Poster: Reproductive Development

Abs # 466: Molecular genetics of self-incompatibility in wild barley, Hordeum bulbosum

Presenter:	Kakeda, Katsuyuki , kakeda@bio.mie-u.ac.jp
Authors	Kakeda, Katsuyuki  (A)   Ibuki, Toshiro  (A)   Suzuki, Junko  (A)   Tadano, Hidetaka  (A)   Kurita, Yuko  (A)   Kowyama, Yasuo  (A)
Affiliations:	(A): Faculty of Bioresources, Mie University

Self-incompatibility (SI) in grasses (Poaceae) is gametophytically controlled by two unlinked loci, S and Z. The two-locus SI system is known to be distributed in the subfamily, Pooideae that involves Lolium, Festuca (Poeae), Hordeum, Secale (Triticeae), Phalaris (Aveneae), etc. As a model plant to understand the molecular basis of the grass SI system, we have used Hordeum bulbosum, a wild self-incompatible species closely related to cultivated barley. An initial study was conducted to search DNA markers linked to each SI locus. Several large populations segregating for the S or Z gene were constructed. Extensive mapping analyses showed that two cDNA markers, HTL and BCD266 were tightly linked to the S and Z loci, respectively, where no recombination was found between the respective loci. Consequently, these markers enabled the efficient determination of S and Z genotypes. As the next approach to clone the S gene, we have used an AFLP-based mRNA fingerprinting (AMF) method with pistil and anther transcripts. Thirty-eight PCR fragments that were amplified specifically from individual S genotypes were detected and cloned. RFLP mapping confirmed a close linkage relationship between the S locus and several of the clones, and a detailed genetic map around the S locus was presented. Further characterization of the S-linked clones, i.e., comparison of allelic sequence differences, analysis of expression patterns, etc. will be reported.