Isolation, Characterization, and Degradation Efficiency Testing of a Paclobutrazol-degrading Bacterium: Deinococcus arenae

Objective: This study aimed to isolate and characterize a bacterium capable of degrading the pesticide paclobutrazol. The strain was obtained from soil enriched with paclobutrazol, and its degradation ability was assessed using gas chromatography (GC).

Methods: A single strain was isolated from the soil solution of Ophiopogon japonicus, a plant exposed to excessive paclobutrazol spraying. Initial isolation utilized dilution and plating methods, followed by separation and purification through the streak plate technique. BLAST analysis revealed the strain's highest similarity to Deinococcus arenae SA1, with 100% homology after removing excess sequences. Subsequently, the degradation efficiency of this bacterium on paclobutrazol was evaluated by gas chromatography.

Results: Quantification using the external standard method yielded a standard curve equation of y=0.0977x-0.412, with a correlation coefficient (R²) of 0.99842. Testing at different time showed that the Deinococcus arenae achieved a degradation rate of 2.49% after three days of degrading paclobutrazol. After five days, the degradation rate increased to 17.58%, reaching 38.66% after seven days, 42.20% after nine days, and 43.87% after eleven days.

Conclusion: The Deinococcus arenae strain exhibited a significant degradation effect on paclobutrazol. This finding suggests potential for developing microbial agents to degrade paclobutrazol, promoting sustainable practices in agriculture.