0000000000408731
AUTHOR
Karin Herbers
Overexpression of a cell wall enzyme reduces xyloglucan depolymerization and softening of transgenic tomato fruits.
Xyloglucan xyloglucosyltransferase/endohydrolase (XTHs: EC 2.4.1.207 and/or EC 3.2.1.151) has been proposed to have a dual role integrating newly secreted xyloglucan chains into an existing wall-bound xyloglucan and restructuring existing cell wall material by catalyzing transglucosylation between previously wall bound xyloglucan molecules. In this work we generated transgenic tomatoes with altered levels of an XTH gene. These transgenic fruits showed significant overexpression of the XTH proteins in comparison with the wild type. Specific XET activity was approximately 4.33 fold higher in the transgenic fruits compared with the wild type fruits, although in both cases the activity decrease…
Xyloglucan endotransglucosylase and cell wall extensibility
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 SlXTH1 in comparison with the wild type, with these results being correlated with the results on specific soluble XET activity, suggesting that SlXTH1 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 SlXTH1 line, where the XET-specific activity and hypocotyl…