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/s10658-007-9153-5

Cited by 25 publications

(26 citation statements)

References 27 publications

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“…Plant preparation and experimental design have been described in reference 45. The inoculation method was based on that proposed by Onfroy et al (56). Briefly, strains were grown for 10 days on V8 medium under white light with a 12-h photoperiod at 20°C before pycnidiospore suspensions were prepared by flooding the surfaces of cultures with sterile distilled water, gently scraping with a glass rod, and filtering the suspension through two layers of sterile cheesecloth.…”

Section: Aflp Analysismentioning

confidence: 99%

“…Symptom development was assessed 2, 4, and 7 days after inoculation, as described by Onfroy et al (56). A semiquantitative scale with scores from 0 to 3 (0, symptom free; 1, flecks appearing; 2, flecks covering half of the area of drop deposition; 3, coalescence of the flecks within the area of drop deposition) was used to score symptoms not extending past the inoculation droplet.…”

Section: Aflp Analysismentioning

confidence: 99%

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Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons

Laloi

Montarry

Guibert

et al. 2016

Appl Environ Microbiol

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Ascochyta blight, caused by the necrotrophic ascomycete Didymella pinodes, is responsible for severe losses in winter and spring pea crops. Despite different climatic conditions, epidemics on winter and spring crops are due to a single population of D. pinodes, suggesting gene flow either between the two crops or from reservoir sources during the cropping season. This should lead to similar pathogenicity characteristics in isolates sampled from the two crops. However, these hypotheses have never been formally tested. We therefore sampled a total of 520 D. pinodes strains throughout a growing season from winter and spring pea plots (WP and SP, respectively) and from winter and spring trap plants (TWP and TSP). Amplified fragment length polymorphism (AFLP) markers revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. These results support the idea that alloinoculum contributes to the carryover of epidemics between winter and spring crops and that the most aggressive isolates are selected as an epidemic progresses. IMPORTANCEAscochyta blight, caused by Didymella pinodes, is responsible for severe losses in pea crops. While previous studies have shown that ascochyta blight epidemics on winter and spring crops are due to a single population of D. pinodes, suggesting that isolates from the two crops present similar pathogenicity characteristics, that hypothesis have never been tested. Genetic analysis of subpopulations sampled throughout a growing season from winter and spring pea plots revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic.T he spatiotemporal dynamics of crop diseases are simultaneously impacted by pathogens, host plants, the environment, and human activities (1, 2). Indeed, whether or not hosts and pathogens interact is determined largely by spatial and temporal components of host and pathogen life history traits (3, 4). These interactions can thus be conceptualized as a continuous sequence of biological cycles, including dormancy, growth, reproduction, dispersal, and pathogenesis (5).Gene flow, resulting from pathogen reproduction and dispersal, can drastically increase the extent to which pathogen epidemics spread across a landscape (6). As such, it is a main factor in the transmission of disease to previously uninfected areas and drives the spatial structure of pathogen populations in fragmented landscapes by influencing the long-term survival and genetic composition of populations (7-9). Individual dispersal events, occurring over periods of days or weeks during both the cropping and intercropping seasons (2), originate from a large number of potential inoculum sources: resting structures in soil (mycelium, oospores, chlamydospores, or sclerotia), infested stubble left on the soil surface, infested seed, and alternative hosts (wild or cultivated plants, including volunteers). The degree ...

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Section: Aflp Analysismentioning

confidence: 99%

Section: Aflp Analysismentioning

confidence: 99%

Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons

Laloi

Montarry

Guibert

et al. 2016

Appl Environ Microbiol

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“…In 2010, to have better control of the inoculation, inoculations were done by depositing a drop of spore suspension on each stipule and pod of ten plants for the seven stages described below. Organs of each node were inoculated with a 10 μl drop of a spore suspension at 10 5 spores ml −1 (Onfroy et al 2007). One drop of inoculum suspension was deposited on the upper surface of each stipule, avoiding the main veins, or on the middle of each pod.…”

Section: Whole Plant Inoculationmentioning

confidence: 99%

“…The inoculation method used was based on that proposed by Heath and Wood (1969) and Onfroy et al (2007), consisting of depositing a drop of pycniospore suspension on detached stipules. In 2010, nine representative stipules or pods of each category previously described, were detached and grouped by three in 14 cm diameter Petri dishes containing three filter paper discs and 10 ml of sterile distilled water in order to maintain humidity.…”

Section: Detached Organsmentioning

confidence: 99%

Influence of plant stage and organ age on the receptivity of Pisum sativum to Mycosphaerella pinodes

