Protein phosphatases 1 and 2A and the regulation of calcium uptake and pollen tube development in Picea wilsonii
Protein phosphatases 1 and 2A and the regulation of calcium uptake and pollen tube development in Picea wilsonii
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云杉蛋白磷酸酶1和2A以及钙吸收和花粉管发育的调节
DOI：
10.1093/treephys/26.8.1001
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发表时间：
2006-08-01
期刊：
影响因子：
4
通讯作者：
Lin, Jinxing
中科院分区：
文献类型：
--
作者：
Kong, Lingan;Wang, Mao;Lin, Jinxing
为研究蛋白磷酸酶1（Protein phosphatases 1）和蛋白磷酸酶2A（Protein phosphatases 2A）在青（Picea wilsonii Mast.）在蛋白磷酸酶抑制剂冈田酸（okadaicacid）和花萼素A（calyculinA）存在和不存在的情况下，在标准培养基中培养花粉粒。在纳摩尔浓度下，这些化合物阻碍了花粉管的生长，导致花粉管的异常形态。Fluo-3的研究表明，抑制剂降低了花粉管尖端到基部的细胞质钙（Ca 2+）梯度，并阻止了细胞外Ca 2+的吸收。透射电镜观察表明，对照花粉管的顶端和亚顶端区域经常发生壁旁体与质膜的融合，而经外源激素处理的花粉管很少发生融合。苯胺蓝染色结果表明，在花粉萌发过程中，胼胝质在花粉管顶端积累。免疫标记的花粉管显示，酸性果胶抗原决定簇识别的单克隆抗体JIM 5存在于尖端区域和侧翼的亚尖端在正常的花粉管。这些表位仅存在于花粉的最顶端区域，且浓度高于对照花粉管。JIM 7识别的酯化果胶在正常花粉管中优先位于顶端区域，而在经处理的花粉管中则位于基部。傅立叶变换红外光谱分析进一步证实了酸性果胶和酯化果胶的分布及其相对含量的变化。这些结果表明，蛋白磷酸酶1或2A，或两者，参与reaulation的Ca ~（2+）的跨质膜吸收，在胞吐活性和细胞壁成分的生物合成，所有的过程中发生在顶端区域的花粉管和控制花粉管发育。
To investigate the roles of protein phosphatases 1 and 2A in the development of pollen tubes of Picea wilsonii Mast., pollen grains were cultured in standard medium in the presence and absence of the protein phosphatase inhibitors okadaic acid and calyculin A. At nanomolar concentrations, these compounds blocked pollen tube growth, causing abnormal morphologies of the pollen tubes. Studies with Fluo-3 revealed that the inhibitors reduced the pollen-tube tip-to-base cytoplasmic calcium (Ca2+) gradient and arrested extracellular Ca2+ uptake. The transmission electron microscope observations indicated that the fusion of paramural bodies with plasma membranes occurred frequently in the tip and sub-tip regions of control pollen tubes, but fusion rarely occurred in inhibitor-treated pollen tubes. Staining with aniline blue showed that callose accumulated in the tip regions of inhibitor-treated pollen tubes. Immunolabeling of pollen tubes revealed that acidic pectin epitopes recognized by the monoclonal antibody JIM5 were present in the tip region and on the flanks of the sub-tip in normal pollen tubes. In inhibitor-treated pollen tubes, these epitopes existed only in the extreme tip region and at higher concentrations than in control pollen tubes. The esterified pectin recognized by JIM7 was located preferentially at the extreme tip region in normal pollen tubes, but at basal sites in inhibitor-treated tubes. Fourier transform infrared (FTIR) analysis further confirmed the changes in acidic and esterified pectin distributions and their relative contents. These results suggest that protein phosphatase 1 or 2A, or both, are involved in the reaulation of Ca2+ uptake across the plasma membrane, in exocytotic activity and in the biosynthesis of cell wall components, all processes that occur in the tip region of pollen tubes and that control pollen tube development.