Biofortification of crops with seven mineral elements often lacking in human diets – iron, zinc, copper, calcium, magnesium, selenium and iodine

Abstract

SummaryThe diets of over two-thirds of the world's population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification). This article reviews aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se). Two complementary approaches have been successfully adopted to increase the concentrations of bioavailable mineral elements in food crops. First, agronomic approaches optimizing the application of mineral fertilizers and/or improving the solubilization and mobilization of mineral elements in the soil have been implemented. Secondly, crops have been developed with: increased abilities to acquire mineral elements and accumulate them in edible tissues; increased concentrations of 'promoter' substances, such as ascorbate, β-carotene and cysteine-rich polypeptides which stimulate the absorption of essential mineral elements by the gut; and reduced concentrations of 'antinutrients', such as oxalate, polyphenolics or phytate, which interfere with their absorption. These approaches are addressing mineral malnutrition in humans globally.

Distribution and Translocation of Selenium from Soil to Grain and Its Speciation in Paddy Rice (Oryza sativa L.)

“…Cereals as the major foodstuff may offer the best opportunity to do so (7). Rice is the world's dominant staple food; for many in Asia it contributes 35-59% of consumed energy, while accounting for 69% of protein intake (8). Nevertheless, in some countries, Se is too low in rice to be sufficient for dietary Se requirement (9).…”

Ectopic expression of a maize calreticulin mitigates calcium deficiency-like disorders in sCAX1-expressing tobacco and tomato

“…understanding of Ca 2+ improvement in plant cells is required in order to positively 12 impact human nutrition and improve fruit and vegetable production. 13 Calcium is unique amongst the elements in plants and animals because it plays 14 both a pivotal structural and, an essential, signaling role (White and Broadley 2003;15 Hirschi 2004).…”

“…(Park et al 2005b; Park et al 2009). However, in some cases, these changes also 12 produce deleterious phenotypes that impact yield (Hirschi 1999; Park et al 2005a). 13 Tempering expression of sCAX1 driven by a different promoter results in healthier 14 plants but they often accumulate less Ca 2+ (Park et al, 2005a).…”

Eats roots and leaves. Can edible horticultural crops address dietary calcium, magnesium and potassium deficiencies?

“…enhancing the mineral content of horticultural produce through breeding and agronomy (4,17) , on dietary intakes of Ca, Mg and K at a population level. Before dietary diversification or biofortification is considered, it is appropriate to identify physiological and evolutionary constraints to increasing the Ca, Mg and K in edible portions of crops, thereby to determine the most suitable crops and crop parts for potential intervention.…”

“…These constraints affect the delivery of minerals to human diets via edible crop parts. Low concentrations of Ca, Mg and K in all crops can also arise when grown in soils of low mineral phytoavailability (4) . Ca is required by plants in large quantities for structural roles in the cell wall and membranes, as a counter-cation for anions in the vacuole, and -critically in terms of its distribution in plant cells -for coordinating responses to developmental cues and environmental challenges through changes in cytosolic Ca 2 + concentration (19,20) .…”