Drought, antinutrients and common beans: the BIO-BELIEF project

The research project Bio-Belief “BIOfortification of common Bean to promote heaLthy dIEt and Food security” (https://www.linkedin.com/company/biobelief/ and https://www.facebook.com/BioBeliefProject; Losa et al. (2022). Food and Energy Security 11:e351. doi: 10.1002/fes3.351; Cominelli et al. (2022). Frontiers Plant Sciences 13:992169. doi: 10.3389/fpls.2022.992169) is financed in the frame of the European Research Area Network for Food Systems and Climate (FOSC). The project consists of a trans-continental consortium including partners from Italy, France, Kenya, Brazil and South Africa aiming to select new biofortified, more drought resilient common bean lines, in order to promote a healthy diet in the general frame of food security. Common beans are a major source of dietary fibres, essential amino acid-rich proteins, some vitamins and they often display a high content in essential minerals (e.g. iron, zinc, calcium). About 60% of world-wide produced common beans are, however, grown in regions subjected to soil water deficit due to environmental drought conditions. Common beans with improved resilience to drought together with a better nutritional value under this condition would, therefore, be a major contributor to human health in the view of a future climate change. One important aspect of the Bio-Belief project is to specifically characterize any change in growth and nutritional value of common beans with a modified seed antinutrient (e.g. phytate) content when these modified bean plants are grown under drought conditions. Seed antinutrients generally affect the bioavailability/bioaccessibilty of important minerals (e.g. iron, zinc, calcium) stored in the seed. Fourteen selected common bean lines, including four commercial lines of interest to Italy and South Africa as well as six mutant lines with reduced seed phytate content, are currently tested for their response to drought treatment and their seed mineral content after drought exposure. Ten of these lines are further assessed in the field under drought stress at 40% field capacity (FC) and non-drought at 80% FC conditions in South Africa using a rain shelter facility, a custom-made rainout plastic mulch facility, and growth without any shelter facility (Cape Province of South Africa), while in Italy all fourteen lines are assessed in a greenhouse. The following data are being collected: leaf wilting score, the number of pods per plant, dry pod yield per plant, number of seeds per pod, seed length, seed width, 100 seeds weight, grain yield per plot, dry shoot biomass, dry root biomass, phytate and micronutrient content. From our experiments, we ultimately expect specific answers to the interesting questions if, for example, any direct relationship between plant growth and seed antinutrient content (phytate) exists. Furthermore, will growth of beans under drought conditions not only affect the overall seed antinutrient content but also the bioavailability/bioaccessibility of micronutrients in the seed. Any potential biofortified lines will finally be exploited in our project by preparing bean-based recipes, which will be characterized for their nutritional profile. In addition, we further intend, as a longer-term strategy of our project, to introduce any useful identified trait, such as better drought tolerance or low antinutrient seed content, into commercially interesting common bean lines by applying the innovative technology of Genome Editing (GE). Finally, as an INCREASE stakeholder, we expect to have not only a better interaction with other European legume researchers and easier access to data bases (genotypic/phenotypic data), but also easier access to reference lines allowing to broaden the use of common beans with useful traits not only in Europe but also in Africa and South America. In this regard, also screening a collection of common bean lines to study the natural variation of the seed phytate content, the relation between phytate and micronutrient in seeds as well as the phytate function in seeds would be useful.