As people stay at home longer hours during the pandemic , more people are raising “pet plants”. Korean researchers published a study that even without direct contact between plants, a plant neighboring another plant produces same microorganisms in their roots through smell from leaves of another plant.
Plant growth-promoting rhizobacteria (PGPR) is now widely used as a means of preventing plant diseases, replacing pesticides. Researchers are attempting to reduce pesticide use worldwide, but have not found effective bacteria. In particular, there has been a lack of research on how these beneficial bacteria affect microorganisms and plants around existing plants.
In this study, the researchers compared and analyzed the types of microorganisms around plants and plant roots after treating beneficial bacteria. Plant roots are an important place where plants release about 30% of their photosynthetic products, providing important nutrients to microbes. It is also a place where pathogenic microbes also multiply and cause diseases.
Therefore, it is important to use root beneficial bacteria to prevent diseases that occur in the roots, and the role of beneficial bacteria is even more important because pesticides are adsorbed by soil particles and cannot reach below the roots. In a previous study, the team found that in the event of a plant disease, the plant’s volatiles carry signals to the surrounding plants. Based on this, after spraying beneficial bacteria on tomato roots, the researchers were able to observe the growth of the beneficial bacteria in the untreated plants.
Therefore, the researchers analyzed microbial colonies in tomato root soil and surrounding tomato root soil where beneficial bacteria were treated, and analyzed volatile substances made in tomato plants when beneficial bacteria were treated. As a result, the researchers found that the types of microorganisms around the roots of tomatoes changed similar to those that treated beneficial bacteria.
Through volatile material analysis, the researchers found that a odor substance called beta-kyrofileen is transferred from beneficial bacteria-treated tomatoes to tomatoes next to them through the air, creating a substance called salicylic acid from the roots of plants that receive the odor substance. Salicylic acid is a substance produced when plants are stressed.
As a result, the microbial diversity of plants that received odor substances from salicylic acid mentioned in the roots changes, creating a type of microbial similar to the root of tomatoes sprinkled with beneficial bacteria.
This research is expected to be used to develop technologies that can create healthy plants that control microorganisms in the roots using beneficial bacteria and volatile substances.
Kong, Hyun Gi, et al. “Achieving similar root microbiota composition in neighbouring plants through airborne signalling.” The ISME Journal (2020): 1-12.