Combined Selenium and Zinc Biofortification of Bread-Making Wheat under Mediterranean Conditions.

Millions of people worldwide have an inadequate intake of selenium (Se) and zinc (Zn), and agronomic biofortification may minimise these problems. To evaluate the efficacy of combined foliar Se and Zn fertilisation in bread making wheat (Triticum aestivum L.), a two-year field experiment was established in southern Spain under semi-arid Mediterranean conditions, by following a split-split-plot design. The study year (2017/2018, 2018/2019) was considered as the main-plot factor, soil Zn application (50 kg Zn ha-1, nor Zn) as a subplot factor and foliar application (nor Se, 10 g Se ha-1, 8 kg Zn ha-1, 10 g Se ha-1 + 8 kg Zn ha-1) as a sub-subplot factor. The best treatment to increase both Zn and Se concentration in both straw, 12.3- and 2.7-fold respectively, and grain, 1.3- and 4.3-fold respectively, was the combined foliar application of Zn and Se. This combined Zn and Se application also increased on average the yield of grain, main product of this crop, by almost 7%. Therefore, bread-making wheat seems to be a very suitable crop to be used in biofortification programs with Zn and Se to alleviate their deficiency in both, people when using its grain and livestock when using its straw.

Foliar zinc biofortification effects in Lolium rigidum and Trifolium subterraneum grown in cadmium-contaminated soil.

Zinc (Zn) is an important micronutrient that can alleviate cadmium (Cd) toxicity to plants and limit Cd entry into the food chain. However, little is known about the Zn-Cd interactions in pasture plants. We characterized the effects of foliar Zn application and Cd uptake by ryegrass (Lolium rigidum L.) and clover (Trifolium subterraneum L.) grown on Cd-contaminated soils; all combinations of foliar Zn applications (0, 0.25 and 0.5% (w/v) ZnSO4·7H2O) and soil Cd concentrations (0, 2.5 and 5 mg Cd kg-1) were tested. For both plant species, soil concentrations of DTPA-extractable Cd and Zn increased with an increase in the Cd and Zn treatments, respectively. Compared with L. rigidum, T. subterraneum accumulated, respectively, 3.3- and 4.1-fold more Cd in the 2.5-Cd and 5-Cd treatments and about 1.3-, 2.3- and 2.8-fold more Zn in the No-Zn, 0.25-Zn and 0.5-Zn treatments. Also, DTPA-Zn concentration was higher in soil after T. subterraneum than L. rigidum growth regardless of Zn applications. Foliar application of 0.25% (w/v) Zn significantly decreased the total Cd concentration in shoots of both species grown in the Cd-contaminated soil and ameliorated the adverse effects of Cd exposure on root growth, particularly in T. subterraneum.

Effect of Fungal Endophytes on Biomass Yield, Nutritive Value and Accumulation of Minerals in Ornithopus compressus.

Yellow serradella (Ornithopus compressus), a valuable pasture species in Mediterranean areas, presents a high diversity of endophytic mycoflora. In the present work, the hypothesis of a significant effect of fungal endophytic species on the parameters of forage production, nutritive value and mineral status of herbage was tested. O. compressus plants were inoculated with each of seven endophytes (four in 2012/2013 and three in 2013/2014). After inoculation, two experiments (under greenhouse and field conditions) were established. Results evidenced a certain influence of several endophytes on herbage yield, nutritive value and mineral status of O. compressus forage. Byssochlamys spectabilis increased herbage biomass yield by around 42% in the field experiment. Stemphylium sp. improved the nutritive value of forage either by increasing crude protein, digestibility and the concentration of essential minerals (such as B, Mo, P or S) or by reducing the concentration of toxic elements such as Al or Pb. In conclusion, the results presented here provide evidence that plant inoculation with endophytes could be a suitable strategy to increase forage yield and its nutritive value or to deal with potential nutrient deficiencies or potential mineral toxicity in forage.

Selenium speciation in malt, wort, and beer made from selenium-biofortified two-rowed barley grain.

Selenium (Se) biofortification of barley is a suitable strategy to increase the Se concentration in grain. In the present paper, the suitability of this Se-biofortified grain for making Se-enriched beer is analyzed. The aim of the present study was to evaluate the effect of different Se fertilizer doses (0, 10, and 20 g of Se ha(-1)) and forms (sodium selenate or sodium selenite) on the Se loss during the malting and brewing processes and Se speciation in grain, malt, wort, and beer. Samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) and high-performance liquid chromatography (HPLC)-ICP-MS for total Se and speciation. Mashing-lautering was the process with the greatest Se loss (83.8%). After malting and brewing, only 7.3% of the initial Se was retained in beer, mainly in selenite form. Even so, the fertilizer application of sodium selenate at 20 g ha(-1) increased the total Se concentration almost 6-fold in the final beer in comparison to the use of grain derived from unfertilized barley. The present paper provides evidence that the use of Se-biofortified barley grain as a raw material to produce Se-enriched beer is possible, and the results are comparable to other methods in terms of efficiency.

Selenium accumulation and speciation in biofortified chickpea (Cicer arietinum L.) under Mediterranean conditions.

BACKGROUND: Millions of people have Se-deficient diets and Se-biofortified crops could prevent such deficiency. The aim of the present study was to evaluate the potential of chickpea for use in Se fertilization programs in order to increase available Se. Two foliar Se fertilizers (sodium selenate and sodium selenite) at four rates (0, 10, 20, 40 g ha(-1)) were tested in the 2010/2011 and 2011/2012 growing seasons in a field experiment conducted under semiarid Mediterranean conditions. RESULTS: Sodium selenate was much more effectively taken by plants than sodium selenite, and there was a strong and linear relationship between total Se content and Se rate for both. For each gram of Se fertilizer, applied either as sodium selenate or sodium selenite, the increases of total Se concentration in grain were 126 and 87, and 25 and 19 µg Se kg(-1) dry weight, in 2010/2011 and 2011/2012, respectively. Se was found to be incorporated into chickpea grains mainly (>70%) as selenomethionine. CONCLUSION: Se-enriched chickpeas would be a good candidate for inclusion in biofortification programs under semiarid Mediterranean conditions and for promotion as a 'functional food'.

Evaluation of the potential of peas (Pisum sativum L.) to be used in selenium biofortification programs under Mediterranean conditions.

Selenium (Se), which has antioxidant, anticancer, and antiviral properties, is an essential micronutrient for humans and animals. This micronutrient is found in high quantity in legumes. Peas have an ever-increasing importance in Spain, and to increase their nutritional value, two foliar Se fertilizers: sodium selenate and sodium selenite, at five different rates: 0, 10, 20, 40, 80 g ha(-1), were studied during the 2010/2011 crop season on semiarid Mediterranean conditions. Sodium selenate was much more effectively taken up by plants compared to sodium selenite. There was a strong linear relationship between the total Se content and Se rate in both sodium selenate and selenite. For each gram of Se fertilization as either sodium selenate or sodium selenite, the increase of total Se concentration in the grain was 148 and 19 µg Se kg(-1) dry weight, respectively. Ingestion of 100 g of peas previously fertilized with 10 g of sodium selenate per hectare would result in an intake of 179 µg of Se. This is almost 90 % of the daily recommended dose needed to reduce the chance of some cancers and about 179 % of the minimum concentration required to prevent Se deficiency diseases in animals. The pea has shown to have a strong ability to uptake and accumulate Se under Mediterranean conditions; therefore, this would make it a very strong candidate for inclusion in biofortification programs aiming to increase Se in the food chain.