Rhizobacterial biofilm and plant growth promoting trait enhancement by organic acids and sugars

Abstract

In the study,Pseudomonas sp. K6 and Pseudomonas monteilii were found to form an enhanced biofilm when cultured in the presence of organic acids and sugars. Here, the highest biofilm could be observed for Pseudomonas sp. K6 (3.08 ± 0.13) and P. monteilii (1.99 ± 0.12) when cultured in presence of 10 µM malic acid. However, maximum production of indole 3 acetic acid (IAA) was observed with 25 µM succinic acid treatment for Pseudomonas sp. K6 (24.33 ± 0.57 µg ml⁻¹) and with 25 µM galactose for P. monteilii (20 ± 0.0 µg ml⁻¹). At the same time, Pseudomonas sp. K6 solubilized the highest quantity of phosphate in the presence of 50 µM citric acid (21.33 ± 0.0 µM) and P. monteilii was observed to produce 32.66 ± 1.25 µM soluble phosphate in the presence of 10 µM galactose. The results of the study demonstrate the role of organic acids and sugars in the enhancement of biofilm formation, IAA production and phosphate solubilization in selected Pseudomonas spp. and highlight the potential use of rhizobacteria in conjugation with supplement for the agricultural applications.

Keywords:

• Biofilm
• PGPR
• organic acid
• atomic force microscopy
• microbial colonization

Acknowledgements

The authors acknowledge the Kerala State Council for Science, Technology and Environment (KSCSTE) for the KSCSTE-SRS Scheme, KSCSTE-KBC-YIPB Programme, DST PURSE II and State Plan Fund project for the instrumentation facility. The authors also acknowledge the Director, Sophisticated Analytical Instrument Facility (SAIF), School of Environmental Sciences, Mahatma Gandhi University, Kottayam, India for providing the Atomic Force Microscope (AFM) facility.

Disclosure statement

The authors declare that they have no conflict of interest.