Determination of the Allelic Composition of the sdw1/denso (HvGA20ox2), uzu1 (HvBRI1) and ari-e (HvDep1) Genes in Spring Barley Accessions from the VIR Collection.

The lodging of barley significantly limits its potential yield, leads to the deterioration of grain quality, and complicates mechanized harvesting. More than 30 dwarfness and semi-dwarfness genes and loci are known for barley, and their involvement in breeding can solve the problem of lodging. The most common dwarfing alleles are of the genes sdw1/denso (HvGA20ox2), uzu1 (HvBRI1), and ari-e (HvDep1). The aim of this study was the design of dCAPS markers for the sdw1.c and ari-e.GP alleles and the molecular screening of barley accessions from the VIR collection for identifying these and other dwarfing alleles commonly used in breeding. Two dCAPS markers have been developed to identify the sdw1.c allele of the HvGA20ox2 gene and ari-e.GP of HvDep1. These dCAPS markers and two known from the literature CAPS and dCAPS markers of the alleles sdw1.a/sdw1.e, sdw1.c, sdw1.d, and uzu1.a were used in the molecular screening of 32 height-contrasting barley accessions. This made it possible to identify the accessions with alleles sdw1.a/sdw1.e, sdw1.c, and sdw1.d of the HvGA20ox2 gene, as well as accessions with a combination of sdw1.c and uzu1.a alleles of the genes HvGA20ox2 and HvBRI1. A comparison of the results of genotyping and phenotyping showed that the presence of dwarfing alleles in all genotypes determines high or medium lodging resistance regardless of the influence of weather conditions. Twelve accessions were found to contain the new allele sdw1.ins of the HvGA20ox2 gene, which differs from the known allele sdw1.c by a larger size of PCR products. It is characterized by the Thalos_2 transposon insertion; the subsequent GTTA insertion, common with the sdw1.c allele; and by a single-nucleotide G→A substitution at the 165 position.

Fullerenol changes metabolite responses differently depending on the iron status of cucumber plants.

The unique properties of carbon-based nanomaterials, including fullerenol, have attracted great interest in agricultural and environmental applications. Iron (Fe) is an essential micronutrient for major metabolic processes, for which a shortage causes chlorosis and reduces the yield of many crops cultivated worldwide. In the current study, the metabolic responses of Cucumis sativus (a Strategy I plant) to fullerenol treatments were investigated depending on the Fe status of plants. Cucumber plants were grown hydroponically, either with [+FeII (ferrous) and +FeIII (ferric)] or in Fe-free (-FeII and -FeIII) nutrient solution, with (+F) or without (-F) a fullerenol supply. Iron species-dependent effects were observed in either Fe-fed or Fe-starved plants, with alteration of metabolites involved in the metabolism of carbohydrates, amino acids, organic acids, lipophilic compounds. Metabolic perturbations triggered by fullerenol in the FeIII-treated plants were in the opposite kind from those in the FeII-treated plants. Whereas in the FeIII-fed plants, fullerenol activated the metabolisation of carbohydrates and amino acids, in the FeII-fed plants, fullerenol activated the metabolisation of lipophilic compounds and repressed the metabolisation of carbohydrates and amino acids. In FeIII-deficient plants, fullerenol stimulated the metabolism of C3 carboxylates and lipophilic compounds while repressing the metabolism of amino acids, hexoses and dicarboxylates, while in FeII-deficient plants, activations of the metabolism of amino acids and dicarboxylates and repression of sterol metabolism by fullerenol were observed. The results indicated that the valence state of Fe sources is of importance for re-programming metabolome responses in cucumber to fullerenol either in Fe-sufficient or Fe-deficient conditions. These investigations are significant for understanding fullerenol interactions and risk assessment in plants with different Fe statuses.

Fullerenol increases effectiveness of foliar iron fertilization in iron-deficient cucumber.

The water-soluble fullerenols are novel carbon-based nanomaterials with unique properties, which afford them with wide agricultural applications. Iron (Fe) deficiency is the most common and widespread nutrition disorder affecting plants. Foliar Fe treatments of plants have been carried out with solutions devoid of fullerenol. In this study, the role of fullerenol [C60(OH)22-24] in alleviation of Fe deficiency in Cucumis sativus (a Strategy I plant) via foliar fertilization was investigated. Cucumber plants were grown hydroponically, either with (Fe) or in Fe-free (-Fe) nutrient solution. The following foliar spray treatments were applied: fullerenol at final concentrations of 1 (F1) and 10 (F10) mg L-1; Fe(II)SO4·7H2O; Fe(II)-EDTA (ethylenediaminetetraacetic acid); and Fe(II)-F1 and Fe(II)-F10. The best used compound was a combination of Fe(II)-sulfate with fullerenol, especially Fe-F1. The addition of fullerenol to Fe(II)-sulfate solutions significantly increased leaf-active Fe (extracted by an Fe(II) chelator) and re-greening at the site of application. The fullerenol-induced mutual influences did not appear when fullerenol was sprayed alone, suggesting a beneficial role of Fe(II)-fullerenol interactions in the penetration of Fe(II) in the leaves and re-greening under Fe-limited conditions. The results are of importance to enhancing the potential of foliar Fe fertilization as the commonly used strategy for ameliorating Fe deficiency and improving crop yield and quality.

Silicon ameliorates iron deficiency of cucumber in a pH-dependent manner.

Strategy I plants may respond to iron (Fe) deficiency by rhizosphere acidification. Here, the role of medium pH-values in silicon (Si)-induced mitigation Fe deficiency in Strategy I plants (Cucumis sativus) was investigated, particularly the metabolites regulated by a lack of Fe, using a target metabolomics approach. Plants were grown hydroponically, either with (+Fe) or in Fe-free (-Fe) nutrient solution, with (+Si) or without (-Si) a Si supply. The nutrient solution was adjusted to pH 5.0 or 6.0 and checked daily. Leaf metabolites potentially involved in Fe transport were determined. The typical Fe responses of cucumber (e.g., decrease in leaf chlorophyll, Fe imbalance) were more pronounced when plants were grown at pH 6.0 than 5.0, during long-term Fe deficiency (15 days). Major metabolites up-regulated by Fe deficiency and found in young leaf were succinic, citric and glutamic acids, respectively; their maximal concentrations occurred in Fe-starved plants grown at pH 6.0 without Si supply. Silicon (Si)-induced effects accompanied with alleviation chlorosis symptoms, were most distinct in plants grown at pH 6.0 for an extended period without Fe. Changes in abundance of metabolites specifically up-regulated by a lack of Fe may be manifested before any Si-induced changes in plant Fe content were apparent, suggesting that metabolite responses are highly sensitive to a Fe-dependent signal altered by Si treatments under Fe deficiency. The results indicate that Si supply was more evident when plants were more stressed by an increase in nutrient solution pH under Fe-limited conditions.