Biotic factors affecting the expression of partial resistance in pea to ascochyta blight in a detached stipule assay

Onfroy, Caroline; Baranger, Alain; Tivoli, Bernard

doi:10.1007/978-1-4020-6065-6_3

Cited by 11 publications

(30 citation statements)

References 25 publications

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“…Indeed, as suggested by Ergon et al (15) and Gaudet et al (20), cold hardening is known to strongly increase the resistance of plants to disease by increasing the PR gene expression. This could explain the similar levels of resistance of all four pea genotypes in the winter conditions and hence the fact that the higher level of resistance of DP than that of the other three hosts was manifest only in spring conditions, confirming earlier observations (38).…”

Section: Discussionsupporting

confidence: 87%

“…The inoculation method used was based on that proposed by Onfroy et al (38), consisting of depositing a drop of spore suspension on detached leaflets. Isolates were grown for 10 days on V8 medium under white light with a 12-h photoperiod at 20°C (wavelengths between 350 and 750 nm) before pycnidiospore suspensions were prepared by flooding the surface of cultures with sterile distilled water, gently scraping with a glass rod, and filtering the suspension through two layers of sterile cheesecloth.…”

Section: Fungalmentioning

confidence: 99%

“…Drops were deposited away from the main veins (38). To avoid drop evaporation, petri dishes were placed into large transparent plastic boxes immediately after inoculum deposition and incubated in a climate chamber for 7 days with a continuous cycle of 14 h of light and 10 h of darkness at either 8 to 10°C or 18 to 20°C (Table 2).…”

Section: Fungalmentioning

confidence: 99%

“…To avoid drop evaporation, petri dishes were placed into large transparent plastic boxes immediately after inoculum deposition and incubated in a climate chamber for 7 days with a continuous cycle of 14 h of light and 10 h of darkness at either 8 to 10°C or 18 to 20°C (Table 2). Symptom development was assessed 2, 3, and 7 days after inoculation, as described by Onfroy et al (38). A 0-to-3 semiquantitative scale (0 ϭ symptom free, 1 ϭ flecks appearing, 2 ϭ flecks covering half of the area of drop deposition, 3 ϭ coalescence of the flecks within the area of drop deposition) was used to score symptoms not extending past the inoculation droplet.…”

Section: Fungalmentioning

confidence: 99%

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A Single, Plastic Population of Mycosphaerella pinodes Causes Ascochyta Blight on Winter and Spring Peas (Pisum sativum) in France

May

Guibert

Leclerc

et al. 2012

Appl Environ Microbiol

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c Plant diseases are caused by pathogen populations continuously subjected to evolutionary forces (genetic flow, selection, and recombination). Ascochyta blight, caused by Mycosphaerella pinodes, is one of the most damaging necrotrophic pathogens of field peas worldwide. In France, both winter and spring peas are cultivated. Although these crops overlap by about 4 months (March to June), primary Ascochyta blight infections are not synchronous on the two crops. This suggests that the disease could be due to two different M. pinodes populations, specialized on either winter or spring pea. To test this hypothesis, 144 pathogen isolates were collected in the field during the winter and spring growing seasons in Rennes (western France), and all the isolates were genotyped using amplified fragment length polymorphism (AFLP) markers. Furthermore, the pathogenicities of 33 isolates randomly chosen within the collection were tested on four pea genotypes (2 winter and 2 spring types) grown under three climatic regimes, simulating winter, late winter, and spring conditions. M. pinodes isolates from winter and spring peas were genetically polymorphic but not differentiated according to the type of cultivars. Isolates from winter pea were more pathogenic than isolates from spring pea on hosts raised under winter conditions, while isolates from spring pea were more pathogenic than those from winter pea on plants raised under spring conditions. These results show that disease developed on winter and spring peas was initiated by a single population of M. pinodes whose pathogenicity is a plastic trait modulated by the physiological status of the host plant. P lant parasites can quickly adapt to their hosts and overcome resistance genes used in crop protection. This process occurs both in agroecosystems, where hosts (cultivars) are typically quite uniform genetically, and in wild pathosystems, where hosts and parasites show high levels of diversity and are structured as metapopulations (12). However, a number of crop plants are grown in complex ecosystems rather than as the monocultures which characterize modern agriculture; this is particularly the case for species grown as both winter and spring cultivars and for which wild relatives occur as weeds or in field margins.From a plant pathology point of view, such complex ecosystems are usually characterized by one or more of the following parameters: (i) spatial and temporal heterogeneity of hosts, which creates patchiness and an often complex age structure, (ii) intraand interspecific diversity, and (iii) multiple host-pathogen interactions. These features favor niche partitioning, as they allow the coexistence on the same host species of different pathogen populations separated in space and/or time. Indeed, ecological differences that lead to niche partitioning can occur in three basic ways: resource partitioning, temporal niche partitioning, and spatial niche partitioning (4, 14, 36). For plant-pathogenic species able to exploit the same host, separation in space and/or time mi...

