Temporal and spatial regulation of pectic (1-->4)-beta-D-galactan in cell walls of developing pea cotyledons: implications for mechanical properties.
Modifications in cell wall pectic polysaccharides are thought to influence cell-cell adhesion and the mechanical properties of plant tissues. Monoclonal antibodies to epitopes occurring in homo- galacturonan and side chains of rhamnogalacturonan I have been used in an immunolocalization study of cell wall architecture of developing pea cotyledons. Pectic (1-->4)-beta-D-galactan appears in cotyledon cell walls at a defined stage late in development (approximately 26-30 days after anthesis), whereas homogalacturonan and pectic (1-->5)-alpha-L-arabinan are present in cotyledon cell walls throughout development. (1-->4)-beta-galactan was restricted to a distinct thin layer at the plasma membrane face of the cell wall. Anion exchange and immunoaffinity chromatography indicated that the (1-->4)-beta-galactan was associated with acidic pectic components. Mechanical compressive testing of pea cotyledons, before and after (1-->4)-beta-galactan appearance, indicated that the cotyledons with the galactan-rich cell wall layer were twice as firm as those with no detectable (1-->4)-beta-galactan.
McCartney
L
L
Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK.
Ormerod
A P
AP
Gidley
M J
MJ
Knox
J P
JP
D000911:Antibodies, Monoclonal; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism*; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D018548:Cotyledon / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D000939:Epitopes; D005685:Galactans / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D007150:Immunohistochemistry; D018532:Pisum sativum / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D010368:Pectins / Q000737:chemistry; D013997:Time Factors
D000911:Antibodies, Monoclonal; D000939:Epitopes; D005685:Galactans; C042491:rhamnogalacturonan I; D010368:Pectins; C003181:polygalacturonic acid