Direct and interactive effects of light and nutrients on the legume-rhizobia mutualism

► We investigate how resource availability affects the legume-rhizobia mutualism. ► In low nutrient, high light environments, rhizobia increased mean plant biomass. ► When plants were light-limited, the net growth benefits to plants were reduced. ► Light limitation also reduced rhizobia growth. ► Benefits to both mutualism partners depend on the availability of traded resources.