Iodine (I) and selenium (Se) are included in the group of beneficial elements. They both play important roles in humans and other animals, particularly in the regulation of thyroid functioning. A substantial percentage of people around the world suffer from health disorders related to the deficiency of these elements in the diet. Salicylic acid (SA) is a compound similar to phytohormones and is known to improve the efficiency of I biofortification of plants. The influence of SA on Se enrichment of plants has not, however, been recognized together with its effect on simultaneous application of I and Se to plants. Two-year studies (2014–2015) were conducted in a greenhouse with hydroponic cultivation of lettuce in an NFT (nutrient film technique) system. They included the application of I (as KIO3), Se (as Na2SeO3) and SA into the nutrient solution. KIO3 was used at a dose of 5 mg I⋅dm-3 (i.e., 39.4 μM I), while Na2SeO3 was 0.5 mg Se⋅dm-3 (i.e., 6.3 μM Se). SA was introduced at three doses: 0.1, 1.0, and 10.0 mg⋅dm-3 nutrient solutions, equivalent to 0.724, 7.24, and 72.4 μM SA, respectively. The tested combinations were as follows: (1) control, (2) I + Se, (3) I + Se + 0.1 mg SA⋅dm-3, (4) I + Se + 1.0 mg SA⋅dm-3 and (5) I + Se + 10.0 mg SA⋅dm-3. The applied treatments had no significant impact on lettuce biomass (leaves and roots). Depending on the dose, a diverse influence of SA was noted with respect to the efficiency of I and Se biofortification; chemical composition of leaves; and mineral nutrition of lettuce plants, including the content of macro- and microelements and selenocysteine methyltransferase (SMT) gene expression. SA application at all tested doses comparably increased the level of selenomethionine (SeMet) and decreased the content of SA in leaves.

In marine algae, vanadium (V) regulates the cellular uptake of iodine (I) and its volatilization as I2, the processes catalyzed by vanadium-dependent haloperoxidases (vHPO). Relationships between I and vanadium V in higher plants, including crop plants, have not yet been described. Little is known about the possibility of the synthesis of plant-derived thyroid hormone analogs (PDTHA) in crop plants. The activity of vHPO in crop plants as well as the uptake and metabolism of iodosalicylates in lettuce have not yet been studied. This studyaimed to determine the effect of V on the uptake and accumulation of various forms of I, the metabolism of iodosalicylates and iodobenzoates and, finally, on the accumulation of T3 (triiodothyronine—as example of PDTHA) in plants. Lettuce (Lactuca sativa L. var. capitata ‘Melodion’ cv.) cultivation in a hydroponic NutrientFilm Technique (NFT) system was conducted with the introduction of 0 (control), 0.05, 0.1, 0.2, and 0.4 µM V doses of ammonium metavanadate (NH4VO3) in four independent experiments. No iodine treatment was applied in Experiment No. 1, while iodine compounds were applied at a dose of 10 µM (based on our own previous research) as KIO3, 5-iodosalicylic acid (5-ISA) and 3,5-diiodosalicylic acid (3,5-diISA) in Experiment Nos. 2, 3 and 4, respectively. When lettuce was grown at trace amount of I in the nutrient solution, increasing doses of V contributed to the increase of (a) I content in roots, (b) I uptake by whole lettuce plants (leaves + roots), and (c) vHPO activity in leaves (for doses 0.05–0.20 µM V). Vanadium was mainly found in roots where the content of this element increased proportionally to its dose. The content of V in leaves was not modified by V introduced into the nutrient solution. We found that5-ISA, 3,5-diISA and T3 were naturally synthesized in lettuce and its content increased when 5-ISA, 3,5-diISA were applied. Quantitative changes in the accumulation of organic metabolites (iodosalicylates and iodobenzoates) accumulation were observed, along with increased T3 synthesis, with its content in leaves exceeding the level of individual iodosalicylates and iodobenzoates. The content of T3 was not affected by V fertilization. It was concluded that iodosalicylates may participate in the biosynthesis pathway of T3—and probably of other PDTHA compounds.

BackgroundThe industrially important yeast Blastobotrys (Arxula) adeninivorans is an asexual hemiascomycete phylogenetically very distant from Saccharomyces cerevisiae. Its unusual metabolic flexibility allows it to use a wide range of carbon and nitrogen sources, while being thermotolerant, xerotolerant and osmotolerant.ResultsThe sequencing of strain LS3 revealed that the nuclear genome of A. adeninivorans is 11.8 Mb long and consists of four chromosomes with regional centromeres. Its closest sequenced relative is Yarrowia lipolytica, although mean conservation of orthologs is low. With 914 introns within 6116 genes, A. adeninivorans is one of the most intron-rich hemiascomycetes sequenced to date. Several large species-specific families appear to result from multiple rounds of segmental duplications of tandem gene arrays, a novel mechanism not yet described in yeasts. An analysis of the genome and its transcriptome revealed enzymes with biotechnological potential, such as two extracellular tannases (Atan1p and Atan2p) of the tannic-acid catabolic route, and a new pathway for the assimilation of n-butanol via butyric aldehyde and butyric acid.ConclusionsThe high-quality genome of this species that diverged early in Saccharomycotina will allow further fundamental studies on comparative genomics, evolution and phylogenetics. Protein components of different pathways for carbon and nitrogen source utilization were identified, which so far has remained unexplored in yeast, offering clues for further biotechnological developments. In the course of identifying alternative microorganisms for biotechnological interest, A. adeninivorans has already proved its strengthened competitiveness as a promising cell factory for many more applications.

