Rapid Epiphytic Colonization of Apple Flowers and the Role of Insects and Rain

Thomson, S. V.; Wagner, Adam; Gouk, S.C.

doi:10.17660/actahortic.1999.489.78

Cited by 5 publications

(6 citation statements)

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“…Between 72 and 120 h after inoculation, the majority of papillae collapsed both on the stigma and the stylar groove. These results reinforced the previous findings of Gouk and Thomson (1999) and Thomson and Gouk (2003), who claimed that stigmatic papillae of 4-to-6-dayold apple flowers were completely collapsed and covered in mucilage.…”

Section: Stigma and Stylesupporting

confidence: 92%

“…Various methods have been worked out for a fast and reliable estimate. Thomson (1992) suggested stigma imprints as a simple, rapid and inexpensive way of monitoring epiphytic populations, enabling the sampling of large numbers of flowers directly in the orchard (Thomson et al 1999). When applying this method, stigmas are touched to the surface of CCT medium, which was specifically designed for detecting E. amylovora (Ishimaru and Klos 1984).…”

Section: Size Of the Bacterial Populationmentioning

confidence: 99%

“…When applying this method, stigmas are touched to the surface of CCT medium, which was specifically designed for detecting E. amylovora (Ishimaru and Klos 1984). The stigma imprint technique was shown to be more sensitive than flower washing for detecting the presence of E. amylovora on the stigmas of inoculated flowers (Thomson et al 1999). Dorgai and Bubán (2002) developed a PCR-based method, in which the population size was estimated by measuring and comparing the strength of the sample PCR signals to those of serial dilutions of known amounts of bacteria.…”

Section: Size Of the Bacterial Populationmentioning

confidence: 99%

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Floral traits affecting fire blight infection and management

Farkas

Mihalik

Dorgai³

et al. 2011

Trees

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Erwinia amylovora, the causative agent of fire blight, colonizes primarily the flowers of the sub-family Maloideae. Commercially important fruit tree species such as apple (Malus domestica) and pear (Pyrus communis) are also affected by the disease. Epiphytic bacterial populations develop on the stigma, from where the pathogen colonizes the hypanthium, aided by moisture. Under favorable conditions, nectar provides a rich medium for growth, which allows bacterial invasion of tissues through the stomata of the nectary. The paper reviews various floral traits that may play a role in the onset and progression of the infection. Flower age, stigma morphology and longevity, the size of epiphytic bacterial population, morphology of the hypanthium, anatomy of the nectary, dynamics of nectar secretion, as well as the volume, concentration and composition of the nectar are discussed in detail, comparing traits of susceptible versus tolerant apple and pear cultivars. Management programs, aiming at the suppression of E. amylovora on floral parts by antibiotics, chemical compounds, natural substances or biological control agents, are also discussed.

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Section: Stigma and Stylesupporting

confidence: 92%

Section: Size Of the Bacterial Populationmentioning

confidence: 99%

Section: Size Of the Bacterial Populationmentioning

confidence: 99%

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Floral traits affecting fire blight infection and management

Farkas

Mihalik

Dorgai³

et al. 2011

Trees

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“…Fire blight is considered as one of the most devastating diseases of apple, with annual losses and costs of control estimated at over $100 million in the U.S. (8). During bloom, E. amylovora (Ea) cells are spread to apple flowers by insects, wind, or rain and multiply on the stigma surface (9). Ea cells can then migrate from the stigma to the hypanthium and enter into the host through the natural opening, the nectarthodes.…”

Section: Introductionmentioning

confidence: 99%

Temporal and spatial dynamics in the apple flower microbiome in the presence of the phytopathogen Erwinia amylovora

et al. 2020

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Plant microbiomes have important roles in plant health and productivity. However, despite flowers being directly linked to reproductive outcomes, little is known about the microbiomes of flowers and their potential interaction with pathogen infection. Here, we investigated the temporal spatial dynamics of the apple stigma microbiome when challenged with a phytopathogen Erwinia amylovora, the causal agent of fire blight disease. We profiled the microbiome from the stigmas of individual flowers, greatly increasing the resolution at which we can characterize shifts in the composition of the microbiome. Individual flowers harbored unique microbiomes at the operational taxonomic unit level. However, taxonomic analysis of community succession showed a population gradually dominated by bacteria within the families Enterobacteriaceae and Pseudomonadaceae. Flowers inoculated with E. amylovora established large populations of the phytopathogen, with pathogen-specific gene counts of >3.0 × 107 in 90% of the flowers. Yet, only 42% of inoculated flowers later developed fire blight symptoms. This reveals that pathogen abundance on the stigma is not sufficient to predict disease outcome. Our data demonstrate that apple flowers represent an excellent model in which to characterize how plant microbiomes establish, develop, and correlate with biological processes such as disease progression in an experimentally tractable plant organ.

