Polyamines, floral induction and floral development of strawberry (Fragaria ananassa Duch.)

Abstract

In the short-day plant, strawberry (Fragaria ananassa Duch.), polyamines (putrescine, spermidine and spermine), conjugated spermidine (water-insoluble compounds) and bound amines (putrescine, spermidine, phenylethylamine, 3-hydroxy, 4-methoxyphenylethylamine) accumulated in the shoot tips during floral induction and before floral emergence. Different associations of free amines and conjugated amines were observed during floral induction, as compared with the reproductive phase. During the whole period of floral development, phenylethylamine (an aromatic amine) was the predominant amine, representing 80 to 90% of the total free amine pool. Phenylethylamine conjugates (water-insoluble compounds) were the predominant amides observed prior to fertilization. These substances decreased drastically after fertilization. In vegetative shoot tips from plants grown continously under long days, free polyamines (putrescine, spermidine) and bound polyamines (putrescine, spermidine) were low and no change was observed. Free amines (spermine and phenylethylamine), bound aromatic amines (phenylethylamine, 3-hydroxy, 4-methoxyphenylethylamine), conjugated spermidine and phenylethylamine did not appear. Male-sterile flowers were distinguished by their lack of conjugated spermidine and phenylethyalamine and by a decrease in free phenylethylamine. In normal and sterile strawberry plants a-DL-difluoromethylomithine (DFMO), a specific irreversible inhibitor of omithine decarboxylase (ODC), caused inhibition of flowering and free and polyamine conjugates. When putrescine was added, polyamine titers and flowering were restored. A similar treatment with cr-DL-difluoromethylarginine (DFMA), a specific, irreversible inhibitor of arginine decarboxylase (ADC), did not affect flowering and polyamine titers. These results suggest that omithine decarboxylase (ODC) and polyamines are involved in regulating floral initiation in strawberry. The relationship between polyamines, aromatic amines, conjugates, floral initiation and male sterility is discussed.Abbreviations: ADC = arginine decarboxylase; ODC = omithine decarboxylase; DFMA = o-DLdifluoromethylarginine; DFMO = o+DL-difluoromethylomithine; Put = putrescine; Spd = spermidine; Spm = spermine; Phen = phenylethylamine; 3H4M Phen = 3-hydroxy, 4-methoxyphenylethylamine.

Relationship between Endogenous Polyamines and Floral Bud Differentiation in Chrysanthemum morifolium under Short-day Conditions

“…There may be a process of Put and Spm transformed to Spd at this stage, what causing Spd accumulate in apical buds. Different with our results, Tarenghi and Martin-Tanguy (1995) reported that conjugated Spd was the predominant amide during the earliest stages of floral differentiation in strawberry. Spd has been noted as a marker for flower induction in many plants (Fiala et al, 1988;Huang et al, 2004).…”

“…Sood and Nagar (2004) reported that, high free Put and Spd concentrations were associated with early stages of flower development, and a steady increase in conjugated Put, Spd and Spm was observed during entire period of flower development, which was different with our results, possibly because of differences in the study species, temperature, or other factors. Tarenghi and Martin-Tanguy (1995) reported that α-difluoromethylornithine (DFMO), an inhibitor of Put synthesis, decreased PA contents in strawberry and inhibited flowering, which could be restored by exogenous application of Put.…”

Involvement of Polyamine in Floral and Fruit Development

“…Promotion of flowering by exogenous polyamines has been demonstrated in Spirodela punctata 20 , tobacco 34 and morning glory 87 . In addition, inhibition of flowering by polyamine inhibitors has been also attempted 20,80 . For instance, exogenous Spd caused more than 20% of floral buds to develop in tobacco thin-layer tissue cultures, whereas all of the buds were vegetative when the cultures were lacking in Spd, indicating the direct role of Spd in floral differentiation 34 .…”

“…JARQ 40 (1) 2006 eral lines of evidence. Firstly, in some plants, an accordant change in total polyamine titers or a single polyamine type accompanies the floral development, as is revealed in Pharbitis nil 19 , Xanthium strumarium 30 , Polianthes tuberosa 31 , strawberry 80 , and tobacco…”

A Novel Polyamine Acyltransferase Responsible for the Accumulation of Spermidine Conjugates in Arabidopsis Seed

“…The hydroxycinnamoyl substituants of spermidine can be coumaroyl, caffeoyl, feruloyl, hydroxyferuloyl, or sinapoyl acyl groups, and mono-, di-, and trisubstituted hydroxycinnamoyl spermidine conjugates have been reported from many plant species (Bienz et al, 2005). They have been identified from flowers and pollen of a wide range of plants, including species in the Acanthaceae (Werner et al, 1995), Asteraceae (Aribaud and Martin-Tanguy, 1994), Brassicaceae (Havelange et al, 1996), Betulaceae, Fagaceae, Juglandaceae (Meurer et al, 1986;Meurer et al, 1988;Bokern et al, 1995), Rosaceae (Strack et al, 1990;Tarenghi and Martin-Tanguy, 1995), and Solanaceae (Leubnermetzger and Amrhein, 1993;Kang and Back, 2006). Among cereals, 4-coumaroyltryptamine and feruloyltryptamine have been identified in maize (Zea mays), while avenanthramides (substituted N-cinnamoylanthranilates) have been isolated from oat (Avena sativa) (Collins, 1989).…”