Pre-breeding for Future Challenges in Nordic apples: European canker
European canker
M. Lateur
• A serious disease which affects more than 100 species • Caused by a fungal pathogen, Neonectria ditissima (formerly Nectria galligena), which is able to cross-infect a wide range of hosts
Marc Lateur
Sporodochia contain Perithecia contain ascospores (genetic conidia (vegetative recombination) reproduction of a fungus)
• The fungus uses both (ascospores and conidia) to enter the host • Damages side branches and the main trank • The infection is spred aerially and with rain splash • There are considerable differences among cultivars in susceptibility to canker
• Resistance to canker is a highly quantitative trait:
information about cultivar performance can be conflicting Methodology:
Inoculations: • Wound inoculations of cut shoots, 3 inoculations/shoot, 1000 conidia/ wound, spring, in a climate chamber, 16 C, 70% RH • Wound inoculations of one-year old trees, 3 inoculations/tree, 1000 conidia/wound, fall-winter and spring, in an unheated greenhouse • ’Natural’ infection under high infection pressure, field
Assessments: • Colonization rate through measurements of lesions at regular time intervals; comparisons mellan cultivars are based on AUC • Infection percentage. Comparisons mellan cultivars are based on ratio of infected leaf scars to the total amount of leaf scars
Comparisons of the results on colonisation rate obtained for cut shoots in Sweden and Norway and on trees in Sweden
45 70 60 Aroma Aroma 40 Aroma 60 Discovery 50 Discovery 35 Discovery 50 30 Elise 40 Elise Elise 40 25 Ingrid Marie Ingrid Marie Karin 30 Schneider 20 30 Katja Katja Katja 15 20 20 Liberty Liberty 10 Liberty 10 10 5 Santana Santana Santana
0 Williams 0 William's 0 William's Pride Pride Pride Time1 Time2 Time3 Time4 Time5 Time6 Time7
a) Cut shoots, Balsgård, 2013 b) Cut shoots, Njos, 2013 c) Trees, Alnarp, 2011-2012 Results
Santana, tree, 57 dpi Discovery, tree, 57 dpi Cox Orange, tree, 57 dpi Fall – winter, 2011-2012 Colonisation rate:
Balsgård, 2013: Elise>Discovery>Katja,IngridMarie>William’s Pride>Liberty, Santana>Aroma
Njos, 2013: William’s Pride>Elise>Karin Schneider>Katja,Liberty>Aroma>Santana>Discovery(?)
Trees, Alnarp, 2011-2012 : Katja>Discovery,Ingrid Marie>Elise>William’sPride>Liberty>Santana>Aroma
Infection %
Trees, Alnarp, 2011-2012: Elise>Katja>Liberty>Ingrid Marie>Santana>William’s Pride (?)>Aroma
45 Aroma
Discovery
40 Elise Enterprise
Frösåker 35 Golden Delicious
Gyllenkroks Astrakan
30 Heta Hornö
Ingrid Marie 25 Jonatan
Katja
20 Konsta
Liberty
Linda 15 Prairefire
Risäter
10 Rubinola
Red Gravensteiner
Rödluvan 5 Rö kaneläpple
0 1 2 3 4 5 70
Angold
Aroma 60 ARX 49-18
COOP 12
Discovery 50 Eir
Elise
Elshof 40 Gala
Gloster
30 Idunn Julyred
Karin Schneider
20 Katja
Leiknes
Liberty
10 Martaeple
Michinoku
Nanna 0 Time1 Time Time3 Time4 Time5 Differences in resistance Level among 58 apple cvs. Potted trees, 2011-2012 25
20
15
10
5
0
Infection percentage under ’natural’ inoculations of one year-old trees QPCR procedure
• Novel primers from a variable region in the N. ditissima genome were developed at our laboratory
• Allows for estimation of the biomass of N. ditissima in the presumably infected tissue, but we were not able to detect the fungus in presumably healthy tissue
Test of the QPCR primers for their specificity
PCR-products obtained with qPCR primer pairs on the following DNA-samples: 1. N. ditissima grown on apple leaves placed on PDA; 2. Clean culture of N. ditissima grown on PDA; 3. Alternaria solani; 4. In-vitro M26; 5. Infected tissue; 6. Negative control We, who are involved:
Larisa Gustavsson, Marjan Ghasemkhani, Anna Zborowska (Alnarp)
Hilde Nybom, Jasna Sehic (Balsgård)
Dag Roen, Kurab Roen (Njos)
Support in statistical analyses: Jan-Eric Englund
International projects:
’FruitBreedomics’ (coord. by Francois Laurens, INRA) WP3 ’Identification of QTL for fruit quality and disease resistance’ WP4 ’Exploring of phenotypic and genetic diversity in European apple and peach
WUR, Netherlands: Eric van de Weg CRA-W, Belgium: Marc Lateur Plant & Food Lmt, New Zealand: Reiny Scheper, Kerry Everett
Thanks! Cox Orange Liberty