Biofilm producing probiotic bacteria enhance productivity and bioactive compounds in tomato

Abstract

The aim was to increase yield and bioactive compounds in tomatoes by application of different biofilm producing plant probiotic bacteria (BPPPB). In this study, sixteen (64%) biofilm producing bacteria (BPB) were identified using 16S rRNA gene sequencing from rhizosphere of tomato plants, comprising the genera of Pseudomonas, Bacillus and Enterobacter. Examined biofilms contained secreted biomolecules including peptidoglycans, proteins, nucleic acids, polysaccharides and lipids, and cell-associated appendages like curli fimbriae. All of the BPB produced multiple probiotic traits in vitro including indole-3-acetic acid, the solubilization of P, Fe, Zn, and K, the fixation of N, and the synthesis of NH3, catalase, acetoin, protease, and cellulase. Tomato plants that have been inoculated with P. poae ESN2, B. aryabhattai ESN3, B. megaterium ESN4, E. cloacae ESN16, P. monteilii ESN26, P. putida ESN32, P. fluorescens ESN35, P. extremorientalis ESN36, and P. chlororaphis ESN37 increased biomass production (4.3–20.7% roots and 6.0–41.7% shoots), yield (4.4–69.1%), total soluble solids (11.2–33.5%), lycopene (28.5–142.8%), β-carotene (27.2–363.6%), phenolics (6.3–52%), flavonoids (10.4–69.2%), and antioxidant capacity (13.3–66.6%) over controls. This is the first report of improvements in tomato yield and bioactive compounds achieved through the application of BPPPB.