Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 5.07

MOLECULAR IDENTIFICATION OF MARKERS LINKED TO POWDERY MILDEW RESISTANCE GENES

A.V. CARLUCCIO, A. CENCI, A. BLANCO

Dipartimento di Biologia e Chimica Agro-Forestale e Ambientale, Università degli Studi di Bari, Via G. Amendola 165/A, 70126 Bari, Italy

wheat, powdery mildew, AFLP, mapping

Wheat is the most widely grown and consumed food crop in many parts of the world. However, powdery mildew, caused by the pathogen Blumeria graminis f.sp. tritici, is a destructive foliar disease in regions with a maritime climate. Triticum turgidum var. dicoccoides accession MG29896 is particularly interesting for high seed protein content and resistance to powdery mildew. This accession was crossed to susceptible durum wheat cultivar Latino and a set of backcross inbred lines (BILs) was produced. These lines were essayed for powdery mildew resistance in field condition and a BC₅F₅ line (5BIL29) showing complete resistance on field conditions. This line was crossed to Latino and the segregation of 400 F₂ plants showed resistance was inherited as single and dominant locus. 120 F₃ progenies were essayed in field condition to confirm F₂ phenotype and to distinguish homozygous resistant and segregant progenies. Pools were produced using DNA from 8 homozygous resistant and from 8 homozygous susceptible F₃ progenies and bulked segregant analysis was performed by using SSR and AFLP.

Two hundred microsatellites were assayed between MG29896 and cultivar Latino and about half of them resulted polymorphic. Unfortunately, no one showed polymorphism between 5BIL29 and Latino.

In order to relieve polymorphism, the AFLP technique was used. Genomic DNA was digested with the restriction endonucleases PstI and MseI, and double-stranded adapters were ligated to the ends of the restriction fragments. Pre-amplification was performed using primers specific for adapters including one selective nucleotide, followed by selective amplification using three selective bases. 62 primer combinations were essayed and more than 6000 bands were amplified. About 130 polymorphism were observed between Latino and 5BIL29 whose 16 between susceptible and resistance bulks. Three AFLP markers resulted linked to the resistance gene and were mapped.