No abstract

Iodine is an essential microelement for human health, and the recommended daily allowance (RDA) of such element should range from 40 to 200 µg day −1 . Because of the low iodine contents in vegetables, cereals, and many other foods, iodine deficiency disorder (IDD) is one of the most widespread nutrient-deficiency diseases in the world. Therefore, investigations of I uptake in plants with the aim of fortifying them can help reach the important health and social objective of IDD elimination. This study was conducted to determine the effects of the absorption of iodine from two different chemical forms-potassium iodide (I − ) and potassium iodate (IO − 3 )-in a wide range of wild and cultivated plant species. Pot plants were irrigated with different concentrations of I − or IO − 3 , namely 0.05% and 0.1% (w/v) I − and 0.05%, 0.1%, 0.2%, and 0.5% (w/v) IO − 3 . Inhibiting effects on plant growth were observed after adding these amounts of iodine to the irrigation water. Plants were able to tolerate high levels of iodine as IO − 3 better than I − in the root environment. Among cultivated species, barley (Hordeum vulgare L.) showed the lowest biomass reductions due to iodine toxicity and maize (Zea mays L.) together with tobacco (Nicotiana tabacum L.) showed the greatest. After the screening, cultivated tomato and potato were shown to be good targets for a fortification-rate study among the species screened. When fed with 0.05% iodine salts, potato (Solanum tuberosum L.) tubers and tomato (Solanum lycopersicum L.) fruits absorbed iodine up to 272 and 527 µg/100 g fresh weight (FW) from IO − 3 and 1,875 and 3,900 µg/100 g FW from I − . These uptake levels were well more than the RDA of 150 µg day −1 for adults. Moreover, the agronomic efficiency of iodine accumulation of potato tubers and tomato fruits was calculated. Both plant organs showed greater accumulation efficiency for given units of iodine from iodide than from iodate. This accumulation efficiency decreased in both potato tubers and tomato fruits at iodine concentrations greater than 0.05% for iodide and at respectively 0.2% and 0.1% for iodate. On the basis of the uptake curve, it was finally possible to calculate the doses of supply in the irrigation water of iodine as iodate (0.028% for potato and 0.014% for tomato) as well as of iodide (0.004% for potato and 0.002% for tomato) to reach the 150 µg day −1 RDA for adults in 100 g of such vegetables, to efficiently control IDD, although these results still need to be validated.

Iodine is an essential microelement for humans and iodine deficiency disorder (IDD) is one of the most widespread nutrient-deficiency diseases in the world. Iodine biofortification of plants provides an attractive opportunity to increase iodine intake in humans and to prevent and control IDD. This study was conducted to investigate the iodine uptake and accumulation in edible portion of two fruit trees: plum and nectarine, and two horticultural crops: tomato and potato. Two type of iodine treatments (soil and foliar spray application), and, for fresh market tomato, two production systems (open field and greenhouse hydroponic culture) were tested. The distribution of iodine in potato stem and leaves, and in plum tree fruits, leaves, and branches was investigated. Iodine content of potato tubers after postharvest storage and processing (cooking), and iodine content of nectarine fruits after postharvest storage and processing (peeling) were also determined. Differences in iodine accumulation were observed among the four crops, between applications, and between production systems. In open field, the maximum iodine content ranged from 9.5 and 14.3 μg 100 g−1 for plum and nectarine fruit, to 89.4 and 144.0 μg 100 g−1 for potato tuber and tomato fruit, respectively. These results showed that nectarine and plum tree accumulated significantly lower amounts of iodine in their edible tissues, in comparison with potato and tomato. The experiments also indicated hydroponic culture as the most efficient system for iodine uptake in tomato, since its fresh fruits accumulated up to 2423 μg 100 g−1 of iodine. Iodine was stored mainly in the leaves, in all species investigated. Only a small portion of iodine was moved to plum tree branches and fruits, and to potato stems and tubers. No differences in iodine content after fruit peeling was observed. A significant increase in iodine content of potato was observed after baking, whereas a significant decrease was observed after boiling. We concluded that iodine biofortified fresh market tomato salad, both from field and hydroponics cultivation, and baked potatoes can be considered as potential functional foods for IDD prevention

Gelatinization temperature and apparent amylose content are key parameters used to describe the eating and cooking qualities of rice. Sequence variants of SSIIa and Waxy genes are important determinants of gelatinization temperature and apparent amylose content, respectively. A collection of Italian non-glutinous japonica rice accessions was characterized for sequence polymorphisms in SSIIa and Waxy genes, in comparison with non-Italian japonica and indica genotypes. For SSIIa two markers, SNP3 and SNP4, were used. A PCR amplification of multiple specific alleles protocol was developed for the identification of G/T polymorphism in 5′ splice site of first intron and A/C polymorphism in exon 6 of the Waxy gene. Based on simple allele-specific PCR, it can be proposed as a user-friendly, cost-effective tool for marker-assisted selection of amylose content. The collection was characterized also for the (CT)n repeats in exon 1 of the Waxy gene. The results showed that while SSIIa haplotypes were rather similar between Italian and non-Italian japonica rice, the Waxy gene haplotype T/A/(CT)18 was largely predominant in Italian accessions, other haplotypes, well represented in non-Italian japonica [T/A/(CT)19] and indica [e.g. G/C/(CT)20] genotypes, were present at lower frequency. Grain starch quality traits as apparent amylose content and RVA profile were also analysed. The In1/Ex6 SNP haplotypes of Wx gene were found to explain 79 % of variation in apparent amylose content, and 36, 22 and 25 %, of variation in the RVA parameters peak viscosity, breakdown and setback, respectively. The additional use of (CT)n repeats marker further improved the association of haplotypes with RVA parameters

Tomato (Solanum lycopersicum Mill.) is sensitive to chilling stress during all stages of plant development. Genetic variation for chilling tolerance exists between cultivated tomato and its related wild species, but intra-specific variation has not been thoroughly investigated so far. Seedlings of 63 tomato accessions were evaluated under low temperature and two contrasting cultivars were identified for the trait: Albenga and San Marzano, the former being more chillingtolerant. To clarify the molecular mechanisms of chilling tolerance in tomato, changes in candidate gene expressions in the two tomato genotypes were analysed, using quantitative RT-PCR. Candidate genes were chosen among those known to be induced by chilling and/or with putative roles in CBF/DREB and ROS-mediated pathways. Results show that besides a CBF regulon, whose function is conserved, ROS and C2H2-type zinc finger protein-mediated cold signalling pathways were also involved in chilling tolerance. Under the chilling stress, the up-regulation of respective transcripts was consistently higher in the chilling-tolerant genotype than in the chilling-sensitive ones