleotide polymorphism markers for detecting hybridization and introgression in poplarThis article is one of a selection of papers published in the Special Issue on Poplar Research in Canada.

2007 ◽  
Vol 85 (11) ◽  
pp. 1082-1091 ◽  
Author(s):  
Patrick G. Meirmans ◽  
Manuel Lamothe ◽  
Pierre Périnet ◽  
Nathalie Isabel
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Native Species ◽  
Populus Deltoides ◽  
Hybrid Poplar ◽  
Restriction Enzymes ◽  
Snp Markers ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Important Species ◽  
Species Specific

The increasing use of exotic and hybrid poplar species in forestry and the lack of genetic barriers between most poplar species may present a risk to the genetic integrity of native poplar species. To monitor any spontaneous hybridization and (or) introgression from exotics into native species, it is essential to have a system for the quick and reliable identification of species. We developed a set of single nucleotide polymorphism (SNP) markers that allows the distinction between five commercially important species of poplar ( Populus balsamifera L., Populus deltoides Marsh., Populus trichocarpa Toor. ex Gray, Populus nigra L., and Populus maximowiczii Henry) and their hybrids. Six genomic regions spanning 6.1 kb were screened at the DNA sequence level to search for discriminating SNPs among the five species. A total of 245 SNPs and indels were found, 86 of which were species specific. A subset of 12 species-specific SNPs was chosen for use with high-throughput SNPstream technology. In addition, 32 species-specific SNPs and indels were found that can be assayed using restriction enzymes. Application of the developed markers to a set of hybrid clones showed that the markers are not only useful for monitoring introgression but also for the verification of breeding material.

scholarly journals Recessive Resistance to Septoria Stem Canker of Hybrid Poplar

2001 ◽  
Vol 91 (11) ◽  
pp. 1081-1084 ◽  
Author(s):  
George Newcombe ◽  
Mike Ostry
Keyword(s):  
Populus Deltoides ◽  
Single Gene ◽  
Hybrid Poplar ◽  
Recessive Gene ◽  
Stem Canker ◽  
Conclusive Evidence ◽  
Recessive Inheritance ◽  
Black Cottonwood ◽  
Septoria Musiva ◽  
Serious Disease

Stem canker, caused by Septoria musiva, is the most serious disease limiting intensive hybrid poplar culture in eastern North America. Populus deltoides (D) is itself resistant, but the susceptibility of western black cottonwood, P. trichocarpa (T) is apparently dominant in the F1 generation. To test a hypothesis of recessive inheritance of canker resistance, a three-generation T × D pedigree was deployed in the field in Iowa and Minnesota. In both sites and in keeping with expectations, P. trichocarpa and its F1 hybrids were susceptible to canker, whereas the P. deltoides parent was resistant. In Iowa, 10 of 70 F2 (TD × TD) individuals were free of canker, suggesting that a single recessive gene might control resistance. In the third year in Minnesota, more resistant individuals than expected were seen in the F2 generation and in TD × D and T × TD backcross progenies due to disease escape. By the fifth year, this was no longer an issue, but winter injury may have eliminated many clones. Qualitatively, however, evidence for recessive inheritance of resistance was still obtained. The only canker-free clones were in the TD × D backcross and the F2 generation, the two progenies in which they were expected. However, conclusive evidence that recessive canker resistance is conferred by a single gene was not obtained in this field study.

scholarly journals Genetic Structure of Mycosphaerella populorum (Anamorph Septoria musiva) Populations in North-Central and Northeastern North America

2005 ◽  
Vol 95 (6) ◽  
pp. 608-616 ◽  
Author(s):  
Nicolas Feau ◽  
Richard C. Hamelin ◽  
Céline Vandecasteele ◽  
Glen R. Stanosz ◽  
Louis Bernier
Keyword(s):  
Genetic Structure ◽  
Populus Deltoides ◽  
Isolation By Distance ◽  
Random Amplified Polymorphic Dna ◽  
Local Level ◽  
Hybrid Poplar ◽  
Data Set ◽  
Haplotypic Diversity ◽  
Septoria Musiva ◽  
Mycosphaerella Populorum

In order to characterize the genetic variation of the poplar pathogen Mycosphaerella populorum (anamorph Septoria musiva), we have studied seven North American populations using the polymerase chain reaction random amplified polymorphic DNA (RAPD) technique. The fungal populations were sampled in 2001 and 2002 by obtaining 352 isolates from cankers and leaf spots in hybrid poplar plantations and adjacent eastern cottonwood (Populus deltoides). A total of 21 polymorphic RAPD markers were obtained with the six RAPD primers used. A fine-level scale analysis of the genetic structure within the populations revealed that subpopulations sampled on P. deltoides and on hybrid trees were not significantly differentiated. In contrast, analyses performed on the entire data set showed high levels of haplotypic diversity and moderate to high genetic differentiation, with 20% of the expected genetic diversity found at the interpopulation level. Moreover, a high and significant correlation between genetic and geographic distances among populations was found, suggesting isolation by distance of the sampled populations. Although the occurrence of the sexual stage of this fungus remained unclear in field populations, five of the six populations were at gametic equilibrium for RAPD loci, suggesting the occurrence of recombination episodes in Septoria musiva populations. Overall, S. musiva appears to consist of differentiated subpopulations, with both asexual and sexual recombination contributing to the local level of genetic structure.

