Compartmentalization of S-RNase and HT-B degradation in self-incompatible Nicotiana
Compartmentalization of S-RNase and HT-B degradation in self-incompatible Nicotiana
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DOI：
10.1038/nature04491
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发表时间：
2006-02-16
期刊：
影响因子：
64.8
通讯作者：
McClure, B
中科院分区：
文献类型：
--
作者：
Goldraij, A;Kondo, K;McClure, B
花粉-雌蕊相互作用是控制植物交配的关键.例如，基于S-RNase的自交不亲和性防止了不同被子植物物种的近亲繁殖。S-RNases被认为具有特异性细胞毒素的功能，其抑制具有与雌蕊中的S-单倍型之一匹配的S-单倍型的花粉。因此，花粉和雌蕊因子相互作用，以防止密切相关的个体之间的交配。其他雌蕊因子，如HT-B，4936-因子和120 kDa的糖蛋白，也需要花粉排斥，但不有助于S-单倍型特异性本身。在这里，我们表明S-RNase被吸收并分类到花粉管中的液泡隔室中。120 kDa糖蛋白的抗体标记隔室膜。当雌蕊不表达HT-B或4936-因子时，S-RNase仍然被隔离，不能引起排斥。类似地，在野生型雌蕊中，相容的花粉管降解HT-B并螯合S-RNase。我们认为S-RNase的运输和HT-B的稳定性是S特异性花粉排斥的核心。
Pollen - pistil interactions are crucial for controlling plant mating. For example, S-RNase-based self-incompatibility prevents inbreeding in diverse angiosperm species. S-RNases are thought to function as specific cytotoxins that inhibit pollen that has an S-haplotype that matches one of those in the pistil. Thus, pollen and pistil factors interact to prevent mating between closely related individuals. Other pistil factors, such as HT-B, 4936-factor and the 120 kDa glycoprotein, are also required for pollen rejection but do not contribute to S-haplotype-specificity per se. Here we show that S-RNase is taken up and sorted to a vacuolar compartment in the pollen tubes. Antibodies to the 120 kDa glycoprotein label the compartment membrane. When the pistil does not express HT-B or 4936-factor, S-RNase remains sequestered, unable to cause rejection. Similarly, in wild-type pistils, compatible pollen tubes degrade HT-B and sequester S-RNase. We suggest that S-RNase trafficking and the stability of HT-B are central to S-specific pollen rejection.