Shanghai Jiao Tong University, Shanghai Institutes for Biological Sciences, China.
Mol Plant. 2008 Jul;1(4):599-610. doi: 10.1093/mp/ssn028. Epub 2008 Jun 23.
As a complex wall system in flowering plants, the pollen outer wall mainly contains aliphatic sporopollenin; however, the mechanism for synthesizing these lipidic precursors during pollen development remains less well understood. Here, we report on the function of the rice tapetum-expressing TDR (Tapetum Degeneration Retardation) gene in aliphatic metabolism and its regulatory role during rice pollen development. The observations of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses suggested that pollen wall formation was significantly altered in the tdr mutant. The contents of aliphatic compositions of anther were greatly changed in the tdr mutant revealed by GC-MS (gas chromatography-mass spectrometry) testing, particularly less accumulated in fatty acids, primary alcohols, alkanes and alkenes, and an abnormal increase in secondary alcohols with carbon lengths from C29 to C35 in tdr. Microarray data revealed that a group of genes putatively involved in lipid transport and metabolism were significantly altered in the tdr mutant, indicating the critical role of TDR in the formation of the pollen wall. Also, a wide range of genes (236 in total-154 up-regulated and 82 down-regulated) exhibited statistically significant expressional differences between wild-type and tdr. In addition to its function in promoting tapetum PCD, TDR possibly plays crucial regulatory roles in several basic biological processes during rice pollen development.
作为开花植物中复杂的壁系统，花粉外壁主要含有脂肪质的孢粉素；然而，花粉发育过程中这些脂类前体的合成机制还不太清楚。在这里，我们报告了水稻绒毡层表达的 TDR（绒毡层退化延迟）基因在脂肪代谢中的功能及其在水稻花粉发育过程中的调控作用。透射电子显微镜（TEM）和扫描电子显微镜（SEM）分析的观察表明，花粉壁的形成在 tdr 突变体中发生了明显改变。GC-MS（气相色谱-质谱）测试表明，花药中脂肪成分的含量在 tdr 突变体中发生了很大变化，特别是脂肪酸、伯醇、烷烃和烯烃的积累减少，而 C29 到 C35 的碳长的仲醇异常增加。微阵列数据分析表明，一组可能参与脂质转运和代谢的基因在 tdr 突变体中发生了显著改变，这表明 TDR 在花粉壁形成中起着关键作用。此外，在野生型和 tdr 之间，有大量的基因（总共 236 个，其中 154 个上调，82 个下调）表现出统计学上显著的表达差异。除了促进绒毡层 PCD 的功能外，TDR 可能在水稻花粉发育过程中的几个基本生物学过程中发挥着关键的调节作用。
