Exploiting Next Generation Sequencing to investigate the genetics of
parsnip root disease and develop a marker assisted breeding strategy
Lauren
1
Chappell
1
Barker ,
1
Clarkson ,
1
Teakle
(L.H.K.Chappell@Warwick.ac.uk) Supervisors: Dr Guy
Dr John
Dr Graham
& Mrs Sue
1Warwick Crop Centre, School of Life Sciences, University of Warwick, Wellesboune, Warwick CV35 9EF
2Elsoms Seeds Ltd, Spalding, Lincolnshire, PE11 1QG
2
Kennedy
Introduction
Pastinaca sativa (parsnips) are a speciality crop within the UK, covering an area of 3100 hectares with a value of £64M annually. Currently the major constraint to production is up to 80% losses
associated with root canker diseases caused by fungal pathogens such as Itersonilia and Mycocentrospora spp. Some resistance to parsnip canker exists but is difficult to select for using traditional
phenotype screening methods. This project will use new technologies to identify and exploit these sources of resistance in addition to developing a variety of methodologies to further understand the
epidemiology of the pathogens.
To develop tools to facilitate breeding for quantitative
resistance to parsnip root canker diseases caused by
Itersonilia and Mycocentrospora spp.
Objectives
1.
2.
3.
4.
5.
To determine the range of fungal pathogens causing
root cankers on parsnip
To obtain Itersonilia pastinacae isolates from
different sources and locations and characterise
them using molecular and biological approaches
To develop screening tests to identify I. pastinacae
resistance in parsnip breeding lines
To determine the pathogenicity of different I.
pastinacae isolates
To develop genetic markers linked to resistance
through QTL mapping and Next Generation
Sequence analysis.
Symptom Data
Root Assay
A Parsnip root assay was
develop to determine
disease resistance within a
P. sativa population.
Breeding and Parent lines
from Elsoms parsnip
breeding program were
tested.
Pot grown roots were inoculated with an agar plug of
Itersonilia or Mycocentrospora and assessed for disease.
Final Lesion Size (cm2)
Aims
Whole genome sequencing of I. pastinacae isolates. Root and
seedling screening for pathogen resistance. QTL mapping from
genotypic and phenotypic data from Elsoms Breeding Lines.
2.08
12.50
6.0
25.00
5.0
14.58
4.0
Itersonilia
Pythium
Other
Mycocentrospora
22.92
3.0
2.0
22.92
Fusarium (various)
Cylindrocarpon
1.0
Figure 2: Identification of number (%) and types of
pathogens isolated from diseased roots harvested from
various locations around the UK
0.0
Future Work
Diseased roots obtained from locations around the UK
including a disease tunnel and field trial (Elsoms).
Symptoms were photographed and classified with
subsequent isolations of tissue made from each root,
and plated onto agar. Plates were incubated at 20°C for
10 days; once mycelial growth was identified colonies
were subcultured. Provisional identification was through
colony and spore morphology with confirmation through
ITS sequencing.
Parsnip Parent Line
Figure 1: Final lesion size for 10 Parsnip Parent line roots
inoculated with I. pastinacae. Showing resistance and
susceptibility within the population.
Figure 3: Examples of symptoms L-R Itersonilia, Pythium,
Other, Mycocentrospora, Fusarium, Cylindrocarpon