Differences in accumulation of soluble α-galactosides during seed maturation of several Vicia species

Abstract

Ab stractCom po si tion and lev els of sol u ble α-galactosides: raffinose fam ily oli go sac cha rides (RFOs) and galactosyl cyclitols (Gal-C) in de vel op ing seeds were mea sured by high res o lu tion gas chro ma tog ra phy (HRGC) method. The stud ies were performed on ma tur ing seeds of sev eral wild and cul ti vated Vicia spe cies: Vicia angustifolia L. (com mon vetch), Vicia cracca L. (bird vetch), Vicia grandiflora Scop. (large yel low vetch), Vicia hirsuta (L.) S.F.Gray (tiny vetch), Vicia sativa L. (garden vetch, spring-grow ing cultivar Kwarta), and Vicia villosa Roth (win ter vetch).In all Vicia spe cies sim i lar pat terns in the ac cu mu la tion of RFOs were ob served. Galactinol -the do nor of galactosyl moieties in α-galactosides biosynthesis was pres ent in the mid dle stage of seed de vel op ment, be fore ap pear ing mea sur able levels of RFOs. Ac cu mu la tion of RFOs started par al lel with seed des ic ca tion pro cess. At first ac cu mu la tion of the raffinose, then few days later stachyose and fi nally verbascose was noticed. In the fi nal stage of seed mat u ra tion the verbascose was the main sol u ble α-galactoside (up to 3 % of dry weight, V. sativa). Be sides the RFOs seeds of three Vicia spe cies (V. cracca, V. hirsuta, and V. villosa) ac cu mu lated D-pinitol and its α-ga lactosides (Gal-C). Mono-galactosylpinitols (sim i lar to raffi nose) ap peared in these spe cies 2-4 days af ter galactinol, di-galactosyl pinitol A (com mon name: ciceritol) and di-galactosyl myo-inositol were pres ent sev eral days later than raffinose, and ac cu mu la tion of tri-galactosyl pinitol A (TGPA) be gan af ter ac cu mu la tion of stachyose. Ma tured seeds of V. hirsuta con tained much more RFOs than Gal-C, op po site to seeds of V. villosa, and V. cracca where con cen tra tion of Gal-C was 4-8-fold higher than RFOs. In V. cracca seeds RFOs were al most re placed by Gal-C.In seeds of V. cracca and V. villosa the level of D-pinitol was sig nif i cantly higher, than the level of myo-inositol. Con tents of both cyclitols de clined rap idly at the be gin ning of seed des icca tion, when ac cu mu la tion of RFOs and Gal-C quickly increased. We sug gest that α-galactosides of D-pinitol can substi tute raffinose fam ily oli go sac cha rides and play sim i lar role dur ing seed maturation and storage.List of ab bre vi a tions: RFOs = raffinose fam ily oligo sac cha rides; Gal-C = galactosyl cyclitols; DAF = day af ter flow er ing; FW = fresh weight; DW = dry weight In tro duc tionRaffinose fam ily oli go sac cha rides (RFOs) are com mon in the plant king dom, mainly as con stit uents in seeds. To RFOs be longs raffinose (α-1→6-D -ga lactoside of su crose), and its ho mol ogous com pounds: stachyose, verbascose and 163

Inhibition of raffinose family oligosaccharides and galactosyl pinitols breakdown delays germination of winter vetch (Vicia villosa Roth.) seeds

“…Both hydrolytic and galactosyltransferase activity of a-galactosidase was found in seeds of V. sativa (Petek et al 1969). However, seeds of this species accumulate only RFOs (Lahuta et al 2005). The data obtained during our study indicate that investigations on the characteristic of a-galactosidase from winter vetch seeds during germination may be necessary to discover the causes of preferential degradation of GPs rather than RFOs.…”

Seed α-D-Galactosides of Selected Vicia Species and Enzymes Involved in Their Biosynthesis

“…However, the seeds of those two species naturally accumulate D-pinitol and pinitol galactosides. Thus, increasing the concentration of free D-pinitol could only enhance the activity of the enzymatic pathway, leading to accumulation of higher amounts of galactosyl pinitols, as suggested previously (Lahuta et al, 2005a). Therefore we decided to feed free cyclitols to explants of Vicia angustifolia, whose mature seed contains the highest level of RFOs among the investigated Vicia species (Tab.…”

“…In this situation, simultaneous biosynthesis of RFOs and galactosyl cyclitols in seed tissues could be dependent on the concentration of galactosyl acceptors such as sucrose and the cyclitols myo-inositol, D-chiro-inositol and D-pinitol. In developing seeds of Vicia hirsuta (tiny vetch), Vicia villosa (winter vetch) and Vicia cracca (bird vetch), higher concentrations of D-pinitol than myo-inositol throughout seed development and maturation coincided with increasing accumulation of galactosyl pinitols and a decrease in RFOs (Lahuta et al, 2005a).…”

Cyclitols in maturing grains of wheat, triticale and barley

“…Changes in the content of free cyclitols during seed development can be a key factor regulating accumulation of α-D-galactosides in maturing seeds (Lahuta et al 2005a). In seeds of various Vicia species, higher concentration of D-pinitol than that of myo-inositol throughout seed development and maturation coincides with accumulation of higher amounts of galactosyl pinitols and affects accumulation of RFOs.…”