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Waterlogging (WL), excess water in the soil, is a phenomenon often occurring during plant cultivation causing low oxygen levels (hypoxia) in the soil. The aim of this study was to identify candidate genes involved in long-term waterlogging tolerance in cucumber using RNA sequencing. Here, we also determined how waterlogging pre-treatment (priming) influenced long-term memory in WL tolerant (WL-T) and WL sensitive (WL-S) i.e., DH2 and DH4 accessions, respectively. This work uncovered various differentially expressed genes (DEGs) activated in the long-term recovery in both accessions. De novo assembly generated 36,712 transcripts with an average length of 2236 bp. The results revealed that long-term waterlogging had divergent impacts on gene expression in WL-T DH2 and WL-S DH4 cucumber accessions: after 7 days of waterlogging, more DEGs in comparison to control conditions were identified in WL-S DH4 (8927) than in WL-T DH2 (5957). Additionally, 11,619 and 5007 DEGs were identified after a second waterlogging treatment in the WL-S and WL-T accessions, respectively. We identified genes associated with WL in cucumber that were especially related to enhanced glycolysis, adventitious roots development, and amino acid metabolism. qRT-PCR assay for hypoxia marker genes i.e., alcohol dehydrogenase (adh), 1-aminocyclopropane-1-carboxylate oxidase (aco) and long chain acyl-CoA synthetase 6 (lacs6) confirmed differences in response to waterlogging stress between sensitive and tolerant cucumbers and effectiveness of priming to enhance stress tolerance.

Waterlogging anomalies have recently increased, causing a reduction in yield and the loss of billions of dollars. Plant selection for increased tolerance to stress factors requires parameters with high sensitivity, as well as fast and inexpensive measurements. The aim of this study was to select tomato and cucumber accessions that reveal sensitivity and tolerance to waterlogging stress at an early vegetative stage. The selection of effective criteria for assessing plants was also an important issue. A total of 19 cucumber (including four highly homozygous) and 16 tomato accessions were evaluated, and plants with three true leaves were examined. The root zone of stressed plants was waterlogged for 7 days in a deep container. Morphological and physiological characteristics were obtained after 7 days of treatment and used for cluster analysis for discrimination of tolerant and sensitive accessions. Significant decreases in Fv/F0, Fv/Fm, Area, PI ABS, ET0/ABS, and ET0/TR0 parameters, as well as increases in DI0/RC, were observed in sensitive accessions, with no changes in tolerant plants. The OJIP test parameters (Fv/F0, PI ABS, DI0/RC, and Area) were more sensitive in selecting for waterlogging stress than Fv/Fm. The present research can be used in breeding programs. Selected accessions will support a detailed explanation of the physiological differences in response to waterlogging stress in tomato and cucumber plants.

Selenium (Se) uptake by plants depends on its form and salicylic acid (SA) can increase the efficiency of plant biofortification in Se. This study investigated the effects of selenite (Na2SeO3) and selenomethionine (SeMet) applied individually or together with SA on a total content of Se, Se speciation forms, yield and content of sugars and ascorbic acid of lettuce, as well as activity of selenocysteine methyltransferase (smt) and methionine methyltransferase (mmt) genes of the Se metabolic pathway. Lettuce was grown in the nutrient film technique (NFT) system. Se and SA were used at doses of 0.5 and 10.0 mg dm−3 of the nutrient solution, respectively. The treatments were: 1. control, 2. Na2SeO3, 3. Na2SeO3 + SA, 4. SeMet, 5. SeMet + SA, 6. SA. Se was accumulated more in the roots than the leaves. SeMet was more effective in biofortification than Na2SeO3. SA enhanced Se uptake, especially organic Se. Plants supplied with SeMet alone or SeMet + SA accumulated in their leaves mainly SeMet and methylselenocysteine (MeSeCys), while those treated with Na2SeO3 or Na2SeO3 + SA accumulated MeSeCys and selenite (SeO3−2). The roots showed no expression of smt, while the expression of two mmt genes was independent of either Se or SA. The leaves of plants supplied with Na2SeO3 demonstrated the strongest expression of mmt and smt.

Genomic in situ hybridization (GISH) has been proved to be the most effective and accurate technique for confirmation of hybrid character. The objective of our study was to adapt and optimize a GISH protocol for identification of donor chromatin in hybrids obtained by interspecific crosses between five Rhododendron taxa (R. aureum, R. brachycarpum, R. catawbiense 'Catharine van Tol', R. catawbiense 'Nova Zembla', and R. yakushimanum 'Koichiro Wada'). Positive results were obtained only when we used mitotic chromosome spreads prepared from anthers. The best differentiation of maternal and paternal chromosomes in hybrid genomes was obtained when 50 ng of probe was applied together with blocking DNA at a concentration of 3.0 microg/microL. The results demonstrate that GISH is a practical tool for detection of alien genomes and analysis of the constitution of the chromosomes in rhododendron hybrids.