Skip to main content
Article thumbnail
Location of Repository

A genetic linkage map of Venturia inaequalis, the causal agent of apple scab

By Xiangming Xu, T. Roberts, Dez J. Barbara, Nick G. Harvey, Liqiang Gao and Daniel J. Sargent


Background\ud \ud Venturia inaequalis is an economically-important disease of apple causing annual epidemics of scab worldwide. The pathogen is a heterothallic ascomycete with an annual cycle of sexual reproduction on infected apple leaf litter, followed by several cycles of asexual reproduction during the apple growing season. Current disease prevention is achieved mainly through scheduled applications of fungicides. Genetic linkage maps are essential for studying genome structure and organisation, and are a valuable tool for identifying the location of genes controlling important traits of interest such as avirulence, host specificity and mating type in V. inaequalis. In this study, we performed a wide cross under in vitro conditions between an isolate of V. inaequalis from China and one from the UK to obtain a genetically diverse mapping population of ascospore progeny isolates and produced a map using AFLP and microsatellite (SSR) markers.\ud Findings\ud \ud Eighty-three progeny were obtained from the cross between isolates C1054 (China) x 01/213 (UK). The progeny was screened with 18 AFLP primer combinations and 31 SSRs, and scored for the mating type locus MAT. A linkage map was constructed consisting of 294 markers (283 AFLPs, ten SSRs and the MAT locus), spanning eleven linkage groups and with a total map length of 1106 cM. The length of individual linkage groups ranged from 30.4 cM (Vi-11) to 166 cM (Vi-1). The number of molecular markers per linkage group ranged from 7 on Vi-11 to 48 on Vi-3; the average distance between two loci within each group varied from 2.4 cM (Vi-4) to 7.5 cM (Vi-9). The maximum map length between two markers within a linkage group was 15.8 cM. The MAT locus was mapped to a small linkage group and was tightly linked to two AFLP markers. The map presented is over four times longer than the previously published map of V. inaequalis which had a total genetic distance of just 270 cM.\ud Conclusions\ud \ud A genetic linkage map is an important tool for investigating the genetics of important traits in V. inaequalis such as virulence factors, aggressiveness and mating type. The linkage map presented here represents a significant improvement over currently published maps for studying genome structure and organisation, and for mapping genes of economic importance on the V. inaequalis genome

Topics: SB
Publisher: BioMed Central Ltd.
Year: 2009
OAI identifier:

Suggested articles


  1. (2002). A: Inheritance and mapping of 11 avirulence genes in Phytophthora sojae. Fungal Genet Biol doi
  2. (2005). An AFLP-marker based genetic linkage map of Heterobasidion annosum locating intersterility genes. Fungal Genet Biol doi
  3. (1996). Apple scab: biology, epidemiology, and management. doi
  4. (2007). BD: Complete genetic linkage maps from an interspecific cross between Fusarium circinatum and Fusarium subglutinans. Fungal Genet Biol doi
  5. (2004). Cam B: Isolation of 21 new polymorphic microsatellite loci in the phytopathogenic fungus Venturia inaequalis. Mol Ecol Notes doi
  6. (2002). Ciuffetti L: A molecular genetic map and electrophoretic karyotype of the plant pathogenic fungus Cochliobolus sativus. Mol Plant-Microbe Interact doi
  7. (2008). Construction of a genetic linkage map of the fungal pathogen of banana Mycosphaerella fijiensis, causal agent of black leaf streak disease Curr Genet doi
  8. (2003). Development and characterisation of polymorphic microsatellite markers from Fragaria viridis, a wild diploid strawberry. Mol Ecol Notes doi
  9. (2008). DJ: Population variation of apple scab (Venturia inaequalis) isolates from Asia and Europe. Plant Dis doi
  10. (1999). F: A high-density molecular map for the rye grass (Lolium perenne) using AFLP markers. Theor Appl Genet doi
  11. (2000). Genome analysis of the plant pathogenic fungus Leptosphaeria maculans: mapping mating type and host specificity loci. Mol Plant Pathol doi
  12. (1998). Gessler C: Genetic analysis of a cross of two Venturia inaequalis strains that differ in virulence. doi
  13. (1999). Gessler C: Genetic diversity of Venturia inaequalis across Europe. Eur J Plant Pathol
  14. (1999). Gessler C: Identification of microsatellite markers and their application to population genetics of Venturia inaequalis. Phytopathology doi
  15. (1998). Gessler C: Inheritance of virulence of Venturia inaequalis toward Malus x domestica cultivars. doi
  16. (1997). Gessler C: Subdivision and genetic structure of four populations of Venturia inaequalis in Switzerland.
  17. (2002). H: A genetic map of Blumeria graminis based on functional genes, avirulence genes, and molecular markers. Fungal Genet Biol doi
  18. (2000). L: Genetic linkage map of the edible basidiomycete Pleurotus ostreatus. Appl Environ Microbiol doi
  19. (2002). MapChart: Software for the graphical presentation of linkage maps and QTLs. doi
  20. (2003). Michelmore R: A genetic map of the lettuce downy mildew pathogen, Bremia lactucae, constructed from molecular markers and avirulence genes. Fungal Genet Biol doi
  21. (2002). R: A genetic map of Gibberella zea (Fusarium graminearum). Genetics
  22. (2003). S: A linkage map of the basidiomycete Coprinus cinereus based on random amplified polymorphic DNA and restriction fragment length polymorphisms. Fungal Genet Biol doi
  23. (2004). T: A genetic linkage map of Cryptococcus neoformans variety neoformans serotype D (Filobasidiella neoformans). Genetics doi
  24. (1996). Tanksley SD: Genetic analysis of RFLPs, GATA microsatellites and RAPDs in a cross between L. esculentum and L. pimpenillifolium. Theor Appl Genet doi
  25. (1991). Tanksley SD: Mendelian factors underlying quantitative traits in tomato: Comparison across species, generations, and environments. Genetics
  26. (1956). The chromosome number. doi
  27. (2008). Xu X-M: Virulence characteristics of apple scab (Venturia inaequalis) isolates from monoculture and mixed orchards. Plant Pathol doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.