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“…Fire blight is considered as one of the most devastating diseases of apple, with annual losses and costs of control estimated at over $100 million in the U.S. (8). During bloom, E. amylovora ( Ea ) cells are spread to apple flowers by insects, wind, or rain and multiply on the stigma surface (9). Ea cells can then migrate from the stigma to the hypanthium and enter into the host through the natural opening, the nectarthodes.…”

Section: Introductionmentioning

confidence: 99%

Temporal and spatial dynamics in the apple flower microbiome in the presence of the phytopathogenErwinia amylovora

Cui

Huntley

Zeng

et al. 2020

Preprint

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17Plant microbiomes have important roles in plant health and productivity. However, 18 despite flowers being directly linked to reproductive outcomes, little is known about the 19 microbiomes of flowers and their potential interaction with pathogen infection. Here, we 20 investigated the temporal dynamics and spatial traits of the apple stigma microbiome 21 when challenged with a phytopathogen Erwinia amylovora, the causal agent of fire blight 22 disease. We profiled the microbiome from the stigmas of a single flower, greatly 23 increasing the resolution at which we can characterize shifts in the composition of the 24 microbiome. Individual flowers harbored unique microbiomes at the OTU level. 25However, taxonomic analysis of community succession showed a population gradually 26 dominated by bacteria within the families Enterobacteriaceae and Pseudomonadaceae. 27 Flowers inoculated E. amylovora established large populations of the phytopathogen, 28 with pathogen specific gene counts of >3.0 x 10 7 in 90% of the flowers. Yet, only 42% of 29 inoculated flowers later developed fire blight symptoms. This reveals pathogen amount 30 on the stigma is not sufficient to predict disease outcome. Our data demonstrate that 31 apple flowers represent an excellent model in which to characterize how plant 32 microbiomes establish, develop, and interact with biological processes such as disease 33 progression in an experimentally tractable plant organ.34 35 36 37 38 39 40 Flowers, the reproductive organs of angiosperms, play a critical role in the plant's 41 lifecycle. The most important function of flowers is to provide a mechanism for 42 pollination, the union of sperm contained within pollen, to the ovules contained in the 43 ovary. The fertilized ovules produce seeds that will later germinate to become the next 44 generation of plants. Yet, unlike other vegetative organs such as the roots, stems, and 45 leaves that are present through a large part of the plant's lifecycle, flowers develop on 46 mature plants and are typically present for the limited period during bloom. As such, 47 research characterizing the microbiome of the flower is generally less developed than for 48 other plant organs. 49 Flowers of apple (Malus domestica) have been subject to considerable research 50 attention as they are the direct precursors of apple fruits, one of the most consumed fruits 51 worldwide (1). The ephemeral nature of apple flowers, with mature flowers from petal 52 open to petal fall only lasting for 5-10 days in spring, offers a unique environment in 53 which to study community succession (1, 2). During bloom, petals open up in a relatively 54 short period of time, typically within one day, which exposes the internal flower parts to 55 the environment and microorganisms. Several of these internal flower parts exude various 56 types of nutrient-rich secretions including nectar, stigmatic exudate, and pollen exudate, 57 for the purpose of attracting pollinators, and inducing the germination of pollen grains (1, 58 3). These secretio...

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Rapid Epiphytic Colonization of Apple Flowers and the Role of Insects and Rain

Cited by 5 publications

References 0 publications

Floral traits affecting fire blight infection and management

Floral traits affecting fire blight infection and management

Temporal and spatial dynamics in the apple flower microbiome in the presence of the phytopathogen Erwinia amylovora

Temporal and spatial dynamics in the apple flower microbiome in the presence of the phytopathogenErwinia amylovora

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