Exploiting Next Generation Sequencing to investigate the genetics of
parsnip root disease and develop a marker assisted breeding strategy
Lauren Chappell (L.H.K.Chappell@Warwick.ac.uk)
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Superivsors: Dr Guy Barker , Dr John Clarkson , Dr Graham Teakle , Mrs Sue Kennedy
1Warwick
Crop Centre, School of Life Sciences, University of Warwick, Wellesbourne, CV35 9EF
2Elsoms Seeds Ltd, Spalding, Lincolnshire, PE11 1QG
Introduction
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Pastinaca sativa (parsnips) are a speciality crop in the UK, covering
an area of 3100ha and a value of £64M annually.
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Major constraint to production is crop losses associated with root
canker diseases caused by fungal pathogens such as Itersonilia and
Mycocentrospora spp.
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Itersonilia pastinacae (I.pastinacae) is a seed borne pathogen that
produces ballistospores and chlamydospores that results in both
foliar and root symptoms.
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Mycocentrospora acerina (M. acerina) is a soil borne pathogen that
produces long living chlamydospores that result in liquorice rot root
symptoms.
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Some resistance to parsnip canker exists but is difficult to select for
using traditional breeding methods.
Aims
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This project aims to develop genetic marker technologies to
identify and exploit these sources of resistance.
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Rapid resistance screening methods and a better understanding
of canker pathogens is also to be investigated.
Symptom Data
• Diseased roots collected from UK locations and classified by symptom
appearance.
• Isolations of tissue made from each root and mycelial colonies
identified through spore morphology and ITS sequencing
Itersonilia
12.50
Pythium
25.00
14.58
Other
Mycocentrospora
22.92
22.92
Fusarium (various)
Cylindrocarpon
• Identification of number (%) and types of pathogens
isolated from diseased P. sativa roots.
Itersonilia infected
parsnip seedlings
Itersonilia pastinacae resistance assay
• P. Sativa lines were artificially inoculated with Itersonilia and.
• Developing lesions were measured to assess current resistance.
• Results indicate range of resistance across P. sativa lines.
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lesion size (cm2)
2.08
Itersonilia infected parsnip Parsnip canker
leaf
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Symptom examples L-R: Itersonilia, Pythium, Other, Mycocentrospora,
Fusarium, Cylindrocarpon.
Future Work
• Further P. sativa lines will be screened for resistance to other canker
pathogens such as Mycocentrospora.
• Itersonilia pathogenicity assays will be developed
• Whole Genome Sequencing will be carried out on Itersonilia isolates to
develop a DNA-based diagnostic test.
• Develop genetic markers for QTL mapping based on genotypic and
phenotypic data from P.sativa line resistance screening.
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P. Sativa lines
Resistance Itersonilia
inoculated parsnip root
Warwick Crop Centre
www.warwick.ac.uk/go/wcc
Susceptible Itersonilia
inoculated parsnip root