College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, People's Republic of China.
Plant Signal Behav. 2011 Mar;6(3):420-1. doi: 10.4161/psb.6.3.14386.
Pear (Pyrus pyrifolia L.) possesses an S-RNase-based gametophytic self-incompatibility (GSI) system, and S-RNase, the self-incompatibility (SI) determinant in the pistil, has also been implicated in the rejection of self-pollen and genetically identical pollen. We have demonstrated that S-RNase depolymerises actin cytoskeleton, triggers mitochondrial alteration and DNA degradation in the incompatible pollen tube, which indicates programmed cell death (PCD) may occur in SI response of Pyrus pyrifolia. Recently, we have identified that S-RNase specifically disrupted tip-localized reactive oxygen species (ROS) of incompatible pollen tube via arrest of ROS formation in mitochondria and cell walls in Pyrus pyrifolia. Furthermore, tip-localized ROS disruption not only decreased the Ca(2+) current and depolymerised the actin cytoskeleton, but it also induced nuclear DNA degradation in the pollen tube. The results mentioned above indicate that a cascade signal pathway may occur in SI of Pyrus pyrifolia and PCD is used to terminate the incompatible pollen tubes growth. In this addendum, we review the cascade signal pathway of Pyrus pyrifolia SI.
梨（Pyrus pyrifolia L.）具有基于 S-RNase 的配子体自交不亲和（GSI）系统，柱头中的 S-RNase 也是自我花粉和遗传上相同花粉排斥的自交不亲和（SI）决定因素。我们已经证明 S-RNase 会解聚肌动蛋白细胞骨架，引发线粒体改变和 DNA 降解在不亲和花粉管中，这表明程序性细胞死亡（PCD）可能发生在梨的 SI 反应中。最近，我们已经确定 S-RNase 通过在梨中阻止线粒体和细胞壁中 ROS 的形成，特异性破坏不亲和花粉管中顶端定位的活性氧（ROS）。此外，顶端定位的 ROS 破坏不仅降低了 Ca(2+)电流并解聚了肌动蛋白细胞骨架，而且还诱导花粉管中的核 DNA 降解。上述结果表明，在梨的 SI 中可能发生级联信号通路，PCD 用于终止不亲和花粉管的生长。在本增补中，我们回顾了梨 SI 的级联信号通路。
