Pre-breeding for Future Challenges in Nordic : 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 in susceptibility to canker

• Resistance to canker is a highly quantitative trait:

information about 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 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 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

Frösåker 35

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

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 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, 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