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Life at the Edge – the Cytology and Physiology of the Biotroph to Necrotroph Transition in Hymenoscyphus Fraxineus During Lesion Formation in Ash

Mansfield, J., Brown, I., Papp‐Rupar, M. (2019) Life at the Edge – the Cytology and Physiology of the Biotroph to Necrotroph Transition in Hymenoscyphus Fraxineus During Lesion Formation in Ash. Plant Pathology, 68 (5). pp. 908-920. ISSN 0032-0862. (doi:10.1111/ppa.13014) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:75720)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
https://doi.org/10.1111/ppa.13014

Abstract

The progress of colonization of ash stems from ascospore inocula of Hymenoscyphus fraxineus was examined by light and electron microscopy. The main aim of the study was to characterize the cytology of the biotroph to necrotroph transition during lesion formation. Following direct penetration into epidermal cells, the fungus produced intracellular hyphae that invaded up to five cells before plant cells died. A lack of close attachment between the hyphal cell wall and plant cell membrane was revealed by plasmolysis of epidermal cells. Plant cells died at the centre of the infection but hyphae at the edge were typically found in living plant cells even around large lesions. During biotrophic invasion, the cytoplasm of penetrated plant cells showed very little response despite the plant cell membrane being in direct contact with the fungal cell wall. Before plant cell death, dark staining of the cytoplasm and proliferation of small vesicles was noted, but organelles retained normal ultrastructure. Dead plant cells contained dark brown, osmiophilic droplets. Penetration between epidermal or collenchyma cells was usually targeted to shared pits and involved constriction of hyphae. The transition to necrotrophy was not associated with a clear change in hyphal morphology. Biotrophic intracellular hyphae contained dense cytoplasm but hyphae in dead plant cells were more vacuolated. Remarkably little plant cell wall degradation was observed despite the fungus penetrating up to 18 cells deep into stem tissue. Features of the development of the ash dieback fungus are compared with other hemibiotrophic pathogens.

Item Type: Article
DOI/Identification number: 10.1111/ppa.13014
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Sue Davies
Date Deposited: 08 Aug 2019 11:07 UTC
Last Modified: 08 Aug 2019 11:09 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/75720 (The current URI for this page, for reference purposes)
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