Pectin Distribution at the Surface of Potato Parenchyma Cells in Relation to Cell−Cell Adhesion

Abstract

The crispness of fruits and vegetables is dependent, predominantly, on the maintenance of cell adhesion. There is a growing body of evidence to suggest that cell adhesion in plants is controlled at the edge of cell faces rather than across the entire cell surface. The aim of the current study has been to exploit antibody-labeling techniques in conjunction with methods that induce cell separation to explore the distribution of highly esterified and weakly esterified pectic polysaccharides on the cell surface. Potato parenchyma tissue was subjected to cooking and chemical treatments, which induced softening through cell separation. Scanning electron microscopy (SEM) revealed characteristic patterns on the surface of these separated cells, which outlined the imprint of neighboring cells. Monoclonal antibodies, JIM5 and JIM7, were used to locate weakly esterified and highly esterified pectin by silver-enhanced immunogold SEM. The edge-of-face structures labeled strongly with JIM5 but not JIM7, indicating that they contained polygalacturonic acid of low ester content. In addition, adhesion of the middle lamella to the face of the primary wall was found to differ from adhesion at the edge of each cell face. This, in conjunction with the antibody-labeling observations, complements previous transmission electron microscopy studies and is consistent with the edge-of-face regions having a specialist role in cell adhesion.

Cadmium-induced alterations of the structural features of pectins in flax hypocotyl

“…Moreover, the abundance of such pectins in these domains has been shown to play an important role in the cohesion of cells (Parker et al 2001;Jarvis et al 2003;Marry et al 2006). A main Wnding in the present study was, in the presence of Cd, a marked increase of the acidic pectins, labelled with the JIM5 and anti-PGA/RGI antibodies, accompanied by a signiWcant decrease of highly methylesteriWed pectins, revealed by the mAb JIM7, in the cell junctions of both epidermis and Wbres.…”

The middle lamella—more than a glue

“…However, in experimental tests in which living plant tissues were mechanically stretched, fracture upon material failure typically occurred within the cell wall material rather than at the ML [38,78]. Zamil et al [79] speculated that the reason for this fracture pattern may be geometrical rather than mechanical.…”

“…The biological role of the ML has been described as early as 100 years ago [37], intercellular adhesion and separation have been studied extensively [19,[38][39][40] and excellent reviews summarize the biological aspects of this structure [7,16,18,41,42]. However, the fact that the ML represents a distinct physical layer with distinct material properties has rarely been covered in detail.…”

Pectin Metabolism and Assembly in the Cell Wall of the Charophyte Green Alga Penium margaritaceum

“…HG with a low degree of methylesterification or nonesterified HG is most abundant in the middle lamella, particularly at intercellular junctions and the corners of intercellular spaces (Bush et al, 2001;Parker et al, 2001;McCartney and Knox, 2002;Guillemin et al, 2005), which are regions where intercellular biomechanical forces are greatest (Jarvis et al, 2003). Ca 2+ is also present at high levels in the middle lamella, especially at the same load-bearing junction areas (Rihouey et al, 1995;Huxham et al, 1999;Bush et al, 2001), giving rise to the idea that Ca 2+ -HG gelation is biomechanically important.…”