White lupin: improving legume-based protein production via intercropping.

Climate change, increased demand for food, industry, and mitigation of environmental impacts are currently driving changes in agricultural practice. Moreover, increasing demand for plant-based protein as substitutes for animal protein or to reduce soybean importations is driving cultivation of high-protein crops. Legumes crops play a critical role in this process. Amongst them is white lupin (Lupinus albus), a so-called orphan species, meaning it has relatively little cultivated surface area worldwide and limited agronomic knowledge. Lupin is, nevertheless, very promising since its seeds have a high content of storage proteins with interesting nutritional properties. It also has low fertilisation requirements since it forms root clusters allowing efficient phosphorus (P) acquisition, along with symbiotic nitrogen (N) fixation by nodules. Nevertheless, lupin cultivation faces important challenges such as yield variability, slow vegetative development, susceptibility to weeds diseases, and water stress. Lupin has an enormous potential for resource-saving practices such as intercropping with non-legumes, because of niche complementarity for N acquisition and facilitation of P transfer to the associated species, which can in turn mitigate weeds and pests, and ensure yield stability. To overcome several bottlenecks associated with lupin cultivation (e.g. nutrient utilisation, drought resistance or limiting the impact of weeds), genetic, metabolic, and agronomic research is required in order to define ideotypes that are particularly well-fitted to sustainable agricultural practices such as intercropping, with optimal protein yield. This is one of the purposes of the trans-disciplinary research programme PULSAR, funded by France 2030, which aims to unlock several bottlenecks in lupin utilisation in agronomy.