Cyanobacteria–bacteria interactions in iron deficient environments

Iron is a limiting nutrient for primary productivity in vast ocean and land regions. The bioavailable concentrations of iron in most ecosystems are extremely low and depend on the geochemical properties of the medium and on the transport capacities of each organism. A prominent strategy for iron acquisition is by producing high-affinity iron chelators called siderophores.

The cyanobacterial species Synechocystis pcc. 6803, for example, does not produce siderophores and depends on a reductive iron uptake strategy. However, it can also utilize siderophores produced by other bacteria. This would lead to a reciprocal network of interactions between primary producers like Synechocystis and siderophore producing heterotrophs which rely on the fixed carbon. In our research, we try to capture cyanobacteria-bacteria interactions in iron deficient environments. Our hypothesis is that these interactions allow the prosperity of both autotrophs and heterotrophs, by maintaining optimal concentrations of iron for the cyanobacteria in exchange for carbohydrates.

The main objective is to generate an experimental system, in which iron and carbohydrates exchange among cyanobacteria and heterotrophic bacteria could be probed. The results of this project will shed light on the ecological, biological and geochemical processes in aquatic and terrestrial environments. This can lead to the development of soil or foliar applications that will supplement commercial iron chelators currently used for plants and algae. Bioavailability of the optimal iron concentration in plants will lead to faster growth and increase both crop size and quantity.