Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA

Plant-Pathosystem Molecular Diversity: A Comparative Analysis Of The Genetic Structure Of Pyrenophora teres And Barley Landrace Populations

Domenico Rau¹ , Giovanna Attene¹ , Nicoletta Ferradini² , Laura Nanni² , Antony H.D. Brown³ , Virgilio Balmas⁴ , Eva Saba¹ , Roberto Papa²

¹  Dipartimento di Scienze Agronomiche e Genetica Vegetale Agraria, Università degli Studi di Sassari, Via E. de Nicola, 07100 Sassari, Italy

²  Dipartimento di Scienze degli Alimenti, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.

³  Plant Industry, Canberra, ACT 2601, Australia

⁴  Dipartimento di Protezione delle Piante, Università degli Studi di Sassari, Via E. de Nicola, 07100 Sassari, Italy

To study the plant-pathogen co-adaptation process two approaches are generally used. The first is to compare the performance of the pathogen on sympatric and allopatric host populations. The second consists in comparing the population structure of both plant and pathogen. When the organization of genetic variation does not match between the two protagonists, stochastic forces rather than co-adaptation are responsible for the maintenance of resistance and virulence. In contrast, it has commonly argued that a parallelism in the population structure for both plant and pathogen is an indicator of co-adaptation. We compare the population genetic structure of six landrace populations of Hordeum vulgare L. as revealed by SSR markers with that of eleven populations (6 of the net form and 5 of the spot form of the pathogen) of Pyrenophora teres Sacc. (Shoem.) analysed with AFLPs. All the barley genotypes and fungal isolates were collected from the same fields but in two different and independent collection. The evolutionary forces likely to be responsible of the observed pattern of genetic variation are investigated.