Self-incompatibility in ryegrass: Homing in on the genes of the S-locus complex

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Type Abstract
Original languageEnglish
Number of pages1
Publication statusPublished - 2013
EventProceedings of the 7th International Symposium on the Molecular Breeding of Forage and Turf - Salt Lake City, United States of America
Duration: 04 Jun 201207 Jun 2012


ConferenceProceedings of the 7th International Symposium on the Molecular Breeding of Forage and Turf
CountryUnited States of America
CitySalt Lake City
Period04 Jun 201207 Jun 2012
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Self-incompatibility (SI) is a genetic mechanism that prevents self-pollination by using a system of recognition between the pollen and the stigma. The genetic control of this mechanism in grasses is hardly understood. In perennial ryegrass
(Lolium perenne L.), SI is controlled by at least two loci, S and Z (Lundqvist, 1954; Hayman, 1956) which have not been characterized in any grass species yet. The S-locus in perennial ryegrass has been mapped on linkage group 1
(Thorogood et al., 2002) but, to date, mapping approaches for gene isolation and cloning have been inconclusive. Using mapping populations especially designed to map the S-locus, fine-mapping has been conducted by genotyping
over 10,000 plants using high resolution melting curve analysis (HRM). So far, the two closest recombinant flanking markers of the S-locus have been mapped at 0.06cM and 0.01cM either side of the S-locus region that contains 6 genes in the rice and 9 genes in the Brachypodium homologous regions. Using these markers as well as several non-recombinant markers, contiguous Lolium BAC clones covering this region have been isolated, sequenced and assembled in order to build up the physical region of the S-locus. Moreover, RNA-seq from stigma and pollen tissue, as well as stigmas pollinated with incompatible and -compatible pollen, has been conducted to corroborate expressed candidate genes and to identify the causative polymorphism that is the basis of S locus specificity.