IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Expression of genes involved in ABA metabolism in relation to primary and secondary thermo dormancies in barley seeds (Hordeum vulgare L.)
Autor/es:
LEYMARIE, JULIETTE; MENDIONDO G.M.; BENECH-ARNOLD ROBERTO L.; CORBINEAU, FRANCOISE
Lugar:
Evry in France
Reunión:
Congreso; Plant Genomics and Beyond; 2009
Resumen:
<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:FR; mso-fareast-language:FR;} @page Section1 {size:595.3pt 841.9pt; margin:70.85pt 70.85pt 70.85pt 70.85pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Seed dormancy is defined as the inability to germinate in apparently favourable environmental conditions. Primary dormancy is acquired during seed development while secondary dormancy generally is induced in mature seeds by environmental conditions which did not allow germination. In barley, dormancy is expressed at high temperatures i.e. dormant caryopses did not germinate at 30°C while they germinated at 20°C. Abscisic acid is known to play a key role in induction and maintenance of seed dormancy. The metabolism of this hormone was studied at transcriptional level in relation to primary or secondary dormancies. Incubation of primary dormant seeds at 30°C induced a secondary dormancy which corresponded to an inability of subsequent germination at 20°C. Expression of genes involved in ABA catabolism (ABA-8’-hydroxylase: HvABA8’OH-1) and synthesis (9-cis-epoxycarotenoid-dioxygenase: HvNCED1 and HvNCED2) was studied by real time RT-PCR on non-dormant, primary and secondary dormant seeds. Both dormancies were associated with maintenance of high levels of embryo ABA content. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 30°C has only a slight effect on ABA content and secondary dormancy. The gene expression suggested a role of HvNCED2 and HvABA8’OH-1in primary dormancy and a specific role for HvNCED1 and HvNCED2 in secondary seed dormancy in regulation of ABA synthesis. Primary and secondary dormancies were both regulated by ABA metabolism but the transcriptional mechanisms involved appear specific according to dormancy type.