木薯块根膨大期韧皮部和木质部比较蛋白组学初步研究

Primary Comparative Proteomics of Phloem and Xylem in Cassava During the Tuberous Root Development

以‘华南8号’木薯块根膨大期的韧皮部和木质部为材料,采用改进酚抽法提取总蛋白,进行一维和二维电泳,电泳图谱经Image Master分析,得到差异蛋白点进行质谱鉴定。结果表明:改进酚抽法可以从木薯块根韧皮部和木质部中提取高质量总蛋白,用于蛋白质组学研究;获得分离性好、分辨率及重复性较高的双向电泳图谱;比较木薯块根韧皮部和木质部双向电泳图谱发现265个差异表达蛋白点,其中29个在韧皮部特异表达,17个在木质部特异表达;成功鉴定出8种差异蛋白,这些蛋白主要参与翻译后修饰、无机离子和氨基酸转运代谢、分子伴侣和信号转导等代谢通路。本研究初步比较木薯块根韧皮部和木质部的蛋白表达差异性,为进一步从蛋白质组水平研究木薯块根膨大过程中淀粉转运、积累和合成调控机制奠定了技术基础。

The improved phenol method was used for total protein extraction from the phloem and xylem tissues of swelling stage tuberous root in cassava eultivar ＇South China 8＇（SC8）, and then these proteins were separated by both one-dimensional and two-dimensional gel electrophoresis （2 -DE）. The obtained typical 2-DE gels were analyzed by ImageMaster software to determine the differential expressed protein spots, and some of them were manually excised for protein in-gel digestion and subsequently identified by MALDI-TOF MS. The main results included： High quality proteins were obtained from root phloem and xylem in cassava using phenol method; High resolution of 2-DE reference maps with good reproducibility were generated for proteomics; Comparison of the 2- DE gels for phloem and xylem generated 265 differential protein spots, of which 29 were specific for phloem and 17 for xylem; Eight proteins were finally identified by MALDI-TOF MS, which were involved in posttranslational modification, amino acid metabolism, inorganic ion transport and metabolism, signal transduction, and so forth. Taken together, comparative proteomics of phloem and xylem from cassava tuberous root were performed and 8 proteins were positively identified. This study provided an important fundamental technology for further proteomic research on the mechanism of starch transport and accumulation during the process of tuberous root development in cassava.