Apple S locus region represents a large cluster of related, polymorphic and pollen-specific F-box genes
Apple S locus region represents a large cluster of related, polymorphic and pollen-specific F-box genes
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DOI：
10.1007/s11103-010-9662-z
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发表时间：
2010-09-01
影响因子：
5.1
通讯作者：
Sassa, Hidenori
中科院分区：
文献类型：
--
作者：
Minamikawa, Mai;Kakui, Hiroyuki;Sassa, Hidenori
蔷薇科（Rosaceae）、茄科（Solanaceae）和车前草科（Plantinaceae）的配子体自交不亲和性（GSI）受一个复杂的S基因座控制，该基因座分别编码雌蕊特异性蛋白、花粉特异性蛋白、胞外核糖核酸酶（S-RNases）和F-box蛋白SFB/SLF。李属（蔷薇科Prunoideae亚科）、茄科（Solanaceae）和梧桐科（Plancinaceae）的SFB/SLF在每个S单倍型中是单拷贝的，而最近鉴定的蔷薇科Maloideae亚科、苹果和日本梨的花粉S候选者SFBB是多拷贝的;从苹果和日本梨的每个S单倍型中分别分离到2个和3个相关的SFBB。在这里，我们表明，苹果（Malus x arctica）SFBBs构成一个基因家族，比最初认为的要大得多。通过筛选来源于S（3）S（9）基因型的BAC文库，分离出20个额外的SFBB样基因/等位基因，并暂时命名为MdFBX 1 -20。除了一个MdFBX显示S单倍型特异性多态性。在239个分离子中，所有多态性MdFBX都与S-RNase完全连锁。此外，FISH显示单态基因MdFBX 11也位于S-RNase附近，S位点位于染色体的亚端粒区域，不靠近着丝粒。所有的MdFBXs特异性地在花粉中表达，除了假基因MdFBX 4，其在所分析的任何器官中不显示表达。系统发育分析表明，最接近的亲属MdFBX的是从不同的S单倍型，这表明增殖MdSFBB/FBX的S单倍型的多样化之前。
Gametophytic self-incompatibility (GSI) of Rosaceae, Solanaceae and Plantaginaceae is controlled by a complex S locus that encodes separate proteins for pistil and pollen specificities, extracellular ribonucleases (S-RNases) and F-box proteins SFB/SLF, respectively. SFB/SLFs of Prunus (subfamily Prunoideae of Rosaceae), Solanaceae and Plantaginaceae are single copy in each S haplotype, while recently identified pollen S candidates SFBBs of subfamily Maloideae of Rosaceae, apple and Japanese pear, are multiple; two and three related SFBBs were isolated from each S haplotype of apple and Japanese pear, respectively. Here, we show that apple (Malus x domestica) SFBBs constitute a gene family that is much larger than initially thought. Twenty additional SFBB-like genes/alleles were isolated by screening of a BAC library derived from S (3) S (9) genotype, and tentatively named MdFBX1-20. All but one MdFBX showed S haplotype-specific polymorphisms. All the polymorphic MdFBXs were completely linked to S-RNase in 239 segregants. In addition, FISH revealed that the monomorphic gene MdFBX11 is also located near S-RNase, and the S locus is located in a subtelomeric region of a chromosome and is not close to the centromere. All MdFBXs were specifically expressed in pollen, except for a pseudogene MdFBX4 that showed no expression in any organs analyzed. Phylogenetic analysis revealed that the closest relatives of most MdFBXs were from a different S haplotype, suggesting that proliferation of MdSFBB/FBXs predates diversification of the S haplotypes.