Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, Beijing, 100093, China.
The State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Plant Mol Biol. 2016 Jun;91(3):287-304. doi: 10.1007/s11103-016-0466-7. Epub 2016 Mar 11.
Maize is unique since it is both monoecious and diclinous (separate male and female flowers on the same plant). We investigated the proteome and phosphoproteome of maize pollen containing modified proteins and here we provide a comprehensive pollen proteome and phosphoproteome which contain 100,990 peptides from 6750 proteins and 5292 phosphorylated sites corresponding to 2257 maize phosphoproteins, respectively. Interestingly, among the total 27 overrepresented phosphosite motifs we identified here, 11 were novel motifs, which suggested different modification mechanisms in plants compared to those of animals. Enrichment analysis of pollen phosphoproteins showed that pathways including DNA synthesis/chromatin structure, regulation of RNA transcription, protein modification, cell organization, signal transduction, cell cycle, vesicle transport, transport of ions and metabolisms, which were involved in pollen development, the following germination and pollen tube growth, were regulated by phosphorylation. In this study, we also found 430 kinases and 105 phosphatases in the maize pollen phosphoproteome, among which calcium dependent protein kinases (CDPKs), leucine rich repeat kinase, SNF1 related protein kinases and MAPK family proteins were heavily enriched and further analyzed. From our research, we also uncovered hundreds of male sterility-associated proteins and phosphoproteins that might influence maize productivity and serve as targets for hybrid maize seed production. At last, a putative complex signaling pathway involving CDPKs, MAPKs, ubiquitin ligases and multiple fertility proteins was constructed. Overall, our data provides new insight for further investigation of protein phosphorylation status in mature maize pollen and construction of maize male sterile mutants in the future.
玉米是独特的，因为它既是雌雄同体的，又是雌雄异花的（同一植株上有单独的雄花和雌花）。我们研究了含有修饰蛋白的玉米花粉的蛋白质组和磷酸化蛋白质组，在这里我们提供了一个全面的花粉蛋白质组和磷酸化蛋白质组，分别包含 100990 个肽段和 6750 个蛋白质，以及 5292 个磷酸化位点，对应于 2257 个玉米磷酸化蛋白质。有趣的是，在我们这里鉴定的总共 27 个过表达磷酸化位点基序中，有 11 个是新的基序，这表明植物中的修饰机制与动物中的不同。花粉磷酸化蛋白质的富集分析表明，包括 DNA 合成/染色质结构、RNA 转录调控、蛋白质修饰、细胞组织、信号转导、细胞周期、囊泡运输、离子和代谢物运输在内的途径，这些途径参与花粉发育、随后的萌发和花粉管生长，受到磷酸化的调控。在这项研究中，我们还在玉米花粉磷酸化蛋白质组中发现了 430 种激酶和 105 种磷酸酶，其中钙依赖蛋白激酶（CDPKs）、富含亮氨酸重复的激酶、SNF1 相关蛋白激酶和 MAPK 家族蛋白被大量富集并进一步分析。从我们的研究中，我们还发现了数百种与雄性不育相关的蛋白质和磷酸化蛋白质，这些蛋白质可能影响玉米的生产力，并作为杂交玉米种子生产的靶标。最后，构建了一个涉及 CDPKs、MAPKs、泛素连接酶和多种育性蛋白的假定复杂信号通路。总的来说，我们的数据为进一步研究成熟玉米花粉中的蛋白质磷酸化状态以及未来构建玉米雄性不育突变体提供了新的见解。
