Evaluation of plant growth promoting rhizospheric bacteria isolated from native Antarctic plants

Dr. Natalia Bajsa, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE)

In Antarctica there are only two native species of vascular plants: the Antarctic grass (Deschampsia antarctica) and the Antarctic carnation (Colobanthus quitensis). In this project we are studying the bacteria that live in the roots of these plants. Some of these bacteria have the ability to help plants nourish and protect them from disease. This occurs in different plants, but is especially relevant in Antarctica, since the conditions are more adverse than in other ecosystems.

In two southern summer campaigns, we collected grass and carnation plants at various sites on King George Island. In the Microbial Ecology Laboratory of IIBCE we study the bacteria that live in their roots. We obtained about 1800 bacteria from different groups (heterotrophic bacteria, fluorescent Pseudomonas and actinobacteria) and analyzed if they have mechanisms to stimulate the growth of plants. Some of these bacteria increase the supply of nutrients such as phosphorus or iron. Others produce plant hormones that improve the development of plants. Others produce antibiotics and enzymes that affect the growth of pathogenic fungi, preventing them from producing disease. Some very special bacteria possess several of the activities described. With these bacteria we will continue working to identify which species they belong to. In addition we want to study how they behave when we add them to the roots of plants, and check that they can improve their growth. For this, we are currently adjusting the way of cultivating Antarctic grasses and carnations under controlled laboratory conditions. Although microorganisms are the most abundant organisms of the Antartitida, they have not been much studied. It is likely that there are a large number of them that is not yet known or presents new and interesting activities to discover.