scholarly journals The Histology of Hybrid Poplar Clones Inoculated with Septoria musiva

Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1524-1530 ◽  
Author(s):  
Jerry E. Weiland ◽  
Glen R. Stanosz
Keyword(s):  
Hybrid Poplar ◽  
Host Responses ◽  
Fungal Colonization ◽  
Wound Surface ◽  
Hybrid Poplars ◽  
Poplar Clones ◽  
Agar Plug ◽  
Septoria Musiva ◽  
Tissue Responses ◽  
Stem Cankers

Septoria musiva causes stem cankers that severely limit production of susceptible hybrid poplars in eastern North America. A field experiment was conducted with resistant clone DN34 and susceptible clone NC11505 in order to (i) identify tissues colonized by the pathogen, (ii) describe tissue responses to S. musiva, and (iii) determine whether tissue responses to S. musiva differed between hybrid poplar clones. Branches of each clone were inoculated by removing the fourth or fifth fully expanded leaf and placing an agar plug colonized by an aggressive isolate of S. musiva over the wound. Seven weeks after inoculation, branches were harvested and prepared for histology. Data from nonwounded control, wounded control, and wounded and inoculated stems were collected and analyzed for effects of clone and treatment. In general, fungal colonization was more extensive in NC11505 and exophylactic and necrophylactic periderms (NPs) of clone DN34 were significantly thicker than those of NC11505, regardless of treatment. The number of NPs produced and the distance from the epidermis to the outermost layer of phellem were significantly affected by the pathogen. Inoculated stems of clone DN34 developed a single NP that formed closer to the wound surface than in wounded controls. In contrast, inoculated stems of NC11505 developed successive NPs and the first NP formed further from the wound surface than in wounded controls. These two host responses to inoculation, as well as measures of exophylactic and necrophylactic periderm thickness, may be useful as markers for the selection of poplar resistant to damage by S. musiva.

scholarly journals The CP4 transgene provides high levels of tolerance to Roundup® herbicide in field-grown hybrid poplars

2002 ◽  
Vol 32 (6) ◽  
pp. 967-976 ◽  
Author(s):  
R Meilan ◽  
K -H Han ◽  
C Ma ◽  
S P DiFazio ◽  
J A Eaton ◽  
...  
Keyword(s):  
Populus Tremuloides ◽  
Populus Deltoides ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Field Studies ◽  
Glyphosate Tolerance ◽  
Hybrid Poplars ◽  
Transgenic Lines ◽  
Identical Number ◽  
Better Than

We tested two genes together in hybrid poplars (genus Populus), CP4 and GOX, for imparting tolerance to glyphosate (the active ingredient in Roundup® herbicide). Using Agrobacterium-based transformation, 80 independent transgenic lines (i.e., products of asexual gene transfer) were produced in a variety of hybrid poplar clones (40 lines in Populus trichocarpa Torr. & Gray × Populus deltoides Bartr., 35 lines in Populus tremula L. × Populus alba L., and five lines in P. tremula × Populus tremuloides Michx.). We evaluated glyphosate tolerance over 2 years in field studies conducted in eastern and western Oregon. Ten percent of our transgenic lines showed no foliar damage or reduced growth after being sprayed with Roundup® at concentrations above normal commercial rates. Lack of damage was associated with expression of the CP4 gene but not of the GOX gene. It was suspected that GOX caused undesirable side effects, so we produced 12 lines into which only the CP4 gene was inserted. The performance of these newly regenerated lines was compared with an identical number of lines, produced in the same genotype, that had previously been engineered to contain both CP4 and GOX. Growth of the lines transformed with just CP4 was significantly better than those containing both genes and exhibited less damage in response to glyphosate treatment. This is the first report of transgenic poplars exhibiting high levels of glyphosate tolerance when grown under field conditions. With a modest transformation effort, it is possible to produce lines with commercially useful levels of glyphosate tolerance and little apparent collateral genetic damage.

Growth and nutrition of hybrid poplars over 3 years after fertilization at planting

2002 ◽  
Vol 32 (2) ◽  
pp. 226-232 ◽  
Author(s):  
K R Brown ◽  
R van den Driessche
Keyword(s):  
Controlled Release ◽  
Populus Deltoides ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Vancouver Island ◽  
Poplar Plantation ◽  
Hybrid Poplars ◽  
Growth And Nutrition ◽  
Controlled Release Fertilizers

A hybrid poplar plantation on eastern Vancouver Island was fertilized at planting with two readily soluble and four controlled-release fertilizers (CRF). The CRFs varied in their duration of release and in their ratio of N to other elements. Fertilizers were applied at rates supplying 0, 13.5, or 27 g N/tree (N0, N13.5, and N27 treatments). The plantation contained one Populus trichocarpa Torr. & Gray × Populus deltoides Bartr. ex Marsh. (T × D) and one P. trichocarpa × Populus maximowiczii A. Henry (T × M) hybrid. The T × D hybrid was consistently larger than the T × M hybrid. After 1 year, stem volumes were 24 and 35% greater in the N13.5 and N27 treatments, respectively; after 3 years, volumes were 9 and 21% greater, respectively. Volumes of trees fertilized with readily soluble fertilizers did not differ from those fertilized with CRFs, but volumes may have differed between CRFs. Growth of poplar on this site appeared to be limited by multiple elemental deficiencies, particularly of N, P, and S.

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