IDENTIFICATION OF REGULATORY GENES INVOLVED IN THE EXPRESSION OF HULL IMPOSED DORMANCY IN DORMANT MALTING BARLEY GRAINS.

MENDIONDO, GUILLERMINA M., JULIETTE LEYMARIE, FRANCOISE CORBINEAU, ROBERTO L. BENECH-ARNOLD

Mendoza

Simposio; 11th International Symposium on Pre-Harvest Sprouting in Cereals; 2007

Seed dormancy is an internal block to germination acquired during seed maturation, and can interfere with malting of barley grains because this industrial process requires germination. Previous results at the physiological level show that both high incubation temperature and hypoxia imposed to the embryo by the glumellae act synergistically to increase embryo sensitivity to inhibitory effect of ABA and interfere with ABA metabolism in dormant grains. The aim of this work was to explore the molecular basis of these responses. Gene expression was analyzed for candidate genes involved in ABA metabolism (HvNCED1, HvABA8OH) and signalling (HvABI5, HvVP1, HvPKABA) under different experimental conditions of temperature and hypoxia that affect the expression of dormancy. Experiments revealed association between the expression level of some of the considered candidate genes and the observed physiological responses resulting from artificially-imposed hypoxia and incubation at high temperatures (i.e. altered ABA metabolism and signalling). These results suggest that part of the observed physiological responses could be regulated at the level of gene expression.