The Leavenworthia self-incompatibility locus (S locus) consists of paralogs (Lal2, SCRL) of the canonical Brassicaceae S locus genes (SRK, SCR), and is situated in a genomic position that differs from the ancestral one in the Brassicaceae. Unexpectedly, in a small number of Leavenworthia alabamica plants examined, sequences closely resembling exon 1 of SRK have been found, but the function of these has remained unclear. BAC cloning and expression analyses were employed to characterize these SRK-like sequences. An SRK-positive Bacterial Artificial Chromosome clone was found to contain complete SRK and SCR sequences located close by one another in the derived genomic position of the Leavenworthia S locus, and in place of the more typical Lal2 and SCRL sequences. These sequences are expressed in stigmas and anthers, respectively, and crossing data show that the SRK/SCR haplotype is functional in self-incompatibility. Population surveys indicate that < 5% of leavenworthia s loci possess such alleles. an ancestral translocation or recombination event involving srk/scr and lal2/scrl likely occurred, together with neofunctionalization lal2/scrl, both haplotype groups now function as locus these findings suggest that alleles can have distinctly different evolutionary origins.© 2017 the authors. new phytologist © trust.
Journal: The New phytologist
DOI: 10.1111/nph.14764
Year: 2017