Proceedings of the XLV
Italian Society of Agricultural Genetics - SIGA Annual Congress
Salsomaggiore Terme, Italy -
26/29 September, 2001
ISBN 88-900622-1-5
Poster Abstract
COMPARATIVE
GENETIC STRUCTURE OF PYRENOPHORA TERES F. SP. TERES AND P. TERES F. SP. MACULATA POPULATIONS INFECTING SARDINIAN BARLEY
LANDRACES
RAU D.*, BROWN A.H.D.**, ATTENE G.*, BALMAS V.***,
SABA E.*, PAPA R.****
*
Dipartimento di Scienze Agronomiche e Genetica Vegetale Agraria,
Università degli Studi di Sassari, Via E. de Nicola, Sassari, Italy
** CSIRO
Plant Industry, Canberra, ACT 2601, Australia
***
Dipartimento di Protezione delle Piante, Università degli Studi di
Sassari, Via E. de Nicola, Sassari, Italy
****
Dipartimento di Biotecnologie Agrarie ed Ambientali, Università degli
Studi di Ancona, Ancona, Italy
Monoconidial isolates of Pyrenophora teres, the causal agent of barley net blotch,
were made from six populations of barley landrace from four agro-ecological
regions of Sardinia. Based on leaf symptoms, the 150 isolates included both the
“net” form (P. teres f. sp. teres) and the “spot” form (P. teres f. sp. maculata) to the disease. DNA was extracted from
the fungal tissue and subsequently subjected to AFLP analysis using two chosen
primer combinations, yielding 121 markers of which 47% were polymorphic in the
pathogen species. Cluster analysis resolved the isolates into two divergent
groups (GST = 0,64) corresponding to the net (46%) and spot (54%)
forms. Five barley populations hosted both forms, but in very different
proportions, implying a complex host – dual pathogen coevolutionary
system involving two related, ecologically similar pathogens. The P. teres f. sp. teres populations were similar in overall
polymorphism to the P. teres f. sp. maculata
populations. However, compared to the spot form, the net form appeared to be
the more flexible in occurring in all fields sampled and showing a higher
population divergence, lower apparent migration, higher linkage disequilibrium
and marginally more clonality.