Xyloglucan Endotransglycosylase Activity, Microfibril Orientation and the Profiles of Cell Wall Properties Along Growing Regions of Maize Roots

Pritchard, Jeremy; Hetherington, Paul; Fry, Stephen C.; Tomos, A. D.

doi:10.1093/jxb/44.8.1281

Cited by 151 publications

(108 citation statements)

References 32 publications

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“…Although XET failed to cause cucumber cell walls to extend in an in vitro assay (McQueenMason et al, 1993), other reports have suggested that XET could be involved in cell wall extensibility. A decrease in XET activity was reported in primary roots of maize with low water potential, which was correlated with a decrease in cell wall extensibility and cell elongation in that region (Pritchard et al, 1993). Also, Wu et al (1994Wu et al ( ,1996 found enhanced XET activity that was correlated with an increase in cell wall extensibility.…”

Section: Introductionmentioning

confidence: 77%

Xyloglucan endotransglucosylase and cell wall extensibility

Miedes

Zarra

Hoson

et al. 2011

Journal of Plant Physiology

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SUMMARY Keywords:Cell wall. Extensibility. Growth. Solanum lycopersicum L. cv. Money Maker. Xyloglucan Transgenic tomato hypocotyls with altered levels of an XTH gene were used to study how XET activity could affect the hypocotyl growth and cell wall extensibility. Transgenic hypocotyls showed significant over-expression (line 13) or co-suppression (line 33) of the SIXTH! in comparison with the wild type, with these results being correlated with the results on specific soluble XET activity, suggesting that SIXTH! translates mainly for a soluble XET isoenzyme. A relationship between XET activity and cell wall extensibility was found, and the highest total extensibility was located in the apical hypocotyl segment of the over-expressing SIXTH! line, where the XET-specific activity and hypocotyl growth were also highest compared with the wild line. Also, in the co-suppression SIXTH! line, total extensibility values were lower than in the wild type line. The study of linkages between cell wall polysaccharides by FTIR showed that hypocotyls over-expressing SIXTH! and having a higher XET-specific activity, were grouped away from the wild line, indicating that the linkages between pectins and between cellulose and xyloglucans might differ. These results suggested that the action of the increased XET activity in the transgenic line could be responsible for the cell wall structural changes, and therefore, alter the cell wall extensibility. On the other hand, results on xyloglucan oligosaccharides composition of the xyloglucan by MALDITOF-MS showed no differences between lines, indicating that the xyloglucan structure was not affected by the XET action. These results provide evidences that XTHs from group I are involved mainly in the restructuring of the cell wall during growth and development, but they are not the limiting factor for plant growth.

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Section: Introductionmentioning

confidence: 77%

Xyloglucan endotransglucosylase and cell wall extensibility

Miedes

Zarra

Hoson

et al. 2011

Journal of Plant Physiology

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“…Some examples are (1) source-sink regulation of water and solute distribution via the phloem (Pritchard, 1994;Nerd and Neumann, 2004), (2) molecular changes (e.g. Pritchard et al, 1993;Wu and Cosgrove, 2000;Rodríguez et al, 2002), (3) changes in plant hormones such as abscisic acid or ethylene (e.g. Bacon et al, 1998;Sharp, 2002), and (4) cell wallstructural changes (e.g.…”

Section: Acid Ph Accelerates Growth Of Roots Under Water Deficitmentioning

confidence: 99%

The Spatially Variable Inhibition by Water Deficit of Maize Root Growth Correlates with Altered Profiles of Proton Flux and Cell Wall pH

