Combating Micronutrient Deficiency and Enhancing Food Functional Quality Through Selenium Fortification of Select Lettuce Genotypes Grown in a Closed Soilless System.

Antonio Pannico,Stefania De Pascale,Maria Giordano,Youssef Rouphael,Christophe El-Nakhel,Silvia Rita Stazi,Marios C Kyriacou

doi:10.3389/fpls.2019.01495

Abstract

Selenium (Se) is an essential trace element for human nutrition and a key component of selenoproteins having fundamental biological and nutraceutical functions. We currently examined lettuce biofortification with Se in an open-gas-exchange growth chamber using closed soilless cultivation for delivering Se-rich food. Morphometric traits, minerals, phenolic acids, and carotenoids of two differently pigmented Salanova cultivars were evaluated in response to six Se concentrations (0–40 μM) delivered as sodium selenate in the nutrient solution. All treatments reduced green lettuce fresh yield slightly (9%), while a decrease in red lettuce was observed only at 32 and 40 μM Se (11 and 21% respectively). Leaf Se content increased in both cultivars, with the red accumulating 57% more Se than the green. At 16 μM Se all detected phenolic acids increased, moreover a substantial increase in anthocyanins (184%) was recorded in red Salanova. Selenium applications slightly reduced the carotenoids content of green Salanova, whereas in red Salanova treated with 32 μM Se violaxanthin + neoxanthin, lutein and β-cryptoxanthin spiked by 38.6, 27.4, and 23.1%, respectively. Lettuce constitutes an ideal target crop for selenium biofortification and closed soilless cultivation comprises an effective tool for producing Se-enriched foods of high nutraceutical value.

Highlights

Selenium (Se) is considered a non-essential mineral nutrient for higher plants (Sors et al, 2005; Pilon-Smits and Quinn, 2010; Malagoli et al, 2015), several studies demonstrate the effectiveness of Se at low concentrations in improving photo-oxidative stress tolerance, delaying senescence and stimulating plant yield (Hartikainen, 2005; Lyons et al, 2009)
Regarding the effect of Se concentration in the nutrient solution, increasing Se concentration to 24 μM resulted in non-significant differences in shoot dry biomass with the control (0 μM) and 16 μM treatments; whereas increasing Se concentration from 0 to 40 μM yielded a significant increase in leaf dry matter content, with the highest values observed at 40 μM (5.7%) (Table 1)
As demand for functional foods with beneficial effects on human health is rising, selenium biofortification of lettuce facilitated in closed soilless cultivation is presently demonstrated as an effective, low-cost method to produce Se-enriched food of high nutritional value

Summary

Introduction

Selenium (Se) is considered a non-essential mineral nutrient for higher plants (Sors et al, 2005; Pilon-Smits and Quinn, 2010; Malagoli et al, 2015), several studies demonstrate the effectiveness of Se at low concentrations in improving photo-oxidative stress tolerance, delaying senescence and stimulating plant yield (Hartikainen, 2005; Lyons et al, 2009). While Se is considered merely beneficial to plants (PilonSmits et al, 2009; Vatansever et al, 2017; Chauhan et al, 2019), it is deemed essential for animal and human nutrition as it constitutes the key component of selenoenzymes and selenoproteins with fundamental biological functions (Rayman, 2002). Most serious consequences have been reported in China, the UK, Eastern Europe, Africa, and Australia (Chen et al, 2002; Lyons et al, 2004), in areas with arable soils of low Se bioavailability that inevitably limits Se entry into the food supply chain

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