UNA REEVALUACIÓN DEL POTENCIAL DEL GIRASOL PARA SINTETIZAR FRUCTANOS

MARTÍNEZ NOËL G; DOSIO G; PUEBLA A; INSANI E; GIORGI ME; TOGNETTI J

Congreso; XXXI RAFV 2016; 2016

Sunflower (Helianthus annuus L.) has traditionally been considered as devoid of fructans, in contrast to its close relative Helianthus tuberosus. However, a recently published EST database indicates that genes coding for the main fructan synthesizing enzymes (1-SST and 1-FFT) are indeed present in sunflower. We hypothesized that sunflower lack of fructans might be the consequence of sucrose concentration being normally lower than required for induction of fructan synthesizing enzymes. We thus performed a field experiment in which capitulums were removed, a procedure that sharply increases sucrose concentration in stem and leaves. An HPLC analysis revealed presence of a low amount of trisaccharide 1-kestose in sunflower stems of control plants, but virtually no higher level fructans. Decapitated plants displayed no increase in trisaccharide levels, but a moderate induction of longer chain fructans was revealed, particularly in stems. Nevertheless, a large effort is needed to elucidate how sunflower potential to accumulate fructans may be effectively elicited in intact plants.