Poster: Reproductive Development

Abs # 490: Molecular characterization of heteromorphic self-incompatibility in Primula vulgaris

Presenter:	McCubbin, Andrew G, amccubbin@wsu.edu
Authors	McCubbin, Andrew G (A)
Affiliations:	(A): Washington State University

Heteromorphic self-incompatibility (HSI) systems in plants, promote out-breeding through a physiological recognition system combined with a set of morphological characteristics. In Primula there are two floral morphs which exhibit reciprocally positioned anthers and stigma, in addition pollen number and size, and the size and shape of stigmatic and stylar cells differ between morphs. These characters act synergistically to prevent inbreeding. HSI is controlled by a single diallelic S -locus, the short style (thrum) morph is determined by the dominant S allele being Ss in genotype and the long styled (pin) morph is homozygous recessive ( ss ). Studies have shown that this S -locus is in fact a supergene – a number of tightly linked genes, with the alleles of at least 7 loci linked and inherited as a single unit. Molecular characterization of this linkage group promises to provide new insights into genetic regulation of floral morphology and physiology. In order to identify genes involved in the control and manifestation of HSI response, we have constructed reciprocally subtracted cDNA libraries between floral tissues of the two morphs, using suppressive subtractive hybridization. The expression patterns and potential linkage to the S -locus of differentially expressed genes are being investigated using Northern and Southern blots. In addition we are constructing a genomic Bacterial Artificial Chromosome library of the thrum genotype of P. vulgaris . S -linked cDNA’s are being used to isolate BAC clones of the S-locus region and these clones will be used to identify additional genes involved in the regulation of HSI. A plant transformation system for P. vulgaris is under development in order to provide an in vivo assay of gene function.