β-1,3-Glucanase gene expression in low-hydrated seeds as a mechanism for dormancy release during tobacco after-ripening
Article first published online: 17 NOV 2004
The Plant Journal
Volume 41, Issue 1, pages 133–145, January 2005
How to Cite
Leubner-Metzger, G. (2005), β-1,3-Glucanase gene expression in low-hydrated seeds as a mechanism for dormancy release during tobacco after-ripening. The Plant Journal, 41: 133–145. doi: 10.1111/j.1365-313X.2004.02284.x
- Issue published online: 17 NOV 2004
- Article first published online: 17 NOV 2004
- Received 31 August 2004; revised 9 October 2004; accepted 13 October 2004.
- coat-imposed dormancy;
- gene expression;
- low-hydrated state;
- seed germination;
- testa rupture
An air-dry developmental state with low-hydrated tissues is a characteristic of most plant seeds. Seed dormancy is an intrinsic block of germination and can be released during after-ripening, that is air-dry storage of mature seeds. Both seed-covering layers, testa and endosperm, cause the coat-imposed dormancy of tobacco (Nicotiana tabacum). After-ripening and over-expression of class I β-1,3-glucanase (βGlu I) confer maternal effects on testa rupture and dormancy release. Very little is known about the molecular mechanisms of after-ripening and whether gene expression is possible in low-hydrated seeds. Transient, low-level βGlu I transcription and translation was detected during tobacco seed after-ripening. 1H NMR 2D micro-imaging showed uneven distribution of proton mobility in seeds. βGlu I gene expression is associated spatially with the inner testa and temporally with the promotion of testa rupture. Local elevation in moisture content seems to permit local, low-level βGlu I gene transcription and translation in the maternal tissues of air-dry, low-hydrated seeds. De novo gene expression is therefore proposed to be a novel molecular mechanism for the release of coat-imposed dormancy during oilseed after-ripening.