Richard¹,

Jumel²,

Rouault³

et al. 2011

Eur J Plant Pathol

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International audienceOn spring pea, ascochyta blight (Mycosphaerellapinodes) frequently appears at the plant base on yellowing stipules and disease scores are higher on basal parts of the plants than on the uppermost parts. In order to investigate the relationship between pea plant growth stage and/ororgan age, and ascochyta blight on whole plants and detached stipules and pods, two experiments were conducted in 2009 and 2010 under controlled conditions. This study showed that plant stage does not influence receptivity to ascochyta blight before the appearance of the first visual signs of senescence (beginning of yellowing). When stipules were green, regardless of the plant stage, no differences of receptivity was observed (except for the youngest stipule(s) at the top of the plant). Plant stageonly had an effect on receptivity by the way of the importance of the visual senescence of the organs and visual senescence has a more predominant effect on plant receptivity than the plant stage considered alone. An effect of the nodal position, linked with the stipule age, was observed on whole plant inoculation, with a decreasing disease severitygradient from the base to the top of the plant which was explained by a greater receptivity for the basal/ older stipules which had begun yellowing. On detached stipules, a higher receptivity was observed as soon as visual senescence had been observed. On pods, during their filling, few symptoms appeared and severity was important as soon as they began to yellow. The effect of ascochyta blight on induced senescence of the infected stipules was also observed

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“…However it is not well understood how partial disease resistance (PDR) components determined in vitro (Diamond and Cooke 1999;Browne and Cooke 2004;Browne 2007) relate to the relationship between Type I and Type II resistances to FHB. Investigation of PDR components are utilised across a range of plant pathogen systems (Herrera-Foessel et al 2007;Onfroy et al 2007;Sandoval-Islas et al 2007). For partial resistance to Puccina hordei in barley, the relative ratio of mature pustules is suggested for potential use in breeding programmes, germplasm screening and use in fundamental studies (Jiang et al 2007).…”

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confidence: 99%

Investigation into components of partial disease resistance, determined in vitro, and the concept of types of resistance to Fusarium head blight (FHB) in wheat

Browne

2008

Eur J Plant Pathol

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This work presents an analysis of the relationship between components of partial disease resistance (PDR) detected using in vitro detached leaf and seed germination assays, inoculated with Microdochium majus, and Fusarium head blight (FHB) resistance to Fusarium graminearum assessed using point inoculation, termed Type II resistance. Relationships between in vitro-determined PDR components and FHB resistance using techniques which inoculate the wheat spike uniformly, termed Type I resistance (incidence and severity), have been reported previously. In this study shorter incubation periods, longer latent periods and shorter lesion lengths in the detached leaf assay and higher germination rates in the seed germination assay were related to greater FHB resistance measured by single point inoculation (Type II), collectively explaining 54% of the variation. Overall the relationships observed for Type II FHB resistance were similar to previous findings for Type I resistances. However, the relative magnitude of effects of the individual PDR components determined in vitro varied between FHB disease resistance parameters. Resistance in seed germination and latent period in the detached leaf assay were more strongly related to resistance assessed by point inoculation (Type II) and severityType I as opposed to incubation period which was most strongly related to disease incidence-Type I. The results provide evidence that individual components of partial disease resistance differentially affect aspects of FHB disease progression in the wheat spike. This work supports the view that the current model of types of resistance is an oversimplification of the interacting mechanisms underlying expression of FHB resistance.Keywords Detached leaf assay . Microdochium majus . Seed germination assay Fusarium head blight (FHB) Type 1 resistance testing in plant breeding is predominantly conducted with inoculum evenly spread over the wheat head, assumed to be resistance to initial infection (Schroeder and Christensen 1963). A number of methods are utilised to achieve the even application of inoculum over the wheat head, typically spray inoculation, natural infection, or spreading infected corn or wheat during crop development. Resistance is subsequently measured as disease incidence and severity or a combination of both. Type II resistance was hypothesised as resistance to spread, determined by point inoculation of a single spikelet (Schroeder and Christensen 1963) conducted in the glasshouse. More recently, disease incidence in field-inoculated nurseries has been regarded as being more strongly related with resisEur J Plant Pathol (

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

Cited by 25 publications

References 27 publications

Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons

Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons

Influence of plant stage and organ age on the receptivity of Pisum sativum to Mycosphaerella pinodes

Investigation into components of partial disease resistance, determined in vitro, and the concept of types of resistance to Fusarium head blight (FHB) in wheat

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