Improving nutrition through biofortification: A review of evidence from HarvestPlus, 2003 through 2016.

The various contributions to this book record the remarkable progress that has been made in the understanding and management of pancreatic diseases over the last decade. The improvement in understanding has led in some cases to better management with improved outcome for the patient, whereas in other areas the way is now clear towards a better prospect for the future.

Progress and Prospects

Zinc (Zn) still represents an important health problem in developing countries, caused mainly by inadequate dietary intake. A large consumption of cereal-based foods with small concentrations and low bioavailability of Zn is the major reason behind this problem. Modern cultivars of cereals have inherently very small concentrations of Zn and cannot meet the human need for Zn. Today, up to 50% of wheat-cultivated soil globally is considered poor in bioavailable Zn. Agricultural strategies that are used to improve the nutritional value of crop plants are known as biofortification strategies. They include genetic biofortification, which is based on classical plant breeding and genetic engineering for larger nutrient concentrations, and greater agronomic biofortification, which is based on optimized fertilizer applications. This review focuses on agronomic biofortification with Zn, which has proved to be very effective for wheat and also other cereal crops including rice. Molecular and genetic research into Zn uptake, transport and grain deposition in cereals are critically important for identifying ‘bottlenecks’ in the biofortification of food crops with Zn. Transgenic plants with large Zn concentrations in seeds are often tested under controlled laboratory or glasshouse conditions with sufficient available Zn in the growth medium for the entire growth period. However, they might not always show the same performance under ‘real-world’ conditions with limited chemical availability of Zn and various stress factors such as drought. What purpose can an upgraded transport and storage system serve if the amount of goods to be transported and stored is limited anyway? Given the fact that the Zn concentrations required to achieve a measurable impact on human health are well above those required to avoid any loss of yield from Zn deficiency, providing crop plants with sufficient Zn through the soil and foliar fertilizer strategy under field conditions is critically important for biofortification efforts.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/ejss.12437

Agronomic biofortification of cereals with zinc: a review

Biofortification is an upcoming, promising, cost-effective, and sustainable technique of delivering micronutrients to a population that has limited access to diverse diets and other micronutrient interventions. Unfortunately, major food crops are poor sources of micronutrients required for normal human growth. The manuscript deals in all aspects of crop biofortification which includes-breeding, agronomy, and genetic modification. It tries to summarize all the biofortification research that has been conducted on different crops. Success stories of biofortification include lysine and tryptophan rich quality protein maize (World food prize 2000), Vitamin A rich orange sweet potato (World food prize 2016); generated by crop breeding, oleic acid, and stearidonic acid soybean enrichment; through genetic transformation and selenium, iodine, and zinc supplementation. The biofortified food crops, especially cereals, legumes, vegetables, and fruits, are providing sufficient levels of micronutrients to targeted populations. Although a greater emphasis is being laid on transgenic research, the success rate and acceptability of breeding is much higher. Besides the challenges biofortified crops hold a bright future to address the malnutrition challenge.

/pdf/biofortified-crops-generated-by-breeding-agronomy-and-4l7h0gswwn.pdf

Biofortified Crops Generated by Breeding, Agronomy, and Transgenic Approaches Are Improving Lives of Millions of People around the World

Nutrient-efficient crops are a solution to the two grand challenges of modern agriculture: improving food security while reducing environmental impacts. The primary challenges are (1) nitrogen (N) and phosphorus (P) efficiency; (2) potassium (K), calcium (Ca), and magnesium (Mg) efficiency for acid soils; and (3) iron (Fe) and zinc (Zn) efficiency for alkaline soils. Root phenotypes are promising breeding targets for each of these. The Topsoil Foraging ideotype is beneficial for P capture and should also be useful for capture of K, Ca, and Mg in acid soils. The Steep, Cheap, and Deep ideotype for subsoil foraging is beneficial for N and water capture. Fe and Zn capture can be improved by targeting mechanisms of metal mobilization in the rhizosphere. Root hairs and phenes that reduce the metabolic cost of soil exploration should be prioritized in breeding programs. Nutrient-efficient crops should provide benefits at all input levels. Although our current understanding is sufficient to deploy root phenotypes for improved nutrient capture in crop breeding, this complex topic does not receive the resources it merits in either applied or basic plant biology. Renewed emphasis on these topics is needed in order to develop the nutrient-efficient crops urgently needed in global agriculture.

https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/nph.15738

Root phenotypes for improved nutrient capture: an underexploited opportunity for global agriculture.

