S-Locus F-Box Proteins Are Solely Responsible for S-RNase-Based Self-Incompatibility of Petunia Pollen
S-Locus F-Box Proteins Are Solely Responsible for S-RNase-Based Self-Incompatibility of Petunia Pollen
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DOI：
10.1105/tpc.18.00615
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发表时间：
2018-12-01
期刊：
影响因子：
11.6
通讯作者：
Kao, Teh-hui
中科院分区：
文献类型：
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作者：
Sun, Linhan;Williams, Justin S.;Kao, Teh-hui
矮牵牛自交不亲和性（SI）受一个多态性S位点的调控。对于每个S-单倍型，S-位点包含雌蕊特异性S-RNase基因和多个花粉特异性S-位点F-box（SLF）基因。功能获得和功能丧失实验都表明，S-RNase单独调节SI中的雌蕊特异性。SLF基因的功能获得实验表明，整套编码的蛋白质构成花粉特异性决定因素。然而，必须进行明确的功能丧失实验，以确定SLF蛋白是否是花粉SI所必需的。在这里，我们使用CRISPR/Cas9在胀果假单胞菌S2 S3植物中产生S-2-SLF 1（S-2单倍型的SLF 1）的两个移码插入缺失等位基因，并检查对S-2花粉的SI行为的影响。在没有功能性S-2-SLF 1的情况下，S-2花粉被雌蕊排斥或保持与雌蕊相容，雌蕊携带8种正常相容的S-单倍型之一。所有的结果都是一致的17个SLF蛋白的S-2单倍型和这8个S-RNases，已确定的功能获得性实验进行之前或在这项工作中的相互作用关系。我们的功能丧失的结果提供了明确的证据，SLF蛋白是唯一负责花粉SI，他们揭示了他们的多样性和复杂的相互作用与S-RNases的关系，以保持SI，同时确保交叉兼容性。
Self-incompatibility (SI) in Petunia is regulated by a polymorphic S-locus. For each S-haplotype, the S-locus contains a pistil-specific S-RNase gene and multiple pollen-specific S-locus F-box (SLF) genes. Both gain-of-function and loss-of-function experiments have shown that S-RNase alone regulates pistil specificity in SI. Gain-of-function experiments on SLF genes suggest that the entire suite of encoded proteins constitute the pollen specificity determinant. However, clear-cut loss-of-function experiments must be performed to determine if SLF proteins are essential for SI of pollen. Here, we used CRISPR/Cas9 to generate two frame-shift indel alleles of S-2-SLF1 (SLF1 of S-2-haplotype) in S2S3 plants of P. inflata and examined the effect on the SI behavior of S-2 pollen. In the absence of a functional S-2-SLF1, S-2 pollen was either rejected by or remained compatible with pistils carrying one of eight normally compatible S-haplotypes. All results are consistent with interaction relationships between the 17 SLF proteins of S-2-haplotype and these eight S-RNases that had been determined by gain-of-function experiments performed previously or in this work. Our loss-of-function results provide definitive evidence that SLF proteins are solely responsible for SI of pollen, and they reveal their diverse and complex interaction relationships with S-RNases to maintain SI while ensuring cross-compatibility.