Browsing by Author "Farwell, Lauren Helen"

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    Cladosporium species: the predominant species present on raspberries from the U.K. and Spain and their ability to cause skin and stigmata infections
    (MDPI, 2023-01-17) Farwell, Lauren Helen; Deakin, Greg; Harris, Adrian Lee; Fagg, Georgina; Passey, Thomas; Verheecke-Vaessen, Carol; Magan, Naresh; Xu, Xiangming
    Raspberry (Rosales: Rosaceae) production in the U.K. has moved rapidly in the last 10 years to under polythene, combined with a reduced availability of broad-spectrum fungicides. Hence, the incidence of previously less prevalent diseases, such as Cladosporium (Capnodiales: Cladosporiaceae), has largely increased. This study aimed to identify the predominant Cladosporium species on raspberry and to understand the nature of its infection on raspberry fruit. Raspberries were collected from farms across the U.K. and Spain and incubated; fungal isolates were then isolated from typical Cladosporium lesions and identified to the species level based on the sequences of the trans elongation factor α and actin genes. Cladosporium cladosporioides (Fres) de Vries was confirmed as the predominant species responsible for infecting raspberry fruit close to harvest on fruit from the U.K. and Spain, being present on 41.5% of U.K. fruit and 84.6% of Spanish fruit. Raspberries were subsequently inoculated at different developmental stages with C. cladosporioides isolates to determine the susceptibility to Cladosporium skin lesions and stigmata infections in relation to the developmental stage. Only the ripening and ripe raspberries were susceptible to Cladosporium, resulting in skin lesions. Cladosporium can colonise the stigmata of raspberries earlier in fruit development and future research is required to determine if such stigmata infections could cause subsequent skin lesion infections. This study has provided the necessary epidemiological information to develop effective management measures against the Cladosporium species.
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    Investigating the inoculum dynamics of Cladosporium on the surface of raspberry fruits and in the air
    (Wiley, 2024-03-21) Farwell, Lauren Helen; Papp-Rupar, Matevz; Deakin, Greg; Magan, Naresh; Xu, Xiangming
    Raspberry production is under threat from the emerging fungal pathogenic genus Cladosporium. We used amplicon-sequencing, coupled with qPCR, to investigate how fruit age, fruit location within a polytunnel, polytunnel location and sampling date affected the fruit epiphytic microbiome. Fruit age was the most important factor impacting the fungal microbiome, followed by sampling date and polytunnel location. In contrast, polytunnel location and fruit age were important factors impacting the bacterial microbiome composition, followed by the sampling date. The within-tunnel location had a small significant effect on the fungal microbiome and no effect on the bacterial microbiome. As fruit ripened, fungal diversity increased and the bacterial diversity decreased. Cladosporium was the most abundant fungus of the fruit epiphytic microbiome, accounting for nearly 44% of all fungal sequences. Rotorod air samplers were used to study how the concentration of airborne Cladosporium inoculum (quantified by qPCR) varied between location (inside and outside the polytunnel) and time (daytime vs. nighttime). Quantified Cladosporium DNA was significantly higher during the day than the night and inside the polytunnel than the outside. This study demonstrated the dynamic nature of epiphytic raspberry fruit microbiomes and airborne Cladosporium inoculum within polytunnels, which will impact disease risks on raspberry fruit.