Disrupting Two<i>Arabidopsis thaliana</i>Xylosyltransferase Genes Results in Plants Deficient in Xyloglucan, a Major Primary Cell Wall Component

Cavalier, David; Lerouxel, Olivier; Neumetzler, Lutz; Yamauchi, Kazuchika; Reinecke, Antje; Freshour, Glenn; Zabotina, Olga A.; Hahn, Michael G.; Burgert, Ingo; Pauly, Markus; Raikhel, Natasha V.; Keegstra, Kenneth

doi:10.1105/tpc.108.059873

Cited by 385 publications

(411 citation statements)

References 101 publications

(159 reference statements)

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“…Although fucogalactoxyloglucan may constitute up to 20% to 25% of the primary cell wall dry weight in dicots (Vogel, 2008), the polysaccharide is, remarkably, dispensable: Arabidopsis plants that completely lack xyloglucan, due to the disruption of two essential xylosyltransferases, have an essentially normal growth habit (Cavalier et al, 2008). This suggests a significant ability to compensate for even drastic effects on xyloglucan composition and quantity.…”

Section: Discussionmentioning

confidence: 99%

Group III-AXTHGenes of Arabidopsis Encode Predominant Xyloglucan Endohydrolases That Are Dispensable for Normal Growth

et al. 2012

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The molecular basis of primary wall extension endures as one of the central enigmas in plant cell morphogenesis. Classical cell wall models suggest that xyloglucan endo-transglycosylase activity is the primary catalyst (together with expansins) of controlled cell wall loosening through the transient cleavage and religation of xyloglucan-cellulose cross links. The genome of Arabidopsis (Arabidopsis thaliana) contains 33 phylogenetically diverse XYLOGLUCAN ENDO-TRANSGLYCOSYLASE/ HYDROLASE (XTH) gene products, two of which were predicted to be predominant xyloglucan endohydrolases due to clustering into group III-A. Enzyme kinetic analysis of recombinant AtXTH31 confirmed this prediction and indicated that this enzyme had similar catalytic properties to the nasturtium (Tropaeolum majus) xyloglucanase1 responsible for storage xyloglucan hydrolysis during germination. Global analysis of Genevestigator data indicated that AtXTH31 and the paralogous AtXTH32 were abundantly expressed in expanding tissues. Microscopy analysis, utilizing the resorufin b-glycoside of the xyloglucan oligosaccharide XXXG as an in situ probe, indicated significant xyloglucan endohydrolase activity in specific regions of both roots and hypocotyls, in good correlation with transcriptomic data. Moreover, this hydrolytic activity was essentially completely eliminated in AtXTH31/AtXTH32 double knockout lines. However, single and double knockout lines, as well as individual overexpressing lines, of AtXTH31 and AtXTH32 did not demonstrate significant growth or developmental phenotypes. These results suggest that although xyloglucan polysaccharide hydrolysis occurs in parallel with primary wall expansion, morphological effects are subtle or may be compensated by other mechanisms. We hypothesize that there is likely to be an interplay between these xyloglucan endohydrolases and recently discovered apoplastic exo-glycosidases in the hydrolytic modification of matrix xyloglucans.

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Section: Discussionmentioning

confidence: 99%

Group III-AXTHGenes of Arabidopsis Encode Predominant Xyloglucan Endohydrolases That Are Dispensable for Normal Growth

et al. 2012

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“…To our knowledge, there is no reported case of xyloglucan existing within a plant cell wall in the absence of cellulose in either eudicots or monocots. One of the postulated roles of xyloglucan in the primary wall is to noncovalently cross-link cellulose microfibrils so that the xyloglucan-cellulose network becomes the major load-bearing structure of the wall (Cavalier et al, 2008). Whether the low levels of xyloglucan permit or are necessary for such a role early in endosperm development is debatable; in any event it cannot fulfill this role in the endosperm beyond 8 DAP when LM15 labeling disappears in endosperm cells.…”

Section: Cellulosementioning

confidence: 99%

Pattern of Deposition of Cell Wall Polysaccharides and Transcript Abundance of Related Cell Wall Synthesis Genes during Differentiation in Barley Endosperm

