Ultrastructural characterization of exine development of the transient defective exine 1 mutant suggests the existence of a factor involved in constructing reticulate exine architecture from sporopollenin aggregates
Ultrastructural characterization of exine development of the transient defective exine 1 mutant suggests the existence of a factor involved in constructing reticulate exine architecture from sporopollenin aggregates
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DOI：
10.1093/pcp/pcm167
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发表时间：
2008-01-01
影响因子：
4.9
通讯作者：
Toriyama, Kinya
中科院分区：
文献类型：
--
作者：
Ariizumi, Tohru;Kawanabe, Takahiro;Toriyama, Kinya
利用T-DNA标记技术分离到一个花粉育性正常但花丝伸长缺陷的拟南芥雄性不育突变体。透射电子显微镜（TEM）分析表明，primexine合成和probacula形成，这被认为是外壁形成的初始步骤，是有缺陷的，和球状孢粉素聚集随机沉积在单核小孢子早期阶段的小孢子上。单核小孢子时期，未能锚在小孢子质膜上的孢粉素聚集体沉积在室壁和室内。然而，在单核小孢子中期，观察到外观正常的外壁，具有基本的网状结构，表明突变体的外壁形成得到恢复。因此，该突变体被命名为瞬时缺陷型外壁1（tde 1）。这些结果表明，tde 1突变影响外壁形成的初始过程，但不损害任何关键过程。我们的研究结果还表明，存在一个特定的因素负责外壁图案在A。thaliana.发现TDE 1基因与已知参与油菜素类固醇（BR）生物合成的DE-ETIOLATED 2基因相同，并且在BR应用的存在下恢复了TDE 1 procula缺陷型表型。这些结果表明，BRs控制外壁图案形成的初始过程的速率或效率。
A male-sterile mutant of Arabidopsis thaliana, in which filament elongation was defective although pollen fertility was normal, was isolated by means of T-DNA tagging. Transmission electron microscopy (TEM) analysis revealed that primexine synthesis and probacula formation, which are thought to be the initial steps of exine formation, were defective, and that globular sporopollenin aggregation was randomly deposited onto the microspore at the early uninucleate microspore stage. Sporopollenin aggregation, which failed to anchor to the microspore plasma membrane, was deposited on the locule wall and in the locule at the uninucleate microspore stage. However, visually normal exine with a basic reticulate structure was observed at the middle uninucleate microspore stage, indicating that the exine formation was restored in the mutant. Thus, the mutant was designated transient defective exine 1 (tde1). These results indicated that tde1 mutation affects the initial process of the exine formation, but does not impair any critical processes. Our results also suggest the existence of a certain factor responsible for exine patterning in A. thaliana. The TDE1 gene was found to be identical to the DE-ETIOLATED 2 gene known to be involved in brassinosteroid (BR) biosynthesis, and the tde1 probacula-defective phenotypes were recovered in the presence of BR application. These results suggest that BRs control the rate or efficiency of initial process of exine pattern formation.