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.

Leaf stripe caused by the fungus Pyrenophora graminea represents a serious threat to grain yield in organically grown barley and in conventional Nordic and Mediterranean districts, for which resistant cultivars are necessary. A medium-density, molecular marker map derived from a 'Steptoe' (partially resistant) x 'Morex' (susceptible) spring barley cross and its derived doubled-haploid mapping population inoculated with the fungus made it possible to identify QTLs of resistance to leaf stripe. In order to investigate isolate-specificity of partial resistance, the 'Steptoe' x 'Morex' segregating population was inoculated with two highly virulent P. graminea isolates, Dg2 and Dg5. The present study demonstrates that partial resistance to leaf stripe of cv 'Steptoe' is governed in part by shared loci and in part by isolate-specific ones. One QTL is common to the resistance for the two isolates, on the long arm of chromosome 2 (2H), two QTLs are linked on chromosome 3 (3H), and the remaining two are isolate-specific, respectively for isolate Dg2 on chromosome 2 (2H) and for isolate Dg5 on chromosome 7 (5H). The QTL in common is that with the major effect on the resistance for each isolate, explaining 18.3% and 30.9% R(2) respectively for Dg2 and Dg5. The isolate-specific QTLs mapped in the 'Steptoe' x 'Morex' barley reference map support the assumption of Parlevliet and Zadoks (1977) that partial resistance may be due to minor gene-for-minor-gene interactions. Map comparisons of the QTLs with the known qualitative resistance genes to leaf stripe, Rdg1 (2H) and Rdg2 (7H), as well as with other QTLs of partial resistance in barley, show that the QTL for resistance to both isolates mapped on the long arm of chromosome 2 (2H) does not coincide with the qualitative Rdg1 gene but is linked to it at about 30 cM. One isolate-specific QTL of resistance to P. graminea, mapped on the short arm of chromosome 2 (2H), is coincident with a QTL for resistance to Pyrenophora teres previously mapped in the 'Steptoe' x 'Morex' cross.

Sugars affect a broad variety of processes, from growth and development to gene expression. Although it has already been shown that sugars act as signaling molecules, little is known about the mechanisms by which plants respond to them. Much progress has been made on understanding sugar sensing and signaling thanks to the analysis of mutants with abnormal sugar response. Some of the genetic strategies applied are based on the inhibitory effect of sugar on post-germinative development of Arabidopsis thaliana. High concentrations of exogenous sugars delay germination and arrest early growth, preventing seedlings from expanding cotyledons and developing true leaves and an extensive root system. The characterization of several Arabidopsis mutants identified for their altered sugar sensitivity has disclosed a network in which sugars and plant hormones cooperate to control seedling development. Remarkably, many mutations turned out to be novel alleles of hormone-related genes, mainly ABA and ethylene. The aspects described above, emphasizing the connections between sugar and plant hormones revealed by mutants derived in seedling-based screens, are reviewed in this paper.

Leaf stripe is a seed-borne disease of barley (Hordeum vulgare) caused by Pyrenophora graminea. Little is known about the genetics of resistance to this pathogen. In the present work, QTL analysis was applied on two recombinant inbred line (RIL) populations derived from two- and six-rowed barley genotypes with different levels of partial resistance to barley leaf stripe. Quantitative trait loci for partial resistance were identified using the composite interval mapping (CIM) method of PLABQTL software, using the putative QTL markers as cofactors. In the L94 x 'Vada' mapping population, one QTL for resistance was detected on chromosome 2H; the same location as the leaf-stripe resistance gene Rdg1 mapped earlier in 'Alf', where it confers complete resistance to the pathogen. An additional minor-effect QTL was identified by further analyses in this segregating population on chromosome 7H. In L94 x C123, two QTLs for resistance were mapped, one each on chromosomes 7H and 2H.

We investigated the effect of auxin and acetylcholine on the expression of the tomato expansin gene LeEXPA2, a specific expansin gene expressed in elongating tomato hypocotyl segments. Since auxin interferes with clathrin-mediated endocytosis, in order to regulate cellular and developmental responses we produced protoplasts from tomato elongating hypocotyls and followed the endocytotic marker, FM4-64, internalization in response to treatments. Tomato protoplasts were observed during auxin and acetylcholine treatments after transient expression of chimerical markers of volume-control related compartments such as vacuoles. Here we describe the contribution of auxin and acetylcholine to LeEXPA2 expression regulation and we support the hypothesis that a possible subcellular target of acetylcholine signal is the vesicular transport, shedding some light on the characterization of this small molecule as local mediator in the plant physiological response.