Grant: Discovery Grants Program - Individual

Pollution caused by antimicrobials and herbicides is an actual problem for many aquatic ecosystems worldwide. Macrophytes and phytoplankton living in these waters play important roles for these ecosystems (CO2 fixation, food resources, nutrient cycling and water purification), but unfortunately these organisms may be very sensitive to water quality variations. It is known that macrophytes are in association with microorganisms - the microbiota. This microbiota influences the growth and development of their hosts, but little is known about the processes involved. Furthermore, on top of the direct effect of environmental factors on the hosts, these types of microorganisms may also be sensitive to various environmental factors, and therefore these factors can indirectly affect the macrophytes. Although the importance of the relationship between the microbiota and their hosts, studies on the impacts of environmental factors on this relationship are lacking. It was recently advance that the microbiota may also have interactions with the surrounding phytoplankton (and vice versa) due to competition for resources or allelopathic interactions, but again how this connection occurs is at its infancy, and nothing is known about how environmental factors may impact this interaction. In this research program, we will study the effects of antimicrobials and herbicides on the interaction between the macrophytes, its microbiota and the surrounding phytoplankton at various levels ranging from the microorganism diversity to the plant physiology. We will investigate how the microbiota of aquatic plants influence the physiology of their hosts by using biochemical, "omic" and physiological approaches. By using similar approaches, we will also explore the impacts of selected environmental factors on the diversity of the microbiota, and to some extent on their physiological functions (such as production of hormones, cycling of nutrients, production of extracellular polymeric substances), and how these changes will influence their host physiology. Finally, we will study the relationship between macrophytes/microbiota and the surrounding phytoplankton in presence or not of various contaminants. During this research program, we will develop an approach to differentiate the direct impact of the environmental factors on the hosts, and the impacts caused by modification of the diversity and the metabolism of the microbiota. This research will permit to better understand the relationships between macrophytes/microbiota and surrounding phytoplankton and how contaminants may influence these relationships. On a long-term, this research will help to explain why some macrophytes and phytoplankton species are less affected by some environmental factors than others. This research program will also enhance our fundamental understanding to increase plant capacity to reclaim contaminants, a much-needed knowledge to improve the efficiency of bioremediation programs.