Characterization of the IAA-Producing and -Degrading Pseudomonas Strains Regulating Growth of the Common Duckweed ( Lemna minor L.)

• Published in: International journal of molecular sciences Vol. 24; no. 24; p. 17207
• Main Authors: Popržen, Tatjana, Nikolić, Ivan, Krstić-Milošević, Dijana, Uzelac, Branka, Trifunović-Momčilov, Milana, Marković, Marija, Radulović, Olga
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 07.12.2023
• Subjects: Aquatic plants; Araceae - metabolism; Bacteria; Biofilms; Carbon; duckweed; indole-3-acetic acid; Indoleacetic Acids - metabolism; Microorganisms; Morphology; Oxidative stress; Phylogenetics; Physiology; plant–microbe interactions; Pseudomonas - metabolism; pseudomonas strains; plant–microbe interactions; duckweed; indole-3-acetic acid; pseudomonas strains
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms242417207

The rhizosphere represents a center of complex and dynamic interactions between plants and microbes, resulting in various positive effects on plant growth and development. However, less is known about the effects of indole-3-acetic acid (IAA) on aquatic plants. In this study, we report the characterization of four strains isolated from the rhizosphere of the common duckweed ( ) with IAA-degradation and -utilization ability. Our results confirm previous reports on the negative effect of IAA on aquatic plants, contrary to the effect on terrestrial plants. A3-104/5 demonstrated particularly beneficial traits, as it exhibited not only IAA-degrading and -producing activity but also a positive effect on the doubling time of duckweeds in the presence of IAA, positive chemotaxis in the presence of IAA, increased tolerance to oxidative stress in the presence of IAA and increased biofilm formation related to IAA. Similarly, C31-106/3 significantly shortened the doubling time of duckweeds in the presence of IAA, while having a neutral effect in the absence of IAA. These traits are important in the context of plant-bacteria interactions and highlight the role of IAA as a common metabolite in these interactions, especially in aquatic environments where plants are facing unique challenges compared to their terrestrial counterparts. We conclude that IAA-degrading and -producing strains presented in this study might regulate IAA effects on aquatic plants and confer evolutionary benefits under adverse conditions (e.g., under oxidative stress, excess of IAA or nutrient scarcity).