Present address: Department of Botany, Queensland University, Brisbane, Queensland 4072, Australia.
A xylem-specific cellulose synthase gene from aspen (Populus tremuloides) is responsive to mechanical stress
Article first published online: 25 DEC 2001
The Plant Journal
Volume 22, Issue 6, pages 495–502, June 2000
How to Cite
Wu, L., Joshi, C. P. and Chiang, V. L. (2000), A xylem-specific cellulose synthase gene from aspen (Populus tremuloides) is responsive to mechanical stress. The Plant Journal, 22: 495–502. doi: 10.1046/j.1365-313x.2000.00758.x
- Issue published online: 25 DEC 2001
- Article first published online: 25 DEC 2001
- Received 3 December 1999; revised 25 February 2000; accepted 20 March 2000.
Angiosperm trees accumulate an elevated amount of highly crystalline cellulose with a concomitant decrease in lignin in the cell walls of tension-stressed tissues. To investigate the molecular basis of this tree stress response, we cloned a full-length cellulose synthase (PtCesA) cDNA from developing xylem of aspen (Populus tremuloides). About 90% sequence similarity was found between the predicted PtCesA and cotton GhCesA proteins. Northern blot and in situ hybridization analyses of PtCesA gene transcripts in various aspen tissues, and PtCesA gene promoter-β-glucuronidase (GUS) fusion analysis in transgenic tobacco, demonstrated conclusively that PtCesA expression is confined to developing xylem cells during normal plant growth. During mechanical stress induced by stem bending, GUS expression remained in xylem and was induced in developing phloem fibers undergoing tension stress, but was turned off in tissues undergoing compression on the opposite side of the bend. Our results suggest a unique role for PtCesA in cellulose biosynthesis in both tension-stressed and normal tissues in aspen, and that the on/off control of PtCesA expression may be a part of a signaling mechanism triggering a stress-related compensatory deposition of cellulose and lignin that is crucial to growth and development in trees.