Endophytic Bacterium Paenibacillus illinoisensis Y11 Promotes Duckweed Growth and Enhances Cadmium Pollution Remediation.

As cadmium (Cd) pollution increases, ecological security becomes increasingly endangered, highlighting the significance of exploring and optimizing sustainable remediation technologies. Phytoremediation, recognized as a promising strategy for environmental restoration, is enhanced when combined with microorganisms, particularly endophytes. Duckweed, known for its high Cd accumulation capacity, holds great potential for remediating Cd pollution. However, the impact of endophytic microorganisms on duckweed's remediation of Cd pollution remains unclear. This study focuses on the endophytic bacterium Paenibacillus illinoisensis Y11 to investigate its effects on duckweed (Lemna minor) growth and duckweed's capacity to remediate Cd pollution. The results indicate that strain Y11 can successfully colonize duckweed under Cd stress, and the colonization by strain Y11 can significantly promote duckweed growth and increase its Cd removal rate. Strain Y11 was evaluated in vitro for plant growth-promoting properties, revealing the capacity to synthesize indole-3-acetic acid and siderophores, solubilize phosphate, and produce 1-aminocyclopropane-1-carboxylate deaminase, all of which contribute to plant growth. This study not only provides valuable microbial resources to enhance the Cd pollution remediation capacity of duckweed, but also establishes a theoretical foundation for the widespread application of endophytic microorganisms in plant-microbe combined remediation techniques.