SUMMARYMolecular-genetic control of the flowering time of temperate-climate plants is best understood in Arabidopsis and the cereals wheat and barley. However, key regulators such as FLC and cereal VRN2 are not found in legumes. Therefore, we used forward genetics to identify flowering time genes in the model legume Medicago truncatula (Medicago) which is induced to flower by vernalisation and long-day photoperiods. A screen of a Tnt1 retroelement tagging population yielded two mutants, spring2 and spring3, with a dominant early flowering phenotype. These mutants overexpress the floral activator FTa1 and two candidate downstream flowering genes SOC1a and FULb, similar to the spring1 somaclonal variant that we identified previously. We demonstrate here that an increase in the expression of FTa1, SOC1a and FULb and early flowering does not occur in all conditions in the spring mutants. It depends on long-day photoperiods but not on vernalisation. Isolation of flanking sequence tags and linkage analysis identified retroelement insertions at FTa1 that co-segregated with the early flowering phenotype in all three spring mutants. These were Tnt1 insertions in the FTa1 third intron (spring3) or the 3′ intergenic region (spring2) and an endogenous MERE1-4 retroelement in the 3′ intergenic region in spring1. Thus the spring mutants form an allelic series of gain-of-function mutations in FTa1 which confer a spring growth habit. The spring retroelement insertions at FTa1 separate long-day input from vernalisation input into FTa1 regulation, but this is not due to large-scale changes in FTa1 DNA methylation or transcript processing in the mutants.

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The present work aimed at the recovery and characterization of dietary fiber and polyphenolic compounds extracted from red grape pomace, a by-product generated after grape fruit processing. High contents of total DF were found in the dietary fiber extracts (57.24%), whereas insoluble fiber was the major fraction (51.70%). And it showed good functional properties, including swelling capacity (4.01-8.32 mL g), water holding capacity (1.91-4.23 g g) and oil holding capacity (0.59-0.65 g g). After separation from the dietary fiber, phenolic extracts with high concentrations of total phenolic compounds and total flavonoids, showed high antioxidant activities, while the separated dietary fiber showed little antioxidant activities. This indicated that the phenolic composition is essential for the antioxidant activity of "antioxidant dietary fiber (ADF)". The identification of individual polyphenols was performed applying the HPLC-ESI-MS/MS technique and 31 compounds have been identified belonging to 4 groups, including anthocyanins, flavonols, flavan-3-ols and phenolic acids. Based on this study, we believe grape juice pomace could potentially be exploited as an inexpensive source of natural dietary fiber and phenolics and possibly used as a functional food ingredient.