Optimizing the indigenous microbial partners for soybean cultivation in Flanders

Soybean (Glycine max) is a vital crop from an economic and environmental point of view. The high protein grains are often used in meat substitutes and the plant does not require much nitrogen fertilization due to its symbiosis with nitrogen-fixing bacteria. Yet, almost all soy used in Belgium is imported, mainly from South America, where cultivating the crop is often linked to deforestation. Increased Belgian soy production would reduce the environmental footprint of this crop. However, local cultivation is difficult because both the plant and commercial inoculants are not acclimated to the relatively cold and wet climate. As a result, protein levels in the beans are not consistently high enough for human consumption. Utilizing native climate-adapted rhizobia offers a viable solution, yet because there is no evolutionary history between local rhizobia and soy it is challenging to find strains that consistently produce active nodules. This project focuses on improving the symbiosis between indigenous rhizobia and soybean through two complementary approaches. Rhizobia will be combined with other bacteria from inside the root nodules to increase soy productivity and yield. Alternatively, rhizobia will be experimentally evolved to improve their adaptation to soybean. Hence, this project aims to enhance the symbiosis of native rhizobia with soybean in two complementary ways to develop and select strains for use as commercial inocula.