State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
J Proteome Res. 2012 Aug 3;11(8):4180-90. doi: 10.1021/pr300295m. Epub 2012 Jul 3.
The pollen tube is a tip-growing system that delivers sperm to the ovule and thus is essential for sexual plant reproduction. Sucrose and other microelements act as nutrients and signaling molecules through pathways that are not yet fully understood. Taking advantage of high-throughput liquid chromatography coupled to mass spectrometry (LC-MS), we performed a label-free shotgun proteomic analysis of pollen in response to nutrient limitation using mass accuracy precursor alignment. We compared 168 LC-MS analyses and more than 1 million precursor ions and could define the proteomic phenotypes of pollen under different conditions. In total, 166 proteins and 42 phosphoproteins were identified as differentially regulated. These proteins are involved in a variety of signaling pathways, providing new insights into the multifaceted mechanism of nutrient function. The phosphorylation of proteins involved in cytoskeleton dynamics was found to be specifically responsive to Ca2+ and sucrose deficiency, suggesting that sucrose and extracellular Ca2+ influx are necessary for the maintenance of cytoskeleton polymerization. Sucrose limitation leads to widespread accumulation of proteins involved in carbohydrate metabolism and protein degradation. This highlights the wide range of metabolic and cellular processes that are modulated by sucrose but complicates dissection of the signaling pathways.
花粉管是一种尖端生长系统，将精子输送到胚珠，因此对有性植物的繁殖至关重要。蔗糖和其他微量元素作为营养物质和信号分子，通过尚未完全理解的途径发挥作用。利用高通量液相色谱-质谱联用（LC-MS），我们利用质量精度前体对齐，对营养限制下花粉的非标记鸟枪法蛋白质组进行了分析。我们比较了 168 次 LC-MS 分析和超过 100 万个前体离子，能够定义不同条件下花粉的蛋白质组表型。总共鉴定出 166 种蛋白质和 42 种磷酸化蛋白质作为差异调节。这些蛋白质参与各种信号通路，为营养功能的多方面机制提供了新的见解。参与细胞骨架动态的蛋白质的磷酸化被发现对 Ca2+和蔗糖缺乏特别敏感，这表明蔗糖和细胞外 Ca2+内流是维持细胞骨架聚合所必需的。蔗糖限制导致参与碳水化合物代谢和蛋白质降解的蛋白质广泛积累。这突出表明，蔗糖调节的代谢和细胞过程范围广泛，但使信号通路的分离复杂化。