Wilson

Burton²,

Collins³

et al. 2012

Plant Physiology

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Immunolabeling, combined with chemical analyses and transcript profiling, have provided a comprehensive temporal and spatial picture of the deposition and modification of cell wall polysaccharides during barley (Hordeum vulgare) grain development, from endosperm cellularization at 3 d after pollination (DAP) through differentiation to the mature grain at 38 DAP. (1→3)-β-d-Glucan appears transiently during cellularization but reappears in patches in the subaleurone cell walls around 20 DAP. (1→3, 1→4)-β-Glucan, the most abundant polysaccharide of the mature barley grain, accumulates throughout development. Arabino-(1-4)-β-d-xylan is deposited significantly earlier than we previously reported. This was attributable to the initial deposition of the polysaccharide in a highly substituted form that was not recognized by antibodies commonly used to detect arabino-(1-4)-β-d-xylans in sections of plant material. The epitopes needed for antibody recognition were exposed by pretreatment of sections with α-l-arabinofuranosidase; this procedure showed that arabino-(1-4)-β-d-xylans were deposited as early as 5 DAP and highlighted their changing structures during endosperm development. By 28 DAP labeling of hetero-(1→4)-β-d-mannan is observed in the walls of the starchy endosperm but not in the aleurone walls. Although absent in mature endosperm cell walls we now show that xyloglucan is present transiently from 3 until about 6 DAP and disappears by 8 DAP. Quantitative reverse transcription-polymerase chain reaction of transcripts for GLUCAN SYNTHASE-LIKE, Cellulose Synthase, and CELLULOSE SYNTHASE-LIKE genes were consistent with the patterns of polysaccharide deposition. Transcript profiling of some members from the Carbohydrate-Active Enzymes database glycosyl transferase families GT61, GT47, and GT43, previously implicated in arabino-(1-4)-β-d-xylan biosynthesis, confirms their presence during grain development.

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“…We quantified two proteins, Xyloglucan XylosylTransferase1 (XXT1) and XXT2, that are involved in xyloglucan synthesis, and XXT2 showed slightly higher abundance (rank 66) than XXT1 (rank 101; Cavalier et al, 2008). However, no Cellulose Synthase-Like C (CslC) proteins that synthesize the xyloglucan backbone were quantified.…”

Section: Quantities Of the Cell Wall Synthesis Machineries In The Golmentioning

confidence: 99%

Label-Free Protein Quantification for Plant Golgi Protein Localization and Abundance

et al. 2014

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The proteomic composition of the Arabidopsis (Arabidopsis thaliana) Golgi apparatus is currently reasonably well documented; however, little is known about the relative abundances between different proteins within this compartment. Accurate quantitative information of Golgi resident proteins is of great importance: it facilitates a better understanding of the biochemical processes that take place within this organelle, especially those of different polysaccharide synthesis pathways. Golgi resident proteins are challenging to quantify because the abundance of this organelle is relatively low within the cell. In this study, an organelle fractionation approach targeting the Golgi apparatus was combined with a label-free quantitative mass spectrometry (dataindependent acquisition method using ion mobility separation known as LC-IMS-MS E [or HDMS E ]) to simultaneously localize proteins to the Golgi apparatus and assess their relative quantity. In total, 102 Golgi-localized proteins were quantified. These data show that organelle fractionation in conjunction with label-free quantitative mass spectrometry is a powerful and relatively simple tool to access protein organelle localization and their relative abundances. The findings presented open a unique view on the organization of the plant Golgi apparatus, leading toward unique hypotheses centered on the biochemical processes of this organelle.

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

Cited by 385 publications

References 101 publications

Group III-AXTHGenes of Arabidopsis Encode Predominant Xyloglucan Endohydrolases That Are Dispensable for Normal Growth

Group III-AXTHGenes of Arabidopsis Encode Predominant Xyloglucan Endohydrolases That Are Dispensable for Normal Growth

Pattern of Deposition of Cell Wall Polysaccharides and Transcript Abundance of Related Cell Wall Synthesis Genes during Differentiation in Barley Endosperm

Label-Free Protein Quantification for Plant Golgi Protein Localization and Abundance

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