title: Accumulation and localization of extensin protein in apoplast of pea root nodule under aluminum stress.
abstract: 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.
authors.affiliation: Department of Botany, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland. Electronic address: marzena_sujkowska@sggw.pl.
authors.forename: Marzena
authors.initials: M
authors.lastname: Sujkowska-Rybkowska
authors.affiliation: Department of Botany, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Borucki
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D002473:Cell Wall / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D006023:Glycoproteins / Q000378:metabolism* / Q000502:physiology; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D018532:Pisum sativum / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D010940:Plant Proteins / Q000378:metabolism* / Q000502:physiology; D053204:Root Nodules, Plant / Q000737:chemistry* / Q000648:ultrastructure; D013312:Stress, Physiological / Q000187:drug effects / Q000502:physiology
chemical_list: D006023:Glycoproteins; D010940:Plant Proteins; C005488:extensin protein, plant; D000535:Aluminum
keywords: Aluminum; Apoplast; Extensin; Infection thread; Nodules; Pisum sativum L.