Tagged: arabinogalactan proteins

Apple and cells

Arabinogalactan proteins (AGPs) and pectins in apple fruits during postharvest storage

Changes in the arrangement of cell wall components determine cell wall properties (integrity, stiffness), thereby affecting the macro properties of fruits, which are important for consumers and industry. The immunocytochemical study was conducted to elucidate the distribution of arabinogalactan proteins (AGPs) and pectic polysaccharides contained in apple (Malus x domestica) fruits during senescence process. Microscopy observations showed spatio-temporal changes in the localization and dependencies between all examined constituents. Leszczuk et al. propose that AGPs are involved in establishment of the cell wall – plasma membrane continuum.

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Glycoprotein distribution in the apple pistil during the progamic phase.

Glycoprotein secretions and pollen tube kinetics in apple

The obturator bridges the downward transit of the pollen tube through style to ovary in many angiosperms. Examining pollen tube growth kinetics in the pistil in Malus × domestica and relating these to changes occurring on the obturator using histochemistry and immunocytochemistry in order to determine how the key access point of the obturator is mediated, Losada and Herrero show that glycoprotein secretion is required for a lightning pollen tube wall elongation on the surface of the obturator. This secretion is depleted following on from the passage of pollen tubes, which strongly suggests that glycoprotein secretion has a pivotal role...

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Laser confocal microscopy image showing binding of the bacterium P. atrosepticum to S. tuberosum root tip.

Galactose-containing enriched root exudates of potato interfere with the growth of Pectobacterium atrosepticum

Potato (Solanum tuberosum) is a major food crop worldwide and its cultivation is fraught with difficulty. This is because potato roots and tubers are susceptible to many devastating diseases caused by soil-borne pathogens. Previous research on potato has been dedicated mainly to the tubers, with less research available on potato root structure and function, the processes of potato root exudation and the production of root border cells. Koroney et al. show that root exudates from S. tuberosum are radically enriched by galactose-containing molecules, including arabinogalactan proteins. The composition of potato root exudates is shown to be affected in response to...

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Quercus suber

AGPs and pectins during cork oak ovule development

Quercus suber is an extremely important forest species in European Western Mediterranean regions, due to its ecological value and economic potential, allowing local sustainable use of natural resources. Although it has a long and complex reproductive cycle and recalcitrant seeds, little is known about what occurs during female gametogenesis. The plant cell wall’s main components arabinogalactan proteins (AGPs) and pectins perform common functions in cell differentiation and organogenesis of reproductive structures, acting as signalling molecules, in sporophyte–gametophyte transition and in pollen–pistil interactions. Lopes et al. assessed the distribution of these molecules during cork oak ovule development.

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AGPs in Trithuria reproductive structures

AGPs in Trithuria reproductive structures

Trithuria is the sole genus of Hydatellaceae, a family of the early-divergent angiosperm lineage Nymphaeales. In order to help determine the early evolution of angiosperm cell-wall structures, Costa et al. use immunocytochemical techniques to examine arabinogalactan protein (AGP) epitopes in T. submersa and find intense labelling in the anthers and in the intine wall, the latter associated with pollen tube emergence. The results agree with labellings obtained for Arabidopsis and confirms the importance of AGPs in angiosperm reproductive structures as essential structural components and probably important signalling molecules.

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