Comparative analysis of the self-incompatibility (S-) locus region of Prunus mume:: identification of a pollen-expressed F-box gene with allelic diversity
Comparative analysis of the self-incompatibility (S-) locus region of Prunus mume:: identification of a pollen-expressed F-box gene with allelic diversity
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DOI：
10.1046/j.1365-2443.2003.00626.x
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发表时间：
2003-03-01
期刊：
影响因子：
2.1
通讯作者：
Takayama, S
中科院分区：
文献类型：
--
作者：
Entani, T;Iwano, M;Takayama, S
背景资料：茄科、蔷薇科和玄参科植物的自交不亲和性（Self-incompatibility，SI）受一个多态位点（S-locus）控制。到目前为止，唯一已知的S-位点产物是一种多态性核糖核酸酶，称为S-RNase，它由花柱组织分泌，被认为是一种细胞毒素，降解不亲和花粉管的RNA。然而，了解S-RNase如何导致S-单倍型特异性抑制的花粉管一直受到阻碍，缺乏克隆的花粉S-决定因素gene.Results：为了确定花粉S-决定因素基因，我们调查了S-位点区域的S-1-和S-7-单倍型的梅（日本杏）的基因组结构，并确定了13个基因周围的S-RNase基因。其中只有一个F-box基因，称为SLF，（S-locus F-box），满足花粉S-决定子基因的条件：（i）与S-RNase基因一起位于S-位点的高度分化的基因组区域内，（ii）在三种分析的S-单倍型中表现出S-单倍型特异性多样性，（iii）在花粉中特异性表达，但在花柱或叶中不表达。结果表明，SLF是SI花粉S决定基因的主要候选基因。
Background: Self-incompatibility (SI) in the Solanaceae, Rosaceae and Scrophulariaceae is gametophytically controlled by a single polymorphic locus, termed the S-locus. To date, the only known S-locus product is a polymorphic ribonuclease, termed S-RNase, which is secreted by stylar tissue and thought to act as a cytotoxin that degrades the RNA of incompatible pollen tubes. However, understanding how S-RNase causes S-haplotype specific inhibition of pollen tubes has been hampered by the lack of a cloned pollen S-determinant gene.Results: To identify the pollen S-determinant gene, we investigated the genomic structure of the S-locus region of the S-1- and S-7-haplotypes of Prunus mume (Japanese apricot), and identified 13 genes around the S-RNase gene. Among them, only one F-box gene, termed SLF (S-locus F-box), fulfilled the conditions for a pollen S-determinant gene: (i) together with the S-RNase gene, it is located within the highly divergent genomic region of the S-locus, (ii) it exhibits S-haplotype specific diversity among three analysed S-haplotypes, and (iii) it is specifically expressed in pollen, but not in the styles or leaves.Conclusion: The results indicate that SLF is a prime candidate for the pollen S-determinant gene of SI.