Sporophytic self-incompatibility genes and mating system variation in Arabis alpina

Tedder, A., Ansell, S.W., Lao, X., Vogel, J.C. and Mable, B.K. (2011) Sporophytic self-incompatibility genes and mating system variation in Arabis alpina. Annals of Botany, 108(4), pp. 699-713. (doi:10.1093/aob/mcr157)

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Publisher's URL: http://dx.doi.org/10.1093/aob/mcr157

Abstract

Background and Aims Sporophytic self-incompatibility (SI) prevents inbreeding in many members of the Brassicaceae, and has been well documented in a variety of high-profile species. Arabis alpina is currently being developed as a model system for studying the ecological genetics of arcticalpine environments, and is the focus of numerous studies on population structure and alpine phylogeography. Although it is highly inbreeding throughout most of its range, populations in central Italy have been identified that show inbreeding coefficients (FIS) more typical of self-incompatible relatives. The purpose of this study was to establish whether this variation is due to a functioning SI system.Methods Outcrossing rate estimates were calculated based on 16 allozyme loci and self-compatibility assessed based on controlled pollinations for six Italian populations that have previously been shown to vary in FIS values. Putative SRK alleles (the gene controlling the female component of SI in other Brassicaceae) amplified from A. alpina were compared with those published for other species. Linkage of putative SRK alleles and SI phenotypes was assessed using a diallel cross.Key Results Functional avoidance of inbreeding is demonstrated in three populations of A. alpina, corresponding with previous FIS values. The presence is described of 15 putative SRK-like alleles, which show high sequence identity to known alleles from Brassica and Arabidopsis and the high levels of synonymous and nonsynonymous variation typical of genes under balancing selection. Also, orthologues of two other members of the S-receptor kinase gene family, Aly8 (ARK3) and Aly9 (AtS1) are identified. Further to this, co-segregation between some of the putative S-alleles and compatibility phenotypes was demonstrated using a full-sibling cross design.Conclusions The results strongly suggest that, as with other species in the Brassicaceae, A. alpina has a sporophytic SI system but shows variation in the strength of SI within and between populations

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mable, Professor Barbara
Authors: Tedder, A., Ansell, S.W., Lao, X., Vogel, J.C., and Mable, B.K.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Annals of Botany
ISSN:0305-7364

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
426221Mating systems and genetic diversity in Arabidopsis lyrataBarbara MableNatural Environment Research Council (NERC)NE/D013461/1RI BIODIVERSITY ANIMAL HEALTH & COMPMED
374091Genomes, pathogens and mate choice - implications for the evolution and maintenance of genetic diversityBarbara MableNatural Environment Research Council (NERC)NE/B50094X/1RI BIODIVERSITY ANIMAL HEALTH & COMPMED