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Dormancy-related genes isolation in Cynara cardunculus var. sylvestris

Raccuia, S. A., Puglia, G., Pappalardo, H., Argento, S., Leonardi, C., Calderaro, P., Melilli, M. G.
Acta horticulturae 2016 no.1147 pp. 315-322
Cynara cardunculus, abscisic acid, dormancy, fruits, genes, germination, gibberellins, seeds, sequence analysis, temperature
Seed physiological dormancy (PD) has been widely described as an inhibiting mechanism of germination completion of an intact viable seed under favourable conditions. Cynara cardunculus var. sylvestris germination is reported to be principally under control of temperature. Hereby we report the effect of fluctuating temperatures on C. cardunculus var. sylvestris germination behaviour with respect to corresponding constant regimes. Cypselae subjected to an alternating thermo-period of 15/5 or 25/15°C germinated above 80%, while fruits imbibed at constant temperatures amounted to 40% for 10°C and to 20% for 20°C showing a significant decrease of germination (p<0.001). In PD seeds the regulation of dormancy is usually associated with the ABA-GA ratio and on ABA sensitivity. Therefore, we isolated GA2ox1 (Gibberellin 2-beta-dioxygenase 1), EXP (Expansin) and DOG1 (Delay Of Germination 1) genes in C. cardunculus, which were showed to have a key role in dormancy regulation in other plant species. The isolation of GA2ox1 gene was confirmed by DNA sequencing and protein domains analysis displayed the functional regions.