This is the report from a BSPP MSc/MRes Bursary.
Click here to read more/apply for one yourself.
The plant pathology knowledge and skills I have gained from this Master’s of Science by Research (MScR) have been numerous. Three institutions supported this project; NIAB, the University of Warwick and the Royal Horticultural Society. Conducting this research provided me not only knowledge of plant pathology for myself but I was also able to contribute some of my findings towards scientific literature through published research. Without the BSPP bursary, I wouldn’t have been unable to take up this opportunity and start my career in plant pathology. Therefore, I am incredibly grateful for schemes such as the BSPP bursary to support MSc/MScR/MRes/MPhil projects.
Blueberry (Vaccinium corymbosum) has rapidly increased in popularity over the last 20 years, primarily because of the health and nutrition benefits associated with the consumption of fruits. Blueberry is not native to the UK and the increase in the commercial growth of this crop raises the likelihood of importing new plant diseases through plant material transports. The exposure of native species of Vaccinium, such as Bilberry (V. myrtillus), to new diseases, is largely unknown as very little data has been published on Bilberry diseases. Equally, due to the absence of data on the diseases present in the UK native Vaccinium, it is also unknown to what extent diseases from wild Vaccinium species can transfer to cultivated species.
The threat of climate change has caused additional pressure on the incidence and severity of disease of crops and wild plants. However, whereas these impacts can be partially controlled within agriculture, in natural plants pathogen exposure can lead to an unpredictable cascade of interactions. Therefore, the assessment of disease in both cultivated Vaccinium and wild Vaccinium gives a great insight into what pathogen species are currently established in the UK and can indicate areas of further research into economic and ecological areas suspected to be most impacted.
Notably, very little is currently known about pathogens in the UK concerning commercial and native Vaccinium species. This makes the screening for current diseases a vital place to identify potential pathogens of this relatively new crop. To attempt to build upon the lack of knowledge within this area, this project aimed to assess disease in bilberry (wild), blueberry and cranberry (cultivated) Vaccinium species.
A field survey of wild and cultivated Vaccinium species across the UK, with the addition of a survey from the public, gave a total of nine pathogen isolates across seven fungal species. Pathogen species were confirmed by analysing nucleotide sequences of the internal transcribed spacer region. Isolates identified were Lasiodiplodia theobromae, Diaporthe vaccinii, Diaporthe sp., Pucciniastrum minimum, Naohidemyces vaccinii, Botrytis cinerea, and Erysiphe elevata. To confirm Kochs postulates and test pathogenicity across different Vaccinium hosts (Blueberry, Bilberry and Cranberry), a detached whole-leaf assay was performed. Notably, this study found P. minimum at two locations within the UK (Scotland and Kent), which had previously not been reported in the UK. A detached leaf assay confirmed Bilberry as a newly identified host. The pathogen E. elevata was also important, as this study confirmed Cranberry as a new host.
All pathogens successfully isolated from diseased plants were found to be fungal. Previous literature and the plant health risk register made by Defra has a greater number of fungal diseases listed for Blueberry and Bilberry than bacterial and viral pathogens. The methodology used in the study was optimised for recovering fungal pathogens and could be the reason for no bacterial and viral pathogens being discovered during the study. This project isolated four fungal pathogen species from five locations of wild UK Bilberry, including Diaporthe vaccinii, Diaporthe spp., Naohidemyces vaccinii and Botrytis cinerea. Of these pathogens, one species, D. vaccinii was not recorded as present in the UK, however, there have been previous outbreaks. Four pathogen isolates from three different species were found on cultivated Vaccinium species. Lasiodiplodia theobromae and Pucciniastrum minimum were found in Blueberry plants and Erysiphe elevata was found on Cranberry. L. theobromae had not previously been recorded to cause disease in UK Blueberry and there was no official report of this pathogen causing disease within the UK. This study found that L. theobromae caused necrosis in both Blueberry and Cranberry leaves. P. minimum was reported to be an emerging disease of Blueberry across Europe, and this project identified two locations where this emerging disease was present in the UK.
This project provided insight into diseases of UK Vaccinium species during the 2021 season. The results concluded that most pathogens found in wild Bilberry were opportunistic. In comparison, commercial Vaccinium crops were of particular significance as pathogens were primary and either not previously recorded in the UK or identified to cause disease in a new plant host. Therefore, the implications of these emerging pathogens in relation to climate change could alter pathogen virulence and severity in UK species. Findings from this project identify targets for UK blueberry breeders to focus on and pathogens to monitor in wild bilberry populations.
Many thanks to the BSPP for the support of this project.
Rosie Latham
University of Warwick
Vaccinium corymbosum cv. ‘Liberty’ and ‘Blue Ribbon’ whole plant exhibiting yellow pustules on the underside of the leaf caused by Pucciniastrum minimum. A) Underside of ‘Blue Ribbon’ mature plant, B) Top side of ‘Blue Ribbon’ mature plant, C) Underside of young ‘Liberty’ plant, D) Close up of uredinia located on the underside of Vaccinium corymbosum cv. ‘Liberty’.
TOP IMAGE: Erysiphe elevata causing powdery mildew symptoms on Vaccinium macrocarpon (Cranberry). (A) Powdery mildew symptoms whole plant and B) symptoms on a young leaf caused by Erysiphe elevata.
This is the report from a BSPP MSc/MRes Bursary.
Click here to read more/apply for one yourself.
