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

Hamelin, Richard; Ferriss, R. S.; Shain, Louis; Thielges, B. A.

doi:10.1139/x94-267

Cited by 14 publications

(12 citation statements)

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“…Similar observations were made in a previous study with M. larici‐epitea (Pei et al ., 1996). In the North American poplar rust M. occidentalis , studies showed that the results from leaf disc inoculation tests generally conformed to the extent of disease in the field (Hamelin et al ., 1994). Such evidence suggests that the leaf disc inoculation test remains an effective means of characterizing host resistance/pathogen virulence in Melampsora on poplar and willow because of its efficiency and simplicity.…”

Section: Discussionmentioning

confidence: 95%

Rust resistance in Salix to Melampsora larici‐epitea

et al. 2004

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A total of 174 Salix (willow) clones belonging to 57 species and 14 interspecific hybrids were inoculated with seven pathotypes of Melampsora larici-epitea using the leaf disc method. Infection types were scored based on the uredinial pustule area data and the inoculum density. A close correlation ( R 2 = 0·82) was found between the average pustule area and the average number of spores produced. Most of the willows were also assessed in the field for rust in 1999. Most willow clones belonging to the species native to western Europe were infected by the rust. In inoculation experiments, uredinia developed on 46 S. viminalis clones, out of a total of 47. In the field, all the S. viminalis clones were infected by rust. Within the subgenus Vetrix , eight out of the 17 willow species that originated from North and South America produced rust pustules in inoculation experiments. Of these, S. pellita was most susceptible. Salix irrorata and S. lasiolepsis var. bracelinae produced well developed pustules after inoculation but no rust infections were detected in the field. In both leaf disc tests and field assessments, no rust infections were found on S. candida , S. cordata , S. drummondiana , S. eriocephala , S. hookeriana , S. houghtonii , S. humilis , S. rigida var. mackenziana and S. syrticola . Of 12 species of subgenus Vetrix native to northeast Asia and Japan, only S. kochiana was susceptible both in inoculation tests and in the field. Salix rossica produced no symptoms in leaf disc tests but showed low levels of infection in the field. The maximum infection type scores in leaf disc tests were highly significantly correlated with field disease severity scores (Spearman rank correlation coefficient was 0·76, P < 1 × 10 − 10 ).

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Section: Discussionmentioning

confidence: 95%

Rust resistance in Salix to Melampsora larici‐epitea

et al. 2004

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“…CH-11 expresses the endochitinase gene ech42 from the biocontrol fungus Trichoderma harzianum under the control of a cauliflower mosaic virus double 35S promoter, alfalfa mosaic virus leader (1). Leaf disks were used in all experiments because they were previously shown to reflect field infections (8). The fifth and sixth leaves from the index leaf were taken from at least five different trees and surface sterilized in a 1% household bleach solution for 5 min and then washed twice in sterile water.…”

Section: Methodsmentioning

confidence: 99%

In Vivo Monitoring of Obligate Biotrophic Pathogen Growth by Kinetic PCR

Boyle

Hamelin

Séguin

2005

Appl Environ Microbiol

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The plant kingdom is constantly challenged by a battery of evolving pathogens. New species or races of pathogens are discovered on crops that were initially bred for disease resistance, and globalization is facilitating the movement of exotic pests. Among these pests, obligate biotrophic parasites make up some of the most damaging groups and have been particularly challenging to study. Here we demonstrate the utility of kinetic PCR (kPCR) (real-time PCR, quantitative PCR) to assess the growth of poplar rust, caused by Melampsora species, by quantification of pathogen DNA. kPCR allowed the construction of reliable growth curves from inoculation through the final stages of uredinial maturation, as well as pathogen monitoring before symptoms become visible. Growth parameters, such as latency period, generation time in logarithmic growth, and the increase in DNA mass at saturation, were compared in compatible, incompatible, and nonhost interactions. Pathogen growth was monitored in different applications dealing with plant pathology, such as host and pathogen diversity and transgenic crop improvement. Finally, the capacity of kPCR to differentiate pathogens in the same sample has broad molecular ecology applications for dynamically monitoring the growth of fungi in their environments or in mixed populations or to measure the efficacy of pest control strategies.

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“…The reliability of arti®cial inoculations of excised organs such as leaf discs have been reported in other pathosystems (HAMELIN et al 1994;FREY and PINON 1997;BE Â NAOUF and PARISI 1998;BROWN et al 1999;EVANS et al 1999;VLEESHOUWERS et al 1999). The reliability of arti®cial inoculations of excised organs such as leaf discs have been reported in other pathosystems (HAMELIN et al 1994;FREY and PINON 1997;BE Â NAOUF and PARISI 1998;BROWN et al 1999;EVANS et al 1999;VLEESHOUWERS et al 1999).…”

Section: Comparison Of the Evaluations For Twisting Rust Susceptibilimentioning

confidence: 83%

“…seedlings with few rust symptoms could be identi®ed as resistant whereas these seedlings could be the result of disease escapes. However, few studies about tree breeding improvement programmes for disease resistance have directly compared ®eld and arti®cial inoculation procedures (MILLER 1983;MARTINSSON 1987;HAMELIN et al 1994;BE Â NAOUF and PARISI 1998). elliottii) to fusiform rust (Cronartium quercuum (Berk) Miyabe ex.…”

Section: Introductionmentioning

confidence: 99%

Reliability of field, greenhouse and cut‐shoot screening procedures for evaluating susceptibility of Scots pine to Melampsora pinitorqua

Quencez¹,

Desprez-Loustau

Bastien³

2001

Forest Pathology

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The reliability of ®eld, greenhouse and cut-shoot screening procedures for the assessment of the susceptibility of Scots pine (Pinus sylvestris) genotypes to Melampsora pinitorqua, the causal agent of twisting rust, was evaluated. Fourteen genotypes evaluated on half-sib progenies after natural infection of 2-year-old plants showed comparable rank for rust susceptibility with those evaluated after controlled inoculation of 1-year-old seedlings in a greenhouse. The dynamic of pycnia production was assessed at 2-day intervals in cut-shoot assays under controlled conditions, giving reliable rankings of Scots pine genotypes between years and being signi®cantly correlated with rust susceptibility assessed after natural infection of 2-year-old progenies. These results underlined the importance of some critical factors such as inoculum load and host phenology in the reliability of susceptibility evaluations assessed under different experimental conditions. Arti®cial inoculation of 1-year-old seedlings in greenhouse experiments could provide a useful early test for the management of Scots pine breeding programmes and study of inheritance of twisting rust susceptibility. However, in speci®c investigations the cut-shoot assay would constitute a reliable laboratory test for studying host± pathogen interactions and the variability in pathogenicity of Melampsora pinitorqua populations.

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

Cited by 14 publications

References 0 publications

Rust resistance in Salix to Melampsora larici‐epitea

Rust resistance in Salix to Melampsora larici‐epitea

In Vivo Monitoring of Obligate Biotrophic Pathogen Growth by Kinetic PCR

Reliability of field, greenhouse and cut‐shoot screening procedures for evaluating susceptibility of Scots pine to Melampsora pinitorqua

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