Biochemical and Immunocytological Characterizations of Arabidopsis Pollen Tube Cell Wall
Biochemical and Immunocytological Characterizations of Arabidopsis Pollen Tube Cell Wall
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DOI：
10.1104/pp.110.158881
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发表时间：
2010-08-01
期刊：
影响因子：
7.4
通讯作者：
Mollet, Jean-Claude
中科院分区：
文献类型：
--
作者：
Dardelle, Flavien;Lehner, Arnaud;Mollet, Jean-Claude
在植物有性生殖过程中，花粉萌发和花粉管生长需要在严格的空间和时间控制下进行发育，以便将精细胞正确地输送到胚珠。花粉管是快速生长的顶端极化细胞，能够感知雌性器官发出的多种引导信号。花粉管通过细胞壁分子的粘附可能是信号电池的一部分。为了研究这些过程中，我们调查了细胞壁的特点，在体外生长的拟南芥（拟南芥）花粉管使用相结合的免疫细胞化学和生物化学技术。结果表明，一个明确的定位细胞壁表位。低酯化的同型半乳糖醛酸抗原决定簇主要分布在顶端后壁。分别沿两个壁层和外壁层内的整个管沿着检测到来自鼠李糖半乳糖醛酸聚糖I表位的木葡聚糖和阿拉伯聚糖。相比之下，高度酯化的同型半乳糖醛酸和阿拉伯半乳聚糖蛋白表位被发现主要与尖端区域相关。花粉管细胞壁的化学分析揭示了阿拉伯糖残基的重要含量（43%），主要来自（1->5）-α-L-阿拉伯聚糖，鼠李糖半乳糖醛酸聚糖I的侧链。最后，基质辅助激光解吸电离飞行时间质谱分析内切葡聚糖酶敏感的木葡聚糖显示质谱与两个主要的寡糖（XLXG/XXLG和XXFG），都是单O-乙酰化，并占总离子信号的68%以上。这些结果表明，与拟南芥孢子体中的其他细胞类型相比，拟南芥花粉管壁具有自己的特征。这些结构特征进行了讨论的花粉管细胞壁的生物合成和生长动力学。
During plant sexual reproduction, pollen germination and tube growth require development under tight spatial and temporal control for the proper delivery of the sperm cells to the ovules. Pollen tubes are fast growing tip-polarized cells able to perceive multiple guiding signals emitted by the female organ. Adhesion of pollen tubes via cell wall molecules may be part of the battery of signals. In order to study these processes, we investigated the cell wall characteristics of in vitro-grown Arabidopsis (Arabidopsis thaliana) pollen tubes using a combination of immunocytochemical and biochemical techniques. Results showed a well-defined localization of cell wall epitopes. Low esterified homogalacturonan epitopes were found mostly in the pollen tube wall back from the tip. Xyloglucan and arabinan from rhamnogalacturonan I epitopes were detected along the entire tube within the two wall layers and the outer wall layer, respectively. In contrast, highly esterified homogalacturonan and arabinogalactan protein epitopes were found associated predominantly with the tip region. Chemical analysis of the pollen tube cell wall revealed an important content of arabinosyl residues (43%) originating mostly from (1-->5)-alpha-L-arabinan, the side chains of rhamnogalacturonan I. Finally, matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of endo-glucanase-sensitive xyloglucan showed mass spectra with two dominant oligosaccharides (XLXG/XXLG and XXFG), both being mono O-acetylated, and accounting for over 68% of the total ion signals. These findings demonstrate that the Arabidopsis pollen tube wall has its own characteristics compared with other cell types in the Arabidopsis sporophyte. These structural features are discussed in terms of pollen tube cell wall biosynthesis and growth dynamics.