Delay of flower senescence by bacterial endophytes expressing 1-aminocyclopropane-1-carboxylate deaminase
Article first published online: 21 AUG 2012
© 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 113, Issue 5, pages 1139–1144, November 2012
How to Cite
Ali, S., Charles, T.C. and Glick, B.R. (2012), Delay of flower senescence by bacterial endophytes expressing 1-aminocyclopropane-1-carboxylate deaminase. Journal of Applied Microbiology, 113: 1139–1144. doi: 10.1111/j.1365-2672.2012.05409.x
- Issue published online: 17 OCT 2012
- Article first published online: 21 AUG 2012
- Accepted manuscript online: 20 JUL 2012 11:50AM EST
- Manuscript Accepted: 18 JUL 2012
- Manuscript Revised: 3 JUL 2012
- Manuscript Received: 17 MAY 2012
The ability of 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing plant growth-promoting bacterial (PGPB) endophytes Pseudomonas fluorescens YsS6 and Pseudomonas migulae 8R6, their ACC deaminase minus mutants and the rhizospheric plant growth-promoting bacterium Pseudomonas putida UW4 to delay the senescence of mini carnation cut flowers was assessed.
Methods and Results
Fresh cut flowers were incubated with either a bacterial cell suspension, the ethylene precursor ACC, the ethylene inhibitor l-α-(aminoethoxyvinyl)-glycine or 0·85% NaCl at room temperature for 11 days. Levels of flower senescence were recorded every other day. To verify the presence of endophytes inside the plant tissues, scanning electron microscopy was performed. Among all treatments, flowers treated with wild-type ACC deaminase-containing endophytic strains exhibited the most significant delay in flower senescence, while flowers treated with the ACC deaminase minus mutants senesced at a rate similar to the control. Flowers treated with Ps. putida UW4 senesced more rapidly than untreated control flowers.
The only difference between wild-type and mutant bacterial endophytes was ACC deaminase activity so that it may be concluded that this enzyme is directly responsible for the significant delay in flower senescence. Despite containing ACC deaminase activity, Ps. putida UW4 is not taken up by the cut flowers and therefore has no effect on prolonging their shelf life.
Significance and Impact of the Study
The world-wide cut flower industry currently uses expensive and potentially environmentally dangerous chemical inhibitors of ethylene to prolong the shelf life of cut flowers. The use of PGPB endophytes with ACC deaminase activity has the potential to replace the chemicals that are currently used by the cut flower industry.