More than two billion people are micronutrient deficient. Polished grains of popular rice varieties have concentration of approximately 2 μg g(-1) iron (Fe) and 16 μg g(-1) zinc (Zn). The HarvestPlus breeding programs for biofortified rice target 13 μg g(-1) Fe and 28 μg g(-1) Zn to reach approximately 30% of the estimated average requirement (EAR). Reports on engineering Fe content in rice have shown an increase up to 18 μg g(-1) in glasshouse settings; in contrast, under field conditions, 4 μg g(-1) was the highest reported concentration. Here, we report on selected transgenic events, field evaluated in two countries, showing 15 μg g(-1) Fe and 45.7 μg g(-1) Zn in polished grain. Rigorous selection was applied to 1,689 IR64 transgenic events for insert cleanliness and, trait and agronomic performances. Event NASFer-274 containing rice nicotianamine synthase (OsNAS2) and soybean ferritin (SferH-1) genes showed a single locus insertion without a yield penalty or altered grain quality. Endosperm Fe and Zn enrichment was visualized by X-ray fluorescence imaging. The Caco-2 cell assay indicated that Fe is bioavailable. No harmful heavy metals were detected in the grain. The trait remained stable in different genotype backgrounds.

/pdf/biofortified-indica-rice-attains-iron-and-zinc-nutrition-3ex0w0eao2.pdf

Biofortified indica rice attains iron and zinc nutrition dietary targets in the field.

One of the major challenges in plant molecular biology is to generate transgenic plants that express transgenes stably over generations. Here, we describe some routine methods to study transgene locus structure and to analyze transgene expression in plants: Southern hybridization using DIG chemiluminescent technology for characterization of transgenic locus, SYBR Green-based real-time RT-PCR to measure transgene transcript level, and protein immunoblot analysis to evaluate accumulation and stability of transgenic protein product in the target tissue.

Molecular Analyses of Transgenic Plants

Abstract Micronutrient deficiencies such as iron (Fe), zinc (Zn), and vitamin A, constitute a severe global public health phenomenon. Over half of preschool children and two-thirds of nonpregnant women of reproductive age worldwide have micronutrient deficiencies. Biofortification is a cost-effective strategy that comprises a meaningful and sustainable means of addressing this issue by delivering micronutrients through staple foods to populations with limited access to diverse diets and other nutritional interventions. Here, we report on the proof-of-concept and early development stage of a collection of biofortified rice events with a high density of Fe and Zn in polished grains that have been pursued further to advance development for product release. In total, eight constructs were developed specifically expressing dicot ferritins and the rice nicotianamine synthase 2 ( OsNAS2 ) gene under different combinations of promoters. A large-scale transformation of these constructs to Bangladesh and Philippines commercial indica cultivars and subsequent molecular screening and confined field evaluations resulted in the identification of a pool of ten events with Fe and Zn concentrations in polished grains of up to 11 μg g −1 and up to 37 μg g −1 , respectively. The latter has the potential to reduce the prevalence of inadequate Zn intake for women of childbearing age in Bangladesh and in the Philippines by 30% and 50%, respectively, compared to the current prevalence. To our knowledge, this is the first potential biotechnology public-sector product that adopts the product cycle phase-gated approach, routinely applied in the private sector. 

/pdf/proof-of-concept-and-early-development-stage-of-market-2r1gchnm.pdf

Proof of concept and early development stage of market-oriented high iron and zinc rice expressing dicot ferritin and rice nicotianamine synthase genes

Lysosomes achieve their function through numerous transporters that import or export nutrients across their membrane. However, technical challenges in membrane protein overexpression, purification, and reconstitution hinder our understanding of lysosome transporter function. Here, we developed a platform to overexpress and purify the putative lysine transporter Ypq1 using a constitutive overexpression system in protease- and ubiquitination-deficient yeast vacuoles. Using this method, we purified and reconstituted Ypq1 into proteoliposomes and showed lysine transport function, supporting its role as a basic amino acid transporter on the vacuole membrane. We also found that the absence of lysine destabilizes purified Ypq1 and causes it to aggregate, consistent with its propensity to be downregulated in vivo upon lysine starvation. Our approach may be useful for the biochemical characterization of many transporters and membrane proteins to understand organellar transport and regulation.

/pdf/lysosome-transporter-purification-and-reconstitution-enoitt0t.pdf

Felichi Mae Arines

Papers

Biofortified indica rice attains iron and zinc nutrition dietary targets in the field.

Molecular Analyses of Transgenic Plants

Proof of concept and early development stage of market-oriented high iron and zinc rice expressing dicot ferritin and rice nicotianamine synthase genes

Lysosome transporter purification and reconstitution identifies Ypq1 pH-gated lysine transport and regulation