A xylogalacturonan epitope is specifically associated with plant cell detachment

Abstract

A monoclonal antibody (LM8) was generated with specificity for xyloglacturonan (XGA) isolated from pea (Pisum sativum L.) testae. Characterization of the LM8 epitope indicates that it is a region of XGA that is highly substituted with xylose. Immunocytochemical analysis indicates that this epitope is restricted to loosely attached inner parenchyma cells at the inner face of the pea testa and does not occur in other cells of the testa. Elsewhere in the pea seedling, the LM8 epitope was found only in association with root cap cell development at the root apex. Furthermore, the LM8 epitope is specifically associated with root cap cells in a range of angiosperm species. In embryogenic carrot suspension cell cultures the epitope is abundant at the surface of cell walls of loosely attached cells in both induced and non-induced cultures. The LM8 epitope is the first cell wall epitope to be identified that is specifically associated with a plant cell separation process that results in complete cell detachment.

The Organization Pattern of Root Border-Like Cells of Arabidopsis Is Dependent on Cell Wall Homogalacturonan

“…The most interesting immunolocalization finding is that LM8 epitopes associated with xylogalacturonan were highly expressed in the secreted mucilage of the qua1-1 mutant. This is consistent with previous reports indicating that xylogalacturonan was specifically associated with plant cell separation phenomena (Willats et al, 2001(Willats et al, , 2004, although the functional relationship between LM8 epitope-containing xylogalacturonan and cell detachment is still not understood. It is also interesting that distinct spatial differences were observed in the occurrence of arabinogalactanprotein epitopes detected with the mAbs JIM13 and LM2 between the wild type and the qua1-1 mutant.…”

“…The anti-pectin mAbs used in this study were JIM5, which recognizes homogalacturonan (Willats et al, 2000), LM8, which recognizes a xylogalacturonan-associated epitope (Willats et al, 2004), LM5 specific to (1/4)-b-Dgalactan (Jones et al, 1997), and LM6 specific to (1/5)-a-L-arabinan (Willats et al, 1998). The mAb CCRC-M1, which is specific for fucosylated side chains of xyloglucan (Puhlmann et al, 1994), was used to label xyloglucan.…”

“…Bars = 20 mm (A, B, D-H, and J) or 50 mm (C and I). ular bases of intercellular adhesion and its loss are not fully understood (Roberts et al, 2002;Jarvis et al, 2003;Willats et al, 2004). This study aims at investigating the role of cell wall polysaccharides in cell attachment and the organization of border-like cells in Arabidopsis.…”

Deciphering the Responses of Root Border-Like Cells of Arabidopsis and Flax to Pathogen-Derived Elicitors

“…These include xyloglucan epitopes, as revealed by the monoclonal antibodies (mAbs) LM15 (Marcus et al, 2008) and CCRCM1 (Puhlmann et al, 1994;Fig. 1, D and E), and pectins including homogalacturonan and xylogalacturonan, as revealed by the mAbs LM19 (Verhertbruggen et al, 2009) and LM8 (Willats et al, 2004), respectively ( Fig. 1, F and G).…”

“…Also, areas of high intensity were found to be associated with corner junctions when using LM19. Finally, the abundance of xylogalacturonan labeling is interesting, as xylogalacturonan [formed by a-(1-4)-linked galacturonic acid and the high degree of substitution by Xyl] is thought to confer enhanced resistance to enzymatic degradation by pathogens (Willats et al, 2004;Jensen et al, 2008).…”