A reevaluation of the sunflower potential to synthesize fructans

MARTÍNEZ-NOEL, G.M.A.; INSANI, E.M.; PUEBLA A.F.; TOGNETTI, J.A; DOSIO, G.A.A.; GIORGI, M.E.

Corrientes

Congreso; XXXI Reunión Argentina de Fisiología Vegetal; 2016

Sociedad Argentina de Fisiología Vegetal

Sunflower (Helianthus annuus L.) hastraditionally been considered as devoid offructans, in contrast to its close relativeHelianthus tuberosus. However, a recentlypublished EST database indicates that genescoding for the main fructan synthesizingenzymes (1-SST and 1-FFT) are indeed presentin sunflower. We hypothesized that sunflowerlack of fructans might be the consequence ofsucrose concentration being normally lower thanrequired for induction of fructan synthesizingenzymes. We thus performed a field experimentin which capitulums were removed, a procedurethat sharply increases sucrose concentration instem and leaves. An HPLC analysis revealedpresence of a low amount of trisaccharide 1-kestose in sunflower stems of control plants, butvirtually no higher level fructans. Decapitatedplants displayed no increase in trisaccharidelevels, but a moderate induction of longer chainfructans was revealed, particularly in stems.Nevertheless, a large effort is needed toelucidate how sunflower potential to accumulatefructans may be effectively elicited in intactplants.