Susceptibility of Populus balsamifera to Septoria musiva: A Field Study and Greenhouse Experiment

A greenhouse inoculation experiment and field study were conducted to determine the cause of an outbreak of Septoria musiva cankers on Populus balsamifera in a northern Alberta plantation. Four clones of P. balsamifera, five clones of putatively resistant P. deltoides, and one susceptible hybrid poplar clone, Northwest, were inoculated with seven isolates identified as S. musiva. Four of the isolates were from P. balsamifera in Alberta and the others were from P. deltoides in Quebec. Results indicated that disease severity was similar for Alberta and Quebec isolates (P = 0.243) and that P. balsamifera had the greatest mean disease severity (x-bar = 4.20), P. deltoides had the lowest (x-bar = 2.76), and Northwest was intermediate (x-bar = 3.45). A genetic analysis comparing six polymorphic polymerase chain reaction restriction fragment length polymorphism loci and the mitochondrial small subunit ribosomal DNA sequences of the seven isolates indicated that the Alberta population was made up of at least three distinct genotypes. Canker incidence and age on Northwest and 56 different clones of P. balsamifera in a plantation were recorded. Canker incidence (P = 0.726) and the canker age distributions (P = 0.994) were similar for the two species. In conclusion, contrary to what has been reported in the literature, P. balsamifera appears to be quite susceptible to Septoria canker.

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A Method to Induce Stem Cankers by Inoculating Nonwounded Populus Clones with Septoria musiva Spore Suspensions

Plant Disease ◽

10.1094/pdis-02-10-0094 ◽

2010 ◽

Vol 94 (10) ◽

pp. 1238-1242 ◽

Cited By ~ 11

Author(s):

Jared M. LeBoldus ◽

Peter V. Blenis ◽

Barb R. Thomas

Keyword(s):

Disease Severity ◽

Hybrid Poplar ◽

Field Studies ◽

Conidial Suspension ◽

Populus Balsamifera ◽

Inoculation Method ◽

Spray Inoculation ◽

Septoria Musiva ◽

Artificial Inoculations ◽

Canker Development

Most artificial inoculations of Populus spp. stems with Septoria musiva have required host wounding to induce canker development; in the absence of wounds, frequencies of cankers have been low. Three greenhouse inoculation experiments were conducted to demonstrate the reliability and repeatability of an inoculation method that did not require wounding. In the first, 16 clones of hybrid poplar were inoculated with three isolates of S. musiva to compare responses following wounding and inoculation with mycelium (wound inoculation) with responses following inoculation of nonwounded trees by spraying with a conidial suspension (spray inoculation). Stem disease severity among clones following spray inoculation was correlated with stem disease severity following wound inoculation. A significant clone–isolate interaction was detected with spray inoculation but not wound inoculation. In the other two greenhouse experiments, 29 clones of hybrid poplar and 69 clones of Populus balsamifera were inoculated with a spore suspension mixture of three isolates. In both cases, the experimental error was similar to that obtained in previous experiments, in which trees were wound inoculated, and was adequately small to permit detection of differences in responses among clones. Ultimately, field studies will be needed to determine the best inoculation method for predicting stem responses to this pathogen under field conditions. However, relative to wound inoculation, spray inoculation of nonwounded trees has the advantage of yielding faster results, permitting inoculation with a mixture of isolates, and not circumventing potential mechanisms for resisting penetration. The ability to infect stems without wounding creates opportunities for numerous types of epidemiological and disease control studies that are difficult to conduct with wound inoculation.

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Systematic status of Campydora Cobb, 1920 (Nematoda: Campydorina)

Nematology ◽

10.1163/156854103322746878 ◽

2003 ◽

Vol 5 (5) ◽

pp. 699-711 ◽

Cited By ~ 6

Author(s):

Peter Mullin ◽

Timothy Harris ◽

Thomas Powers

Keyword(s):

Maximum Likelihood ◽

Ribosomal Dna ◽

Dna Sequences ◽

Maximum Parsimony ◽

Phylogenetic Analyses ◽

Small Subunit ◽

Systematic Position ◽

Nominal Species ◽

Competing Hypotheses ◽

Small Subunit Ribosomal Dna

AbstractThe systematic position of Campydora Cobb, 1920, which possesses many unique morphological features, especially in pharyngeal structure and stomatal armature, has long been a matter of uncertainty with the 'position of the Campydorinae' (containing only Campydora) being questionable. A review of the morphology of C. demonstrans, the only nominal species of Campydora concluded that the species warranted placement as the sole member of a monotypic suborder, Campydorina, in the order Dorylaimida. Others placed Campydorina in the order Enoplida. We conducted phylogenetic analyses, using 18s small subunit ribosomal DNA sequences generated from a number of taxa in the subclasses Enoplia and Dorylaimia, to evaluate these competing hypotheses. Although precise taxonomic placement of the genus Campydora and the identity of its closest living relatives is in need of further investigation, our analyses, under maximum parsimony, distance, and maximum likelihood criteria, unambiguously indicate that Campydora shares a common, more recent, ancestry with genera such as Alaimus, Pontonema, Tripyla and Ironus (Enoplida), rather than with any members of Dorylaimida, Mononchida or Triplonchida.

