Golgi enzymes that synthesize plant cell wall polysaccharides: finding and evaluating candidates in the genomic era

Perrin, Robyn M.; Wilkerson, Curtis G.; Keegstra, Kenneth

doi:10.1007/978-94-010-0668-2_7

Cited by 28 publications

(34 citation statements)

References 99 publications

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“…One interpretation of the lack of past success in purifying XyG glucan synthase using conventional biochemical protein purification approaches is that the XyG glucan synthase and XyG XTs form complexes, in which the concomitant activities of these enzymes are needed to synthesize XyG (Ray, 1980;Hayashi and Matsuda, 1981b;Hayashi et al, 1988;Gordon and Maclachlan, 1989;Hayashi, 1989;Brummell et al, 1990;Perrin et al, 2001). However, the development of an acceptor-based XyG XT assay by Faik et al (2002) showed that it is possible to measure XyG XT activity in detergentsolubilized pea microsomes independent of XyG glucan synthase activity, which was verified by heterologous expression studies of either XXT1 or XXT2 (Faik et al, 2002;Cavalier and Keegstra, 2006).…”

Section: Discussionmentioning

confidence: 99%

Disrupting TwoArabidopsis thalianaXylosyltransferase Genes Results in Plants Deficient in Xyloglucan, a Major Primary Cell Wall Component

et al. 2008

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Xyloglucans are the main hemicellulosic polysaccharides found in the primary cell walls of dicots and nongraminaceous monocots, where they are thought to interact with cellulose to form a three-dimensional network that functions as the principal load-bearing structure of the primary cell wall. To determine whether two Arabidopsis thaliana genes that encode xylosyltransferases, XXT1 and XXT2, are involved in xyloglucan biosynthesis in vivo and to determine how the plant cell wall is affected by the lack of expression of XXT1, XXT2, or both, we isolated and characterized xxt1 and xxt2 single and xxt1 xxt2 double T-DNA insertion mutants. Although the xxt1 and xxt2 mutants did not have a gross morphological phenotype, they did have a slight decrease in xyloglucan content and showed slightly altered distribution patterns for xyloglucan epitopes. More interestingly, the xxt1 xxt2 double mutant had aberrant root hairs and lacked detectable xyloglucan. The reduction of xyloglucan in the xxt2 mutant and the lack of detectable xyloglucan in the xxt1 xxt2 double mutant resulted in significant changes in the mechanical properties of these plants. We conclude that XXT1 and XXT2 encode xylosyltransferases that are required for xyloglucan biosynthesis. Moreover, the lack of detectable xyloglucan in the xxt1 xxt2 double mutant challenges conventional models of the plant primary cell wall.

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Section: Discussionmentioning

confidence: 99%

Disrupting TwoArabidopsis thalianaXylosyltransferase Genes Results in Plants Deficient in Xyloglucan, a Major Primary Cell Wall Component

et al. 2008

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“…Many strategies to identify these transferases can be applied (Perrin et al, 2001), and it could be expected that results will come quickly. However, because no l-arabinosyltransferases have been identified in any organism, the bioinformatics approach will be difficult.…”

Section: Discussionmentioning

confidence: 99%

Solubilization of an Arabinan Arabinosyltransferase Activity from Mung Bean Hypocotyls