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Section: Discussionsupporting

confidence: 87%

Section: Fungalmentioning

confidence: 99%

Section: Fungalmentioning

confidence: 99%

Section: Fungalmentioning

confidence: 99%

See 2 more Smart Citations

A Single, Plastic Population of Mycosphaerella pinodes Causes Ascochyta Blight on Winter and Spring Peas (Pisum sativum) in France

May

Guibert

Leclerc

et al. 2012

Appl Environ Microbiol

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“…The objective was to compare the susceptibility to M. pinodes of stipules at different nodes on a plant in order to determine if numbers of lesions counted on stipules in splash experiments related solely to number of spores introduced by splash dispersal rather than an interaction between splash dispersal and tissue susceptibility. This test was performed for plants at three vegetative growth stages (6‐leaf, 8‐leaf and 10‐leaf) using the method proposed by Onfroy et al . (2007).…”

Section: Methodsmentioning

confidence: 99%

Effect of pea canopy architecture on splash dispersal of Mycosphaerella pinodes conidia

Schoeny¹,

Menat²,

Darsonval³

et al. 2008

Plant Pathology

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To investigate the hypothesis that disrupting pathogen movement within the plant canopy could slow the development of aschochyta blight, the effect of pea canopy architecture on splash dispersal of Mycosphaerella pinodes -conidia was studied in controlled conditions using a rainfall simulator generating rain events (2 mm) in still air. In intra-plant dispersal experiments, a source constituted by a semi-leafless pea plant with a single infectious lesion (108 pycnidia per cm 2 of lesion, 1685 conidia per pycnidium) was placed in the middle of eight healthy target plants. Spore deposition was estimated by the number of lesions that developed on each stipule of the source (auto-deposition) and target (allodeposition) plants after incubation. Rates of deposition on the source and target plants were 0·53 and 0·47, respectively. On the source plant, most of the spores were splashed downwards, with few spores remaining at the infectious node and very few spores moving upwards. In inter-plant dispersal experiments, potted plants were grouped to constitute 1-m 2 canopies. A range of canopy architectures was achieved by using different plant densities and growth stages. A suspension of conidia was placed in the centre of each canopy. Resulting horizontal dispersal gradients were generally described by a negative exponential model. Canopies with a leaf area index (LAI) greater than 0·48 produced gradients with slopes that were not significantly different. A less dense canopy (LAI 0·36) produced a significantly steeper slope. Half-distances were short and ranged between 1·6 and 6·5 cm. The barrier rate, calculated as the ratio of the mean number of lesions assessed on isolated plants to the mean number of lesions assessed on plants in canopies, increased with increasing canopy LAI.

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Imaging with spatio-temporal modelling to characterize the dynamics of plant-pathogen lesions

Leclerc¹,

Jumel²,

Hamelin

et al. 2022

Preprint

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Within-host spread of pathogens is an important process for the study of plant-pathogen interactions. However, the development of plant-pathogen lesions remains practically difficult to characterize and quantify beyond the common traits such as lesion area. We tackle the spatio-temporal dynamics of interactions by combining image-based phenotyping with mathematical modelling. We consider the spread of Peyronellaea pinodes on pea stipules that were monitored daily with visible imaging. We assume that pathogen propagation on host-tissues can be described by the Fisher-KPP model where lesion spread depends on both a logistic local growth and an homogeneous diffusion. Model parameters are estimated using a variational data assimilation approach on sets of registered images. This modelling framework is used to compare the spread of an aggressive isolate on two pea cultivars with contrasted levels of partial resistance. We show that the expected slower spread on the most resistant cultivar is actually due to a decrease of diffusion and, to a lesser extent, local growth. These results demonstrate that spatial models with imaging allows one to disentangle the processes involved in host-pathogen interactions. Hence, promoting model-based phenotyping of interactions would allow a better identification of quantitative traits thereafter used in genetics and ecological studies.

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Biotic factors affecting the expression of partial resistance in pea to ascochyta blight in a detached stipule assay

Cited by 11 publications

References 25 publications

A Single, Plastic Population of Mycosphaerella pinodes Causes Ascochyta Blight on Winter and Spring Peas (Pisum sativum) in France

A Single, Plastic Population of Mycosphaerella pinodes Causes Ascochyta Blight on Winter and Spring Peas (Pisum sativum) in France

Effect of pea canopy architecture on splash dispersal of Mycosphaerella pinodes conidia

Imaging with spatio-temporal modelling to characterize the dynamics of plant-pathogen lesions

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