The Soil Microbial Community and Grain Micronutrient Concentration of Historical and Modern Hard Red Spring Wheat Cultivars Grown Organically and Conventionally in the Black Soil Zone of the Canadian Prairies

Examining Heterogeneity of Food Fortification and Biofortification Business Models: Emerging Evidence for a Typology

Efforts to address Micronutrient deficiencies (MNDs) in lower-and middle-income countries (LMICs) have been gaining pace in recent years. Commodities such as staple foods (e.g., cereals, roots, and tubers) and condiments (e.g., salt) have been targeted as ‘vehicles’ for fortification and biofortification through numerous projects and initiatives. To date, there have been mixed experiences with delivery and coverage with very little documented on the range of business models applied in different geographies, business conditions and polities and this makes classification and measurement of success and failure difficult. This research aims to address this gap in knowledge through proposing a typology that clarifies similarities (internal heterogeneity) and differences (external heterogeneity) between models and that can allow all types to be defined by the combination of attributes. Building on a comprehensive literature review; NVivo was used to code initiatives from 34 key references (955 cases in total) which have been grouped into 17 categories. Using non-metric multidimensional scaling (NMDS) we find evidence of four business model groupings that typify fortification initiatives: (1) Large-scale private, unregulated, (2) Mixed-Scale, private, unregulated (3) Large-scale, public-private, regulated; and (4) Large-scale, private, regulated. We characterise these four groups with country examples and suggest that this typology can help the discourse around viability of food fortification initiatives.

Selenium accumulation by plants

BACKGROUND

Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg(-1) dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg(-1) dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000-15 000 mg Se kg(-1 )dry matter and are called Se hyperaccumulators.

SCOPE

This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues.

CONCLUSIONS

The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated into non-functional proteins, through the synthesis of less toxic Se metabilites. There is potential to breed or select crops with greater Se concentrations in their edible tissues, which might be used to increase dietary Se intakes of animals and humans.