Self‐incompatibility in Petunia is controlled by the polymorphic S‐locus, which contains S‐RNase encoding the pistil determinant and 16–20 S‐locus F‐box (SLF) genes collectively encoding the pollen determinant. Here we sequenced and assembled approximately 3.1 Mb of the S₂‐haplotype of the S‐locus in Petunia inflata using bacterial artificial chromosome clones collectively containing all 17 SLF genes, SLFLike1, and S‐RNase. Two SLF pseudogenes and 28 potential protein‐coding genes were identified, 20 of which were also found at the S‐loci of both the S_6a‐haplotype of P. inflata and the S_N‐haplotype of self‐compatible Petunia axillaris, but not in the S‐locus remnants of self‐compatible potato (Solanum tuberosum) and tomato (Solanum lycopersicum). Comparative analyses of S‐locus sequences of these three S‐haplotypes revealed potential genetic exchange in the flanking regions of SLF genes, resulting in highly similar flanking regions between different types of SLF and between alleles of the same type of SLF of different S‐haplotypes. The high degree of sequence similarity in the flanking regions could often be explained by the presence of similar long terminal repeat retroelements, which were enriched at the S‐loci of all three S‐haplotypes and in the flanking regions of all S‐locus genes examined. We also found evidence of the association of transposable elements with SLF pseudogenes. Based on the hypothesis that SLF genes were derived by retrotransposition, we identified 10 F‐box genes as putative SLF parent genes. Our results shed light on the importance of non‐coding sequences in the evolution of the S‐locus, and on possible evolutionary mechanisms of generation, proliferation, and deletion of SLF genes.

中文翻译：

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包含17个S-Locus F-Box基因和涉及自我不相容性的S-RNase基因的矮牵牛S-基因座区的序列分析

矮牵牛的自交不亲和性受多态性S-基因座控制，S-基因座包含编码雌蕊决定簇的S-RNase和共同编码花粉决定簇的16-20个S-locus F-box（SLF）基因。在这里，我们使用细菌人工染色体克隆（共包含所有17个SLF基因，SLFLike1和S-RNase）对大约3.1 Mb的矮牵牛S基因座的S _2型单倍体进行了测序和组装。两个SLF假基因和28的潜在蛋白质编码基因进行了鉴定，其中20也被发现在小号两者的-loci小号_6A的-haplotype P.胀和小号_Ñ自相容的-haplotype矮牵牛酸枣，但不是在自相容马铃薯（Solaum tuberosum）和番茄（Solanum lycopersicum）的S残基。对这三种S单倍型的S基因座序列的比较分析显示了SLF侧翼区域的潜在遗传交换。基因，在不同类型的SLF之间以及在不同S单倍型的相同类型SLF的等位基因之间产生高度相似的侧翼区域。在侧翼区的高度序列相似性可以经常通过类似于长末端重复反转录因子的存在下，将其在富集进行说明小号的所有三个-loci小号-haplotypes，并在所有的侧翼区域小号-locus基因检查。我们还发现了转座因子与SLF假基因的关联的证据。基于SLF基因是通过逆转位衍生而来的假设，我们鉴定出10个F-box基因作为推定的SLF亲本基因。我们的结果揭示了非编码序列在S基因座进化中的重要性，以及SLF基因的产生，增殖和缺失的可能进化机制。