Sujkowska-Rybkowska Marzena, Borucki Wojciech
Department of Botany, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
Department of Botany, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
Micron. 2014 Dec;67:10-19. doi: 10.1016/j.micron.2014.06.006. Epub 2014 Jun 25.
Cell wall components such as hydroxyproline-rich glycoproteins (HRGPs, extensins) have been proposed to be involved in aluminum (Al) resistance mechanisms in plants. We have characterized the distribution of extensin in pea (Pisum sativum L.) root nodules apoplast under short (for 2 and 24h) Al stress. Monoclonal antibodie LM1 have been used to locate extensin protein epitope by immunofluorescence and immunogold labeling. The nodules were shown to respond to Al stress by thickening of plant and infection thread (IT) walls and disturbances in threads growth and bacteria endocytosis. Immunoblot results indicated the presence of a 17-kDa band specific for LM1. Irrespective of the time of Al stress, extensin content increased in root nodules. Further observation utilizing fluorescence and transmission electron microscope showed that LM1 epitope was localized in walls and intercellular spaces of nodule cortex tissues and in the infection threads matrix. Al stress in nodules appears to be associated with higher extensin accumulation in matrix of enlarged thick-walled ITs. In addition to ITs, thickened walls and intercellular spaces of nodule cortex were also associated with intense extensin accumulation. These data suggest that Al-induced extensin accumulation in plant cell walls and ITs matrix may have influence on the process of IT growth and tissue and cell colonization by Rhizobium bacteria.
细胞壁成分，如富含羟脯氨酸的糖蛋白（HRGPs，伸展蛋白），被认为参与了植物对铝（Al）的抗性机制。我们已经表征了在短期（2小时和24小时）铝胁迫下，豌豆（Pisum sativum L.）根瘤质外体中伸展蛋白的分布。单克隆抗体LM1已被用于通过免疫荧光和免疫金标记来定位伸展蛋白的表位。结果表明，根瘤对铝胁迫的反应是植物细胞壁和感染丝（IT）壁增厚，以及感染丝生长和细菌内吞作用受到干扰。免疫印迹结果表明存在一条对LM1特异的17 kDa条带。无论铝胁迫时间如何，根瘤中伸展蛋白的含量都会增加。利用荧光显微镜和透射电子显微镜进一步观察表明，LM1表位定位于根瘤皮层组织的细胞壁和细胞间隙以及感染丝基质中。根瘤中的铝胁迫似乎与扩大的厚壁感染丝基质中更高的伸展蛋白积累有关。除了感染丝外，根瘤皮层增厚的细胞壁和细胞间隙也与强烈的伸展蛋白积累有关。这些数据表明，铝诱导的伸展蛋白在植物细胞壁和感染丝基质中的积累可能会影响感染丝的生长过程以及根瘤菌对组织和细胞的定殖。