Fan

Neumann

2004

Plant Physiology

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Growth of elongating primary roots of maize (Zea mays) seedlings was approximately 50% inhibited after 48 h in aerated nutrient solution under water deficit induced by polyethylene glycol 6000 at 20.5 MPa water potential. Proton flux along the root elongation zone was assayed by high resolution analyses of images of acid diffusion around roots contacted for 5 min with pH indicator gel. Profiles of root segmental elongation correlated qualitatively and quantitatively (r 2 5 0.74) with proton flux along the surface of the elongation zone from water-deficit and control treatments. Proton flux and segmental elongation in roots under water deficit were remarkably well maintained in the region 0 to 3 mm behind the root tip and were inhibited from 3 to 10 mm behind the tip. Associated changes in apoplastic pH inside epidermal cell walls were measured in three defined regions along the root elongation zone by confocal laser scanning microscopy using a ratiometric method. Finally, external acidification of roots was shown to specifically induce a partial reversal of growth inhibition by water deficit in the central region of the elongation zone. These new findings, plus evidence in the literature concerning increases induced by acid pH in wall-extensibility parameters, lead us to propose that the apparently adaptive maintenance of growth 0 to 3 mm behind the tip in maize primary roots under water deficit and the associated inhibition of growth further behind the tip are related to spatially variable changes in proton pumping into expanding cell walls.

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“…Changes in expansion rate are therefore essentially linked to cell-wall rheological properties, via the activities of enzymes such as xyloglucan endotransglycosylase (XET) (Pritchard et al, 1993), expansins (MacQueen-Mason & Cosgrove, 1995 ;Reinhardt et al, 1998) or peroxidases (Thompson et al, 1998), under the control of chemical signals such as ABA (Ben Haj Salah & Tardieu, 1997) and\or of hydraulic signals (Chazen & Neuman, 1994 ;Ben Haj Salah & Tardieu, 1997). Leaf expansion can finally be considered as the result of both epidermal cell division and epidermal cell expansion.…”

Section: F Tardieu Et Almentioning

confidence: 99%

Modelling leaf expansion in a fluctuating environment: are changes in specific leaf area a consequence of changes in expansion rate?

1999

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Leaf expansion rate varies with leaf temperature, photon flux density (PPFD), evaporative demand and soil water status. In most simulation models, it is calculated every day by multiplying the amount of carbohydrate available to leaves by specific leaf area (SLA). However, leaf expansion rate is considerably reduced by mild water deficits which do not affect photosynthesis, and is not affected by a reduction in the PPFD intercepted during rapid leaf expansion. Specific leaf area undergoes a several-fold variability depending on PPFD, soil water status and time of day. It is increased when environmental conditions have a greater depressive effect on expansion rate than on photosynthesis, and is decreased in the opposite case. It is therefore appropriate to model leaf expansion independently of the plant carbon budget. Consistent characteristics can be deduced from a series of experiments, allowing a model of leaf expansion to be proposed. (i) Time courses of relative leaf expansion rate and of epidermal cell division rate are well conserved within a plant and across a large range of environmental conditions, provided that durations and rates are expressed in thermal time. Maximum relative rates are common to all zones of a leaf and to all leaves of a plant, in maize and sunflower. (ii) A water deficit, or a reduction in intercepted PPFD, imposed in the first half of the period of leaf development affects the relative expansion rate in the deficit only, but permanently affects the absolute expansion rate. In contrast, a reduction in PPFD causes no effect on leaf expansion if imposed in the rapid expansion period when the leaf is autotrophic. (iii) Expansion rate is related to evaporative demand and to the concentration of ABA in the xylem sap with relationships that apply under both field and laboratory conditions. (iv) Tissue expansion and epidermal cell division behave as independent processes which determine epidermal cell area at each time.

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Xyloglucan Endotransglycosylase Activity, Microfibril Orientation and the Profiles of Cell Wall Properties Along Growing Regions of Maize Roots

Cited by 151 publications

References 32 publications

Xyloglucan endotransglucosylase and cell wall extensibility

Xyloglucan endotransglucosylase and cell wall extensibility

The Spatially Variable Inhibition by Water Deficit of Maize Root Growth Correlates with Altered Profiles of Proton Flux and Cell Wall pH

Modelling leaf expansion in a fluctuating environment: are changes in specific leaf area a consequence of changes in expansion rate?

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