Poster: Reproductive Development

Abs # 463: Molecular analysis of the S haplotypes lacking SLG in the genome of self-incompatible Brassica rapa (syn. campestris)

Presenter:	Takada, Yoshinobu , u0202008@iwate-u.ac.jp
Authors	Takada, Yoshinobu  (A)   Kakizaki, Tomohiro  (A)   Suzuki, Go  (B)   Shiba, Hiroshi  (C)   Takayama, Seiji  (C)   Isogai, Akira  (C)   Watanabe, Masao  (A)
Affiliations:	(A): Faculty of agriculture, Iwate University (B): Division of Natural Science, Osaka Kyoiku University (C): Graduate School of Biological Sciences, Nara Institute of Science and Technology

Self-incompatibility (SI) system prevents self-fertilization and promotes outbreeding by rejecting pollen from plants with the same S haplotype. In the SI response of Brassica species, self-pollen is rejected on the surface of the papilla cells. The SI of Brassica species is sporophytically controlled by a single locus with S multiple alleles. From the molecular dissection of the S locus on the last decade, three highly polymorphic SI genes, SLG (a gene encoding S locus glycoprotein), SRK (a gene encoding S receptor kinase), and SP11 (a gene encoding S locus protein 11). The SRK and SP11 genes determine the S specificity of the stigma and pollen, respectively, though the precise function of SLG in SI has been not determined. In the present study, we performed DNA gel blot analysis for S32, S33, and S36 haplotypes of B. rapa showing normal SI phenotype, and concluded that there might be no SLG gene in their genome. RNA gel blot analysis of the SLG-less S haplotypes indicated the possible existence of eSRK (ectodomain SRK) transcripts in the stigma. These three S haplotypes are informative resources to discern the molecular mechanism of the SI reaction without SLG.