Nunan¹,

Scheller²

2003

Plant Physiology

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The biosynthesis of polysaccharides destined for the plant cell wall and the subsequent assembly of the cell wall are poorly understood processes that are currently the focus of much research. Arabinan, a component of the pectic polysaccharide rhamnogalacturonan I, is composed of arabinosyl residues connected via various glycosidic linkages, and therefore, the biosynthesis of arabinan is likely to involve more than one arabinosyltransferase. We have studied the transfer of [ 14 C]arabinose (Ara) from UDP-l-arabinopyranose onto polysaccharides using microsomal membranes isolated from mung bean (Vigna radiata) hypocotyls. [ 14 C]arabinosyl and [ 14 C]xylosyl residues were incorporated into endogenous products due to the presence of UDP-Xyl-4-epimerase activity. Enzymatic digestion of endogenous products with endo-arabinanase released very little radiolabeled sugars, whereas digestion with arabinofuranosidase released some [ 14 C]Ara. Microsomal membranes solubilized with the detergent octyl glucoside were able to add a single [ 14 C]Ara residue onto (135)-linked ␣-l-arabino-oligosaccharide acceptors. The reaction had a pH optimum of 6.5 and a requirement for manganese ions. However, enzymatic digestion of the radiolabeled oligosaccharides with endo-arabinanase and arabinofuranosidases could not fully release the radiolabeled Ara residue, indicating that the [ 14 C]Ara residue was not a (132)-, (133)-, or (135)-linked ␣-l-arabinofuranosyl residue. Rather, mild acid treatment of the product suggested that the radiolabeled Ara residue was in a pyranose conformation, and this result was confirmed by thin-layer chromatography of radiolabeled partially methylated sugars. Using microsomal membranes separated on a discontinuous sucrose gradient, the arabinosyltransferase activity appears to be mainly localized to Golgi membranes.Pectic polysaccharides are major components of primary plant cell walls and middle lamella. Three main types of pectic polysaccharides have been identified, homogalacturonan, rhamnogalacturonan I (RG I), and rhamnogalacturonan II (RG II). RG I is composed of a backbone of alternating [34-␣-d-GalA-(132)-␣-l-Rha- (13] in which some of the rhamnose residues are substituted with complex side chains containing Ara and Gal residues. The composition and size of these side chains varies depending on the plant species, tissue type, and stage of development (O'Neill et al., 1990;Carpita and Gibeaut, 1993). In general, the arabinan side chains consist of a linear chain of (135)-linked ␣-l-arabinofuranosyl residues that may be substituted at the O-3 and/or O-2 with additional arabinofuranosyl residues (Carpita and Gibeaut, 1993;Schols and Voragen, 2002).The study of the biosynthesis of plant cell wall polysaccharides in plants is a growing field, but to date, very few genes encoding glycosyltransferases have been characterized (Edwards et al., 1999;Perrin et al., 1999;Faik et al., 2002). Notably, many different transferases must be involved in pectin biosynthesis, but until very recently, none had been isola...

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“…Matrix polysaccharides, including pectate, are synthesised in Golgi-derived vesicles and released to the wall by exocytosis (Northcote and Pickett-Heaps 1966;Moore et al 1991;Perrin et al 2001), where they are deposited around the cellulose microfibrils at the inner wall face. But many find their way into the existing wall structure (Northcote and Pickett-Heaps 1966;Ray 1967).…”

Section: Cell Wall Biosynthesismentioning

confidence: 99%

Cell wall biosynthesis and the molecular mechanism of plant enlargement

Boyer¹

2009

Functional Plant Biol.

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Abstract.Recently discovered reactions allow the green alga Chara corallina (Klien ex. Willd., em. R.D.W.) to grow well without the benefit of xyloglucan or rhamnogalactan II in its cell wall. Growth rates are controlled by polygalacturonic acid (pectate) bound with calcium in the primary wall, and the reactions remove calcium from these bonds when new pectate is supplied. The removal appears to occur preferentially in bonds distorted by wall tension produced by the turgor pressure (P). The loss of calcium accelerates irreversible wall extension if P is above a critical level. The new pectate (now calcium pectate) then binds to the wall and decelerates wall extension, depositing new wall material on and within the old wall. Together, these reactions create a non-enzymatic but stoichiometric link between wall growth and wall deposition. In green plants, pectate is one of the most conserved components of the primary wall, and it is therefore proposed that the acceleration-deceleration-wall deposition reactions are of wide occurrence likely to underlie growth in virtually all green plants. C. corallina is one of the closest relatives of the progenitors of terrestrial plants, and this review focuses on the pectate reactions and how they may fit existing theories of plant growth.

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Golgi enzymes that synthesize plant cell wall polysaccharides: finding and evaluating candidates in the genomic era

Cited by 28 publications

References 99 publications

Disrupting TwoArabidopsis thalianaXylosyltransferase Genes Results in Plants Deficient in Xyloglucan, a Major Primary Cell Wall Component

Disrupting TwoArabidopsis thalianaXylosyltransferase Genes Results in Plants Deficient in Xyloglucan, a Major Primary Cell Wall Component

Solubilization of an Arabinan Arabinosyltransferase Activity from Mung Bean Hypocotyls

Cell wall biosynthesis and the molecular mechanism of plant enlargement

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