Cell wall modification involving XTHs controls phytochrome-mediated petiole elongation in Arabidopsis thaliana.
The shade avoidance syndrome serves to improve the competitive power of plants growing in crowded plant communities. An important element of avoiding shade is to rapidly elongate shoots and outgrow competing neighbours. We investigated the role of cell wall modifying proteins expansins and xyloglucan endotransglucosylase/hydrolases (XTHs) in mediating this vital elongation growth in Arabidopsis thaliana. These proteins act on the cell wall and modify it to make it more extensible thereby facilitating cellular expansion. We found that XTHs are essential for shade-induced growth in Arabidopsis. Expansin activity on the other hand was not regulated in plants exposed to shade. Shade also resulted in rapid apoplastic acidification which is necessary for the optimal activity of cell wall modifying proteins such as XTHs and expansins.
Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, the Netherlands. r.sasidharan@uu.nl
Rashmi
R
Sasidharan
Ronald
R
Pierik
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000502:physiology / Q000528:radiation effects; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D008027:Light; D010834:Phytochrome / Q000378:metabolism*; D018520:Plant Shoots / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D010834:Phytochrome; D016695:Glycosyltransferases; C473049:xyloglucan - xyloglucosyltransferase