Selenium accumulation in lettuce germplasm

Abstract

Selenium (Se) is an essential micronutrient for animals and humans. Increasing Se content in food crops offers an effective approach to reduce the widespread selenium deficiency problem in many parts of the world. In this study, we evaluated 30 diverse accessions of lettuce (Lactuca sativa L.) for their capacity to accumulate Se and their responses to different forms of Se in terms of plant growth, nutritional characteristics, and gene expression. Lettuce accessions responded differently to selenate and selenite treatment, and selenate is superior to selenite in inducing total Se accumulation. At least over twofold change in total Se levels between cultivars with high and low Se content was found. Synergistic relationship between Se and sulfur accumulation was observed in nearly all accessions at the selenate dosage applied. The change in shoot biomass varied between lettuce accessions and the forms of Se used. The growth-stimulated effect by selenate and the growth-inhibited effect by selenite were found to be correlated with the alteration of antioxidant enzyme activities. The different ability of lettuce accessions to accumulate Se following selenate treatment appeared to be associated with an altered expression of genes involved in Se/S uptake and assimilation. Our results provide important information for the effects of different forms of Se on plant growth and metabolism. They will also be of help in selecting and developing better cultivars for Se biofortification in lettuce.

Selenato e selenito na produção, nutrição mineral e biofortificação com selênio em cultivares de alface¹

“…Nesse sentido, Hopper & Parker (1999) relataram que o selenito é rapidamente convertido em formas orgânicas de Se, as quais são incorporadas em proteínas em substituição ao S, causando toxidez mais rapidamente quando comparado ao selenato. Os resultados encontrados no presente estudo são semelhantes ao observado por Ríos et al (2008), ao avaliarem a biofortificação com Se e a indução da capacidade antioxidante em plantas de alface utilizando o selenato e selenito, e ao verificado por Ramos et al (2011), ao estudarem a variação genotípica em diversos germoplasmas de alface.…”

“…Entretanto, a essencialidade desse elemento para as plantas ainda é motivo de controvérsia no meio científico (Zhu et al, 2009;PilonSmits & Quinn, 2010). Há relatos que o Se pode ajudar as plantas a se manterem por mais tempo fisiologicamente ativas, aumentando a produção vegetal (Hartikainen et al, 2000;Lyons et al 2009;Ramos et al, 2011).…”

Agronomic biofortification of carrot with selenium

“…Although selenium has not been demonstrated to be essential in plants, many studies show that, when supplied in low doses, Se benefits plant growth and production (Kápolna et al, 2009;Ramos et al, 2011;Boldrin et al, 2013;Zhu et al, 2017).…”

“…Studies have shown the success of biofortification with Se in lettuce, rice, wheat and broccoli (Ramos et al, 2011;Boldrin et al, 2013;Zembala et al, 2010;Ávila et al, 2014). In this sense, carrot (Daucus carota L.), a widely consumed vegetable, renders great potential to this practice, since it presents a high content of carotenoids.…”

Selenium Biofortification in Rice - A pragmatic perspective

“…The role of this element in plants is still controversial Pilon-Smits and Quinn, 2010), yet some studies seem to indicate that selenium maintain plants physiologically active for longer life periods, which in some cases determines an increasing crop production (Hartikainen et al, 2000;Lyons et al, 2009;Ramos et al, 2011). Nevertheless, is worth emphasizing that, in biofortification programs the form of selenium applied must be taken into account (Zhang and Sparks, 1990), since plant species not have different uptake capacities, but also the accumulation of selenium forms (selenite, selenite and organic forms of selenium) in the soil can vary (Kabata-Pendias, 1999 cf.…”