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...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 C3S 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.展开更多
Transmission electron microscopy was conducted to characterize the mature pollen grains in the massulae of Habenaria sagittifera at anthesis to understand its ultramicroscopic features of mature pollen grains of this ...Transmission electron microscopy was conducted to characterize the mature pollen grains in the massulae of Habenaria sagittifera at anthesis to understand its ultramicroscopic features of mature pollen grains of this species. I found that(a) pollen walls on the surface of the massula consisted of several layers, which included the tectum, baculum, nexine-1, nexine-2, and intine, whereas pollen walls within the massula were comprised of less layers, lacking tectum and baculum;(b) both vegetative and generative nuclei in mature pollen grains were predominated by highly condensed chromatin, which occupied over half of the nuclear volume; and(c) the pollen grains did not contain lipid droplets, starch grains,or storage proteins, indicative of the absence of macromolecular storage reserves. In summary, the structural difference between walls on the surface of the massula and walls within the massula, the highly condensed status of the vegetative nucleus, and the absence of macromolecular storage reserves were the most noticeable ultramicroscopic characteristics of mature pollen grains of H. sagittifera.展开更多
西葫芦花粉壁蛋白质提取液,经气液色谱分析表明,其中糖的部分含有20.4%鼠李糖,15.3%岩藻糖,11%甘露糖,11%半乳糖,31%葡萄糖,4%阿拉伯糖以及微量的木糖。用伴刀豆球蛋白 A(简称 Con A)亲和层析分离纯化花粉壁糖蛋白,经聚丙烯酰胺凝胶等...西葫芦花粉壁蛋白质提取液,经气液色谱分析表明,其中糖的部分含有20.4%鼠李糖,15.3%岩藻糖,11%甘露糖,11%半乳糖,31%葡萄糖,4%阿拉伯糖以及微量的木糖。用伴刀豆球蛋白 A(简称 Con A)亲和层析分离纯化花粉壁糖蛋白,经聚丙烯酰胺凝胶等电聚焦电泳分析表明,有三条 PAS 阳性反应的糖蛋白带Ⅰ、Ⅱ、Ⅲ,其等电点分别为5.2,6.0和6.3。糖蛋白经恒沸点盐酸水解,用氨基酸自动分析仪分析其中氨基酸组成。结果表明,三条糖蛋白的氨基酸组成相当一致。甘氨酸、谷氨酸和丝氨酸是其中的主要的氨基酸,约占氨基酸总量的50—60%。蛋氨酸,苯丙氨酸,异亮氨酸及酪氨酸含量较低。各糖蛋白中的赖氨酸含量的高低与其等电点是一致的。展开更多
文摘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 C3S 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.
基金supported by Natural Science Foundation of Shandong Province(ZR2015HL115)National Natural Science Foundation(31300545)
文摘Transmission electron microscopy was conducted to characterize the mature pollen grains in the massulae of Habenaria sagittifera at anthesis to understand its ultramicroscopic features of mature pollen grains of this species. I found that(a) pollen walls on the surface of the massula consisted of several layers, which included the tectum, baculum, nexine-1, nexine-2, and intine, whereas pollen walls within the massula were comprised of less layers, lacking tectum and baculum;(b) both vegetative and generative nuclei in mature pollen grains were predominated by highly condensed chromatin, which occupied over half of the nuclear volume; and(c) the pollen grains did not contain lipid droplets, starch grains,or storage proteins, indicative of the absence of macromolecular storage reserves. In summary, the structural difference between walls on the surface of the massula and walls within the massula, the highly condensed status of the vegetative nucleus, and the absence of macromolecular storage reserves were the most noticeable ultramicroscopic characteristics of mature pollen grains of H. sagittifera.
文摘西葫芦花粉壁蛋白质提取液,经气液色谱分析表明,其中糖的部分含有20.4%鼠李糖,15.3%岩藻糖,11%甘露糖,11%半乳糖,31%葡萄糖,4%阿拉伯糖以及微量的木糖。用伴刀豆球蛋白 A(简称 Con A)亲和层析分离纯化花粉壁糖蛋白,经聚丙烯酰胺凝胶等电聚焦电泳分析表明,有三条 PAS 阳性反应的糖蛋白带Ⅰ、Ⅱ、Ⅲ,其等电点分别为5.2,6.0和6.3。糖蛋白经恒沸点盐酸水解,用氨基酸自动分析仪分析其中氨基酸组成。结果表明,三条糖蛋白的氨基酸组成相当一致。甘氨酸、谷氨酸和丝氨酸是其中的主要的氨基酸,约占氨基酸总量的50—60%。蛋氨酸,苯丙氨酸,异亮氨酸及酪氨酸含量较低。各糖蛋白中的赖氨酸含量的高低与其等电点是一致的。
