Ending all forms of hunger by 2030, as set forward in UN-SDG2, is a daunting but essential task, given the limited timeline ahead and the negative global health and socio-economic impact of hunger. Malnutrition or hidden hunger due to micronutrient deficiencies affects about one third of the world population and severely jeopardizes economic development. Staple crop biofortification through gene stacking, using a rational combination of conventional breeding and metabolic engineering strategies, should enable a leap forward (Van Der Straeten et al., 2020).
Enhancing folate content in staple crops by metabolic engineering is a cost-effective and sustainable strategy to eradicate folate malnutrition – a highly underestimated problem- worldwide. We successfully developed folate biofortified rice and potato using metabolic engineering, combining genes from the folate biosynthesis pathway (Storozhenko et al., 2007; De Lepeleire et al., 2018). Polished biofortified rice seeds hold the amount to support the daily need of pregnant women. Further combination with a folate binding protein allowed to stabilize the folates upon storage at high temperature (Blancquaert et al., 2015). In addition, we proved that the folate-enriched rice is a valuable source of dietary folates (Kiekens et al., 2015). Recently, we developed strategies to enhance additional B-vitamins, offering tools to combine these with vitB9 to obtain multibiofortified rice by gene stacking. Moreover, we generated first prototype lines with a higher provitamin A content in combination with a higher folate content, and ventured into other multi-micronutrient combinations. The principles of these multibiofortification approaches will be discussed in a broader context.