Pollen-pistil interaction in Brassicaceae

1.我们在拟南芥花粉粒和乳突细胞中表达了黄色cameleon 3.6（一种基于绿色荧光蛋白（GFP）的Ca^2+指示剂），并监测了授粉过程中[Ca^2+]_cyt的动态。在花粉粒中，[Ca^<2+>]_cyt在花粉萌发后迅速增加，并一直保持到萌发。与以往的离体萌发研究一样，在生长期的花粉管顶端也观察到了[Ca^<2+>]_cyt振荡，但振荡频率比离体萌发时快，[Ca^<2+>]_cyt也比离体萌发时高。在授粉后的乳突细胞中，[Ca^<2+>]_cyt连续三次显著增加，均发生在花粉粒附着部位的下方。[Ca花粉含水后，^<2+>]_cyt先增加，花粉伸出后又增加。[Ca^<2+]_cyt的第三次也是最显著的增加发生在花粉管进入乳突细胞壁时.我们exa ...更多信息 挖掘的作用，肌动蛋白，一个关键的细胞骨架组成部分调节运输系统的水化和发芽，在乳头细胞在异花授粉。用罗丹明鬼笔环肽染色，我们表明，异花授粉诱导肌动蛋白聚合。通过监测瞬时表达的GFP-mTalin，我们观察了跨花粉附着位点的肌动蛋白束的浓度和肌动蛋白重组。我们进一步表明，外套的交叉花粉是足以介导这种反应。肌动蛋白解聚药物细胞松弛素D（CD）显着抑制花粉水合作用和萌发过程中异花授粉，进一步强调了肌动蛋白在这些过程中的作用。此外，三维电子显微镜断层扫描显示肌动蛋白细胞骨架与顶端空泡网络的密切联系。异花授粉导致液泡重排向花粉附着的网站。两者合计，我们的数据表明，异花授粉差异影响肌动蛋白细胞骨架的动态变化，导致液泡结构与水合和发芽。少

1. We expressed yellow cameleon 3.6, a Ca^<2+> indicator based on green fluorescent protein (GFP), in the pollen grains and papilla cells of Arabidopsis thaliana and monitored [Ca^<2+>]_cyt dynamics during pollination. In the pollen grain, [Ca^<2+>]_cyt, increased at the potential germination site soon after hydration and remained augmented until germination. As in previous in vitro germination studies, [Ca^<2+>]_cyt oscillations were observed in the tip region of the growing pollen tube, but the oscillation frequency was faster and [Ca^<2+>]_cyt was higher than had been observed in vitro. In the pollinated papilla cell, remarkable increases in [Ca^<2+>]_cyt occurred three times in succession, just under the site of pollen-grain attachment. [Ca^<2+>]_cyt increased first soon after pollen hydration, with a second increase occurring after pollen protrusion. The third and most remarkable [Ca^<2+>]_cyt increase took place when the pollen tube penetrated into the papilla cell wall.2. We exa … More mined the role of actin, a key cytoskeletal component regulating the transport system for hydration and germination, in the papilla cell during cross-pollination. Using rhodamine-phalloidin staining, we showed that cross-pollination induced actin polymerization. By monitoring transiently expressed GFP-mTalin, we observed the concentration of actin bundles at the cross-pollen attachment site and actin reorganization. We further showed that the coat of cross-pollen is sufficient to mediate this response. The actin-depolymerizing drug cytochalasin D (CD) significantly inhibited pollen hydration and germination during cross-pollination, further emphasizing a role for actin in these processes. Additionally, three-dimensional electron microscopic tomography revealed the close association of the actin cytoskeleton with an apical vacuole network. Cross-pollination led to vacuolar rearrangements toward the site of pollen attachment. Taken together, our data suggest that cross-pollination differentially affect the dynamics of actin cytoskeleton leading to changes in vacuolar structure associated with hydration and germination. Less