Sonnewald U (2001)
Publication Status: Published
Publication Type: Journal article
Publication year: 2001
Publisher: SPRINGER-VERLAG
Book Volume: 212
Pages Range: 279-287
Journal Issue: 2
To study the function of xyloglucan endotransglycosylase (XET) in vivo we isolated, a tomato (Lycopersicon esculentum Mill.) XET cDNA (GenBank AA824986) from the homologous tobacco (Nicotiana tabacum L.) clone named NtXET-1 (Accession no. D86730). The expression pattern revealed highest levels of NtXET-1 mRNA in organs highly enriched in vascular tissue. The levels of NtXET-1 mRNA decreased in midribs with increasing age of leaves. Increasing leaf age was correlated with an increase in the average molecular weight (MW) of xyloglucan (XG) and a decrease in the relative growth rates of leaves. Transgenic tobacco plants with reduced levels of XET activity were created to further study the biochemical consequences of reduced levels of NtXET-1 expression. In two independent lines, total XET activity could be reduced by 56% and 37%, respectively, in midribs of tobacco plants transformed with an antisense construct. The decreased activity led to an increase in the average MW of XG by at least 20%. These two lines of evidence argue for NtXET-1 being involved in the incorporation of small XG molecules into the cell wall by transglycosylation. Reducing the incorporation of small XG molecules will result in a shift towards a higher average MW. The observed reduction in NtXET-1 expression and increase in the MW of XG in older leaves might be associated with strengthening of cell walls by reduced turnover and hydrolysis of XG.
APA:
Sonnewald, U. (2001). Functional characterisation of Nicotiana tabacum xyloglucan endotransglycosylase (NtXET-1): generation of transgenic tobacco plants and changes in cell wall xyloglucan. Planta, 212(2), 279-287.
MLA:
Sonnewald, Uwe. "Functional characterisation of Nicotiana tabacum xyloglucan endotransglycosylase (NtXET-1): generation of transgenic tobacco plants and changes in cell wall xyloglucan." Planta 212.2 (2001): 279-287.
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