1-aminocyclopropane-1-carboxylate deaminase from Pseudomonas fluorescens promoting the growth of Chinese cabbage and its polyclonal antibody.

Bacterial 1-aminocyclopropane-1-carboxlyate (ACC) deaminase (AcdS) is an enzyme that cleaves ACC, a precursor of the plant hormone ethylene, into α-ketobutyrate and ammonia. The acdS gene was cloned from Pseudomonas fluorescens, which was capable of improving the seedling of Chinese cabbage under salinity condition. The recombinant AcdS (rAcdS) exhibited optimal activity at pH 8.5 and 30°C. Strong activity was sustained at up to 100 mM NaCl. The polyclonal anti-P. fluorescens AcdS antibody was produced in a rabbit that had been immunized with the purified rAcdS. This antibody successfully recognized the homologous antigens derived from the total proteins of isolated plant growth-promoting microorganisms. A statistically significant correlation was observed between the intensity of hybridization signal and AcdS activity measured by a biochemical method, suggesting its application as a useful indicator for active deaminases.