Association of some Plant Defense Enzyme activities with Systemic Resistance to Bacterial wilt Disease induced in Tomato Plants by Pseudomonas aeruginosa Strain OD13

Author: Anjali Suansia and Akshaya Kumar Senapati

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Abstract

Controlling Ralstonia solanacearum and its impact on tomato crops is a challenge due to its wide host range and environmental adaptability. Chemical pesticides have been used but raise health and environmental concerns. One promising approach is the utilization of antibiotic-producing fluorescent pseudomonads (FPs). FPs are used as a biocontrol tool for bacterial wilt in tomato, enhancing plant growth through induced systemic resistance (ISR). The study aimed to investigate the induction of plant defense-related enzymes against R. solanacearum in tomato plants upon treatment with Pseudomonas aeruginosa strain OD13. The Pseudomonas isolates were obtained from the rhizosphere of solanaceous crops grown in various districts of Odisha. Four treatments were employed, including a control, R. solanacearum inoculation, OD13 application, and a combination of OD13 application and R. solanacearum inoculation. Tomato seedlings were sampled at various time points, and the activity of stress-related enzymes such as peroxidase (POX), phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), lipoxygenase (LOX), and total phenol content were measured. The maximum activity of peroxidase was observed in the treatment of P. aeruginosa OD13 + R. solanacearum after 24 hours of incubation (14.81±0.48 µ.mol/Δ 470 nm/min/mg protein) compared to the control. Similarly, the treatment of P. aeruginosa OD13 challenged with R. solanacearum showed higher levels of PAL and PPO activity at 36 hours after inoculation (43.07±0.62 µ.mol/trans cinnamic acid/min/mg protein and 44.33±1.25 Δ A420 nm/min/mg protein, respectively). Lipoxygenase (LOX) activity was higher in P. aeruginosa OD13 challenged with R. solanacearum at 48 hours (49±1.42 Δ A234 nm/min/mg protein). The total phenol content was significantly increased with P. aeruginosa OD13 + R. solanacearum (83.5±1.32 µg of catechol/min/mg protein) and P. aeruginosa OD13 alone (70.5±0.98 µg of catechol/min/mg protein) treated tomato seedlings at 24 hours after inoculation compared to the control. These results suggest that P. aeruginosa OD13 induces a defense response and contributes to resistance against bacterial wilt disease in tomato plants. Overall, the findings of this study demonstrate that P. aeruginosa strain OD13 can effectively induce plant defense-related enzymes in tomato plants. These induced defense responses have the potential to enhance the plant's resistance against various pathogens, highlighting the potential use of OD13 as a beneficial rhizobacterium for plant protection in tomato cultivation.

Keywords

Pseudomonas, defense-related, peroxidase, phenylalanine ammonialyase, polyphenol oxidase, Lipoxygenase

Conclusion

Our findings suggest that Pseudomonas aeruginosa OD13 has the potential to induce ISR (Induced Systemic Resistance) and can be utilized as a bioinoculant for the management of bacterial wilt, caused by Ralstonia solanacearum, in tomato plants. The beneficial rhizobacterium exhibits a protective mechanism against soil-borne pathogens, making it a promising candidate for disease control in tomato cultivation. By harnessing the ISR pathway, P. aeruginosa OD13 enhances the plant's natural defense system, providing an effective means to combat bacterial wilt. These results highlight the potential of P. aeruginosa OD13 as a biocontrol agent, offering sustainable and environmentally friendly solutions for tomato crop protection.

References

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How to cite this article

Anjali Suansia and Akshaya Kumar Senapati (2022). Association of some Plant Defense Enzyme activities with Systemic Resistance to Bacterial wilt Disease induced in Tomato Plants by Pseudomonas aeruginosa Strain OD13. Biological Forum – An International Journal, 14(4): 1342-1349.