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Rapid identification of Prototheca zopfii by nested polymerase chain reaction based on the nuclear small subunit ribosomal DNA

Journal of Dermatological Science ◽

10.1016/j.jdermsci.2008.10.009 ◽

2009 ◽

Vol 54 (1) ◽

pp. 56-59 ◽

Cited By ~ 3

Author(s):

Masanobu Onozaki ◽

Koichi Makimura ◽

Atsuhiko Hasegawa

Keyword(s):

Polymerase Chain Reaction ◽

Ribosomal Dna ◽

Small Subunit ◽

Rapid Identification ◽

Chain Reaction ◽

Nested Polymerase Chain Reaction ◽

Prototheca Zopfii ◽

Polymerase Chain ◽

Small Subunit Ribosomal Dna

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A phylogenetic study of the Micarea prasina group shows that Micarea micrococca includes three distinct lineages

The Lichenologist ◽

10.1017/s0024282909990211 ◽

2009 ◽

Vol 42 (1) ◽

pp. 7-21 ◽

Cited By ~ 21

Author(s):

Paweł CZARNOTA ◽

Beata GUZOW-KRZEMIŃSKA

Keyword(s):

Maximum Likelihood ◽

Ribosomal Dna ◽

Dna Sequences ◽

Maximum Parsimony ◽

Small Subunit ◽

Sister Species ◽

Phylogenetic Study ◽

Rdna Sequences ◽

Small Subunit Ribosomal Dna

AbstractThe phylogeny of the Micarea prasina group was investigated using mitochondrial small subunit ribosomal DNA sequences from 14 taxa representing this group, four other members of the genus Micarea, and Psilolechia lucida as an outgroup. A total of 31 new mtSSU rDNA sequences were generated, including 10 from the M. micrococca complex. Bayesian, maximum parsimony (MP) and maximum likelihood (ML) methods were used to analyse the data. The results show that M. micrococca is not monophyletic and forms three strongly supported lineages: 1) M. micrococca s. str., 2) M. byssacea (Th. Fr.) Czarnota, Guzow-Krzemińska & Coppins comb. nov., and 3) a putative taxon that requires further studies. Micarea viridileprosa is a sister species to M. micrococca s. str. and the recently described M. nowakii is a sister species to M. prasina s. str. The placement of M. tomentosa within the M. prasina group is confirmed. Micarea hedlundii appears to be more closely related to the M. micrococca complex than M. prasina s. str. Descriptions, illustrations, taxonomic remarks, distribution and habitat data for M. micrococca s. str. and M. byssacea are provided. A lectotype for Biatora byssacea Hampe non Zwackh and a neotype for Catillaria prasina β [var.] byssacea are selected.

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Phylogeny of the Micareaceae inferred from nrSSU DNA sequences

The Lichenologist ◽

10.1017/s0024282904013507 ◽

2004 ◽

Vol 36 (1) ◽

pp. 27-35 ◽

Cited By ~ 12

Author(s):

Heidi L. ANDERSEN ◽

Stefan EKMAN

Keyword(s):

Bayesian Inference ◽

Maximum Likelihood ◽

Dna Sequences ◽

Phylogenetic Analyses ◽

Sister Group ◽

Small Subunit ◽

Sensu Stricto ◽

Confidence Set ◽

Tree Topologies ◽

Small Subunit Ribosomal Dna

The phylogeny of the Micareaceae and the genus Micarea Fr. was studied using 39 nuclear small subunit ribosomal DNA sequences. Phylogenetic analyses were carried out using maximum parsimony, maximum likelihood, and Bayesian inference. A confidence set of trees was estimated using expected likelihood weights to investigate a series of hypotheses of monophyly. Tree topologies were very similar between methods and differed only in the placement of a few poorly supported branches. The results indicate that the Micareaceae in its current circumscription belongs in the Lecanorales, but that it is not monophyletic. Psilolechia, Micarea with a ‘non-micareoid’ photobiont, Micarea sensu stricto and Byssoloma form a paraphyletic grade in this study. Micarea sensu stricto and Byssoloma (Pilocarpaceae) form a strongly supported monophyletic group, which constitutes the sister group to the Bacidiaceae. Scoliciosporum A. Massal has sometimes been considered close to Micarea, but no support was found for that hypothesis.

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